New meroterpenoid compounds from the culture of mushroom Panus lecomtei.

Two new meroterpenoid compounds (1 and 2) together with five known meroterpenoid derivatives (3-7) were isolated from solid culture of mushroom Panus lecomtei. The structures of new compounds were confirmed by the analysis of NMR and HR-ESI-MS spectroscopic data. The biosynthetic pathway of 1-7 was postulated. All isolated compounds were evaluated for antibacterial activities against Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa and Bacillus Calmette-Guérin. Compound 3 exhibited weak antibacterial activity against Bacillus Calmette-Guérin with the inhibition rate of 83.6% at 100 µmol·L-1. Other compounds showed no antibacterial activities against all tested pathogens at 100 µmol·L-1.

Interdependent nitric oxide and hydrogen peroxide independently regulate the coix seed oil-induced triterpene acid accumulation in Ganoderma lingzhi.

Recent progress has been made in adding exogenous vegetable oils in culture media to promote bioactive metabolite production in several medicinal mushrooms, but the mechanism is still unclear. In this study, we found that the vegetable oil coix seed oil (CSO) could induce the biosynthesis of triterpene acids (TAs) and also significantly increase cytoplasmic nitric oxide (NO) and hydrogen peroxide (H2O2) concentrations in the mycelium of Ganoderma lingzhi. The change in TA biosynthesis caused by CSO could be reversed by adding NO scavenger or H2O2 scavenger, and adding NO scavenger or H2O2 scavenger resulted in the reduction of the cytoplasmic H2O2 or NO concentration under CSO treatment, respectively. Moreover, adding NO scavenger or H2O2 scavenger reversed TA biosynthesis, which could be rescued by H2O2 or NO donor, respectively. Taken together, our study indicated that both NO and H2O2 were involved in the regulation of TA biosynthesis, and CSO-activated NO and H2O2 were interdependent but independently regulated the TA biosynthesis under CSO treatment in G. lingzhi.

Efficient Accumulation and In Vitro Antitumor Activities of Triterpene Acids from Submerged Batch--Cultured Lingzhi or Reishi Medicinal Mushroom, Ganoderma lucidum (Agaricomycetes).

Triterpene acids are among the major bioactive constituents of lucidum. However, submerged fermentation techniques for isolating triterpene acids from G. lucidum have not been optimized for commercial use, and the antitumor activity of the mycelial triterpene acids needs to be further proven. The aim of this work was to optimize the conditions for G. lucidum culture with respect to triterpene acid production, scaling up the process, and examining the in vitro antitumor activity of mycelial triterpene acids. The key conditions (i.e., initial pH, fermentation temperature, and rotation speed) were optimized using response surface methodology, and the in vitro antitumor activity was evaluated using the MTT method. The optimum key fermentation conditions for triterpene acid production were pH 6.0; rotation speed, 161.9 rpm; and temperature, 30.1°C, resulting in a triterpene acid yield of 291.0 mg/L in the validation experiment in a 5-L stirred bioreactor; this yield represented a 70.8% increase in titer compared with the nonoptimized conditions. Furthermore, the optimized conditions were then successfully scaled up to a production scale of 200 L, and a triterpene productivity of 47.9 mg/L/day was achieved, which is, to our knowledge, the highest reported in the large-scale fermentation of G. lucidum. In addition, the mycelial triterpene acids were found to be cytotoxic to the SMMC-7721 and SW620 cell lines in vitro. Chemical analysis showed that the key active triterpene acid compounds, ganoderic acids T and Me, predominated in the extract, at 69.2 and 41.6 mg/g, respectively. Thus, this work develops a simple and feasible batch fermentation technique for the large-scale production of antitumor triterpene acids from G. lucidum.

Improving the fermentation production of the individual key triterpene ganoderic acid me by the medicinal fungus Ganoderma lucidum in submerged culture.

Enhanced ganoderic acid Me (GA-Me, an important anti-tumor triterpene) yield was attained with the medicinal fungus Ganoderma lucidum using response surface methodology (RSM). Interactions were studied with three variables, viz. glucose, peptone and culture time using a Central Composite Design (CCD). The CCD contains a total of 20 experiments with the first 14 experiments organized in a fractional factorial design, with the experimental trails from 15 to 20 involving the replications of the central points. A polynomial model, describing the relationships between the yield of GA-Me and the three factors in a second-order equation, was developed. The model predicted the maximum GA-Me yield of 11.9 mg·L−1 for glucose, peptone, culture time values of 44.4 g·L−1, 5.0 g·L−1, 437.1 h, respectively, and a maximum GA-Me yield of 12.4 mg·L−1 was obtained in the validation experiment, which represented a 129.6% increase in titre compared to that of the non-optimized conditions. In addition, 11.4 mg·L−1 of GA-Me was obtained in a 30-L agitated fermenter under the optimized conditions, suggesting the submerged culture conditions optimized in the present study were also suitable for GA-Me production on a large scale.

Evaluation of black tea polyphenol extract against the retrogradation of starches from various plant sources.

The effects of black tea polyphenol extract (BTPE) on the retrogradation of starches from different plant sources were studied using differential scanning calorimetry (DSC) and X-ray diffraction (XRD). DSC analysis shows that the gelatinization temperature of maize starch and starches from different rice varieties increased with increasing BTPE level. After storage at 4 °C, BTPE at a concentration of 15% markedly retarded the retrogradation of maize starch and starches from different rice varieties. Native maize starch and starches from different rice varieties showed typical A-type X-ray diffraction patterns, while native potato starch showed a typical B-type X-ray diffraction pattern. Adding BTPE significantly affected the crystalline region and intensities of X-ray diffraction peaks of maize and rice starch granules. It is concluded that adding BTPE markedly inhibits the retrogradation of maize starch and starches from different rice varieties, but has no significant influence on the gelatinization and retrogradation characteristics of potato starch.