Microwave-assisted Extraction of Polysaccharides from Bamboo (Phyllostachys acuta) Leaves and their Antioxidant Activity

Polysaccharides were isolated from Phyllostachys acuta leaves by microwave-assisted extraction under various temperatures and time. The obtained polysaccharides were characterized by acid hydrolysis, the Folin-Ciocalteu method, and Fourier transform infrared spectroscopy (FTIR). The major monosaccharides presented in the extracts were arabinose (258.0 mg/g to 414.5 mg/g), galactose (167.0 mg/g to 289.2 mg/g), and glucose (157.4 mg/g to 246.7 mg/g) along with some mannose, fructose, and xylose. The total phenol yield of the bamboo leaves was 0.31 mg/g to 0.73 mg/g. The FTIR spectra revealed that the polysaccharides mostly consisted of beta-glycosidic linkages. For the cytotoxicity, the presence of polysaccharides considerably elevated the multiplication of HepG2 cells and showed no growth inhibition for the samples. For the antioxidant activities, the polysaccharides exhibited excellent abilities both in the diphenyl picrylhydrazyl radical potential (DPPH) assay and ferric reducing antioxidant potential (FRAP) assay. The results suggest that bamboo leaf polysaccharides have great potential to be applied in the food, healthcare, and pharmaceutical fields.