Emodin-Provoked Oxidative Stress Induces Apoptosis in Human Colon Cancer HCT116 Cells through a p53-Mitochondrial Apoptotic Pathway Emodin;Human colon cancer HCT116 cells;ROS;p53;Mitochondrial apoptosis; Emodin, a natural anthraquinone isolated from the traditional Chinese medicine Radix rhizoma Rhei, can induce apoptosis in many kinds of cancer cells. This study demonstrated that emodin induces apoptosis in human colon cancer HCT116 cells by provoking oxidative stress, which subsequently triggers a p53-mitochondrial apoptotic pathway. Emodin induced mitochondrial transmembrane potential loss, increase in Bax and decrease in Bcl-2 expression and mitochondrial translocation and release of cytochrome c to cytosol in HCT116 cells. In response to emodin-treatment, ROS increased rapidly, and subsequently p53 was overexpressed. Pretreatment with the antioxidant NAC diminished apoptosis and p53 overexpression induced by emodin. Transfecting p53 siRNA also attenuated apoptosis induced by emodin, Bax expression and mitochondrial translocation being reduced compared to treatment with emodin alone. Taken together, these results indicate that ROS is a trigger of emodin-induced apoptosis in HCT116 cells, and p53 expression increases under oxidative stress, leading to Bax-mediated mitochondrial apoptosis.

One new alkaloid, named as acremolin C (1), was isolated from static culture of Antarctic fungus, Aspergillus sydowii SP-1, in an investigation of the antimicrobial constituents of this Antarctic microorganism, and its structure was determined by spectroscopic methods. Additionally, four known compounds, cyclo-(L-Trp-L-Phe) (2), 4-hydroxyphenylacetic acid (3), (7S)-(+)-hydroxysydonic acid (4) and (7S, 11S)-(+)-12-hydroxysydonic acid (5), were isolated and identified. Biological studies disclosed that compounds 2, 4 and 5 showed moderate inhibitions against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE) as comparing to tigecycline, while compound 1 displayed weak inhibition activities against MRSA and MRSE.

Seeds of Cassia obtusifolia L. are known as homology of medicine and food material, which is a commonly consumed beverage in China. One new compound, 8-hydroxy-1,7-dimethoxy-3-methylanthracene-9,10-dione-2-O-β-d-glucoside (1), together with 11 known compounds, including seven anthraquinones (2–8), was isolated from the seeds. The 2D NMR data of compound 2 are reported for the first time. The structures of the compounds were established on the basis of 1D and 2D NMR, IR and HR-ESI-MS spectra. The cytotoxic activities of all the compounds against five cell lines (LO2, HCT-116, A549, HepG2 and SGC7901) were evaluated by using CCK8 methods. Compounds 1, 3 and 7 show moderate cytotoxicity towards HCT-116 cells compared with oxaliplatin.