Evaluating Biological Activities Of Crude Polysaccharides Extracted From Mycelia Of Ganoderma Species Collected From Vietnam.

Abstract

Ganoderma species have been known for their bioactivities. One of the bioactive compounds from them is polysaccharides. Conventionally, fruiting bodies of Ganoderma species are used. However, as it takes time to cultivate the fruiting bodies and they also form with limited numbers under nature condition. In addition, initial study suggested that mycelia of Ganoderma would contain the same bioactive polysaccharides as the fruiting bodies and it takes much shorter time to culture the mycelia. Thus, the major purposes of this study was to investigate bioactivities of crude polysaccharides extracted from mycelia of select Ganoderma species collected from Vietnam including Ganoderma sinense and an unidentified red reishi. The evaluated bioactivities are antioxidant, antimicrobial and α-glucosidase inhibitory activities. The mycelial biomass production of G. sinense and the unidentified red reishi obtained after three weeks were 1.26 g/L and 1.09 g/L, respectively. In term of crude polysaccharides production from the mycelia, their amounts were 2.58% and 2.27%, respectively. Although there were no antimicrobial and alpha-glucosidase inhibitory activities observed from the crude polysaccharides extracted of both two species, they were found to possess antioxidant activities, which was determined by using DPPH test. IC50 value of the crude polysaccharides extracted from mycelia of G. sinense was 7.49mg/ml and that of the unidentified red reishi was 9.45mg/ml. In term of cytotoxicity, the crude polysaccharides were tested against two human cancer cell lines including HeLa and MCF7 by Sulforhodamine B (SRB) assay. The results showed that both the two samples could slightly inhibit MCF7, but they have none inhibition towards HeLa cell growth. The results from this current study suggest that even though the amounts of mycelial polysaccharides are higher than those of fruiting bodies of the same studied species, but they do not necessarily possess the same bioactivities. This would need further study for confirmation, but more caution should be taken in consideration when replacing medicinal Ganoderma fruiting bodies with their mycelia.