Extraction and purification of total flavonoids from Cannabis sativa fibers and their evaluation for antioxidant and antibacterial activities

Abstract

Extraction and purification of total flavonoids from cannabis fiber extracts were studied by using ethyl acetate and three different resins. The results indicated that the HPD-500 resin was appropriate and its adsorption data were well fitted to pseudo-second-order kinetics model. Purified with HPD-500, 8.36% purity of flavonoids can be obtained. The chemical structure showed that the flavonoid extracts had C=C, C-H, C-O and rutin derivatives. The thermal decomposition of Cannabis sativa fiber extracts can be divided into four stages, which was in agreement with the thermal decomposition properties of flavonoids in the literature. The shielding effect of polyvinyl alcohol (PVA) on ultraviolet-visible light was enhanced by the addition of flavonoid extracts, and the transmittance decreased from 82.89% to 59.12%. The results of antioxidant activities of the HPD-500 purified flavonoids showed that ·DPPH radical scavenging increased from 10.18% to 17.19% and ·O2− increased from 5.09% to 8.97% correspondingly. The results of antibacterial testing showed that the antibacterial activities of PVA with purified flavonoids were 63% higher than that of PVA without flavonoids. This indicated that the purified flavonoids from hemp fibers can be used as a source of potential antioxidant and antibacterial agents.