Ehretia laevis (Boraginaceae) Khandu, Smooth Ehretia, Desi Papdi

Aug 12

24 min read

Ehretia laevis, known as Khandu or Desi Papdi in the Indian subcontinent, is a medium-sized deciduous tree whose unassuming appearance, a modest stature, smooth grey bark, and small white flowers, conceals a pharmacological profile of considerable breadth. It belongs to the Boraginaceae, the borage family, a lineage better known for the wound-healing comfrey (Symphytum) and the omega-3-rich echium than for medicinal trees. Yet in the Ayurvedic and folk medical systems of India, the bark, leaves, and roots of E. laevis have been employed for centuries as a treatment for rheumatism, syphilis, skin diseases, and wounds. Unlike the extensively commercialised Azadirachta indica or the mythologically charged Selaginella bryopteris, this tree has attracted only sporadic scientific attention. The research that does exist, spanning 2023 to 2025, has begun to illuminate its anti-inflammatory, antioxidant, antimicrobial, and wound-healing activities, validating traditional knowledge while making plain the scale of the investigative deficit. Ehretia laevis is a quiet pharmacopoeia, waiting for systematic inquiry.

1. Taxonomic Insights

Species: Ehretia laevis Roxb.

Family: Boraginaceae (Borage Family); Subfamily: Ehretioideae

Genus: Ehretia

Synonyms: Ehretia laevis var. platyphylla (Merr.) I.M.Johnst., Ehretia laevis var. pubescens (Benth.) I.M.Johnst.

The genus Ehretia was named by Patrick Browne in 1756 to honour Georg Dionysius Ehret (1708–1770), a preeminent botanical illustrator whose exquisite plates of plants and flowers were widely reproduced in the botanical literature of Enlightenment Europe. The genus comprises approximately 50 species of trees and shrubs distributed across the tropics and subtropics of Africa, Asia, Australia, and the Americas. The specific epithet laevis is Latin for "smooth" or "polished," referring to the characteristic smooth, pale bark that distinguishes this species from its rougher-barked congeners. The species was described by William Roxburgh in his Flora Indica (1824).

Botanical Description

Ehretia laevis is a small to medium-sized, deciduous or nearly evergreen tree, typically reaching 6 to 12 metres in height, with a short, stout trunk and a spreading, rounded crown. The tree is often multi-stemmed from the base. The overall impression is of a modest, unremarkable tree, easily overlooked in the mixed deciduous forests it inhabits.

Key Identification Features:

The bark is the most distinctive feature: smooth, pale grey to creamish-white, thin, and exfoliating in small, papery, irregular flakes. The trunk and branches are unarmed (without thorns or spines). The leaves are alternate, simple, broadly ovate to elliptic, 7 to 18 centimetres long and 4 to 12 centimetres wide, with an acute to acuminate apex and a rounded to broadly cuneate base. The margin is entire or occasionally slightly undulate. The leaf surface is glabrous and glossy above, paler and glabrous to very sparsely pubescent beneath, with 4 to 7 pairs of prominent secondary veins. The petiole is 1.5 to 3 centimetres long.

The inflorescence is a terminal or axillary, much-branched, corymbose cyme, 5 to 15 centimetres across, bearing numerous small flowers. The flowers are white, fragrant, and actinomorphic. The calyx is 5-lobed, small, and persistent. The corolla is 5-lobed, with a short tube and spreading, oblong lobes, approximately 5 to 7 millimetres across. Stamens are 5, exserted, with dorsifixed anthers. The ovary is superior, 4-locular, with a single style and a bifid stigma. The fruit is a globose drupe, 5 to 8 millimetres in diameter, green turning to orange-red and finally dark brown or black when fully ripe. The fruit contains 4 small, hard pyrenes (nutlets), each containing a single seed. The mesocarp is thin and mucilaginous.

Distribution: The species is native to the Indian subcontinent (India, Pakistan, Nepal, Bhutan, Bangladesh, Sri Lanka), Myanmar, Thailand, Laos, Vietnam, Cambodia, southern China, and the Andaman Islands. It has been introduced to parts of East Africa and the Caribbean. It grows from sea level to approximately 1200 metres elevation, typically in mixed deciduous forests, scrublands, and along forest margins.

Conservation Status: The species has not been formally assessed for the IUCN Red List. It is locally common across much of its range and is not considered threatened, though deforestation and habitat fragmentation may impact local populations.

Etymology

The generic name Ehretia commemorates Georg Dionysius Ehret. The specific epithet laevis is Latin for "smooth." The Hindi name "Khandu" and the Marathi "Khandu" are of uncertain derivation but are widely used across central and western India. "Desi Papdi" translates loosely to "native papdi," referencing the tree's indigenous status and its resemblance to other trees called Papdi in the region.

2. Common Names

3. Related Herbs from the Boraginaceae Family

Ehretia laevis belongs to the Boraginaceae, a family of approximately 2000 species distributed worldwide, characterised by rough, hairy foliage (from cystoliths, mineralised concretions of calcium carbonate in the leaf epidermis) and the production of pyrrolizidine alkaloids, naphthoquinones, and allantoin.

Symphytum officinale (Comfrey): The most famous medicinal member of the family, renowned for its wound-healing and bone-knitting properties, attributed largely to allantoin, a cell-proliferation-promoting compound. Allantoin's presence in the Boraginaceae provides a comparative framework for understanding the wound-healing activity of Ehretia species.

Borago officinalis (Borage): An edible and medicinal herb rich in gamma-linolenic acid (GLA) and with documented anti-inflammatory and adaptogenic properties. Its seed oil is a commercial nutraceutical.

Arnebia euchroma (Ratanjot): An important Ayurvedic and Unani herb, the roots of which yield the red naphthoquinone pigment shikonin and its derivatives, with potent antimicrobial, anti-inflammatory, and anticancer activities. The naphthoquinone chemotype is shared with Ehretia.

Cordia dichotoma (Indian Cherry, Lasora): A close relative within the Boraginaceae, used in Ayurveda for its demulcent, expectorant, and wound-healing properties. Its mucilaginous fruits and bark parallel the mucilaginous bark of E. laevis.

Heliotropium indicum (Indian Turnsole): A weedy Boraginaceae used in traditional medicine for wound healing, skin diseases, and inflammation. It also contains pyrrolizidine alkaloids, a toxicological concern for the family that requires screening in Ehretia.

The Boraginaceae is chemically defined by the co-occurrence of pyrrolizidine alkaloids (hepatotoxic in some species, absent or present in trace amounts in others), naphthoquinones (with antimicrobial and anti-inflammatory activity), phenolic acids (particularly rosmarinic acid), and allantoin (wound-healing). The chemical characterisation of Ehretia laevis is incomplete, and the presence or absence of hepatotoxic pyrrolizidine alkaloids has not been definitively established, a significant toxicological gap.

4. Medicinal Uses: Summary of Primary and Secondary Actions

Primary Actions:

Anti-inflammatory: This is the most extensively documented pharmacological activity of E. laevis. Methanolic and aqueous extracts of the bark and leaves have demonstrated significant, dose-dependent inhibition of carrageenan-induced paw edema, formalin-induced arthritis, and cotton pellet granuloma in rodent models. The activity is comparable to standard non-steroidal anti-inflammatory drugs (NSAIDs) at higher doses and is attributed to the triterpenoid and phenolic fractions.

Wound Healing: Bark and leaf extracts have demonstrated significant wound healing activity in excision, incision, and dead space wound models in rats. Treated wounds show faster wound contraction, increased tensile strength, elevated hydroxyproline content (a marker of collagen deposition), and improved histopathological architecture. The mechanism involves promotion of fibroblast proliferation, collagen synthesis, and angiogenesis.

Antioxidant: Extracts exhibit potent free radical scavenging activity in DPPH, ABTS, hydroxyl radical, and superoxide radical assays. The activity correlates strongly with total phenolic and flavonoid content. IC50 values in the range of 30 to 55 μg/mL for DPPH scavenging have been reported for methanolic bark extract.

Antimicrobial: Extracts show broad-spectrum antibacterial activity, with notable potency against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa. Antifungal activity against Candida albicans, Aspergillus niger, and dermatophytes has also been documented. The naphthoquinone and triterpenoid fractions are believed to be responsible.

Analgesic: Animal studies using acetic acid-induced writhing, hot plate, and tail-flick models have demonstrated significant, dose-dependent analgesic activity of bark and leaf extracts. The analgesic mechanism involves both peripheral (COX inhibition) and possibly central components.

Secondary Actions:

Antidiabetic: Methanolic leaf and bark extracts have shown hypoglycemic activity in alloxan-induced and streptozotocin-induced diabetic rat models, with improvements in lipid profile parameters. α-Amylase and α-glucosidase inhibitory activities have been demonstrated in vitro.

Hepatoprotective: Bark extracts have demonstrated protective effects against carbon tetrachloride and paracetamol-induced hepatotoxicity in rats, with significant reductions in serum ALT, AST, and ALP levels, and improvement in hepatic histoarchitecture.

Anthelmintic: Leaf and bark extracts show dose-dependent paralytic and lethal activity against Pheretima posthuma in vitro, supporting the traditional use for intestinal worms.

Antipyretic: Bark decoctions are used traditionally for fever. Animal studies using the yeast-induced pyrexia model have demonstrated antipyretic activity comparable to paracetamol.

Antiulcer: Bark extracts have shown gastroprotective activity against ethanol-induced and aspirin-induced gastric ulcers in rats.

Anticancer: Preliminary in vitro studies have shown cytotoxic activity of bark and leaf extracts against human cancer cell lines, including breast (MCF-7), colon (HCT-116), and lung (A549) cells.

Diuretic: Animal studies have demonstrated increased urine output and electrolyte excretion following oral administration of leaf extract.

Medicinal Parts

Bark: The most frequently used medicinal part. A decoction is taken orally for rheumatism, fever, and as a blood purifier. The paste is applied externally to wounds, ulcers, and inflamed joints. The bark is considered the richest source of naphthoquinones and triterpenoids.

Leaves: Used as a poultice for wounds, boils, and rheumatic joints. Leaf juice is applied to skin diseases and is taken internally, mixed with honey, for cough. Young leaves are consumed as a vegetable in some regions, contributing to the nutritional management of deficiency disorders.

Roots: Used similarly to the bark, though less commonly. A decoction is taken for rheumatism and urinary complaints. The root paste is applied to skin diseases.

Fruits: The ripe fruits are edible and are consumed raw. They are mucilaginous and sweetish, with a slightly astringent aftertaste. The fruit pulp is sometimes used as a demulcent for sore throat.

5. Phytochemistry

The phytochemistry of Ehretia laevis is dominated by naphthoquinones, triterpenoids, and phenolic compounds. The alkaloid fraction has been detected but remains poorly characterised, representing a significant toxicological concern given the family's production of hepatotoxic pyrrolizidine alkaloids.

5.1 Naphthoquinones

Naphthoquinones are quinone compounds derived from naphthalene and represent the most characteristic and pharmacologically significant secondary metabolites of the Boraginaceae.

Shikonin and alkannin: These enantiomeric naphthoquinone pigments are the defining constituents of the related genera Arnebia, Alkanna, and Lithospermum, and have been reported from some Ehretia species. Their presence in E. laevis is probable but requires definitive confirmation. Shikonin possesses potent antimicrobial, anti-inflammatory, wound-healing, and anticancer activities.

Ehretianone: A prenylated naphthoquinone isolated from E. laevis with demonstrated antimicrobial and anti-inflammatory activity. It is a chemotaxonomic marker for the species.

Ehretione and related naphthoquinones: Additional naphthoquinone compounds identified in the bark, contributing to the antimicrobial and wound-healing activities.

5.2 Triterpenoids

α-Amyrin, β-amyrin, and their acetates: Pentacyclic triterpenoid alcohols with well-established anti-inflammatory, analgesic, and gastroprotective activities. They are present in significant quantities in the bark.

Lupeol and betulin: Pentacyclic triterpenoids with anti-inflammatory, anticancer, and wound-healing properties. Lupeol is a potent inhibitor of NF-κB and COX-2.

Oleanolic acid and ursolic acid: Triterpenoid acids with hepatoprotective, anti-inflammatory, and anticancer activities. Their presence has been confirmed in the leaves.

5.3 Phenolic Compounds

Rosmarinic acid, caffeic acid, chlorogenic acid, and ferulic acid: Caffeoylquinic acid derivatives and related phenolic acids with potent antioxidant and anti-inflammatory activities. Rosmarinic acid is a chemotaxonomic marker for the Boraginaceae and is likely present in significant quantities in E. laevis.

Quercetin, kaempferol, rutin, and their glycosides: Flavonols contributing to the antioxidant and anti-inflammatory profile of the leaves and bark.

5.4 Allantoin

Allantoin, a purine derivative with established cell-proliferation-promoting, keratolytic, and wound-healing properties, is present in many Boraginaceae, including comfrey (Symphytum). Its presence in E. laevis has been suggested but requires confirmation. If present, allantoin would contribute significantly to the wound-healing activity of the plant.

5.5 Alkaloids

Preliminary phytochemical screening has indicated the presence of alkaloids in E. laevis, yielding positive reactions with Dragendorff's and Mayer's reagents. The specific alkaloid profile, critically including the presence or absence of hepatotoxic 1,2-unsaturated pyrrolizidine alkaloids (PAs), has not been determined. This is the most significant phytochemical and toxicological gap in the current knowledge of the species.

5.6 Other Compounds

β-Sitosterol and stigmasterol are the major phytosterols. Tannins and mucilage are abundant in the bark, contributing to its astringency and demulcent properties. The mucilage is composed of complex polysaccharides that form a protective, soothing layer on mucosal surfaces and skin.

6. Mechanisms of Action

6.1 Anti-inflammatory Mechanism

The anti-inflammatory activity of E. laevis involves multiple, converging pathways. The triterpenoid fraction (α-amyrin, β-amyrin, lupeol) inhibits the activation of NF-κB, preventing the transcription of COX-2, iNOS, and pro-inflammatory cytokines (TNF-α, IL-1β, IL-6). Naphthoquinones, including ehretianone, contribute a direct COX-2 inhibitory component. Rosmarinic acid and other phenolic compounds suppress the complement cascade and inhibit 5-lipoxygenase (5-LOX), reducing leukotriene synthesis. The net effect is a broad-spectrum suppression of both the cyclooxygenase and lipoxygenase arms of the arachidonic acid cascade, complemented by NF-κB pathway inhibition. This multi-target mechanism mirrors that of several synthetic NSAIDs but with a potentially more balanced inhibition profile.

6.2 Wound Healing Mechanism

The wound-healing activity is the clinical translation of the combined pharmacological properties of the plant. Allantoin, if confirmed present, directly stimulates fibroblast proliferation and collagen synthesis, accelerating the proliferative phase of wound healing. The triterpenoids (lupeol, α-amyrin) promote angiogenesis, the formation of new blood vessels essential for granulation tissue development. The antimicrobial activity of naphthoquinones and triterpenoids reduces the bacterial load in the wound bed, preventing infection and the consequent prolongation of the inflammatory phase. The anti-inflammatory activity ensures a timely transition from the inflammatory to the proliferative phase, preventing the chronic inflammation that characterises non-healing wounds. The mucilage forms a protective, moist film over the wound surface, maintaining the optimal hydration that promotes epithelial cell migration. This multi-factorial mechanism, simultaneously antimicrobial, anti-inflammatory, proliferative, and protective, explains the wound-healing efficacy observed in animal models.

6.3 Antimicrobial Mechanism

Naphthoquinones, including ehretianone, are redox-active compounds that undergo one-electron reduction by cellular reductases to generate semiquinone radicals. These radicals undergo redox cycling in the presence of molecular oxygen, producing superoxide anion and other reactive oxygen species that damage bacterial DNA, proteins, and membrane lipids. Triterpenoids contribute by disrupting bacterial membrane integrity, increasing permeability and causing leakage of cytoplasmic contents. This dual oxidative and membrane-targeting mechanism provides broad-spectrum antimicrobial coverage.

6.4 Analgesic Mechanism

The analgesic activity involves both peripheral and central components. The peripheral component is mediated by COX inhibition and the consequent reduction in prostaglandin E2 synthesis, reducing the sensitisation of peripheral nociceptors. This is evidenced by the efficacy of the extract in the acetic acid writhing test, a model of peripheral inflammatory pain. The efficacy in the hot plate and tail-flick tests, which measure central nociceptive processing, suggests an additional central component, possibly involving opioidergic or monoaminergic pathways, though this requires specific investigation with antagonist reversal studies.

6.5 Hepatoprotective Mechanism

The hepatoprotective effect against carbon tetrachloride is primarily antioxidant-mediated. The phenolic fraction, including rosmarinic acid and flavonoids, scavenges the trichloromethyl radicals generated during CCl4 metabolism, preventing the initiation of lipid peroxidation in hepatocyte membranes. The triterpenoids, particularly oleanolic acid and ursolic acid, contribute by stabilising hepatocyte membranes and by inhibiting the NF-κB-mediated inflammatory amplification of hepatic injury. The reduction in serum transaminases reflects preserved hepatocyte membrane integrity.

7. Traditional and Ethnobotanical Uses

7.1 Rheumatic and Arthritic Pain

Formulation: Bark paste, leaf poultice, or bark decoction.

Preparation and Use: In the Ayurvedic and folk medical traditions of central and western India, the fresh bark of E. laevis is ground into a paste with a small amount of water and applied topically to painful, swollen joints. A poultice of warmed leaves is similarly used. Internally, a decoction of the bark (10 to 15 grams in 400 millilitres water, boiled and reduced to 150 millilitres) is taken in divided doses throughout the day. The tree is considered a vatahara (vata-pacifying) remedy, specifically indicated for amavata (rheumatoid arthritis) and sandhigata vata (osteoarthritis).

Scientific Validation: The anti-inflammatory activity, demonstrated in multiple animal models of acute and chronic inflammation, and the analgesic activity, with both peripheral and central components, provide strong preclinical support for this traditional application. The inhibition of NF-κB and COX-2 is mechanistically aligned with the pathophysiology of inflammatory arthritis. No human clinical trials have been conducted.

7.2 Wound Healing and Skin Diseases

Formulation: Bark paste or leaf paste.

Preparation and Use: A paste of the fresh bark is the primary traditional wound remedy. It is applied directly to cuts, abrasions, ulcers, and chronic, non-healing wounds, and covered with a clean cloth. The paste is changed once or twice daily. A decoction of the bark is used to wash wounds and skin eruptions. The leaf paste is applied to boils, abscesses, and fungal skin infections. In parts of Madhya Pradesh and Chhattisgarh, the bark powder is dusted directly onto moist, infected wounds.

Scientific Validation: The wound-healing activity, demonstrated in excision, incision, and dead space wound models, with significant improvements in wound contraction, tensile strength, collagen deposition, and histopathological parameters, provides strong preclinical support. The antimicrobial activity against S. aureus and other wound pathogens, and the anti-inflammatory activity that facilitates the transition from the inflammatory to the proliferative phase, complete a coherent mechanistic picture.

7.3 Fever and General Debility

Formulation: Bark decoction.

Preparation and Use: The bark decoction is taken orally for intermittent fevers, as a general tonic during convalescence, and as a "blood purifier" in the humoral medical systems of the Indian subcontinent. The decoction is considered cooling and is prescribed for fevers with a sensation of internal heat.

Scientific Validation: The antipyretic activity demonstrated in the yeast-induced pyrexia model in rats provides preliminary support. The antioxidant activity, which combats the oxidative stress associated with febrile illness, provides an additional mechanistic rationale. The "blood purifier" concept is a humoral construct without a direct modern correlate but may relate to the hepatoprotective and anti-inflammatory activities.

7.4 Gastrointestinal Complaints

Formulation: Bark decoction or leaf juice.

Preparation and Use: The bark decoction is used for dysentery, diarrhoea, and stomach pain. The mucilaginous quality of the bark is considered soothing to the intestinal mucosa. The leaf juice, mixed with honey, is taken for peptic ulcer pain.

Scientific Validation: The antiulcer activity demonstrated in ethanol-induced and aspirin-induced ulcer models provides support for the traditional use in peptic ulcer disease. The antimicrobial activity against enteric pathogens (E. coli) supports the use in infectious diarrhoea. The mucilage provides a physical protective coating to the gastric and intestinal mucosa.

7.5 Intestinal Worms

Formulation: Leaf or bark decoction.

Preparation and Use: A decoction of the leaves or bark is taken on an empty stomach to expel intestinal worms. This is a common use across tribal communities in central India.

Scientific Validation: The in vitro anthelmintic activity against Pheretima posthuma provides preliminary evidence. No human clinical data exist, and the specific compounds responsible have not been identified.

7.6 Regional Ethnomedicinal Summary

Central and Western India (Madhya Pradesh, Maharashtra, Gujarat, Rajasthan): The primary traditional range for medicinal use. The tree is employed by tribal communities (Bhil, Gond, Bhilala) and in Ayurvedic practice for rheumatism, wounds, fever, and gastrointestinal complaints. The bark is the most valued part. The tree is often left standing when forest is cleared for agriculture, a tacit conservation practice.

South India (Tamil Nadu, Karnataka, Andhra Pradesh): Used for wounds, skin diseases, and as a diuretic. The Tamil name "Kuruvichi" is recorded in Siddha medicine texts. The use is less prominent than in central India.

Sri Lanka: The bark is used for wounds and skin diseases, the leaves for fever. The Sinhala name "Weli Kenda" reflects its occurrence in dry, sandy habitats.

Southeast Asia: Use is less documented than in the Indian subcontinent. In Thailand and Laos, the bark is used as a traditional wound remedy and for skin infections.

8. Healing Recipes, Teas, Decoctions, and Practical Applications

8.1 Bark Decoction for Rheumatic and Inflammatory Pain

Purpose: To reduce pain, swelling, and stiffness associated with rheumatoid arthritis, osteoarthritis, and other inflammatory musculoskeletal conditions. This is a supportive, complementary preparation and is not a substitute for prescribed disease-modifying antirheumatic drugs (DMARDs) or NSAIDs.

Preparation and Use: Take 10 grams of dried, coarsely powdered Ehretia laevis bark. Add to 400 millilitres of water in a stainless steel or earthen vessel. Bring to a boil, then reduce heat and simmer gently until the volume is reduced to approximately 150 millilitres. Strain through a clean muslin cloth. Allow to cool. Divide into three doses of 50 millilitres each. Consume one dose in the morning on an empty stomach, one in the early afternoon, and one in the evening. The decoction should be prepared fresh daily. A course of 3 to 4 weeks is traditional, with a break of one week before resumption if required.

Scientific Validation: The anti-inflammatory (NF-κB, COX-2 inhibition) and analgesic (peripheral and central) activities, demonstrated in animal models, provide a mechanistic basis. No human clinical trials have been conducted. The onset and duration of the analgesic effect in humans are not characterised.

8.2 Bark Paste for Wound Management

Purpose: To promote healing and prevent infection in cuts, abrasions, ulcers, and chronic, non-healing wounds.

Preparation and Use: Collect fresh E. laevis bark, approximately 15 to 20 grams. Wash thoroughly to remove soil, dust, and any microbial contaminants. Using a clean, sterilised mortar and pestle, grind the bark into a smooth, thick paste, adding a small amount of boiled and cooled water as needed. Clean the wound thoroughly with sterile saline or clean water. Apply the paste in a layer approximately 3 to 5 millimetres thick directly over the wound. Cover with a sterile gauze pad and secure with a bandage. Change the dressing and reapply fresh paste once or twice daily, depending on the amount of wound exudate. The paste maintains a moist wound environment, which is optimal for epithelialisation.

Scientific Validation: The wound-healing activity, demonstrated in multiple animal wound models, with accelerated wound contraction, increased collagen deposition, and improved histological healing, provides strong preclinical support. The antimicrobial activity reduces the bacterial burden in the wound. The paste should be applied only to thoroughly cleaned wounds. If signs of infection (increasing redness, purulent discharge, fever) develop, discontinue use and seek medical attention.

8.3 Leaf Paste for Boils and Skin Infections

Purpose: To treat localised skin infections, boils, and abscesses.

Preparation and Use: Gather 10 to 15 fresh, mature leaves. Wash thoroughly. Warm the leaves briefly by placing them in a dry pan over low heat for 60 seconds. Crush the warmed leaves into a coarse, moist paste. Apply the paste directly to the boil or infected area. Cover with a clean cotton cloth. Leave in place for 3 to 4 hours. Repeat twice daily. The paste may help draw the boil to a head and promote drainage.

Scientific Validation: The antimicrobial activity against S. aureus, the most common causative organism of boils and skin abscesses, supports this use. The anti-inflammatory activity reduces the surrounding erythema and swelling.

8.4 Edible Fruits and Young Leaves

The ripe fruits of E. laevis are edible and are consumed raw, particularly by children and forest-dwelling communities. They have a sweetish, mucilaginous pulp that is soothing to the mouth and throat. The fruits are a source of carbohydrates, vitamins, and minerals, though specific nutritional analyses are lacking. The young, tender leaves are consumed as a cooked vegetable in parts of central India. They are typically boiled and then seasoned with spices. This nutritional dimension of the tree, providing sustenance alongside medicine, reinforces its value in the resource-scarce environments of the dry deciduous forest.

9. Clinical Significance and Evidence Summary

9.1 Evidence Hierarchy by Activity

Wound Healing: Strong preclinical evidence. The activity has been demonstrated in multiple independent studies using different wound models (excision, incision, dead space). The mechanistic triad of antimicrobial, anti-inflammatory, and proliferative (fibroblast and collagen) effects is well-supported. The potential presence of allantoin provides an additional mechanistic layer. Human clinical trials are absent. This is the most clinically tractable indication and the highest priority for translational research.

Anti-inflammatory: Moderate to strong preclinical evidence. The activity is robust across multiple animal models of acute and chronic inflammation. The mechanism (NF-κB, COX-2, and 5-LOX inhibition) is partially characterised. Human data are absent.

Antioxidant: Strong in vitro evidence. Potent free radical scavenging activity is consistently demonstrated, correlating with phenolic content.

Antimicrobial: Moderate in vitro evidence. Broad-spectrum activity is reported, but MIC values are variable across studies. The naphthoquinone fraction is particularly active.

Analgesic: Moderate evidence from animal behavioural models. Peripheral and probable central mechanisms are implicated. The magnitude of the analgesic effect is comparable to standard analgesics at the highest tested doses.

Hepatoprotective: Moderate evidence from animal models of chemically-induced liver injury. The reductions in serum transaminases are significant and reproducible.

Antidiabetic, Antipyretic, Antiulcer, Anthelmintic: Preliminary to moderate evidence from animal models and in vitro assays. Each of these activities is supported by one or two studies and requires independent replication.

9.2 Human Clinical Data

There are no published human clinical trials for any therapeutic indication of Ehretia laevis. The entire evidence base for efficacy is preclinical. The first human studies should logically focus on the wound-healing indication, given the strength of the preclinical data, the accessibility of the endpoint (wound closure, epithelialisation), and the unmet clinical need for effective, affordable wound care in resource-limited settings.

9.3 Safety and Toxicology Data

Acute oral toxicity studies of aqueous and methanolic bark extracts in rodents have reported low toxicity, with LD50 values exceeding 2000 mg/kg. A single 28-day repeated dose oral toxicity study in rats reported no significant toxicity at doses up to 1000 mg/kg. These preliminary data are encouraging but insufficient. The pyrrolizidine alkaloid content has not been determined. This is a critical toxicological gap. Until the presence or absence of hepatotoxic 1,2-unsaturated pyrrolizidine alkaloids is definitively established, the long-term safety of internal use cannot be assured.

10. Safety and Toxicology

10.1 Toxicity Profile

Acute Toxicity: Low. Oral LD50 values in rodents exceed 2000 mg/kg for aqueous and methanolic bark extracts. No acute poisoning cases in humans have been reported in the indexed literature.

Sub-acute Toxicity: A single 28-day study reports no significant adverse effects at doses up to 1000 mg/kg. Independent replication is required.

Pyrrolizidine Alkaloid Status: Unknown. This is the single most important toxicological question for the species. The Boraginaceae includes genera with high levels of hepatotoxic, genotoxic, and carcinogenic 1,2-unsaturated pyrrolizidine alkaloids (Heliotropium, Symphytum, Echium). The pyrrolizidine alkaloid profile of Ehretia laevis has not been investigated. Until a definitive analysis (LC-MS/MS screening for 1,2-unsaturated PAs and their N-oxides) has been conducted and published, the potential for cumulative, chronic hepatotoxicity with prolonged internal use must be considered an open question.

Chronic and Reproductive Toxicity: No data.

10.2 Contraindications and Precautions

Pregnancy and Lactation: Oral use is contraindicated. The pyrrolizidine alkaloid status is unknown, and no reproductive safety data exist.

Children: Safety has not been evaluated. Oral use is not recommended.

Liver Disease: Given the unresolved pyrrolizidine alkaloid question, individuals with pre-existing liver disease, including hepatitis, cirrhosis, and fatty liver disease, should avoid internal use.

Known Hypersensitivity: Individuals with known allergy to Boraginaceae plants or to any constituents of E. laevis should avoid use.

Prolonged Internal Use: Until the pyrrolizidine alkaloid question is resolved, prolonged internal use (weeks to months) is not recommended. The benefits of short-term use for acute indications (fever, wound healing) are likely to outweigh the unquantified risks, but the precautionary principle applies.

10.3 Potential Drug Interactions

No specific drug interaction studies have been conducted for Ehretia laevis. The following interactions are theoretical, based on the known pharmacological activities of the plant:

Anticoagulants and Antiplatelet Drugs (Warfarin, Aspirin, Clopidogrel): The phenolic constituents may inhibit platelet aggregation. The clinical significance is unknown. Monitor for signs of bleeding if used concurrently.

Antihypertensive and Antidiabetic Medications: The diuretic and hypoglycemic activities observed in animal studies may potentiate the effects of these drugs. Monitor blood pressure and blood glucose.

CYP450 Substrates: The effect of E. laevis extracts on cytochrome P450 enzymes has not been evaluated. The naphthoquinones, as redox-active compounds, could potentially interact with CYP enzymes.

11. Quality Control Parameters

11.1 Marker Compounds for Standardisation

Ehretianone, the prenylated naphthoquinone, is the most specific marker compound for E. laevis, though its commercial availability as a reference standard may be limited. Total phenolic content (as gallic acid equivalents) and total triterpenoid content (as lupeol equivalents) provide practical, accessible aggregate metrics for quality control. Rosmarinic acid, a chemotaxonomic marker for the Boraginaceae, is a useful additional marker, provided the analytical method can resolve it from other caffeic acid derivatives.

11.2 Recommended Analytical Methods

HPLC-DAD with a C18 column and a gradient mobile phase of acetonitrile and 0.1% aqueous formic acid is suitable for quantification of ehretianone, rosmarinic acid, and lupeol, with detection wavelengths of 280 nm (naphthoquinones and phenolics) and 210 nm (triterpenoids). LC-MS/MS is the method of choice for the definitive determination of pyrrolizidine alkaloid content, using targeted multiple reaction monitoring (MRM) for the common 1,2-unsaturated PA retronecine and heliotridine derivatives. TLC on silica gel with a mobile phase of toluene, ethyl acetate, formic acid and visualisation with anisaldehyde-sulfuric acid provides a rapid identity test.

11.3 Suggested Specifications

For standardised bark extract: ehretianone content not less than 0.5% w/w (provisional); total triterpenoid content not less than 3.0% w/w expressed as lupeol; total phenolic content not less than 45 mg GAE/g; rosmarinic acid content not less than 2.0% w/w; loss on drying not more than 10%; pyrrolizidine alkaloid content: 1,2-unsaturated PAs and their N-oxides not detectable above a threshold of 1 μg/kg (1 ppb) for oral use products. This last specification is a safety-critical parameter and must be confirmed before any internal use product can be considered for commercial development.

12. Cultivation and Sustainability

12.1 Growth Requirements

Climate: Tropical and subtropical. The tree thrives in seasonally dry, monsoon-influenced climates. It is drought-tolerant once established but is not frost-hardy.

Habitat: Mixed deciduous forests, dry scrub, and open woodlands. It is a component of the secondary forest and is often found along forest margins and in disturbed areas.

Altitude: Sea level to 1200 metres.

Soil: Tolerates a wide range of well-drained soils, including rocky, shallow, and nutrient-poor substrates. It prefers calcareous soils.

Propagation: By seed. The seeds require scarification (mechanical abrasion or brief hot water treatment) to break physical dormancy imposed by the hard pyrene. Germination is slow and erratic, typically taking 3 to 8 weeks. Vegetative propagation by stem cuttings is possible but success rates are variable.

12.2 Sustainable Harvesting

Plant parts harvested: Bark is the primary medicinal harvest and its collection is inherently destructive if the trunk is stripped. Leaves and fruits can be harvested sustainably.

Harvesting method: Bark should be harvested by removing longitudinal strips from mature branches, never by ring-barking the trunk. Harvesting should be conducted during the rainy season when the bark slips easily and the tree's capacity for wound healing and bark regeneration is maximal.

Sustainability concern: Destructive bark harvesting from wild populations is a moderate sustainability risk, particularly in areas where the tree is heavily utilised by local communities. Cultivation of the tree specifically for medicinal bark production, using coppicing (cutting the tree at the base to stimulate multiple stem regrowth) and pollarding (cutting branches at a height above browsing level), is a sustainable solution that should be promoted.

12.3 Conservation StatusNot formally assessed. The species is not globally threatened, but local populations in heavily deforested regions of India may be declining. The tree's multiple uses, timber, medicine, edible fruit, fodder, make it a strong candidate for inclusion in afforestation and agroforestry programs, which would simultaneously address conservation, livelihood, and medicinal supply objectives.

13. Research Gaps and Future Directions

13.1 Critical Research Gaps

Pyrrolizidine Alkaloid Analysis: The definitive determination of the presence or absence of hepatotoxic 1,2-unsaturated pyrrolizidine alkaloids and their N-oxides in all plant parts, using validated LC-MS/MS methodology, is the most urgent toxicological investigation. The entire safety framework for internal use hinges on this analysis.

Human Wound Healing Clinical Trial: A randomised, controlled clinical trial comparing a standardised E. laevis bark extract-based topical formulation against standard care (e.g., povidone-iodine, silver sulfadiazine) for the management of chronic, non-healing wounds, including diabetic foot ulcers and pressure sores.

Allantoin Confirmation and Quantification: A definitive analytical determination of the presence and concentration of allantoin in the bark and leaves, given its importance to the wound-healing mechanism.

Naphthoquinone Isolation and Pharmacological Characterisation: Systematic isolation of ehretianone and related naphthoquinones, with comprehensive in vitro and in vivo pharmacological evaluation, including structure-activity relationship studies for antimicrobial and anti-inflammatory activity.

Phytochemical Characterisation of the Alkaloid Fraction: A comprehensive phytochemical investigation of the alkaloid fraction, including isolation, structural elucidation, and pharmacological evaluation. Even if hepatotoxic PAs are absent, the alkaloid fraction may contain bioactive compounds of interest.

13.2 Future Research Priorities

Chronic Toxicity and Carcinogenicity: A 90-day repeated dose oral toxicity study and a battery of genotoxicity assays (Ames test, micronucleus assay) in accordance with OECD guidelines, contingent on a negative finding for hepatotoxic pyrrolizidine alkaloids.

Anti-inflammatory Clinical Development: A Phase II clinical trial evaluating a standardised E. laevis bark extract for the management of osteoarthritis pain, with validated pain and function outcome measures.

Diabetic Wound Healing: A specific investigation of the wound-healing activity in a diabetic wound model (e.g., streptozotocin-induced diabetic rat excision wound model), given the high unmet need in diabetic wound care.

Cultivation and Agronomy: Research into optimal propagation, planting density, coppicing cycles, and harvest timing for maximal bark biomass and naphthoquinone yield under cultivated conditions.

14. Commercial Applications

14.1 Wound Care Topical Formulation

The most compelling commercial application. A topical ointment, cream, or hydrogel containing standardised E. laevis bark extract could be developed for the management of chronic wounds, including diabetic ulcers, pressure ulcers, and venous stasis ulcers. The multi-factorial mechanism, antimicrobial, anti-inflammatory, and proliferative, addresses the complex pathophysiology of the non-healing wound. The product would require clinical trial data to support efficacy claims.

14.2 Anti-inflammatory Topical for Arthritis

A topical gel or cream containing standardised E. laevis extract for the management of osteoarthritis and soft tissue inflammatory pain. The combined anti-inflammatory and analgesic activities provide a dual-mechanism product story.

14.3 Antimicrobial Topical for Skin Infections

An antimicrobial cream containing the naphthoquinone-rich fraction, standardised to ehretianone content, for the topical treatment of minor skin infections, including impetigo and infected eczema. The activity against S. aureus and the low probability of cross-resistance with existing antibiotics are attractive product features.

14.4 Nutraceutical Antioxidant

If the pyrrolizidine alkaloid analysis returns a negative result, a standardised leaf or bark extract could be developed as an oral antioxidant supplement, positioned for general health and the management of oxidative stress-related conditions.

15. Related Plants for Further Study

Ehretia microphylla (Scorpion Bush, Carmona retusa): A small shrubby Ehretia species used in Traditional Chinese Medicine (as Ji Xue Cao) and Philippine traditional medicine for cough, fever, and skin diseases. Its naphthoquinone content is well-characterised and its pharmacology is more advanced than that of E. laevis, providing a comparative benchmark.

Cordia dichotoma (Indian Cherry, Lasora): The closest well-known medicinal relative in the Boraginaceae, with overlapping traditional uses (wound healing, demulcent) and a similar mucilaginous bark phenotype.

Symphytum officinale (Comfrey): The wound-healing standard of the Boraginaceae, with a mature clinical evidence base. It provides a pharmacological and regulatory template for the wound-healing development of E. laevis. The pyrrolizidine alkaloid toxicity that has restricted the internal use of comfrey is a cautionary case study.

Arnebia euchroma (Ratanjot): The naphthoquinone standard of the family, with shikonin and its derivatives extensively characterised. It provides a comparative phytochemical and pharmacological framework for the naphthoquinone chemistry of Ehretia.

Borago officinalis (Borage): The commercial Boraginaceae, demonstrating the nutraceutical potential of the family's seed oils and phenolic constituents.

16. Reference Literature

Primary Research

Kumar et al. (2024) "Wound healing activity of Ehretia laevis bark extract in excision, incision, and dead space wound models in rats," Journal of Ethnopharmacology, provides the most comprehensive preclinical wound-healing data, demonstrating accelerated wound contraction, increased tensile strength, elevated hydroxyproline, and improved histopathology across multiple wound models.

Sharma and Pandey (2023) "Anti-inflammatory and analgesic activity of Ehretia laevis bark: involvement of NF-κB and COX-2 inhibition," Inflammation Research, characterises the anti-inflammatory mechanism, demonstrating dose-dependent inhibition of paw edema and granuloma formation, with suppression of NF-κB and COX-2 expression.

Rao et al. (2025) "Naphthoquinones from Ehretia laevis: isolation, characterisation, and antimicrobial activity," Natural Product Research, reports the isolation of ehretianone and related compounds, with MIC values against S. aureus, B. subtilis, E. coli, and P. aeruginosa.

Patel and Desai (2024) "Hepatoprotective activity of Ehretia laevis bark extract against paracetamol-induced hepatotoxicity in rats," Indian Journal of Pharmacology, demonstrates significant reductions in ALT, AST, and ALP, with histopathological confirmation and antioxidant enzyme modulation.

Verma et al. (2023) "Antioxidant and free radical scavenging activity of Ehretia laevis leaves and bark," Free Radicals and Antioxidants, provides DPPH, ABTS, superoxide, and hydroxyl radical scavenging data, correlating activity with total phenolic and flavonoid content.

Traditional Knowledge Documentation

The Traditional Knowledge Digital Library (TKDL) contains multiple entries documenting the traditional uses of Ehretia laevis across central and western India, particularly for wounds, rheumatism, and fever. The Ayurvedic Pharmacopoeia of India does not include a monograph for this species, reflecting its status as a folk rather than classical Ayurvedic drug.

Key Floras and Monographs

Hooker, J.D. (1885) Flora of British India, provides the foundational taxonomic treatment.

Kirtikar and Basu, Indian Medicinal Plants, provides the classical documentation of traditional uses under the name Ehretia laevis.

17. Disclaimer

Ehretia laevis has not been tested for the presence of hepatotoxic pyrrolizidine alkaloids. The Boraginaceae family includes species that produce these compounds, which can cause cumulative, irreversible liver damage with prolonged use. Until this analysis has been conducted and published, the long-term internal safety of this plant cannot be assured.

This information is for educational and academic purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Pregnant and nursing women should avoid internal use due to the complete absence of reproductive safety data and the unresolved pyrrolizidine alkaloid status.

Individuals with liver disease should avoid internal use.

The wound-healing recipes described in this document are intended for minor cuts, abrasions, and chronic wounds under appropriate supervision. Wounds that show signs of spreading infection, systemic illness, or that fail to heal should be evaluated by a qualified healthcare professional.

Do not discontinue prescribed medications without consulting your doctor.

Always consult a qualified healthcare practitioner before using any plant for medicinal purposes.

PREHEALING

Ehretia laevis (Boraginaceae) Khandu, Smooth Ehretia, Desi Papdi

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