Apoptosis induction of colorectal cancer cells HTL-9 in vitro by the transformed products of soybean isoflavones by Ganoderma lucidum.

Soybean isoflavones have been one of the potential preventive candidates for antitumor research in recent years. In this paper, we first studied the transformation of soybean isoflavones with the homogenized slurry of Ganoderma lucidum. The resultant transformed products (TSI) contained (703.21±4.35) mg/g of genistein, with transformed rates of 96.63% and 87.82% of daidzein and genistein, respectively, and TSI also could enrich the bioactive metabolites of G. lucidum. The antitumor effects of TSI on human colorectal cancer cell line HTL-9, human breast cancer cell line MCF-7, and human immortalized gastric epithelial cell line GES-1 were also studied. The 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay showed that TSI could dramatically reduce the viability rates of HTL-9 cells and MCF-7 cells without detectable cytotoxicity on GES-1 normal cells when the TSI concentration was lower than 100 µg/ml. With 100 µg/ml of TSI, HTL-9 cells were arrested in the G1 phase, and late-apoptosis was primarily induced, accompanied with partial early-apoptosis. TSI could induce primarily early-apoptosis by arresting cells in the G1 phase of MCF-7 cells. For HTL-9 cells, Western-blot and reverse-transcriptase polymerase chain reaction (RT-PCR) analysis showed that TSI (100 µg/ml) can up-regulate the expression of Bax, Caspase-3, Caspase-8, and cytochrome c (Cyto-c), indicating that TSI could induce cell apoptosis mainly through the mitochondrial pathway. In addition, the expression of p53 was up-regulated, while the expression of Survivin and nuclear factor κB (NF-κB) was down-regulated. All these results showed that TSI could induce apoptosis of HTL-9 cells by the regulation of multiple apoptosis-related genes.

Submerged fermentation production and characterization of intracellular triterpenoids from Ganoderma lucidum using HPLC-ESI-MS.

As the main bioactive metabolites of Ganoderma lucidum, triterpenoids have various pharmacological effects. In this paper, the nutritional requirements and culture conditions of a submerged culture of G. lucidum were optimized using the response surface methodology; maximum mycelia biomass and intracellular triterpenoid production reached 1.87 g/100 ml and 93.21 mg/100 ml, respectively, for a culture consisting of wort 4.10% (0.041 g/ml) and yeast extract 1.89% (0.0189 g/ml), pH 5.40. For the first time, we established that wort, which is cheap and abundant, can replace the more commonly used glucose as the sole source of carbohydrate. Using high-performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS), 10 major ganoderic acids were tentatively identified based on the predominant fragmentation pathways with the elimination of H2O and CO2, as well as cleavage of the D-ring.