Antioxidative and Immunomodulatory Activities of the Exopolysaccharides from Submerged Culture of Hen of the Woods or Maitake Culinary-Medicinal Mushroom, Grifola frondosa (Agaricomycetes) by Addition of Rhizoma gastrodiae Extract and Its Main Components.

Grifola frondosa (hen of the woods or maitake) is a famous culinary-medicinal mushroom, and its exopolysaccharides (EPSs) have biological activities with or without supplementation with exogenous additives. In this study, a Rhizoma gastrodiae extract was added to a G. frondosa fermentation system. P-hydroxylbenzaldehyde (HBA), the main product of R. gastrodiae, had the highest utilization rate in the fermentation process (42%). In addition, the EPSs of G. frondosa after addition of R. gastrodiae extract (REPS), of HBA (HEPS), or of a standard solution according to the main component ratio of R. gastrodiae extract (CEPS) were obtained. We then determined the antioxidant and immunomodulatory activities of EPS, REPS, HEPS, and CEPS. Overall, REPS showed the highest antioxidant activities compared with EPS and HEPS (P < 0.05) but similar to that of CEPS (P > 0.05). The half-inhibitory concentration (ED50) values of REPS (< 4 mg/mL) were lower than those of EPS, HEPS, and CEPS. Moreover, REPS was better able to stimulate phagocytosis and nitric oxide production of RAW 264.7 macrophages than were the others, without a significant difference from CEPS (P > 0.05). An interesting and important finding is that a R. gastrodiae extract can increase antioxidant and immunomodulatory activities of EPS preparations from G. frondosa, and the standard solution of the main components of the R. gastrodiae extract may be better for simulating fermentation performed by G. frondosa and biological activities of its major products.

Experimental analysis on the main contents of Rhizoma gastrodiae extract and inter-transformation throughout the fermentation process of Grifola frondosa.

Gastrodin (GA), p-hydroxylbenzaldehyde (HBA), p-hydroxybenzyl alcohol (gastrodigenin, HA) and parishin not only are the major active ingredients of Rhizoma gastrodiae, but exist transformed relations from each other throughout the fermentation process of Grifola frondosa in this work. We had found that parishin (non-free gastrodin) almost could completely transformed into gastrodin (GA, free gastrodin) after R. gastrodiae alcohol extract was sterilized by moist heat (121 °C, 30 min), but before was added into submerged cultivation of G. frondosa. However, interestingly and importantly, gastrodin re-synthesized of parishin after R. gastrodiae alcohol extract's addition into submerged cultivation of G. frondosa. In addition, the reduction of p-hydroxylbenzaldehyde and p-hydroxybenzyl alcohol in G. frondosa fermentation process reconfirmed that the G. frondosa strain 51616 really could synthesize gastrodin into parishin by submerged fermentation. This paper firstly also reported G. frondosa's effects on R. gastrodiae.

Enhancement of mycelial growth and polysaccharide production in Ganoderma lucidum (the Chinese medicinal fungus, 'Lingzhi') by the addition of ethanol.

Methanol, ethanol, 1-propanol and 2-propanol, at 1.5% (v/v), enhanced the growth and polysaccharide production of Ganoderma lucidum. Ethanol was the most effective at 1.5% (v/v) for increasing the biomass production, however, the maximal polysaccharide concentration was produced with 2% (v/v) ethanol in the medium. There was no new polysaccharide component produced by the addition of ethanol.