Antioxidant, antibacterial and DNA protective activities of protein extracts from Ganoderma lucidum

Crude proteins of cultured mycelia and fruiting bodies of Ganoderma lucidum were investigated for antioxidant, antibacterial and DNA protective activities. It was found that the half maximal inhibitory concentration (IC50) of the mycelia protein and fruiting bodies protein extracts against 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) radical (ABTS(•+)) were 2.47 ± 0.01 and 2.77 ± 0.11 μg protein/ml and against 2,2-diphenylpicrylhydrazyl radical (DPPH(•)) were 2.5 ± 0.01 and 3.42 ± 0.01 μg protein/ml, respectively. The ferric reducing-antioxidant power (FRAP) values of those samples were 1.73 ± 0.01 and 2.62 ± 0.01 μmole trolox/μg protein respectively. Protein hydrolysates prepared by pronase exhibited a weaker antioxidant activity. Both crude proteins showed antibacterial activity, whereas only the mycelia protein extract could protect DNA damage by hydroxyl ((•)OH) radicals. This protein extract was partial purified by Diethyl amino ethyl (DEAE)-Sepharose column and Sulfopropyl (SP)-Sepharose column, obtained major protein with molecular weight about 45 kilo Dalton (kDa). In conclusion, G. lucidum protein extracts have promise potential for applications as antioxidant and antibacterial agents.