Theoretical Study of the Radical Scavenging Activity of Shikonin and Its Derivatives

A series of shikonin derivatives have been designed and their radical scavenging activity has been characterized by the B3LYP/6-31 ＋G（d） approach. The hydrogen bond properties of the studied structures were investigated using the atoms in molecules （AIM） theory. The calculated results reveal that the hydrogen bond is important for good scavenging activity. The introduction of electron-drawing （electron-donating） groups increases （decreases） the scavenging activities of radical and radical cations of shikonin derivatives. Shikonin derivatives appear to be good candidates for the single-electron-transfer mechanism, particularly for -N（CH3）2 derivative. Taking this system as an example, we present an efficient method for the investigation of radical scavenging activity from theoretical point of view. With the current work, we hope to highlight the radical scavenging activity of hydroxynaphtho- quinones derivatives and stimulate the interest for further studies and exploitation in pharmaceutical industry.

Component Analysis and Free Radicals Scavenging Activity of Physalis alkekengi L. Polysaccharide

A crude polysaccharide was extracted from Physalis alkekengi L. fruit. HPLC was used for the component analysis of the polysaccharide. The results indicate that Physalis alkekengi L. polysaccharide（PAP） was composed of rhamnose, xylose, arabinose, galactose, and glucose. Free radicals scavenging activity of PAP was studied through 3 free radicals scavenging tests. PAP exhibited high scavenging effects on OH and DPPH radicals, and both the scavenging rates were about 80%. The scavenging rate of O2^- radical was about 22%.

Syntheses and Crystal Structures of [Na(H_2O)_(1/2)]X and NH_2(CH_2CH_3)_2X and Antioxidant Activity of the Former

In order to enhance the water-solubility and biological utilization rate of chrysin, sodium 5,7-dihydroxylflavone-8-sulfonate （1, [Na（H2O）1/2]X, X = C15H9OSO3, 5,7-dihydroxylfla- vone-8-sulfonate） was synthesized and its structure was identified on the basis of NMR, FT-IR and elemental analysis. The assembly of 5,7-dihydroxylflavone-8-sulfonate with diethylamide cation afforded diethylamide 5,7-dihydroxylflavone-8-sulfonate （2, NH2（CH2CH3）2X） which was characterized by FT-IR and elemental analysis. The crystal structures of 1 and 2 were determined by X-ray single-crystal diffraction analysis. The crystal of 1 is of triclinic system, space group P1, with a = 8.5628（13）, b = 12.8916（19）, c = 13.562（2） A, α = 82.494（1）, β = 78.601（2）, γ = 84.033（2）°, C30H20Na2O15S2, Z = 2, Mr = 730.59, V = 1450.3（4） A3, Dc = 1.673 g/cm3, F（000） = 748, p = 0.295 mm^-1, the final R = 0.0641 and wR = 0.1458. The crystal of 2 crystallizes in the triclinic system, space group Pi, with a = 7.689（2）, b = 11.184（3）, c = 11.734（3） A, α = 74.268（3）, βl = 81.751（4）, γ= 87.991（3）°, C19H21NO7S, Z = 2, Mr= 407.43, V= 961.2（4） A3, Dc = 1.408 g/cm3, F（000） = 428, p = 0.210 mm^-1, the final R = 0.0484 and wR = 0.1195. In 1, the three-dimensional structure is organized into organic and inorganic regions; the flavone skeletons are stacked into organic regions by π...π staeking interactions; inorganic regions are generated by Na-O coordination bonds among sulfonate groups, coordinated water molecules and NaI. The sulfonate groups play an important role as a bridge of inorganic and organic regions. One-dimensional chain structure of 2 is extended by N-H…O hydrogen bonds and π...π stacking interactions. Furthermore, the antioxidant activity of 1 was evaluated. The scavenging activity of 1 to DPPH free radical is better than that of the parent compound chrysin.

Comparative Study of the Antioxidant Activity of Two Popular Green Tea Beverages Available in the Local Market of Saudi Arabia

Antioxidants have numerous applications due to their multiple roles in diminishing harmful effects of oxidative stress. The objective of this work was to highlight the importance of green tea by evaluating the antioxidant activity of the most popular green tea brands in Saudi Arabia, Lipton and Rabea. To our knowledge, no studies have so far been done to estimate the antioxidant activity of these brands. To determine the antioxidant activities of these two brands, 10 mg/ml of each brand was extracted and their total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, hydrogen peroxide scavenging activity, ferric reducing power and ferrous ion chelating effect were measured. The TPC of Lipton tea was 678.7 υg of gallic acid equivalents (GAE)/10mg, whereas in Rabea tea, the TPC was 647.1 υg GAE/10mg. The presence study indicated that there were no significant differences in total phenolic contents and the percentage inhibition as shown in DPPH and H2O2 assays among Lipton and Rabea green teas. Moreover, it was found that all assays have exhibited high antioxidant activity in both green teas. In conclusion, our study showed evidence for evenness and stability of the antioxidant activity of the two commercial green teas available in the markets of Saudi Arabia. Continued researches are needed to further the current knowledge on the health-promoting effects of this popular beverage using different supplements by different mechanisms.

Antioxidant Activity of Pigment Extracted from Green-Wheat-Bran

The anthocyanin pigment extracted from green-wheat-bran was studied to identify its antioxidant activity.The antioxidant activities of the pigment were evaluated by anti-lipid peroxidation,total antioxidant activity （TAA）,superoxide anion radical scavenging activity （SARSA）,active oxygen scavenging activity （AOSA）,and DPPH （1,1-diphenyl-2 picrylhydrazyl free radical） radical scavenging activity.The results showed that the pigment had higher antioxidant activity and TAA,SARSA,AOSA and DPPH.scavenging activities at a certain concentration than Vc （antiscorbutic vitamin,vitamin C）,and the capacity increased with the increase of pigment concentration.Its TAA was 51.06 U mL-1,1.73 times of Vc,and SARSA 18 025.21 U mL-1,2.26% higher than Vc,and AOSA 3 776.31 U mL-1,1.24 times of Vc.As to the DPPH.scavenging activity of the pigment,there was a trend that higher concentration performed higher activity significantly improved with the company of Vc.The pigment showed significant antioxidant activities evaluated by different assays.Results will provide a better understanding on antioxidant activity of green wheat and allow the screening or breeding of green wheat varieties with higher antioxidant activity for food processing.

Phytochemical screening and in vitro evaluation of antioxidant and antimicrobial activities of Kedrostis africana(L.)Cogn

Objective: To investigate phytochemical, antioxidant and antimicrobial activities of Kedrostis africana(K. africana).Methods: Dried tubers of K. africana were extracted in acetone, water and ethanol. The total phenol, flavonoid, proanthocyanidin and tannin contents were determined spectrometrically. The antioxidant activity was examined using 2,2-diphenyl-1-picrylhydrazyl,2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt, nitric oxide and hydrogen peroxide assays. The antimicrobial activity was determined by agar dilution method using minimum inhibitory concentration against 3 g positive and three gram negative strains while four fungal strains were also investigated.Results: Total phenol, flavonoids, proanthocyanidin and tannin contents ranged from(5.32 ± 0.01) to(10.51 ± 0.01) mg GAE/g;(42.58 ± 0.02) to(529.23 ± 0.01) mg QE/g;(15.05 ± 0.00) to(585.64 ± 0.00) mg CE/g and(0.301 ± 0.010) to(0.937 ± 0.000) mg TAE/g, respectively. The IC_(50) values of the ethanol extract for 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and hydrogen peroxide were 0.054 and 0.057 mg/mL,respectively, aqueous extract had an IC_(50) value of 0.135 7 mg/mL for nitric oxide while the acetone extract had an IC_(50) value of 0.300 mg/mL for 2,2-diphenyl-1-picrylhydrazyl.The ethanol extract demonstrated effective antimicrobial activity against the tested pathogenic species with minimum inhibitory concentrations values ranging from 2.5–5.0 mg/mL for bacteria and(0.312 5–5.000 0) mg/mL for fungi, respectively.Conclusions: The tuber of K. africana showed potent free radical scavenging property and antimicrobial activity.

Effect of pH on Antioxidant and Phytochemical Activities of Mulhatti Roots (Glycyrrhiza glabra L.)

Glycyrrhiza glabra L.is the most widely used herb in the ancient history of Ayurvedic medicine,as a medicinal value as well as an aromatic herb,and it is commonly known as Mulhatti.Mulhatti roots are useful for medically and are also a good source of phytoproducts and secondary metabolites present in Mulhatti roots are triterpenoid saponin,glycosides,glycyrrhizin,prenylated biaurone,licoaagrone,7-acetoxy-2-methylisoflavone,4-methylcoumarin,liqcoumarin,glycyrrhetinic acid,quercetin,liquiritigenin,isoliquiritigenin,etc.This study was carried out to study the evaluation of phenolic compounds,2,2-diphenyl-1-picrylhydrazyl(DPPH)free radical activity and general antioxidant capacity of water extracts of Mulhatti roots prepared at different pH values,namely 2,4,7 and 9.Data have shown great differences in terms of results.Most of the phenolic compounds are at pH 7(19.25),followed by pH 9(17.25),pH 2(14.62)and pH 4(8.89 mg GAE/g),respectively.Similarly,the flavonoid data also showed variations,the maximum has been present in pH 2(5.39),then pH 7(3.02),pH 9(1.79)and pH 4(1.40 mg CE/g),respectively.The value for DPPH IC50 free radical scavenging activity was the lowest at pH 7(82.22),followed by pH 2(110.40),pH 4(111.99)and pH 9(146.24μg/mL)and IC50 reference standard(ascorbic acid)was 59.52μg/mL in distilled water.The total capacity of the antioxidant was the highest at pH 2(9.93)followed by pH 4(5.54),pH 7(5.34)and pH 9(4.23 mg AAE/g).According to current research,pH 7 is the best for phytochemicals as well as antioxidants that catch harmful radicals.

Radical-scavenging activities of marine-derived xyloketals and related chromanes

Xyloketals,a new type of antioxidants from a marine mangrove fungus,have potential pharmacological properties.In this paper,the radical-scavenging activities of a series of synthetic xyloketals and related chromanes toward 2,2-diphenyl-1-picrylhydrazyl(DPPH)and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS)were evaluated by absorption spectrometry.One of the compounds(compound 10)displayed significant antioxidative action against DPPH and ABTS.A structure-activity analysis showed that the reactive sites on these compounds correlated with a hydroxygroup and also with ketal or aromatic H substituents.Based in part on a density functional theory(DFT)calculation of compound 10,the antioxidant mechanism of this chromane was deduced as a possible radical-scavenging mechanism by a sequential proton loss electron-transfer(SPLET)process.

Anthelmintic, antimicrobial, antioxidant and cytotoxic activity of Caltha palustris var. alba Kashmir, India

The methanolic extract obtained from the root portion of Caltha palustris var. alba was evaluated for its anthelmintic efficacy against gastrointestinal nematodes of sheep under both in vitro and in vivo conditions using worm motility inhibition(WMI) assay and fecal egg count reduction(FECR) assay, respectively. The extract was subjected to antimicrobial activity using agar-well diffusion method against different bacterial strains. In addition the extract was evaluated for cytotoxic and antioxidant activity against cultured THP-1(Leukemia), A-549(Lung), HCT-15(Colon), Cervix(HeLa) and PC-3(Prostrate) cell lines by SRB and DPPH radical scavenging assays. The extract used resulted in mean %WMI of 94.44%, as observed when the worms were put in lukewarm buffer for 30 min after exposure to different treatments. The mean mortality index of the sample was 0.95. The lethal concentration(LC50) was 0.11 mg·mL-1. Cell lines were exposed to concentration of 100 μg·mL-1 of extract for 48 h, which reduced the viability of these cell lines. The same plant extract also showed 55.58% DPPH radical scavenging activity.

A new polyphenol, 1, 3-di-O-caffeoyl-5-O-(1-methoxyl-2-O-caffeoyl-4-maloyl)-quinic acid, isolated from cultured cells of Saussurea involucrata

The present study was designed to isolate the polyphenol constituents of cultured cells of Saussurea involucrata. The polyphenol type constituents were isolated using chromatography methods, and then characterized by spectral analysis. 1,1-Diphenyl-2-picrylhydrazyl radical 2,2-Diphenyl-1-(2,4,6-trinitrophenyl)-hydrazyl(DPPH) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid(ABTS) free radical scavenging were assayed using Vitamin C as the positive control. One new polyphenol 18, 1, 3-di-O-caffeoyl-5-O-(1-methoxyl-2-O-caffeoyl-4-maloyl)-quinic acid, together with 17 known compounds, was isolated and characterized. In conclusion, Compound 18 was a new caffeoyl maloyl quinic acid type polyphenol and showed desired vitro anti-oxidant activity. Compounds 1–5, 9, 10, 14, 15, and 17 were isolated from cultured cells of Saussurea involucrata for the first time.

Nutrients and anti-nutrients of high chlorophyll-mungbean sprouts as affected by different periods of germination and sprouting stages

The variation of nutrient and anti-nutrient compounds in commercial mungbean cultivars(Chinat 72,MS-1,Chinat 80,and L3-8)during seven periods of germination and sprouting was determined.The seeds were selected randomly at 6 h of soaking(1^(st)stage),23 h(2^(nd)stage),47 h(3^(rd)stage),71 h(4^(th)stage),77 h(5^(th)stage)of sprouting,and 12 h,and 24 h of sunshine exposing(6th and 7th stage,respectively).It was found that nutrition compositions(including protein content,crude fiber content,vitamin C content,total minerals,and HCL-extractability of minerals)of all cultivars significantly increased with germination and sprouting.At the last stage,the total phenol was the highest amount which was not significantly different from all cultivars.The total antiradical capacity(%,DPPH inhibition)increased up to the maximum value in the last two stages of sprouting.The results showed that the phytic acid,the anti-nutrient component decreased with the consequence of germination,and reached the untraceable value at the last stage.In addition,the highest amount of chlorophyll(7.15-8.99 mg/100 g)was found in Chinat 72 and MS-1 cultivars at the last stage of sprouting,comparing to Chinat 80 and L3-8 cultivars.It is therefore recommended to consume high chlorophyll mungbean sprout with the benefits of high nutrient constituents and low price purchase comparing to other green vegetables.

Preparation and Characterization of Two Wood Vinegars Obtained from Hull of Spina Date Seed and Shell of Peanut

Two new kinds of wood vinegars（WVs） from the hull of spina date seed（HSDS） and the shell of peanut（PS） were prepared. 32 Major components in the two kinds of WVs were identified and determined by gas chro- matograph-mass spectrometery. The total phenolic content was determined and the antioxidant activity of the WV was measured. The total phenolic contents of PSWV and HSDSWV were 75.9 and 98.1 rag/L, respectively, when they were expressed as catechol equivalents. In 1,1-diphenyl-2-picrylhydrazyl assay, free radical scavenging activity of HSDSWV was also superior than that of PSWV. In addition, the antioxidant activities of the two kind of WVs exhibited a good positive correlation with total phenolic content, and the linear correlation coefficients ranged from 0.9594 to 0.9970. The two kind of WVs could be used in the fields of food and medicine due to their powerful antioxidant activities.

Evaluation of antioxidant activities of Hippophae rhamnoides Linn leaves extracts

Objective:To investigate the antioxidant activity of aqueous,methanol,ethanol,acetone,ethyl acetate,chloroform and n-hexane extracts of Hippophae rhamnoides(H.rhamnoides)leaves.Methods:Antioxidant activity was evaluated by using in-vitro antioxidant assays model 1,1’-diphenyl-2-picrylhydrazyl radical-scavenging activity.The antioxidant activities were compared with standard antioxidant agents such as ascorbic acid.Results:The antioxidant activities(%inhibition)of all the tested extracts were increased in the order i.e.menthol>ethanol>aqueous>acetone>chloroform>ethyl acetate>n-hexane.The methanol extract EC_(50)(μg/mL)value was compatible with vitamin C(standard).The antioxidant activity of H.rhamnoides leaves extracts increased in a dose dependent manner.Conclusions:It was observed that H.rhamnoides was a potential resource of antioxidants and thus could put off numerous radical linked diseases.