Degreasing Of Astragalus Complanatus Study On In Vitro Antioxidant Activity Of Ethanol Extracts

Synthetic antioxidants, such as butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) exert their effects by different mechanisms, like breaking chain reaction and scavenging reactive oxygen species. However, use of such compounds has been restricted because of their toxicity and the carcinogenic effect. Therefore, there is an increasing interest in natural antioxidants for their high-performance, low-cost and wide availability. Semen Astragali Complanati is the ripe seed of the Astragalus Complanatus R. Br, family Leguminosae. In China pharmacopeia (PRC Pharmacopeia,1990), it is indicated that the traditional Chinese herb increases Yang, acts primarily on kidney and liver channels and improves function of sexual performance. It is widely distributed in northeast, northwest and north China. Flavonoids of Semen Astragali Complanali (FAC) is pharmacologically active, and it has been demonstrated to resist aging, protect liver, inhibit platelet aggregation and enhance the central nervous system and so on. A series of functional food made from Semen Astragali Complanati has been available in the market. It has been reported that it possessed superoxide scavenging activity, but, up to now, its antioxidant activities in vitro have never been systematically studied. The present study aimed to interpret its antioxidant mechanism and facilitate utilities of Semen Astragali Complanati.The present study was performed to evaluate the antioxidant activities of Semen Astragalus Complanati in three parts as follows:The first part was to obtain the defatted ethanolic extracts from Semen Astragali Complanati (ESA), and to determine the content of active component using spectrophotometry.Second, in vitro antioxidant activities of ESA was determined in different chemical systems, includingβ-carotene/linoleic acid assay, reducing power assay, determination of scavenging activities on OPPH·/O2-/·OH, and Fe2+induced lipid peroxidation assay.Third, Hydrogen radical was used as pro-oxidant to investigate the mitochondrial protective effects of ESA against oxidative damage. This study was conducted in parallel as follows: preparation of rat liver mitochondrial using differential centrifugation in 0.25 M sucrose buffer, Fe2+/Vc or Fe2+/H2O2-induced isolated rat liver mitochondrial damage, evaluation the inhibition of mitochondrial swelling degree, the lipid peroxidation and the protein carbonyl formation by ESA, notably, to study the influence of ESA on ATPase activity and the generation of superoxide anion.The main results of this paper showed that: First, the rate of yields of ESA was 6.73%, and its main active components were sugar, ployphenols and flavonoids,44.92%,14.24% and 7.47% respectively.Second, ESA displayed strong scavenging activities on free radical in dose-dependent manner but various mechanisms in different systems. The IC50 of scavenging activities on DPPH·, O2-·,·OH were 419.1μg/mL,117.9μg/mL and 224.4μg/mL respectively. The scavenging activities of ESA on the·OH was inferior to O2-·,but better than DPPH·.Third, ESA possessed certain reducing power, which was positively correlated with concentration. As far as reducing power was concerned,4.2 mg/mL of ESA was equal to 160μg/mL of Vc or 300μg/mL of BHT. ESA significantly inhibited theβ-carotene bleaching, and the inhibition activity of ESA at 150μg/mL,600μg/mL,1200μg/mL was better than 50μg/mL of Vc in theβ-carotene/linoleic acid assay. ESA can well block the Fe2+induced lipid peroxidation chain reaction of polyunsaturated fatty acid from egg yolk, and the IC50 were 1.7 mg/mL.Forth, ESA remarkably protected mitochondrial from·OH induced oxidative damage. The possible machanisms were inhibition of·OH induced mitochondrial swelling, lipid peroxidation and the protein carbonyl formation, reduction of superoxide anion generation, as well as increasing the ATPase activity.Fifth, in vitro antioxidant activities of ESA could be comprehensive effects of flavonoids, sugar and ployphenols from ESA.In conclusion, ESA showed effective antioxidant activities. It terminated free radical chain reactions by scavenging reactive oxygen species, and counteracting active oxygen by supplying electrons and hydrogen, or by protecting mitochondrial from oxidative damage. Better stability than vitamin C and better security than BHT implied it can be developed into natural antioxidant.