Cytotoxic Evaluation and Elucidation of Dammarane-Type Triterpenoids Isolated from the Exocarp of Aglaia cucullata (Meliaceae)

Aglaia cucullata is a mangrove plant with a tropical Asian distribution. It is used as traditional medicine for the treatment of diarrhea, inflammation, skin diseases, and heart diseases. Several compounds isolated from A. cucullata have demonstrated cytotoxic activity against various human cancer cells. Cancer therapies such as surgery, chemo-, and radiotherapy have many side effects. However, the use of natural bioactive compounds such as triterpenoid in cancer treatment can be used as an alternative to reduce these side effects. Therefore, the discovery of bioactive compounds from plants is very important to improve aspects of discovery and development of sustainable new anticancer drug candidates. Here, we report the chemical structures of seven known dammarane-type triterpenoids (1–7) isolated from A. cucullata exocarp and evaluate their cytotoxicity against B16-F10 melanoma skin cancer cells. The isolated compounds included cabraleahydroxylactone 3α-acetate (1), (20S)-20-hydroxydammar,24-en-3α-ol (2), (20S)-20-hydroxydammar,24-en-3-on (3), methyl 20(S)-hydroxy-3,4-secodammar-4(28),24-diene-3-oic acid (4), 3-epi ocotillol II (5), cabraleone (6), and ocotillone (7). The n-hexane extract was found to be active against B16-F10 cells, exhibiting an IC50 value of 7.85 ± 0.22 µg/mL. Fractionation of this extract subsequently identified the compound (20S)-20-hydroxydammar 24-en-3-on (3) as an active substance with an IC50 value of 21.55 ± 0.25 µM, comparing favorably with the positive control cisplatin (12.90 µg/mL; 43.00 µM). These results provide further evidence of the genus Aglaia as a source of cytotoxic cancer drug leads. In addition, compound 3 has potential as a convincing therapeutic agent for further research in the context of sustainable drug development, especially the development of new safe cancer chemotherapeutic agents.