Effects of isoimperatorin on proliferation and apoptosis of human gastric carcinoma cells.

Resistance to apoptosis is an characteristic of cancer cells that serves a critical function in tumor development and represents a target for antitumor therapy. Isoimperatorin (ISOIM), a coumarin compound, exhibits antitumor functions in multiple types of tumor cells. However, its antitumor effects and molecular mechanisms with respect to gastric cancer have not been elucidated. The present study assessed the anti-proliferative and apoptotic effects of ISOIM on human BGC-823 gastric cancer cells and elucidated its underlying molecular mechanisms. Cell proliferation was evaluated using MTT assays. Analysis of cell morphology was performed by hematoxylin and eosin, Hoechst 33258 and acridine orange/ethidium bromide staining. In addition, cell cycle and apoptosis was evaluated using flow cytometry analysis; expression of apoptosis-associated proteins was studied by western blotting. The results of the present study revealed that ISOIM significantly inhibited cell proliferation by arresting the cell cycle at the G2/M phase and induced apoptosis by increasing Bcl-2-associated X (Bax) expression with a concomitant decrease in Bcl-2 expression, resulting in a decreased Bcl-2/Bax ratio compared with the control. In addition, ISOIM treatment also resulted in cytochrome c translocating from the mitochondria to the cytosol. Furthermore, caspase-3 was significantly activated in response to treatment with ISOIM, suggesting that apoptosis in BGC-823 cells is induced in the mitochondrial pathway. Taken together, the results of the present study indicate that ISOIM may significantly induce apoptosis in BGC-823 cells and that the pro-apoptotic mechanisms of ISOIM could be associated with the mitochondrial pathway.

In vitro antioxidant and antimicrobial activities of flavonoids from Panax notoginseng flowers.

Panax notoginseng and its flowers are both well-known traditional Chinese medicinal herbs. To date, antimicrobial and antioxidant activities of flavonoids from P. notoginseng flowers (PNF) remain unclear. In this study, antimicrobial and antioxidant activities of flavonoids from PNF were investigated. The crude flavonoids were purified using a column (25 cm × 1.5 cm) packed with AB-8 macroporous adsorption resin. Compared with ascorbic acid, the purified flavonoids excelled in scavenging activities on 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid, superoxide anion and hydroxyl radicals at 0.2-1.0 mg/mL concentration. However, flavonoids exhibited weaker reducing power than ascorbic acid at 20-100 µg/mL concentration. In addition, the flavonoids exhibited obvious inhibitory effects on Staphylococcus aureus, Aeromonas hydrophila and Pseudomonas aeruginosa. These results clearly indicate that flavonoids from PNF are effective in scavenging free radicals and have the potential to be used as antioxidants and antimicrobial agents, and also provide the theoretical data for supporting the use of PNF in food, pharmaceutical and cosmetics industries.