Study On The Antioxidant Activity Of Polygonum Cuspidatum Rhizoma And Osmanthus Fragrans (Thunb.) Lour Pulp

Searching for antioxidant active component from natural origins remains is one of the most important approaches in discovering natural antioxidants, and traditional medicinal plants or folk herbs have proved to be very important sources. In this thesis, antioxidant capability of Polygonum cuspidatum and Osmanthus fragrans pulp was compared and estimated by several established biochemical assays in vitro: 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals scavenging assay, 2,2'-azino-bis (3- ethylbenzothiazoline- 6-sulfonic acid) diamonium salt (ABTS) free radicals scavenging assay, reducing power assay which assess electron donation capacity and phosphomolybdenum assay which investgate total antioxidant capacity, Total phenolics content and Total flavone content.Part 1: Study on antioxidant activity of Polygonum cuspidatumPolygonum cuspidatum S. et Z. belongs to the Polygonaceae perennial herb group widely distributed in China. It was traditionally used in China and Japan as a folk medicine for the treatment of atherosclerosis and for other therapeutic purposes such as scalds, burns, laxation, a diuretic, and for the treatment of suppurative dermatitis in the oriental medicine. In this thesis, antioxidant activities of Polygonum cuspidatum ethanol extract (EE), total anthraquinones (TA) and three different acid parts were compared. It is showed that TA and strong acid part (SAP) exhibited excellent antioxidant activity than that of BHT and resveratrol. Four activities compounds were isolated from TA. There are rhein, emodin, chrysophanol and physcion. But antioxidant activities of these compounds were weaker than BHT and resveratrol expect rhein which was near to resveratrol. Therefore, the strong antioxidant activity of TA and SPA was the cooperation of all the single compounds. Moreover, TA and SPA were appended into food as a food additive. The research investigated that antioxidant activtity of TA and SPA was stronger than BHT. Hence, they are expected to be empoldered as natural antioxidants.Part 2: Study on antioxidant activity of Osmanthus fragrans pulpThe flowers, fruits and roots of O. fragrans, a species of the Oleaceae family, have been widely used in the TCM or folklore medicine to treat liver and stomach pains. Only minorty O. fragrans seeds are keeping as the seed cultivating in the becoming year. The majority of the seeds are left and regards as a waste material. And it may cause the environmental problems. In this thesis, antioxidant activities of O. fragrans was estimated and filtrated. The filtration result indicated that methanol soluble fraction (MSF) extracted from crude ethanol extract was the activity component. Furthermore, acute toxicity study in rats of provided that MSF was non-toxic (MTD (Maximum Tolerated Dose) in rat's > 34.28 g/kg). Two known compounds were isolated from the O. fragran for the first time. The structures of these compounds were identified to be Oleoside dimethyl ester (1) and salidroside (2). And the antioxidant properties of two compounds also evaluated through these established methods. Results from the antioxidant properties evaluation show that salidroside exerted powerful antioxidant activities in all test system. Therefor, salidroside had great potential as natural antioxidant. This study provides a basical date for value exploitation and utilization of O. fragran pulp.