Evaluation of radicals scavenging, immunity-modulatory and antitumor activities of longan polysaccharides with ultrasonic extraction on in S180 tumor mice models

Longan (Dimocarpus longan Lour.) is used as a traditional edible and medicinal material in China. In this paper, the effects of polysaccharides from longan pulp with ultrasonic extraction (UELP) on the radicals scavenging, immunity-modulatory and antitumor activities in S180 tumor mice models were investigated. UELP showed excellent scavenging activity on the hydroxyl radicals and a,a-diphenyl-1-picrylhydrazyl (DPPH) radicals, and obtained the almost complete scavenging effect. UELP with medium-dose (200 mg/kg) and low-dose (100 mg/kg) had potent immune-modulatory effects in S180 tumor mice model and exhibited significant effect on delayed-type hypersensitivity (DTH) response, macrophage phagocytosis and ConA-stimulated splenocyte proliferation as compared with model control treatment (p < 0.01). The results still showed that UELP had great antitumor effects, and maximum inhibition rate was obtained at medium-dose and low-dose (200 and 100 mg/kg).