Cellulase-assisted extraction of polysaccharides from Malva sylvestris: Process optimization and potential functionalities.

Enzyme-assisted extraction process of the water-soluble Malva sylvestris polysaccharides (MSPs) was optimized using response surface methodology (RSM). The highest yield (10.40%) of MSPs was achieved at 5.64% cellulase, 55.65°C temperature, 3.4h time, and 5.22 pH. Three homogeneous polysaccharide fractions (MSP-1, MSP-2, MSP-3) were purified by DEAE-cellulose and Sephadex G-100 chromatography, which were composed of galactose, glucuronic acid, arabinose, rhamnose and mannose in different molar ratios with molecular weight range of 2.6×105-8.8×105Da. The fractions could significantly increase antioxidant, antitumor and antimicrobial activities in a dose-dependent pattern. MSP-2 revealed stronger antioxidant activities than MSP-1 and MSP-3, including reducing power and scavenging activity of DPPH and OH radicals. The antiproliferative activity of MSP-2 (1.0mg/mL) on the growth of A549 and HepG2 cells was 45.1% and 53.2%, respectively. The Gram-positive bacteria (Bacillus cereus PTCC 1015 and Staphylococcus aureus PTCC 1112) compared with Gram-negative ones (Escherichia coli PTCC 1763 and Salmonella typhimurium PTCC 1709) showed less sensitivity against the various MSPs (3-15mg/mL).