Indian kinotree

Indian Kinotree (Pterocarpus marsupium Roxb.): A Comprehensive Reference

1. Identity and Botanical Classification

Botanical and Scientific Names

Pterocarpus marsupium Roxb. (named by William Roxburgh, 1799) belongs to the family Fabaceae (subfamily Faboideae). In English, the tree is known as the Indian Kinotree or Malabar Kino. Its regional vernacular names include Vijayasar or Vijaysar (Hindi), Hannemara (Kannada), Venga or Vengai (Malayalam/Tamil), Asaaha (Marathi), and Asanah (Sanskrit). Additional synonyms in botanical literature include Lingoum marsupium (Roxb.) Kuntze and Pterocarpus bilobus G. Don.

Pterocarpus marsupium, also known as Malabar kino or Indian kino, is a medium-to-large, deciduous tree that can grow up to 31 m (102 ft) tall. It is native to India, occurring in parts of the Western Ghats in the Karnataka–Kerala region and in the forests of Central India, as well as in Nepal and Sri Lanka.

Morphological Description

The tree is tall and deciduous, reaching 30 m in height with a girth of up to 5 m. The bark is grey and peels in irregular scales with pink and white markings. Its leaves are large, leathery, and alternate. The species is widely distributed across the central, western, and southern regions of India.

Conservation Status

The Indian kinotree is listed on the IUCN Red Data List as a direct result of excessive exploitation of its wood. More specifically, the plant is being harvested in an unsustainable way due to demand for its wood, and the IUCN Red List has classified P. marsupium as Near Threatened.

Common Preparations and Dosage Forms

Traditionally and commercially, multiple parts of the tree are employed. The heartwood, bark, leaves, and gum resin have been most frequently employed for medicinal purposes. Heartwood and bark are rich in polyphenols (notably pterostilbene, epicatechin, marsupsin, and pterosupin), tannins, and flavonoids. The kino gum, a red, astringent exudate historically used as a tonic and for diarrhea, is today less common in supplements than wood and bark extracts.

Historical pharmaceutical preparation of kino followed official pharmacopeial methods: kino was officially defined as "the spontaneously dried juice of Pterocarpus marsupium Roxburgh (Fam. Leguminosae)." According to the British Pharmacopoeia, "Kino is the juice obtained from incisions in the trunk of Pterocarpus marsupium, heated to boiling and evaporated to dryness," and was known in commerce as East Indian, Malabar, Madras, or Cochin kino. This exudate is obtained by making incisions in the bark, catching the red sap, and drying it in the sun; it comes to market in small, angular, brittle, and shining pieces of a very dark brownish-red colour.

Extracts have been prepared using many methods, including infusion, maceration, decoction, and percolation. In contemporary supplement contexts, the plant is available as standardized extract powder, capsules and tablets, and as a proprietary extract. A notable standardized commercial extract is Silbinol® (Sabinsa Corp.). In several traditional communities, the bark is used as a remedy for diabetes by making a wooden tumbler from the heartwood, filling it with water overnight, and consuming it in the morning.

2. Traditional and Historical Use

Ayurvedic Medicine

Pterocarpus marsupium is a prominent medicinal plant in the traditional Ayurvedic and Unani systems of medicine, and has garnered significant attention for its diverse bioactive compounds and therapeutic potential. The plant is indigenous to the Indian subcontinent and is known for its antidiabetic, antioxidant, anti-inflammatory, and antimicrobial effects.

Vijaysar is mentioned as a powerful rejuvenator and a treatment for a number of metabolic illnesses in traditional Ayurvedic texts. The heartwood of P. marsupium is considered a possible source of medications for leprosy and fungal conditions. Classical Ayurvedic indications, rendered in Sanskrit nosological terms, include Madhumeha, Prameha, Sthoulya, Kustha, Udarda, Visarpa, Shwitra, Shotha, Palitya, Abhighataja Vedana, Bhagna, Atisar, Pravahika, Krimi, Dantashoola, Raktapitta, and Raktavikara — covering diabetes, obesity, skin diseases, wounds, diarrhea, worm infestations, and bleeding disorders.

In Ayurveda, P. marsupium has been classified as a Rasayana herb — used to rejuvenate and restore balance in the body. It has been traditionally used to treat Madhumeha (diabetes), obesity, diarrhea, eczema, and menstrual disorders.

P. marsupium is best known for its antidiabetic potential and has been widely prescribed for the management of diabetes mellitus. Ancient Ayurvedic texts describe the use of its heartwood in the form of decoctions or water infusions for glycemic control.

In traditional Indian medicine, the plant is used in the treatment of prameha (diabetes), medodosa (obesity), pandu (anemia), kustha (leprosy), and krmiroga (worm infestation). In Nepal, a wooden tumbler made from the heartwood of the plant is used to drink water as a classical remedy for diabetes.

Ethnobotanical Uses in Sri Lanka and Broader Region

Pterocarpus marsupium Roxb. (known as Gammalu in Sinhala) heartwood and bark have been used as antidiabetic remedies in many cultures for thousands of years. Aqueous extract of the wood has a long history of use in the treatment of diabetes mellitus. Literature also suggests that P. marsupium is useful in treating leprosy, skin diseases, diarrhea, asthma, bronchitis, greyness of hair, and other common conditions.

Traditional Preparations for Non-Diabetic Conditions

Extracts of the leaves, flowers, and gum of the tree have been used medicinally in the treatment of diarrhea, toothache, fever, urinary tract disorders, and skin infections. The bark extract has long been regarded as useful in the therapy of diabetes. Heartwood is considered astringent, anthelmintic, anti-inflammatory, and analgesic. The gum exudate from the tree, known as "Kino," is employed as an astringent.

Historically, in Western pharmacopoeias, infusions of the kino gum were used internally. The most common historical method of exhibition was making an infusion with two drachms of kino in eight fluid ounces of boiling water, strained when cold; the addition of myrica bark and capsicum made a preparation used for uterine haemorrhage, while pimento and cinnamon were combined with kino for mild haemorrhages and painful diarrhea.

3. Phytochemical Composition and Key Active Constituents

Major Bioactive Compounds

The phytochemicals present in P. marsupium include pterostilbene, (−)-epicatechin, pterosupin, marsupsin, pentosan, pseudobaptigenin, liquiritigenin, isoliquiritigenin, garbanzol, 5-deoxykaempferol, propterol B, marsupinol, irisolidone-7-O-α-L-rhamnopyranoside, alkaloids, tannins, p-hydroxybenzaldehyde, β-eudesmol, erythrodirol-3-monoacetate, marsupol, carpusin, and propterol — obtained mainly from the heartwood and root.

The plant is rich in polyphenols such as marsupin, pterosupin, epicatechin, pterostilbene and flavonoids including pteroside, pteroisoauroside, carsupin, liquiritigenin, and marsupol. The heartwood is particularly valued for its rich content of polyphenolic compounds like epicatechin, marsupsin, and pterostilbene, which are associated with antioxidant, antidiabetic, and cardioprotective effects.

Among newly identified constituents are Pterocarposide and Sabioside, in addition to the well-established flavonoids, tannins, and terpenoids. Kino gum contains kinotannic acid at approximately 70–80%.

Primary phytoconstituents present in the bark include liquiritigenin, isoliquiritigenin, pterosupin, epicatechin, and pterostilbene. Phytochemical testing has shown the presence of carbohydrates, glycosides, saponins, tannins, flavonoids, alkaloids, phenolic compounds, fixed oils, and fats from various parts of the plant.

P. marsupium also contains 2,3,6-trimethyl-1,4-naphthoquinone (TM-NQ), which in vitro is a reversible monoamine oxidase inhibitor also occurring in tobacco leaf and may cause skin, eye, and respiratory irritation.

The Kino Gum (Resin) as a Distinct Material

According to historical analyses, kino consists of approximately 40% tannic acid, with traces of gallic acid, kinoic acid, pectin, ulmic acid, inorganic salts, and excess earthy bases. Water dissolves kino almost perfectly; alcohol also acts freely on it, and a tincture does not cause a precipitate on the addition of water — confirming it to be neither a simple resin nor a gum.

4. Established Mechanisms of Action

Antidiabetic Mechanisms

Multiple mechanisms responsible for the hypoglycaemic effects of P. marsupium have been identified, including beta-cell regeneration, insulin release, and insulin-like actions of some isolated compounds. (−)-Epicatechin, a flavonoid isolated from the bark, has shown insulin-like effects, effects on beta-cell regeneration, and insulin release. Several compounds including pterostilbene and marsupsin isolated from the heartwood have been identified as compounds with hypoglycaemic effects.

(−)-Epicatechin has been shown not only to regenerate pancreatic β-cells but also to exhibit other activities including promoting insulin release, converting pro-insulin to insulin, facilitating oxygen uptake in fat cells and other tissues, and converting glucose to glycogen, in rats.

Epicatechin regulates glucose production through AKT and AMPK modulation in HepG2 cells. Some of the mechanisms through which P. marsupium elicits antidiabetic activity include suppressing inflammatory mediators like cytokines and TNF-α in diabetic rats, and improving lipid profiles and liver function.

Mechanisms proposed for the hypoglycemic action of the Indian Kinotree extract include stimulation or regeneration of beta cells and extrapancreatic effects. The isoflavone from P. marsupium may activate glucose transport, improving glucose uptake in a manner similar to insulin.

Pterocarpus marsupium is among the most important medicinal plants in the Indian system of traditional medicine for the treatment of hyperglycemia. Dipeptidyl peptidase-4 (DPP-4) inhibitors are an emerging class of anti-diabetic agents, and studies have explored whether naturally occurring P. marsupium semi-standardized extracts may possess DPP-4 inhibitory activity in vitro and in vivo.

Anti-inflammatory Mechanisms

P. marsupium extract demonstrates selective COX-2 inhibitory activity, and the PGE2 inhibitory activity of the extract is related to its pterostilbene content. PM extract, pterostilbene, and resveratrol inhibited PGE2 production from LPS-stimulated human peripheral blood mononuclear cells (PBMC) with IC50 values of 3.2 ± 1.3 μg/mL, 1.0 ± 0.6 μM, and 3.2 ± 1.4 μM, respectively. In a COX-1 whole blood assay, PM extract was not effective, while in a COX-2 whole blood assay, PM extract decreased PGE2 production, indicating COX-2 specific inhibition.

Antioxidant Mechanisms

Both the acetone/IPA extract and the ethanol extract of stem wood of P. marsupium exhibited a dose-dependent antioxidant activity. In a 1,1-diphenyl-2-picrylhydrazyl (DPPH) test used to assess the bark extract's in vitro antioxidant activity, the bark extract of P. marsupium showed an IC50 of 53.0 μg/mL (compared to ascorbic acid's IC50 of 34.0 μg/mL as standard).

5. Scientific Evidence by Area of Use

5.1 Diabetes and Glycemic Control

Preclinical Evidence (Animal and In Vitro)

The antidiabetic activity of P. marsupium is the most studied of its properties. Anti-diabetic activity was evaluated at Delhi Institute of Pharmaceutical Sciences and Research (DIPSAR) in a neonatal rat model in which Type 2 diabetes was induced by streptozotocin (90 mg/kg, i.p.). Aqueous extract of P. marsupium at doses of 100 and 200 mg/kg decreased both fasting and postprandial blood glucose in type 2 diabetic rats.

In a further rat study (neonatal streptozotocin model), aqueous extract of P. marsupium at doses of 100 and 200 mg/kg was given orally for 4 weeks. After treatment, both doses decreased fasting and postprandial blood glucose; the 200 mg/kg dose had a more pronounced effect on postprandial hyperglycemia. The drug also improved body weight of diabetic animals. Cytokine TNF-α was found elevated in untreated diabetic rats due to chronic systemic inflammation, and the aqueous extract at both doses significantly (P < 0.001) decreased the elevated TNF-α level in type 2 diabetic rats.

The antidiabetic activity of various subfractions of the alcohol extract of the bark of P. marsupium was evaluated in alloxan-induced diabetic rats. The effect of these extracts on lipid profile and liver function tests was also assessed. Parameters measured included plasma glucose, total protein, cholesterol, triglycerides, alkaline phosphatase, SGOT, and SGPT. The results indicated the effective role of P. marsupium in controlling diabetes-related metabolic alterations beyond glucose levels.

P. marsupium reversed damage to the beta cells and actually repopulated the islets, causing a nearly complete restoration of normal insulin secretion. Epicatechin, pterostilbene, marsupin, and pterosupin present in the plant enhance insulin sensitivity.

In an alloxan-induced diabetic mouse model, the combined effects of glibenclamide (GLB) and P. marsupium (PM) extract were studied at doses of 500 μg/kg body weight (GLB) and 150 mg/kg body weight (PM extract) for 15 days. ALX-induced hyperglycemia and other adverse effects were nearly normalized by GLB and PM co-treatment, as evidenced by marked suppression of glucose levels.

Human and Clinical Evidence

A multicentric clinical trial conducted by the Indian Council of Medical Research (ICMR) on patients with non-insulin-dependent diabetes mellitus (NIDDM) observed that Pterocarpus marsupium was as effective as tolbutamide, with no adverse effects reported.

Hydroextracts of P. marsupium and Gymnema sylvestre, administered for 6 months, reduced blood glucose, HbA1C, total cholesterol, LDL, VLDL, and oxidative stress in NIDDM patients. HDL levels also improved in these subjects.

Despite substantial preclinical evidence, clinical studies on P. marsupium remain limited, and issues related to standardization and dosage persist. The overall body of human evidence for antidiabetic effects is preliminary: early clinical observations are encouraging but the trial populations are small, design quality is variable, and long-term randomized controlled trial data are scarce.

5.2 Anti-inflammatory Effects

Studies have been reported demonstrating the ability of P. marsupium as a specific COX-2 inhibitor. In a study involving healthy human volunteers, oral use of 450 mg of PM extract did not decrease PGE2 production ex vivo in a whole blood assay (WBA). Pterostilbene levels in serum were increased but were 5-fold lower than the observed IC50 for PGE2 inhibition in LPS-stimulated PBMC. No changes from baseline of safety parameters were observed and no extract-related adverse events occurred during the study. This indicates that while pterostilbene reaches systemic circulation at the tested dose, the serum concentrations achieved may be insufficient to produce COX-2 inhibition in the intact human body. Evidence for anti-inflammatory effects in humans is therefore considered preliminary and inconclusive at standard supplement doses.

In laboratory studies, acetone/IPA extracts showed antibacterial activity against Gram-positive bacteria, while the acetone/IPA extract was also found to have anti-inflammatory activity that was time and dose-dependent.

5.3 Cardiovascular and Lipid-Lowering Effects

Studies indicate that P. marsupium has hypolipidemic effects, including reduction of serum cholesterol, triglycerides, and low-density lipoprotein (LDL) levels. These properties contribute to its cardioprotective potential, particularly in diabetes-associated cardiovascular complications.

P. marsupium extract shows promising results in hypertriglyceridaemia. The plant also finds use as a cardiotonic agent. In a rodent model of atherosclerosis induced by a high-fat diet, histology revealed reduced lipid infiltration in PM-treated rats, and PM extract exhibited anti-atherogenic and antioxidant effects. Evidence in this area is derived from preclinical animal models and limited human observational data; no large, dedicated cardiovascular outcome trials are available.

5.4 Hepatoprotective Effects

Hepatoprotective effects of P. marsupium have been observed in experimental models of liver injury. Treatment with plant extracts resulted in normalization of liver enzymes and improvement in hepatic antioxidant status, indicating protection against toxin- and drug-induced hepatic damage. The plant has been scientifically reported for hepatoprotective activity. All available evidence in this area is preclinical; no clinical hepatoprotection trials are published.

5.5 Anti-cataract Activity

P. marsupium extract also shows promising results in cataract. Anti-cataract activity of P. marsupium bark and Trigonella foenum-graecum seeds extract was assessed in alloxan-diabetic rats and published in the Journal of Ethnopharmacology (2004). This area of research is entirely preclinical (animal model); no human studies on cataract prevention or reversal have been published.

5.6 Antimicrobial Activity

Extracts of P. marsupium have shown antimicrobial activity against various bacterial and fungal strains. Various research studies demonstrated polar and nonpolar constituents of the plant showing antimicrobial and anti-plasmodial activities against Streptococcus agalactiae, Candida krusei, and others. Evidence is preclinical and limited to in vitro studies.

5.7 Analgesic Activity

In laboratory studies, the acetone/IPA extract was found to have anti-inflammatory activity that was time and dose-dependent. The ethanolic extract showed analgesic activity that was dose-dependent. No human analgesic trials have been conducted.

5.8 Antioxidant Activity

Extracts of P. marsupium have been reported to possess a wide range of biological activities including antioxidant activity. Pterostilbene, an active molecule from the bark of the tree, has antioxidant and anti-inflammatory properties, and a standardized extract (PME) containing 90% pterostilbene at 200 mg per day was evaluated in a clinical safety study. The clinical study showed that serum antioxidant enzyme levels were evaluated as a secondary outcome; hematological, lipid, glycemic, thyroid profiles, and liver and renal functions remained within the normal range in all participants.

6. Body Systems and Health Areas Associated with Indian Kinotree

• Endocrine / Metabolic system: Best known for antidiabetic potential and widely prescribed in traditional medicine for the management of diabetes mellitus.
• Cardiovascular system: Scientifically reported to induce hypolipidemic and cardiotonic activities.
• Hepatic system: Scientifically reported for hepatoprotective and anti-ulcer activity.
• Immune / Inflammatory system: Reported to possess anti-inflammatory and antioxidant properties.
• Gastrointestinal system: Its bark and gum are prominent for treating conditions such as stomach-ache, diarrhea, and urinary complaints.
• Ocular system: Extract shows promising results in cataract prevention in preclinical settings.
• Integumentary system (skin): Traditionally used in Ayurvedic and Unani medicine for wound healing and various skin conditions.
• Musculoskeletal / analgesic: The ethanolic extract showed dose-dependent analgesic activity in preclinical studies.

7. Dosage Forms and Dosages Reported in Studies

Dosages used in scientific investigations have varied considerably depending on the extract type, preparation, and model system. The following are dosages as stated in published sources:

• Animal studies (rodent models): Aqueous extract of P. marsupium at doses of 100 and 200 mg/kg was given orally to rats for 4 weeks. Earlier reports found P. marsupium to be non-toxic up to 8 g/kg in albino mice, and the effective dose in rats varied from 100 to 250 mg/kg.
• Human safety study (PME/Silbinol®): A randomized, double-blind, placebo-controlled study evaluated a standardized P. marsupium extract (PME) containing 90% pterostilbene at 200 mg per day in healthy adults. Sixty participants were randomized to receive PME at 100 mg or placebo capsule twice a day for two months.
• Human COX-2 inhibition study: In healthy human volunteers, oral use of 450 mg PM extract per day resulted in elevated pterostilbene levels in serum, but these were below the active concentration observed in vitro.
• Historical/traditional infusion dose: The most common traditional method was making an infusion with two drachms of kino in eight fluid ounces of boiling water, strained cold; the dose was from a fluid drachm to a fluid ounce.
• Dietary supplement formulation dose (patent-reported): When dietary supplements were administered as a daily serving size of approximately 48 grams, the formulation typically included 0.2 to 2.5 grams of P. marsupium extract product, with approximately 1.0 gram per daily serving reported as an example.

No universally accepted or regulatory-approved therapeutic dosage has been established for P. marsupium in any major pharmacopoeia or regulatory authority guidance document, and issues related to standardization and dosage persist.

8. Safety Considerations and Drug Interactions

Short-Term Safety Profile

In the two-month randomized controlled safety trial, hematological, lipid, glycemic, thyroid profiles, and liver and renal functions remained within the normal range in all participants, with no difference between the PME group and placebo.

In the COX-2 inhibition study in healthy human volunteers administered 450 mg PM extract, no changes from baseline of safety parameters were observed and no extract-related adverse events occurred.

The ethanolic extract of stem wood was found to be nontoxic in preclinical evaluation.

Known or Potential Drug Interactions

Pterocarpus marsupium may interact with medications that affect blood sugar levels. Caution is advised when combining it with anti-diabetic drugs, as it may potentiate their effects, possibly leading to hypoglycemia.

In the animal literature, PM extract (150 mg/kg body weight) combined with glibenclamide (500 μg/kg body weight) in alloxan-induced diabetic mice produced synergistic effects greater than either drug individually in regulating hyperglycemia. While this suggests a beneficial synergistic combination in the animal model, it also implies a risk of additive hypoglycemia if combined with insulin secretagogues in clinical practice.

Toxic Constituent Note

P. marsupium contains 2,3,6-trimethyl-1,4-naphthoquinone (TM-NQ), which in vitro is a reversible monoamine oxidase inhibitor also found in tobacco leaf; it may cause skin, eye, and respiratory irritation. The clinical significance of this constituent at concentrations found in standard extracts or preparations has not been established in published human studies.

Gaps in Safety Data

Despite the plant's therapeutic promise, concerns regarding its safety and toxicity remain incompletely explored, and there is a need for comprehensive toxicological studies. Long-term toxicological data in humans are lacking, and no major governmental or intergovernmental health body (WHO, EMA, EFSA, NIH-ODS) has issued an evidence-based monograph or formal assessment of this ingredient at the time of this writing.

9. Conservation and Sustainability Note

The economic value of P. marsupium has been increasing, mainly recognised for its timber use. This species is also valuable for medicine and feed. Its genetic resource base has significantly decreased as a result of heavy historical use, and given its vulnerability to both climate change and human activity, this multipurpose tree species must be managed sustainably and conserved in its native environments.

References

• Pterocarpus marsupium: An Ethnopharmacological Treasure with Emerging Clinical Relevance — International Journal of Pharmaceutical Sciences (2026)
• A Short-Term Safety Evaluation of Silbinol® — an Extract from Pterocarpus marsupium in Healthy Adults — PMC / PubMed (PMID 37671486)
• Selective COX-2 inhibition by a Pterocarpus marsupium extract characterized by pterostilbene, and its activity in healthy human volunteers — PubMed (PMID 15931573)
• Isolation of (−)-Epicatechin from Pterocarpus marsupium and its Pharmacological Actions — PubMed (PMID 17340403)
• The study of aqueous extract of Pterocarpus marsupium Roxb. on cytokine TNF-α in type 2 diabetic rats — PMC
• Evaluation of effect of alcoholic extract of heartwood of Pterocarpus marsupium on in vitro antioxidant, anti-glycation, sorbitol accumulation and inhibition of aldose reductase activity — PMC
• Phytochemical screening and study of antioxidant, antimicrobial, antidiabetic, anti-inflammatory and analgesic activities of extracts from stem wood of Pterocarpus marsupium Roxburgh — PMC (PubMed PMID 28512598)
• Co-administration of Pterocarpus marsupium Extract and Glibenclamide Exhibits Better Effects in Regulating Hyperglycemia — PubMed (PMID 36366849)
• Therapy with methanolic extract of Pterocarpus marsupium Roxb and Ocimum sanctum Linn reverses dyslipidemia and oxidative stress in alloxan induced type I diabetic rat model — PubMed (PMID 21106356)
• A molecular connection of Pterocarpus marsupium, Eugenia jambolana and Gymnema sylvestre with dipeptidyl peptidase-4 in the treatment of diabetes — PubMed (PMID 24074231)
• Potential benefits of Pterocarpus marsupium heartwood extract on high fat diet induced rodent model of atherosclerosis — PubMed (PMID 41503798)
• Pterocarpus marsupium — ScienceDirect Topics overview
• Review on phytochemistry and pharmacology of Pterocarpus marsupium: A journey of traditional medicine — ScienceDirect (2026)
• Antidiabetic Effects of Pterocarpus marsupium (Gammalu) — ResearchGate
• Pharmacology of Pterocarpus marsupium Roxb — Medicinal Plant Research
• Pterocarpus marsupium: Bridging the Gap Between Traditional Medicine and Modern Pharmacology — Journal of Population Therapeutics and Clinical Pharmacology
• Pterocarpus marsupium — Wikipedia (for nomenclature and distribution)
• Pterocarpus marsupium — Auroville Herbarium (nomenclature)
• Indian kino tree (Pterocarpus marsupium): propagation, micropropagation, and biotechnology — ResearchGate
• A Pharmacognostic, phytochemical and pharmacological review of Pterocarpus marsupium — Journal of Drug Delivery and Therapeutics
• The ancient healing power of Pterocarpus marsupium — Flora Journal (2024)
• Pterocarpus Marsupium. Kino. — Henriette's Herbal Homepage (Eclectic historical pharmacopoeia)
• Kino — U.S. and British Pharmacopoeia historical entry, Henriette's Herbal
• Indian kino: Blood Sugar Support, Antioxidant Benefits, Dosage, and Safety — VitaLibrary