Optimization of the extraction of polysaccharides from tobacco waste and their biological activities.

A response surface methodology was used to optimize the parameters for extracting the polysaccharides from tobacco waste (TWPs) using hot water. The extraction process, carried out under the following optimized parameters: an extraction temperature of 90°C, a ratio of water to raw material of 54, and an extraction time of 115min, allowed an experimental yield of 28.32±1.78%. The chemical composition analysis showed that TWPs were composed of mannose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose and arabinose with the following molecular ratio: 1.00:2.69:1.29:2.29:5.23:6.90:3.92. The molecular weights of its four major fractions were 0.558, 1.015, 16.286, and 151.194kDa. Bioactivity experiments showed that TWPs not only decreased the reactive oxygen species level in salt-stressed tomato seedlings, but also possessed significant antioxidant activities in vitro. Antioxidant activity in vivo further showed that TWPs could significantly increase the activities of antioxidant enzymes including superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT), and decrease the level of malondialodehyde (MDA). In addition, according to the acute toxicity test, TWPs did not cause behavioral changes or any death of mice. This study provides an effective method to utilize tobacco waste resources.