In-vitro Antimicrobial, Antioxidant, and Anticancer Activity of Canarium zeylanicum, Pterocarpus marsupium, and Dipterocarpus zeylanicus Resins

Abstract

Background: Sri Lanka is home to numerous endemic plant species with potential therapeutic benefits. These plants are sources for novel chemical compounds with biological activity. This study investigates the biological properties of resins from three endemic plants, an area that has received limited scientific attention. Objectives: To evaluate antimicrobial, antioxidant, and anticancer activities of Canarium zeynalicum (Kekuna), Pterocarpus marsupium (Gammalu), and Dipterocarpus zeylanicus (Hora) resins Methods: Crude extract of resins from Canarium zeylanicum, Dipterocarpus zeylanicus and Pterocarpus marsupium were prepared via sequential extraction using hexane, ethyl acetate, and methanol separately. Antimicrobial assays were done by agar disk diffusion method against Gram- positive Staphylococcus aureus, Bacillus subtilis, Gram-negative Pseudomonas aeruginosa, Escherichia coli, and fungal species Candida albicans, Candida tropicalis. Gentamicin and fluconazole were used as positive controls for antibacterial and antifungal assays, respectively; solvent-only discs served as negative controls. Antioxidant activity was evaluated by 2,2- diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method with ascorbic acid as a reference over a concentration range of 10 - 0.08 mg/mL. The anticancer potency of crude extracts (50-0.4 mg/mL) was assessed on BT-474 breast cancer cells, with cell viability assessed by dimethylthiazol-carboxymethoxyphenyl-sulfophenyl-tetrazolium assay. Results: All extracts showed antimicrobial activity against at least one of the microbes tested. Methanol extract of P. marsupium displayed the strongest inhibition against Gram-positives, S. aureus (17.2±0.2 mm) and fungi C. albicans (15.1±0.1 mm), while ethyl acetate extract of C. zeylanicum was most effective against Gram-negatives, P. aeruginosa (14.2±0.2 mm). The methanol extract of P. marsupium showed an excellent DPPH radical scavenging activity (IC50: 0.011 mg/mL). All extracts showed anticancer activity. The highest anticancer activity was in the D. zeylanicus hexane extract, even at 0.4 mg/mL level. Conclusions: The crude resin extracts showed antimicrobial, antioxidant, and anticancer properties. These results highlight the importance of further research to isolate and characterize novel bioactive compounds.