Exploring the Cosmeceutical Potential of Six Malaysian Indigenous Tropical Fruit Trees: Radical Scavenging, Anti-Tyrosinase, and Photoprotective Activities Evaluation.

Malaysian indigenous tropical fruit trees have been reported to possess various biological activities, but remain largely underutilized. This study aims to investigate the skin-lightening cosmeceutical potential of six Malaysian indigenous tropical fruit trees, namely Averrhoa bilimbi, Baccaurea motleyana, Bouea macrophylla, Cynometra cauliflora, Garcinia celebica, and Syzygium malaccense. Herein, crude ethanol and its fractionated extracts (hexane, chloroform, and ethyl acetate) from the leaves and twigs were evaluated for total phenolic content (TPC), radical scavenging, tyrosinase inhibitory activity, and sun protection factor (SPF) values. The results revealed that B. macrophylla leaf ethyl acetate fractionated extract exhibited the highest TPC (577.47 ± 16.15 mg GAE/g extract), very strong radical scavenging activity (EC50 < 50 µg/mL) across DPPH•, ABTS•+, and superoxide anion (O2 •-) assays, as well as the highest SPF value (28.64 ± 0.51). Liquid chromatography-mass spectrometry (LC-MS) analysis identified the presence of m-trigallic acid (1), cis-coutaric acid (2), and ellagic acid (3), which may contribute to its noticeable bioactivities. Meanwhile, B. macrophylla twig ethanol extract exhibited the strongest mushroom tyrosinase inhibitory activity (IC50 55.51 ± 1.99 µg/mL). Collectively, these findings suggest that the twig ethanol extract and leaf ethyl acetate fractionated extract of B. macrophylla are promising natural ingredients for potential skin-lightening cosmeceutical applications.