Phytochemical Characterisation and Biological Activities of Pterocarpus santalinus L. Heartwood Extracts: Pharmacological and Cosmeceutical Perspectives

Abstract

Aim: This study characterised the phytochemical constituents of Pterocarpus santalinus L. heartwood extracts and evaluated their in vitro antioxidant, antimicrobial, anti-inflammatory, anticancer, and cosmeceutical activities. Methodology: Heartwood powder was extracted separately with methanol and ethanol using a Soxhlet apparatus. The extracts underwent qualitative phytochemical screening and high-performance liquid chromatography. Antimicrobial activity was assessed against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. Antioxidant, anti-inflammatory, and anticancer activities were evaluated using the DPPH, protein-denaturation inhibition, and MTT assays, respectively. Tyrosinase inhibition and transepidermal water-loss reduction were examined to assess cosmeceutical potential. Results: Santalin A, Santalin B, flavonoids, and lignans were detected chromatographically, while qualitative screening identified tannins, saponins, steroids, terpenoids, alkaloids, flavonoids, and phenolic compounds. The methanolic extract exhibited antioxidant activity with an IC₅₀ of 42.6 µg/mL. Inhibition zones against the tested microorganisms ranged from 15.0 ± 0.4 to 25.0 ± 0.8 mm. Protein-denaturation inhibition reached 68% at 500 µg/mL. The extract produced concentration-dependent cytotoxicity against HeLa cells, with 81.8% growth inhibition at 500 µg/mL and an IC₅₀ of 198.7 µg/mL. Tyrosinase inhibition reached 78% at 300 µg/mL, while transepidermal water loss decreased by 35% after seven days. Conclusion: The findings demonstrate multiple in vitro biological activities of the heartwood extract. Further toxicological, mechanistic, in vivo, and clinical investigations are necessary before therapeutic or cosmeceutical application.