Betulinic acid prevents alcohol-induced liver damage by improving the antioxidant system in mice

Betulinic acid (BA), a pentacyclic lupane-type triterpene, has a wide range of bioactivities. The main objective of this work was to evaluate the hepatoprotective activity of BA and the potential mechanism underlying the ability of this compound to prevent liver damage induced by alcohol in vivo. Mice were given oral doses of BA (0.25, 0.5, and 1.0 mg/kg) daily for 14 days, and induced liver injury by feeding 50% alcohol orally at the dosage of 10 ml/kg after 1 h last administration of BA. BA pretreatment significantly reduced the serum levels of alanine transaminase, aspartate transaminase, total cholesterol, and triacylglycerides in a dose-dependent manner in the mice administered alcohol. Hepatic levels of glutathione, superoxide dismutase, glutathione peroxidase, and catalase were remarkably increased, while malondialdehyde contents and microvesicular steatosis in the liver were decreased by BA in a dose-dependent manner after alcohol-induced liver injury. These findings suggest that the mechanism underlying the hepatoprotective effects of BA might be due to increased antioxidant capacity, mainly through improvement of the tissue redox system, maintenance of the antioxidant system, and decreased lipid peroxidation in the liver.

Gossypol acetic acid induces apoptosis in RAW264.7 cells via a caspase-dependent mitochondrial signaling pathway

To investigate the effects of gossypol acetic acid (GA) on proliferation and apoptosis of the macrophage cell line RAW264.7 and further understand the possible underlying mechanism responsible for GA-induced cell apoptosis, RAW264.7 cells were treated with GA (25~35 micromol/L) for 24 h and the cytotoxicity was determined by MTT assay, while apoptotic cells were identified by TUNEL assay, acridine orange/ethidium bromide staining and flow cytometry. Moreover, mitochondrial membrane potential (DeltaPsi(m)) with Rhodamine 123 and reactive oxygen species (ROS) with DCFH-DA were analyzed by fluorescence spectrofluorometry. In addition, the expression of caspase-3 and caspase-9 was assessed by Western Blot assay. Finally, the GA-induced cell apoptosis was evaluated by flow cytometry in the present of caspase inhibitors Z-VAD-FMK and Ac-LEHD-FMK, respectively. GA significantly inhibited the proliferation of RAW264.7 cells in a dose-dependent manner, and caused obvious cell apoptosis and a loss of DeltaPsi(m) in RAW264.7 cells. Moreover, the ROS production in cells was elevated, and the levels of activated caspase-3 and caspase-9 were up-regulated in a dose-dependent manner. Notably, GA-induced cell apoptosis was markedly inhibited by caspase inhibitors. These results suggest that GA-induced RAW264.7 cell apoptosis may be mediated via a caspase-dependent mitochondrial signaling pathway.

Synthesis and identification of penicillic-acid antigens from Penicillium cyclopium / 生物工程学报

To establish a new immune assay for Penicillic Acid (PA) from Penicillium cyclopium, we studied the synthesis of conjugated complete antigens for penicillic acid. PA was conjugated to bovine serum album (BSA) and ovalbumin (OVA) by 1-ethyl-3-(3-dimethyl-aminopropyl) carbodiimide hydrochloride (EDC). The artificial antigens PA-BSA and PA-OVA were identified by ultraviolet spectrometric scanning, SDS-PAGE and immunization. Results showed that the absorption peak of conjugation were different from that of the carrier protein alone and of the PA. The conjugated ratio of PA and BSA was 23.2:1 and that of PA and OVA was 10.4:1. Balb/c mice were immunized by the artificial antigen of PA-BSA, with PA-OVA as coating antigen. The average titer of antiserums was more than 12 800 by indirect ELISA. The obtained antigens offered a basis for developing immunoassay method.