Ancient Indian Tree Leaves Show Drug-Like Power Against Inflammation and Infection

In the forests and farmlands of Chhattisgarh, India, tribal healers have for generations turned to the kachnar tree, Bauhinia variegata, to treat wounds, fevers, infections and inflammatory complaints. Its bark, leaves, flowers and buds are boiled into decoctions, ground into powders and applied as topical remedies, yet the scientific literature has never fully explained why the plant seems to work. A new study from researchers at Guru Ghasidas Vishwavidyalaya has now subjected those folkloric claims to a rigorous, two-pronged examination, combining laboratory assays with computer simulations of how the plant’s molecules interact with human drug targets. The results, published in Discover Chemistry, suggest that the tribal reputation of kachnar rests on a genuine chemical foundation.

The research team, led by Renuka Ekka and supervised by Bharti Ahirwar, began by collecting fresh leaves from Kunkuri in the Jashpur district and having the plant formally identified by botanists at the university’s Department of Botany, where a voucher specimen was deposited for future reference. Before any biological testing could begin, the leaves underwent a full pharmacognostic workup. Thin sections of leaf and petiole were stained with safranin, mounted in glycerin and examined under the microscope, revealing a dorsiventral lamina with a single-layered upper epidermis, two to three layers of tightly packed palisade tissue and a spongy mesophyll riddled with air spaces. The petiole showed a thick collar of collenchyma, seven to nine cell layers deep, wrapped around V- or U-shaped vascular bundles sheathed in sclerenchyma, with calcium oxalate crystals scattered through the cortex.

These anatomical details matter more than they might first appear. Microscopic fingerprints, together with physicochemical parameters such as ash values, moisture content, swelling index, foaming index and extractive values, constitute the quality-control toolkit of herbal medicine. Because a plant can degrade in storage or be adulterated with inferior material, establishing a reproducible anatomical and physical profile is the first step toward turning a folk remedy into a standardized medicine. The team’s measurements of total ash, acid-insoluble ash and water-soluble ash now provide a benchmark against which future batches of kachnar leaf material can be authenticated and graded.

With the plant material authenticated, the researchers defatted the powdered leaves with petroleum ether and then ran an exhaustive ethanol extraction in a Soxhlet apparatus at 40 to 60 degrees Celsius for eight to ten hours. The dark green extract represented a yield of roughly 6.46 percent of the starting plant material. Preliminary screening confirmed the presence of alkaloids, flavonoids, saponins, tannins, proteins and carbohydrates, while glycosides and steroids were absent. Quantification proved more striking: the extract contained 446.85 milligrams of flavonoids per gram, expressed as quercetin equivalents, and 137.04 milligrams of phenolics per gram, expressed as gallic acid equivalents. Flavonoids and phenolic compounds are the chemical workhorses of plant antioxidant defense, and their abundance here hinted at potent biological activity.

Two complementary assays put that hint to the test. In the ABTS radical decolorization assay, which measures a compound’s ability to quench a stable blue-green radical cation, the extract achieved half-maximal scavenging at a concentration of 218.76 micrograms per milliliter, compared with 203.52 micrograms per milliliter for the ascorbic acid standard. The FRAP assay, which tracks the reduction of ferric iron to its ferrous form at low pH, gave a nearly identical half-maximal value of 217.59 micrograms per milliliter against 185.26 for the standard. The extract therefore fell only modestly short of pure vitamin C, a remarkable result for a crude mixture, and one that the authors attribute to the hydroxyl groups on its flavonoid payload, which donate electrons and hydrogen atoms to neutralize destructive free radicals before they can peroxidize lipids or damage DNA.

The antimicrobial results were more measured but still encouraging. Using the agar well diffusion method, the extract produced inhibition zones of 5 to 30 millimeters against Escherichia coli, and follow-up testing against Pseudomonas aeruginosa showed clear concentration-dependent activity: zones grew from 2.5 millimeters at 100 milligrams per milliliter to 8.5 millimeters at 400 milligrams per milliliter for E. coli, and from 1.0 to 5.5 millimeters for P. aeruginosa. Estimated minimum inhibitory concentrations came out at 100 milligrams per milliliter for E. coli and 50 for P. aeruginosa. The standard antibiotic tetracycline outperformed the extract, as expected, but the dose-responsive pattern supports the plant’s traditional use against infection, and the authors note that broader testing against Gram-positive organisms is needed to map the full antibacterial spectrum.

Anti-inflammatory activity was assessed with the bovine serum albumin denaturation assay, a widely used surrogate in which protection of protein structure stands in for suppression of inflammatory tissue damage. At 100 micrograms per milliliter the extract inhibited denaturation by 16.45 percent, rising to 23.28 percent at 200 and 34.21 percent at 400 micrograms per milliliter. Diclofenac sodium, the reference drug, achieved 24.6, 33.86 and 47.67 percent at the same doses. The extract trailed the drug at every concentration, yet the steep, dose-dependent curve confirmed appreciable in vitro anti-inflammatory potential, providing the experimental half of the validation the study set out to achieve.

The computational half proved even more provocative. The team docked five major kachnar flavonoids, rutin, quercetin, apigenin, kaempferol and catechin, into the catalytic pocket of cyclooxygenase-2, the enzyme whose overactivity drives prostaglandin-mediated inflammation and which diclofenac targets clinically. Every flavonoid outscored the drug. Rutin led with a binding affinity of minus 9.6 kilocalories per mole, followed by quercetin at minus 9.2, apigenin at minus 9.1 and kaempferol at minus 9.0, all well ahead of diclofenac’s minus 6.7. Rutin’s forest of hydroxyl groups forged multiple conventional hydrogen bonds with residues including Gln192, Gly354, His351, Tyr355 and Phe580, while quercetin and kaempferol anchored themselves through hydrogen bonding to Tyr130, Gly45 and Cys47 supplemented by pi-alkyl contacts with hydrophobic residues. Surface mapping of hydrogen bond donors and acceptors showed that the plant compounds complemented the binding pocket more thoroughly than diclofenac did.

Binding energy alone does not make a drug, so the researchers also ran the flavonoids through ADMET and drug-likeness prediction using SwissADME and pkCSM, screening against Lipinski’s Rule of Five. Apigenin, catechin, quercetin and kaempferol all passed, with molecular weights below 500 daltons and balanced lipophilicity between 0.53 and 3.22, and all four showed intestinal absorption above 70 percent, comparable to diclofenac. Apigenin emerged with the most favorable profile, combining moderate polarity with the highest predicted blood-brain barrier score among the flavonoids. Rutin, despite its stellar docking score, stumbled pharmacokinetically: its 610-dalton mass, high polar surface area and negative logP predicted poor absorption and negligible brain penetration, leading the authors to suggest that nano-delivery systems might rescue its bioavailability. Encouragingly, none of the compounds were predicted to inhibit the CYP3A4 or CYP2D6 metabolic enzymes, and all were flagged AMES-negative, indicating low risks of drug-drug interactions and mutagenicity.

Taken together, the study offers something rarer than another plant extract with activity in a dish: a mechanistic bridge between ethnobotanical tradition and molecular pharmacology. The same flavonoids that dominate the leaf chemistry also dominate the docking rankings, and the in vitro antioxidant, antimicrobial and anti-inflammatory results align with the computational predictions rather than sitting in isolation. The authors are careful to frame the work as a starting point rather than a finish line, calling for wider antimicrobial panels, preclinical studies and formulation development before any of these compounds reach the clinic. But the message for drug discovery is clear: when tribal healers in central India spent centuries refining their use of kachnar, they were running an experiment whose results modern science is only now learning to read, and the molecules hidden in its leaves may yet yield therapeutic leads that no laboratory would have thought to synthesize from scratch.

Subject of Research: Scientific validation of the traditional anti-inflammatory, antimicrobial and antioxidant uses of Bauhinia variegata through phytochemical analysis, in vitro assays and molecular docking

Article Title: Scientific validation of tribal medicinal claims of Bauhinia variegata (L.) through integrated In-Silico and experimental approaches

Article References: Ekka, R., & Ahirwar, B. (2026). Scientific validation of tribal medicinal claims of Bauhinia variegata (L.) through integrated In-Silico and experimental approaches. Discover Chemistry, 3(1), Article 455. https://doi.org/10.1007/s44371-026-00908-x

Image Credits: AI Generated

DOI: 10.1007/s44371-026-00908-x

Keywords: Bauhinia variegata, ethnomedicine, flavonoids, molecular docking, COX-2, ADMET, antioxidant, antimicrobial, anti-inflammatory, phytochemistry, drug discovery, tribal medicine