RESUMO
The response surface methodology was used to optimise the extraction conditions of Ganoderma lucidum based on a Box-Behnken design. A quadratic model sufficiently simulated the response of ganoderic acid H with a determination coefficient (R(2)) of 0.98. The optimal condition for extracting triterpenoids was determined to be 100.00% ethanol at 60.22°C for 6.00 h, under which the yield of the reference triterpenoid ganoderic acid H increased from 0.88 to 2.09 mg/g powder. Following extraction, triterpenoid-enriched fraction was further isolated into 23 fractions, and 7 fractions were identified as ganoderic acids A, B, D, G, H and I and ganoderenic acid D. Of the seven triterpenoids, ganoderenic acid D was most cytotoxic with IC50 values of 0.14 ± 0.01, 0.18 ± 0.02 and 0.26 ± 0.03 mg/mL in Hep G2, Hela and Caco-2 cells, respectively. While ganoderic acids A, G and H were relatively non-cytotoxic. The variation of inhibitory effects for these triterpenoids was likely related to their chemical structures.
