2012). In addition to seven known steroid derivatives, Gao et al. reported two new polyoxygenated steroids, namely, penicisteroids A and B (61–62) from the culture of Penicillium chrysogenum QEN-24S, an endophytic fungus of an unidentified marine red algal species of the genus Laurencia (Rhodomelaceae). Compound 61 was the first steroid having tetrahydroxy and C-16-acetoxy groups. Its absolute configuration was assigned by application check details of the modified Mosher’s method. All isolated compounds
were tested for their cytotoxicity against seven tumor cell lines. Penicisteroide A (61) displayed selective activity against epithelial carcinoma (HeLa), pancreatic carcinoma (SW1990), and lung cancer (NCI-H460) cells with IC50 values of 29.6, 61.2 and 79.1 μM, respectively, while the other compounds displayed only weak activity. Compound 61 was the strongest cytotoxic compound and it was the only steroid possessing a hydroxyl group at C-6 compared to 62 and 63, a structural feature most likely responsible for its cytotoxic activity (Gao et al. 2011a). The fungus Talaromyces flavus, which was isolated from leaves of a mangrove plant
Sonneratia apetala (Lythraceae), collected on the coastal saltmarsh of the South China Sea, afforded four new norsesquiterpene peroxides, BIBW2992 talaperoxides A-D (64–67), as well as one known analogue, steperoxide B (68). Their structures were elucidated mainly by 1D and 2D NMR as well as mass spectrometry. Furthermore, the absolute configurations of 64, 65, and 68 were obtained by single-crystal X-ray diffraction. All compounds were further evaluated for their cytotoxic activity against human cancer cell lines, including breast (MCF-7,
MDA-MB-435), hepatoma (HepG2), cervical (HeLa), and prostatic (PC-3) cancer cells, using the MTT method. Compounds 65 and 67 showed cytotoxicity toward all tested cancer cell lines with IC50 values between 2.8 and 9.4 μM. In particular, compound 67 showed promising growth inhibitory Anacetrapib Rabusertib effects towards MDA-MB-435, HepG2, and PC-3 cells with IC50 values of 3.6, 3.6 and 2.8 μM, respectively. Interestingly, when tested at a concentration of 50 μg/mL against several pathogenic microorganisms, such as Staphylococcus aureus (ATCC 27154), Escherichia coli (ATCC25922), Sarcina ventriculi (ATCC 29068), Pseudomonas aeruginosa (ATCC 25668), Candida albicans (ATCC 10231), and Aspergillus niger (ATCC 13496), none of the compounds showed inhibitory effects (Li et al. 2011a). Chemical investigation of the endophytic fungus Phomopsis sp., isolated from Alpinia malaccensis (Zingiberaceae), afforded four new cytotoxic metabolites, including benquione (69), LMA-P2 (70), LMA-P3 (71) and benquinol (72), together with four known products. 69–72 were identified based on their NMR spectra as well as by HRMS, and the absolute configuration of 70 was confirmed by X-ray crystallography. Benquoine (69) is a new 14-membered lactone generated from cyclization of benquinol (72).