Use of a single method in the extraction of the seed storage globulins from several legume species. Application to analyse structural comparisons within the major classes of globulins

In this study, a single, improved methodology was used to extract, fractionate and purify the 11S (legumin-type or related to the α-conglutin from Lupinus albus L.), 7S (vicilin-type or related to the β-conglutin from L. albus) and 2S (related to the γ-conglutin from L. albus) families of proteins from eight legume species: L. albus, Glycine max (L.) Merr., Pisum sativum L., Vicia faba L., Cicer arietinum L., Phaseolus vulgaris L., Lens culinaris Med. and Arachis hypogaea L. The sedimentation coefficients obtained varied from 1.9 to 8.1 for the γ-conglutinrelated proteins, from 5.1 to 10.5 for the β-conglutin-related proteins and from 12.0 to 14.9 for the α-conglutin-related globulins. The γ-conglutin-related proteins is the most heterogenous group. Antibodies produced against each type of γ-conglutin polypeptide chain recognize the other polypeptide chain as well as other polypeptides in the corresponding globulins from all species examined. The 7S globulins are typically composed of a large number of polypeptides, covering a wide range of molecular masses (10 to 70 kD). The presence of disulphide bonds is apparently absent and the occurrence of glycopolypeptides is not widespread. Finally, the 11S globulins are characteristically formed by a limited number of polypeptides that may be divided into a lighter group (20-25 kD) and a heavier group (35-50 kD). The presence of disulphide bonds is apparently widespread but the occurrence of glycopolypeptides seems to be relatively rare. Both the 7S family and the 11S globulins studied by immunoblotting exhibit a low level of structural similarity.     

云南球花石斛提取物体外自由基清除活性研究

目的研究药用植物球花石斛(Dendrobium thyrsiflorum)95%乙醇、石油醚、乙酸乙酯、正丁醇、甲醇5种粗提物体外自由基清除活性.方法采用DPPH自由基清除法对云南球花石斛五种提取物的体外自由基清除作用进行研究.结果球花石斛乙酸乙酯粗提物的自由基清除效果最显著,其IC50为0.11 mg/m L.结论球花石斛提取物在自由基清除活性方面有一定的应用价值,该研究工作对球花石斛的开发应用,提供一定的科学依据.     

女贞子三萜类化学成分及其体外抗氧化活性的研究

目的研究女贞子中三萜类成分及体外抗氧化活性。方法用甲醇浸提,反复硅胶柱色谱分离,并测定DPPH自由基的清除率。结果分离鉴定了4个三萜类化合物:3-乙酰齐敦果酸、19α-羟基-3-乙酰熊果酸、齐墩果酸、熊果酸,均具有清除DPPH自由基的能力。结论抗氧化活性为19α-羟基-3-乙酰熊果酸>3-乙酰齐敦果酸>熊果酸>齐墩果酸。     

Inhibition of Platelet Aggregation and In Vitro Free Radical Scavenging Activity of Dried Fruiting Bodies of Pleurotus eous

Objective: To evaluate the ethyl acetate, methanol and aqueous extracts of dried fruiting bodies of Pleurotus eous for its anti-platelet activity on human volunteer''s blood. And also to analyze the free radical scavenging property of the extracts of P.eous by using various in vitro models. Methods: Anti-platelet activity of dried fruiting bodies of P.eous was evaluated by in vitro model using blood platelets. Inhibition of platelet aggregation was monitored after pre-incubation of platelets with the crude extracts of mushroom P.eous. Antioxidant activities of extracts of P.eous were evaluated by different in vitro experiments, namely, 1, 1-diphenyl- 2-picryl hydrazyl (DPPH), superoxide, hydroxyl radical and lipid peroxide radical models. Results: Crude extracts of mushroom P.eous inhibited platelet aggregation dose-dependently which was induced by adenosine diphosphate (ADP). At a maximum concentration of 10 mg/mL, methanol extract effected 64.02% inhibition of lipid per-oxidation and 50.12% scavenging effect on superoxide anion radical. Aqueous extract of P.eous have shown 69.43% chelating ability on ferrous ions, 24.27% scavenging effect on hydroxyl radical and 49.57% scavenging effect on DPPH radical at 10 mg/mL. Increasing concentrations of the extract were found to cause progressively decreasing of the intensity of absorbance. Conclusions: Anti-platelet effects could be related in part to the polyphenolic compounds present in the extracts. Antioxidant activity results indicated the free radical scavenging property of the extracts of P.eous which might be due to the high content of phenolic compounds and flavonoids.     

Alleviation of alcoholic liver injury by betaine involves an enhancement of antioxidant defense via regulation of sulfur amino acid metabolism

Previous studies suggested that the hepatoprotective activity of betaine is associated with its effects on sulfur amino acid metabolism. We examined the mechanism by which betaine prevents the progression of alcoholic liver injury and its therapeutic potential. Rats received a liquid ethanol diet for 6 wk. Ethanol consumption elevated serum triglyceride and TNFα levels, alanine aminotransferase and aspartate aminotransferase activities, and lipid accumulation in liver. The oxyradical scavenging capacity of liver was reduced, and expression of CD14, TNFα, COX-2, and iNOS mRNAs was induced markedly. These ethanol-induced changes were all inhibited effectively by betaine supplementation. Hepatic S-adenosylmethionine, cysteine, and glutathione levels, reduced in the ethanol-fed rats, were increased by betaine supplementation. Methionine adenosyltransferase and cystathionine γ-lyase were induced, but cysteine dioxygenase was down-regulated, which appeared to account for the increment in cysteine availability for glutathione synthesis in the rats supplemented with betaine. Betaine supplementation for the final 2 wk of ethanol intake resulted in a similar degree of hepatoprotection, revealing its potential therapeutic value in alcoholic liver. It is concluded that the protective effects of betaine against alcoholic liver injury may be attributed to the fortification of antioxidant defense via improvement of impaired sulfur amino acid metabolism.     

Brain neuroprotection by scavenging blood glutamate

Excess glutamate in brain fluids characterizes acute brain insults such as traumatic brain injury and stroke. Its removal could prevent the glutamate excitotoxicity that causes long-lasting neurological deficits. As blood glutamate scavenging has been demonstrated to increase the efflux of excess glutamate from brain into blood, we tested the prediction that oxaloacetate-mediated blood glutamate scavenging causes neuroprotection in a pathological situation such as closed head injury (CHI), in which there is a well established deleterious increase of glutamate in brain fluids. We observed highly significant improvements of the neurological status of rats submitted to CHI following an intravenous treatment with 1 mmol oxaloacetate/100 g rat weight which decreases blood glutamate levels by 40%. No detectable therapeutic effect was obtained when rats were treated IV with 1 mmol oxaloacetate together with 1 mmol glutamate/100 g rat. The treatment with 0.005 mmol/100 g rat oxaloacetate was no more effective than saline but when it was combined with the intravenous administration of 0.14 nmol/100 g of recombinant glutamate-oxaloacetate transaminase, recovery was almost complete. Oxaloacetate provided neuroprotection when administered before CHI or at 60 min post CHI but not at 120 min post CHI. Since neurological recovery from CHI was highly correlated with the decrease of blood glutamate levels (r=0.89, P=0.001), we conclude that blood glutamate scavenging affords brain neuroprotection Blood glutamate scavenging may open now new therapeutic options.     

Role of plasma protein and low-molecular weight substances in the change of hydroxyl radical scavenging activity in hemodialysis patients

While it is well known that hemodialysis (HD) patients with end stage renal failure are exposed to high oxidative stress, there is not a general opinion regarding whether antioxidant activity is high or low in these patients. We evaluated the variation of plasma hydroxyl radical scavenging activity (p-HRSA) by a single-session of HD in 69 patients by using a new system, reactive flow-injection electron spin resonance. And then comparing p-HRSA with their biochemical parameters, we tried to elucidate what components affected p-HRSA in the HD patients. The average of p-HRSA significantly increased after HD and the variation of p-HRSA by HD was correlated with that of plasma total protein (TP). In 5 patients however, their p-HRSA decreased after HD, in spite of increasing TP. In pre-HD, the p-HRSA values and hydroxyl radical scavenging activity of low-molecular weight fraction of plasma were significantly higher in these 5 patients than in patients whose p-HRSA increased after HD. These 5 patients were in an inflammatory state. These findings suggest that p-HRSA is mainly affected by TP, but caution should be exercised in patients who have high p-HRSA before HD and whose p-HRSA does not increase after HD.     

Increase in the free radical scavenging activities of American ginseng by heat processing and its safety evaluation

We previously reported the increase in free radical scavenging activities of Korean ginseng (KG, Panax ginseng C.A. Meyer) by heat processing. In the United States, American ginseng (AG, Panax quinquefolium L.) is a more commonly used herbal medicine than KG, but heat processing-induced chemical and activity changes of AG are not well known. Therefore, we compared the changes in ginsenosides, total phenolic contents, Maillard reaction product (MRP) levels, and several free radical scavenging activities of AG by heat processing. In addition, a short-term toxicity assessment in rats was also conducted for the identification of certain toxic effects of AG after heat processing. As a result, the ginsenosides were deglycosylated at carbon-20 and their total contents were lowered, but the total phenolic contents and MRP levels of AG were about 2.5 and 9.3 times increased, respectively, by heat processing. In addition, all free radical scavenging activities of AG were significantly increased by heat processing. Moreover, there were no toxic signs or decreases in renal and hepatic function parameters of rats administered heat-processed AG. Therefore, heat processing, as in KG, is a useful method to enhance the free radical scavenging activities of AG by the increases in total phenolic contents and MRP levels.     

Scavenging capacity of strawberry tree (Arbutus unedo L.) leaves on free radicals

Despite strawberry tree (Arbutus unedo L.) leaves had a long use in traditional medicine due to its antiseptic, diuretic, astringent and depurative properties, the potential of their antioxidant activity are still lacking. Our study goals to assess the antioxidant and free radical scavenging potential of water, ethanol, methanol and diethyl ether extracts of A. unedo leaves. Total phenols content was achieved spectrophotometrically using Folin–Ciocalteau reagent with gallic acid as standard. Antioxidant activity was evaluated using three different methods: reducing power of iron (III)/ferricyanide complex assay, scavenging effect on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals and scavenging effect on superoxide radicals by using the PMS–NADH–nitroblue tetrazolium system. Ethanol extracts of A. unedo leaves were the highest in reducing power (IC₅₀ 232.7 μg/mL) and DPPH scavenging effect (IC₅₀ 63.2 μg/mL) followed by water extracts (with IC₅₀ of 287.7 and 73.7 μg/mL, respectively); whereas diethyl ether extracts were the lowest. In the scavenging on superoxide radical assay, methanol extracts obtained the best results (IC₅₀ 6.9 μg/mL). For all the methods tested the antioxidant activity was concentration dependent. In accordance with antioxidant activity, highest total phenols content were found in ethanol, followed by water, methanol and diethyl ether extract. The results indicated that A. unedo leaves are a potential source of natural antioxidants.