IngredientsPterocarposide is a rare phytochemical belonging to the isoaurone class of natural compounds, specifically an isoaurone C-glucoside. It was isolated as an isoaurone C-glucoside — the first compound of this type — from an aqueous extract of the heartwood of Pterocarpus marsupium. The isolation and structure elucidation of this novel chemical entity, named pterocarposide, was first reported by Handa and colleagues in 2000.
Naturally occurring 2(3H)-benzofuranones are extremely rare, and no prior literature reported the natural occurrence of 2(3H)-benzofuranone glycosides — either C–C or C–O linked. Thus, pterocarposide is the first naturally occurring isoaurone glycoside.
Pterocarposide has been assigned CAS registry number 264876-26-8 and was disclosed as a C-glycoside isolated from Pterocarpus marsupium in a European patent application. Its molecular formula is C₂₁H₂₀O₉, confirmed by mass spectrometry and NMR. Spectroscopic data revealed the unique structure of pterocarposide, including a C-glucose moiety.
Pterocarpus marsupium Roxb., also known as Indian Kino or Bija Sar, is the primary botanical source of pterocarposide. Pterocarpus marsupium is a deciduous tree native to parts of India, Nepal, and Sri Lanka. The tree belongs to the family Fabaceae (Leguminosae) and can reach considerable heights; it is a large deciduous tree that can reach heights of 30 meters.
Other constituents of Pterocarpus marsupium include pterocarpol, a novel C-glucoside identified as 1-(2′,6′-dihydroxyphenyl)-β-D-glucopyranoside, pterocarposide, Vijayosin, marsuposide, flavon C-glucoside, C-β-D-glucopyranosyl-2,6-dihydroxyl benzene, B-eudesmol, triterpene alcohol, and erythrodiol-3-monoacetate. The plant contains many flavonoids, glycosides, catechins, stilbenoids, and tannins that exhibit therapeutic properties.
The original isolation procedure used 5 kg of powdered heartwood of Pterocarpus marsupium, which was exhaustively extracted with hot water (4 × 16 litres). The concentrated extract (500 g) was suspended in water and successively partitioned with ethyl acetate and n-butanol. This procedure yielded 160 mg of pterocarposide via aqueous extraction and chromatography. The structure was arrived at using spectroscopic data.
In more recent isolation work, the isolation of phytoconstituents from the bark of Pterocarpus marsupium was accomplished by column chromatography, yielding pterocarposide as a yellow powder alongside sabioside (a creamish powder) and pterostilbene (a white powder). These isolated compounds were initially identified by thin-layer chromatography (TLC) followed by IR, 1D NMR, 2D NMR, and mass spectrometric analysis.
Several phytochemical constituents of plants in the genus Pterocarpus have been reported, including flavonoids, isoflavonoids, terpenoids, phenolic acids, and fatty acids. Bioactive compounds found in P. marsupium include flavonoids, tannins, terpenoids, and newly identified constituents like pterocarposide and sabioside. Pterocarposide is notable as the sole representative of a structurally unprecedented class of natural product — the isoaurone C-glycosides — and is considered one of the marker compounds of the heartwood/bark.
In the Indian Ayurvedic system of medicine, the heartwood of Bijasar (Pterocarpus marsupium; family Leguminosae) has been extensively used to treat diabetes mellitus. The use of Vijaysar (the common Ayurvedic name for P. marsupium) dates back over two millennia, with references found in the Charaka Samhita and Sushruta Samhita.
According to Ayurvedic texts, the heartwood of Pterocarpus marsupium Roxb. is used in the treatment of Krimiroga (worm infestation), Kustha (leprosy), Prameha (diabetes), Pandu (anemia), and Medodosa (obesity). The heartwood was used as a depurative, hemostatic, and rejuvenating agent, and was employed to treat many life-threatening diseases such as diabetes, bronchitis, and leprosy.
Within the Sushruta Samhita (Chikitsa Sthana, 6th chapter), Bijaka (Vijaysar) is recommended for all skin diseases, and was applied as a general skin tonic over extended periods of 3–4 months to treat chronic skin diseases such as vitiligo, eczema, and psoriasis.
The extract has been prepared using many methods, including infusion, maceration, decoction, and percolation. A particularly well-known and widely practiced traditional preparation involves the use of heartwood tumblers: the heartwood was historically fashioned into special wooden tumblers, which were filled with water and left overnight. The wood is used by making a wooden "Miracle" tumbler/glass for keeping the water overnight and consuming it early in the morning to keep sugar levels under control.
Historically, the plant was used in treatment of diarrhea, toothache, fever, urinary tract, and skin infections. Heartwood extract of Pterocarpus marsupium has been used in Ayurveda to treat various diseases such as leprosy, diabetes, asthma, and bronchitis.
Species within the Pterocarpus genus, particularly P. indicus and P. santalinus, have been recorded as traditional remedies in old Indonesian herbal literature (Cabe puyang warisan nenek moyang). These plants have found application in traditional medicine for the treatment of inflammatory diseases, gonorrhoea, infection, coughs, mouth ulcers, boils, and diarrhea, as well as for pain management. Heartwood and bark have been used as antidiabetic remedies in many cultures for thousands of years.
Vernacular names for P. marsupium across different regions highlight the widespread recognition and use of this medicinal tree in traditional medicine systems including Ayurveda, Unani, and folk medicine.
Pterocarposide occupies an unusual and chemically important position in the phytochemical literature. Among naturally occurring isoaurones, only a few compounds have been reported — namely, marginalin, isoaurostatin, 4,6,4′-trihydroxyisoaurone, and pterocarposide — the first isoaurone C-glucoside. Its rarity makes it a structurally distinct marker compound within the broader polyphenolic profile of P. marsupium.
Pterocarposide, the first isoaurone C-glucoside, was isolated from Pterocarpus marsupium. As a C-glucoside, pterocarposide differs from conventional O-glucosides: in C-glycosides, the sugar moiety is bound directly through a carbon–carbon bond to the aglycone, rendering it more resistant to chemical and enzymatic hydrolysis.
Pterocarposide is one of numerous bioactive molecules found in the heartwood and bark of P. marsupium. Several chemical constituents — including pterostilbene, (−)-epicatechin, pterosupin, and marsupsin — have been identified and isolated. Pterocarposide, sabioside, and pterostilbene are three phytoconstituents co-occurring in the traditional medicinal plant Pterocarpus marsupium.
Pterostilbene, a naturally derived non-flavonoid polyphenol compound with potential therapeutic applications, is identified as a significant constituent of Pterocarpus marsupium heartwood. Each compound contributes independently and potentially synergistically to the pharmacological profile of the plant. Research into pterocarposide-specific pharmacology has developed more recently, as earlier studies predominantly examined crude extracts and other isolated compounds.
The most studied proposed mechanism for pterocarposide's biological activity is agonism at the peroxisome proliferator-activated receptor gamma (PPAR-γ). In silico molecular docking studies performed against the PPAR-γ protein and compared with the standard pharmaceutical pioglitazone demonstrated that pterocarposide showed significant interactions, with a docking interaction energy of −7.924 kcal/mol.
In TR-FRET (time-resolved fluorescence resonance energy transfer) PPAR-γ binding assays, pterocarposide exhibited an EC₅₀ value of 6.253 µM against the PPAR-γ protein. In functional in vitro assays, pterocarposide exhibited glucose uptake enhancement of 59% and lipid lowering activity of 61%.
This phytochemistry research on P. marsupium phytoconstituents showed their potential against diabetes mellitus through PPAR-γ agonism. The biological relevance of PPAR-γ engagement is well-established in the broader pharmacological literature: PPAR-γ agonists increase peripheral insulin sensitivity by increasing the transcription of genes that, in turn, increase glucose uptake; they also improve insulin-stimulated glucose disposal in muscle, increase insulin signaling, reduce circulating levels of free fatty acids, and stimulate adipocyte differentiation.
A disclosed patent composition containing pterocarposide and sabioside isolated from Pterocarpus marsupium was explored for its therapeutic potential in activating AMPK and inhibiting gluconeogenesis. Pterocarposide composition treatment at concentrations of 0.1 and 0.5 mM inhibited dexamethasone-induced glucose production in H4IIE cells, to a similar extent as that of insulin (100 nM). This gluconeogenesis inhibition via AMPK activation represents a second, complementary mechanism distinct from PPAR-γ agonism, potentially contributing to reduced hepatic glucose output.
ADME (absorption, distribution, metabolism, excretion) predictions showed that pterocarposide and sabioside might be candidates as oral drugs. The in silico studies were validated through biological studies. It should be noted, however, that in silico ADMET profiling is predictive and does not substitute for clinical pharmacokinetic studies, which have not yet been conducted specifically for pterocarposide.
While the following mechanisms have been documented for P. marsupium crude extracts and co-occurring compounds rather than for pterocarposide specifically, they provide context for the plant's overall therapeutic profile: extracts from various parts of P. marsupium exhibit antidiabetic properties including inhibition of α-amylase and α-glucosidase enzymes, augmentation of insulin secretion, and enhancement of insulin sensitivity. In vitro studies in HepG2 cells found significant decreases in oxidative stress, cell damage, and apoptosis in extract-treated cells, suggesting that the heartwood of P. marsupium offers good defense against oxidative stress and improves glucose uptake.
Research using isolated pterocarposide demonstrated potential against diabetes mellitus through PPAR-γ agonism. Pterocarposide was isolated from the bark of P. marsupium and structurally analysed by IR, 1D NMR, 2D NMR, DEPT 135° and LCMS-MS. The study employed both binding assays and functional cell-based models. Pterocarposide exhibited 59% glucose uptake in functional in vitro assays. These findings are preliminary in nature — generated in cell-based systems — and have not yet been confirmed in animal or human studies specific to the isolated compound.
Studies focusing specifically on the roles of secondary metabolites from the plant in managing diabetes are lacking. An in silico approach was presented to describe the antidiabetic potential of plant metabolites previously isolated from 70% methanol extracts of the heartwood. Seven compounds isolated from the plant were docked with ten macromolecules that are known antidiabetic targets, to calculate binding affinity and visualize ligand–receptor interactions.
Animal studies of P. marsupium extracts provide supporting — though not pterocarposide-specific — evidence for antidiabetic activity. The antidiabetic activity of various subfractions of the alcohol extract of the bark of Pterocarpus marsupium was evaluated in alloxan-induced diabetic rats, and the butanol subfraction exhibited significant antidiabetic activity; the effects on lipid profile and liver function tests were also assessed to evaluate activity in controlling diabetes-related metabolic alterations. Ethanolic seed extract of Pterocarpus marsupium at 100 mg/kg and 200 mg/kg significantly reduced blood glucose levels compared to disease control rats on days 1, 7, 14, and 21.
No randomized controlled clinical trials examining pterocarposide in isolation in humans have been identified. Clinical evidence pertains to whole-plant preparations or multicompound formulations. A prospective, open, non-randomized, interventional study enrolled 56 uncontrolled hyperglycemic (Type 2 diabetes mellitus) patients already taking oral hypoglycemic drugs. P. marsupium was used as add-on therapy with glimepiride plus metformin, or glimepiride plus metformin plus pioglitazone, for 12 weeks with four-weekly clinical review visits, at a dosage of 2–4 g/day of wood powder. At the end of treatment, mean fasting blood glucose, postprandial blood glucose, and glycosylated hemoglobin were significantly improved compared to baseline (p < 0.05), with no adverse events reported. However, the open, non-randomized design substantially limits causal inference.
Heartwood extracts of P. marsupium have traditionally been used to manage diabetes-like conditions, and numerous studies have been published to validate the plant extract's potential in treating diabetes mellitus. However, studies focusing on the roles of specific secondary metabolites — such as pterocarposide — in managing diabetes are lacking.
Evidence strength for glucose-lowering activity of pterocarposide specifically: preliminary and largely in vitro/in silico. Evidence for the parent plant extract is more extensive but still dominated by preclinical models and small, unblinded clinical studies.
In functional in vitro assays, pterocarposide showed lipid lowering activity of 61%, surpassing co-isolated sabioside (56%) and pterostilbene (19%). This was assessed in cell culture systems. At the level of whole-plant extracts, Pterocarpus marsupium showed significant decreases in triglyceride levels, serum cholesterol levels, and LDL levels, and increased HDL levels and total protein levels compared to the disease control group in animal studies.
Extracts of Pterocarpus marsupium have also shown promising results in hypertriglyceridemia.
Evidence strength for lipid-lowering activity of pterocarposide specifically: in vitro only. Animal and limited human evidence exists for the plant extract as a whole.
The plant also finds its use as a hepatoprotective agent. Preclinical studies using extracts of P. marsupium have been conducted: marker enzymes such as ALT, AST, alkaline phosphatase, lactate dehydrogenase, and bilirubin were significantly elevated in CCl₄-induced hepatotoxic rats; these enzymes were significantly decreased in groups treated with plant extract. In methanol extract-treated animals, the toxic effect of CCl₄ was controlled significantly by restoration of the levels of serum bilirubin, protein, and enzymes as compared to the normal and the standard drug silymarin-treated groups. These studies are animal-based and involve whole extracts, not pterocarposide specifically.
Evidence strength for hepatoprotection: preclinical (animal) only; no pterocarposide-specific human data.
Several investigational studies have demonstrated that the Pterocarpus genus has various pharmacological activities including analgesic, anti-diabetic, anti-inflammatory, anti-cancer, hepatoprotective, anti-microbial, anti-bacterial, anti-diarrhoeal, memory-enhancing activity, antioxidant, and anti-hyperlipidemic activity. Key biological effects documented for P. marsupium include antidiabetic, anti-inflammatory, neuroprotective, cardioprotective, and anticancer properties, with emphasis on their molecular mechanisms.
Anti-inflammatory effects reported for the broader plant extract include COX-2 inhibitory activity: studies have been reported demonstrating the ability of P. marsupium extract to act as a specific COX-2 inhibitor. No published peer-reviewed studies specifically examining pterocarposide's anti-inflammatory mechanism in isolation have been identified.
Evidence strength for anti-inflammatory activity attributed to pterocarposide specifically: not yet established; evidence exists for whole-plant preparations in preclinical models.
Methanolic extract of P. marsupium at concentrations of 23.43–93.75 µg/mL was found to be safe and effective in reducing oxyradicals in HepG2 cells; a concentration of 93.75 µg/mL improved glucose uptake efficiently. Within the literature on Pterocarpus species more broadly, free radical scavenging activity has been observed across multiple assay types. Pterocarposide itself has not been the subject of dedicated peer-reviewed antioxidant studies separate from the plant extract; antioxidant claims related to pterocarposide-containing preparations are inferred from mixed-extract data.
Evidence strength for antioxidant activity: indirect; attributed to the plant extract as a whole, not to pterocarposide as an isolated compound in validated human-relevant systems.
P. marsupium is reported to have a positive effect in the management of diarrhea, toothache, fever, urinary tract, and skin infections. Antimicrobial activity at the extract level has been documented in laboratory studies. No published studies isolating pterocarposide's contribution to antimicrobial activity from that of the broader extract have been identified in peer-reviewed sources.
Evidence strength for antimicrobial activity specifically attributable to pterocarposide: not established.
Preparations from Pterocarpus marsupium, which contains pterocarposide, have been made using methods including infusion, maceration, decoction, and percolation. The traditional wooden tumbler method — soaking heartwood pieces overnight and drinking the resulting water — represents the simplest and most culturally widespread preparation, though pterocarposide content in such preparations has not been systematically quantified in the peer-reviewed literature.
The following dosages refer to whole plant preparations (bark powder, extracts), not to isolated pterocarposide, for which human dosage data are unavailable:
For pterocarposide as an isolated compound in in vitro research, pterocarposide composition treatment at concentrations of 0.1 and 0.5 mM was used to inhibit dexamethasone-induced glucose production in H4IIE hepatoma cells. In PPAR-γ protein binding assays, pterocarposide exhibited an EC₅₀ of 6.253 µM. These concentrations are in vitro benchmarks only and cannot be directly extrapolated to human dosing.
No dedicated clinical safety studies specific to pterocarposide as an isolated compound have been identified in the peer-reviewed literature. Safety data pertain to whole-plant preparations and co-occurring compounds. In a two-month randomized, double-blind, placebo-controlled study (n = 60 healthy adults) using a standardized P. marsupium extract at 200 mg/day, the hematological, lipid, glycemic, thyroid profiles and liver and renal functions remained within the normal range in all participants, with no difference between the extract and placebo groups.
An ethanolic extract from stem wood of P. marsupium was found to be nontoxic in preclinical evaluation.
The most clinically relevant interaction concern arises from pterocarposide's proposed mechanism of action as a PPAR-γ agonist and potential inhibitor of gluconeogenesis. Combined use of the plant's preparations alongside antidiabetic pharmaceuticals may produce additive or synergistic blood glucose-lowering effects. In the observed clinical study, P. marsupium was used as add-on therapy with glimepiride plus metformin, or triple therapy including pioglitazone, for 12 weeks. While no adverse events were reported in that particular study, the combination of a PPAR-γ activating natural compound with pioglitazone (also a PPAR-γ agonist) theoretically warrants attention, though clinical data quantifying this risk remain absent.
The hypoglycaemic effects, antidyslipidaemic effects, antioxidative effects, and safety of P. marsupium heartwood and bark have been scientifically validated using a multitude of in vitro and in vivo studies. The novel action of the drug on pancreatic beta-cells and absence of acute toxicity may offer new hope for diabetics in the future.
The safety record for pterocarposide as a pure isolated compound is essentially unstudied in humans. The absence of reported toxicity in crude extract studies cannot be directly extrapolated to concentrated or isolated pterocarposide. No reproductive toxicity, genotoxicity, or long-term toxicity studies specific to pterocarposide have been identified in published literature. The compound's in silico ADMET profile was evaluated in preclinical modelling: ADME predictions showed pterocarposide might be a candidate as an oral drug. However, these are computational projections pending experimental validation.
A 2026 review highlights that P. marsupium contains diverse bioactive compounds including newly identified constituents like pterocarposide and sabioside, and that key biological effects including antidiabetic, anti-inflammatory, neuroprotective, cardioprotective, and anticancer properties are discussed with emphasis on their molecular mechanisms. Extraction methods such as solvent extraction, supercritical fluid extraction, and column chromatography are being critically examined for their efficiency in isolation of bioactive compounds.
In the near future, further investigational studies are needed to isolate and characterize the bioactive compounds present as lead molecules in drug discovery research. Heartwood extracts of P. marsupium have traditionally been used to manage diabetes-like conditions, and numerous studies have been published to validate the plant extract's potential in treating diabetes mellitus. However, studies focusing on the roles of secondary metabolites from the plant in managing diabetes are lacking.
The existing body of evidence strongly suggests that pterocarposide is a chemically distinctive and pharmacologically active natural compound, primarily characterized to date through in vitro, in silico, and preclinical models. Rigorous clinical trials examining pterocarposide as an isolated compound — with defined dosing, pharmacokinetics, safety monitoring, and comparison to standard care — have not yet been conducted and represent the primary gap in its evidence base.
Health conditions that Pterocarposide may help support.
Body systems that Pterocarposide may help support.
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