Biological Activities of Triterpenoids and Phenolic Compounds from <i>Myrica</i> <i>cerifera</i> Bark

Seven triterpenoids, 1 – 7 , two diarylheptanoids, 8 and 9 , four phenolic compounds, 10 – 13 , and three other compounds, 14 – 16 , were isolated from the hexane and Me OH extracts of the bark of Myrica cerifera L. (Myricaceae). Among these compounds, betulin ( 1 ), ursolic acid ( 3 ), and myricanol ( 8 ) exhibited cytotoxic activities against HL 60 (leukemia), A549 (lung), and SK ‐ BR ‐3 (breast) human cancer cell lines ( IC 50 3.1 – 24.2 μ m ). Compound 8 induced apoptotic cell death in HL 60 cells ( IC 50 5.3 μ m ) upon evaluation of the apoptosis‐inducing activity by flow cytometric analysis and by Hoechst 33342 staining method. Western blot analysis on HL 60 cells revealed that 8 activated caspases‐3, ‐8, and ‐9 suggesting that 8 induced apoptosis via both mitochondrial and death receptor pathways in HL 60. Upon evaluation of the melanogenesis‐inhibitory activity in B16 melanoma cells induced with α ‐melanocyte‐stimulating hormone ( α ‐ MSH ), erythrodiol ( 7 ), 4‐hydroxy‐2‐methoxyphenyl β ‐ d ‐glucopyranoside ( 13 ), and butyl quinate ( 15 ) exhibited inhibitory effects (65.4 – 86.0% melanin content) with no, or almost no, toxicity to the cells (85.9 – 107.4% cell viability) at 100 μ m concentration. In addition, 8 , myricanone ( 9 ), myricitrin ( 10 ), protocatechuic acid ( 11 ), and gallic acid ( 12 ) revealed potent DPPH radical‐scavenging activities ( IC 50 6.9 – 20.5 μ m ).

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