No abstract

Four unusual indole-terpenoids, penerpenes A−D (1−4), along with two known ones paxilline (5) and emindole SB (6), were isolated from the marine-derived fungus Penicillium sp. KFD28. The absolute structures of 1−4 were elucidated on the basis of spectroscopic data and ECD spectra analysis along with quantum ECD calculations. Compounds 1 and 2 showed potent inhibitory activity toward protein tyrosine phosphatases (PTP1B and TCPTP). Plausible biosynthetic pathways of compounds 1−4 are proposed.

α-Mangostin, isolated from the hulls of Garcinia mangostana L., was found to have in vitro cytotoxicity against 3T3-L1 cells as well as inhibiting fatty acid synthase (FAS, EC 2.3.1.85). Our studies showed that the cytotoxicity of α-mangostin with IC50 value of 20 µM was incomplicated in apoptotic events including increase of cell membrane permeability, nuclear chromatin condensation and mitochondrial membrane potential (ΔΨm) loss. This cytotoxicity was accompanied by the reduction of FAS activity in cells and could be rescued by 50 µM or 100 µM exogenous palmitic acids, which suggested that the apoptosis of 3T3-L1 preadipocytes induced by α-mangostin was via inhibition of FAS. Futhermore, α-mangostin could suppress intracellular lipid accumulation in the differentiating adipocytes and stimulated lipolysis in mature adipocytes, which was also related to its inhibition of FAS. In addition, 3T3-L1 preadipocytes were more susceptible to the cytotoxic effect of α-mangostin than mature adipocytes. Further studies showed that α-mangostin inhibited FAS probably by stronger action on the ketoacyl synthase domain and weaker action on the acetyl/malonyl transferase domain. These findings suggested that α-mangostin might be useful for preventing or treating obesity.

Six new prenylated hydroquinones of ganocalidin A–F (1–6) and two new compounds of ganocalicine A (7) and B (8), together with sixteen known compounds (9–24) were isolated from an extract of the fruiting body of Ganoderma calidophilum.