Identification and Characterization of Anticancer Compounds Targeting Apoptosis and Autophagy from Chinese Native Garcinia Species

Natural compounds from medicinal plants are important resources for drug development. Active compounds targeting apoptosis and autophagy are candidates for anti-cancer drugs. In this study, we collected Garcinia species from China and extracted them into water or ethanol fractions. Then, we performed a functional screen in search of novel apoptosis and autophagy regulators. We first characterized the anti-proliferation activity of the crude extracts on multiple cell lines. HeLa cells expressing GFP-LC3 were used to examine the effects of the crude extracts on autophagy. Their activities were confirmed by Western blots of A549 and HeLa cells. By using bioassay guided fractionation, we found that two caged prenylxanthones from Garcinia bracteata, neobractatin and isobractatin, can significantly induce apoptosis and inhibit autophagy. Our results suggest that different Garcinia species displayed various degrees of toxicity on different cancer cell lines. Furthermore, the use of a high content screening assay to screen natural products was an essential method to identify novel autophagy regulators.