OBJECTIVETo investigate the differences of total flavonoid (TF) content and antifree radical activity between the-leaves of bamboo and Gingo biloba, as well as their seasonal changes.

METHODSpectrophotometery and Chemiluminescence methods were adopted to determine TF and half inhibiting concentration (IC50) on active oxygen free radicals of the leaves of bamboo, phyllostachys nigra (Lodd. ex. Lindl.) Munro, and Ginkgo biloba. Two kinds of leaves were picked in the same plot at the same time monthly.

RESULTThe TF of bamboo leaf varied in the range of 0.67%-1.71% (in dry basis of leaf, below as same) throughout a year, the minimum apparing in June and the maximum in July, then going down obviously, and remaining at a much high lever during November to next April. However, the TF of Ginkgo bilabo leaf varied in 1.48%-2.49% during whole growing period, early April to late November. It ascended with the growth of leaf, reaching the top during June and July, the going down slowly, and finally another peak appeared before defoliation. The average IC50 values on O2-. and .OH of bamboo leaf were at 11.0 micrograms.mL-1 and 5.3 mg.mL-1, and Ginkgo biloba at 19.0 micrograms.mL-1 and 3.6 mg.mL-1, respectively.

CONCLUSIONThe TF content and anti-free radical activity the bamboo leaf are comparable with the leaf of ginkgo biloba, which is a kind of potential resources for natural antioxidant and free radical scavenger.

Flavonoids ; analysis ; pharmacology ; Free Radical Scavengers ; pharmacology ; Ginkgo biloba ; chemistry ; Plant Leaves ; chemistry ; Plants, Medicinal ; chemistry ; Poaceae ; chemistry ; Seasons

OBJECTIVETo study the chemical constituents of Dendrobium devonianum and identify the material basis components of its function, and then provide the basis for development and utilization of D. devonianum.

METHODThe constituents were separated and purified on the chromatography of silica gel, Sephadex LH-20 and RP-18 silica gel, and then their structures were elucidated based on the spectra data. ABTS method was used to evaluate the free radical scavenging activity of the phenolic compounds among them.

RESULTNine compounds were isolated and identified as 2,3,4,9-tetrahydro-1H-pyrido[3,4-b] indole-3-carboxylic acid (1), 2'-deoxythymidine (2), adenosine (3), N-trans-p-coumaroyl tyramine (4), N-trans-p-feruloyl tyramine (5), 3-methoxy-4-hydroxybenzaldehyde (6), 4-hydroxybenzaldehyde (7), 3,4-dihydroxybenzoic acid methyl ester (8), and 4-hydroxy-3,5-dimethoxybenzoic acid (9). Compound 5 showed good antioxidant activity with IC50 1. 61 mmol. L-1, Compound 9 showed weak antioxidant activity with IC50 35.72 mmol. L-1.

CONCLUSIONAll these compounds were isolated from D. devonianum for the first time. Among them, compounds 5 and 9 had some antioxidant activity.

Dendrobium ; chemistry ; Drugs, Chinese Herbal ; chemistry ; isolation & purification ; pharmacology ; Free Radical Scavengers ; chemistry ; isolation & purification ; pharmacology ; Inhibitory Concentration 50

OBJECTIVETo study the scavenging effects of Lu-Duo-Wei, thiourea, superoxide dismutase, and sodium azide on carbon disulfide-induced generation of hydroxyl radicals.

METHODSPhenanthroline-CuSO(4)-Vit C-H(2)O(2) chemiluminescence system (PHEN system) containing alcohol was established to probe the influence of various concentrations of carbon disulfide on hydroxyl radicals emission intensity and the scavenging effects of Lu-Duo-Wei and other antioxidants on carbon disulfide-induced hydroxyl radicals were observed.

RESULTSThe average emission intensity of PHEN system containing alcohol appeared lower luminescence [91.03 x 10(3) (cp6s)] and longer time (75 s) to get the peak than the system without alcohol [96.11 x 10(3) (cp6s), 55 s]. The specific scavenger of hydroxyl radical, thiourea, showed clear inhibitory effect on the system. Carbon disulfide in the range of 40 - 160 mmol/L promoted the generation of hydroxyl radical, however, this effect could be efficiently inhibited by thiourea. 160 mmol/L carbon disulfide in PHEN system without copper seemed as an activator to promote the luminescence, while in PHEN system withdrawing phenanthroline appeared some weak action of luminescence agent at low concentration. Meanwhile, Lu-Duo-Wei may efficiently scavenge hydroxyl radicals induced by carbon disulfide in PHEN system but superoxide dismutase and sodium azide had little effects on the system.

CONCLUSIONCarbon disulfide may induce PHEN system to generate hydroxyl radicals and Lu-Duo-Wei may efficiently scavenge these free radicals and play an important role in protection against oxidative injury induced by carbon disulfide.

Carbon Disulfide ; pharmacology ; Drugs, Chinese Herbal ; pharmacology ; Free Radical Scavengers ; pharmacology ; Hydroxyl Radical ; antagonists & inhibitors ; chemistry ; metabolism ; Luminescent Measurements ; Phenanthrolines ; chemistry ; Superoxide Dismutase ; pharmacology ; Thiourea ; pharmacology

Catechin and its analogues are varied and distributed widely. They have significant bioactivity on clearing free radical, anti-cancer, anti-flammatory, anti-allergic, anti-mutation, anti-aging, improving liver function, and so on. Recently, catechins (GTC) in green tea have given rise to comprehensive attention all over the world, and will have a wonderful prospect. The progress in studies of the structures, spectrum characters, resources and bioactivities of catechin and its analogues has been reviewed.
Animals ; Antineoplastic Agents, Phytogenic ; pharmacology ; Catechin ; analogs & derivatives ; chemistry ; pharmacology ; Free Radical Scavengers ; pharmacology ; Humans ; Platelet Aggregation Inhibitors ; pharmacology

OBJECTIVETo isolate and analyse the chemical composition in the essential oils and free radical scavenging activity of different crude extracts from the fresh and dry leaves of vegetable plants of Lactuca sativa L. (L. sativa).

METHODSThe essential oils and volatile chemical constituents were isolated from the fresh and dry leaves of L. sativa (lettuce) grown in Sultanate of Oman by hydro distillation method. The antioxidant activity of the crude extracts was carried out by well established free radical scavenging activity (DPPH) method.

RESULTSAbout 20 chemical compounds of different concentration representing 83.07% and 79.88% respectively were isolated and identified by gas chromatography-mass spectroscopy in the essential oils isolated from the fresh and dry leaves as α-pinene (5.11% and 4.05%), γ-cymene (2.07% and 1.92%), thymol (11.55% and 10.73%), durenol (52.00% and 49.79%), α-terpinene (1.66% and 1.34%), thymol acetate (0.99% and 0.67%), caryophyllene (2.11% and 1.98%), spathulenol (3.09% and 2.98%), camphene (4.11% and 3.65%), limonene (1.28% and 1.11%) representing these major chemical compounds. However, some other minor chemical constituents were also isolated and identified from the essential oil of lettuce including β-pinene, α-terpinolene, linalool, 4-terpineol, α-terpineol, o-methylthymol, L-alloaromadendrene and viridiflorene.

CONCLUSIONSThe chemical constituents in the essential oils from the locally grown lettuce were identified in the following classes or groups of chemical compounds such as monoterpenes, sesquiterpenes volatile organic compounds and their oxygenated hydrocarbons. Therefore, the essential oils and the crude extracts from Omani vegetable species of lettuce are active candidates which would be used as antioxidant, antifungal or antimicrobial agents in new drugs preparation for therapy of infectious diseases.

Antioxidants ; chemistry ; pharmacology ; Free Radical Scavengers ; chemistry ; pharmacology ; Gas Chromatography-Mass Spectrometry ; Humans ; Lettuce ; chemistry ; Oils, Volatile ; chemistry ; pharmacology ; Plant Extracts ; chemistry ; pharmacology ; Plant Leaves ; chemistry

OBJECTIVETo evaluate the antioxidant activities of different chemical constituents from Astragalus mongholicus Bunge and their protection against xanthine (XA)/xanthine oxidase (XO)-induced toxicity in PC12 cells.

METHODSThe compounds of Astragalus mongholicus Bunge were isolated by chromatography and the structures were elucidated on the basis of spectral data interpretation. Their antioxidant activities were detected by 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities in a cell-free system. Meanwhile, the effects against XA/XO-induced toxicity were assessed using MTT assay in PC12 cells.

RESULTSTen principal constituents were isolated and identified as formononetin (I), ononin (II), calycosin (III), calycosin-7-O-beta-D-glucoside (IV), 9,10-dimethoxypterocarpan-3-O-beta-D-glucoside (V), adenosine (VI), pinitol (VII), daucosterol (VIII), beta-sitoster (IX) and saccharose (X) from Astragalus mongholicus Bunge. The compounds I, III, and IV scavenged DPPH free radicals in vitro. Formononetin and calycosin were found to inhibit XA/XO-induced cell injury significantly, with an estimated EC50 of 50 ng/mL.

CONCLUSIONCompound II, VI, and VII are first reported in this plant. Calycosin exhibits the most potent antioxidant activity both in the cell-free system and in the cell system.

Animals ; Astragalus Plant ; chemistry ; Drugs, Chinese Herbal ; chemistry ; pharmacology ; Free Radical Scavengers ; chemistry ; pharmacology ; Free Radicals ; metabolism ; Isoflavones ; chemistry ; pharmacology ; PC12 Cells ; Rats ; Xanthine ; toxicity ; Xanthine Oxidase ; toxicity

OBJECTIVETo study the phytochemical screening of different extracts from Citrullus colocynthis (C. colocynthis ) seeds extracts and to assess their antioxidant activity on the DPPH free radical scavenging.

METHODSPhytochemical screening, total content of polyphenols and flavonoids of C. colocynthis seeds extracts, including a crude aqueous extract (E1), a defatted aqueous extract (E2), a hydromethanolic extract (HM), an ethyl acetate extract (EA) and a n-butanol extract (n-B) was carried out according to the standard methods and to assess their corresponding effect on the antioxidant activity of this plant.

RESULTSNone of these extracts contained detectable amount of alkaloid, quinone, antraquinone, or reducing sugar. Catechic tannins and flavonoids were abundant in E1, HM and EA, whilst terpenoids were abundantly present in E1 and n-B but only weekly in HM. Coumarins were found in E2, EA and n-B. Polyphenols, expressed as gallic acid equivalent, amounted, per 100 g plant matter, to 329, 1002 and 150 mg in EA, HM an E1 respectively. Flavonoids, expressed as catechin equivalent, amounted, per 100 g plant matter to 620, 241 and 94 mg in EA, HM and E1 respectively. Comparable values were found in n-B and E1, with lower values in E2. Quercetin, myricetin and gallic acid were found in the EA and HM extracts by thin layer chromatography, The antioxidative effect of these extracts yielded, when tested at a concentration of 2 000 µg/mL in a 1,1-diphenyl-2-picrylhydrazyl assay, a reducing percentage of 88.8% with EA, 74.5% with HM and 66.2% with E1, and corresponding IC50 of 350, 580 and 500 µg/mL as compared to 1.1 µg/mL for ascorbic acid.

CONCLUSIONSThese qualitative and quantitative analytical data document the presence in C. colocynthis extracts of such chemical compounds as flavonoids responsible for the antioxidant activity, as well as other biological activities of this plant.

Antioxidants ; chemistry ; pharmacology ; Biphenyl Compounds ; chemistry ; Citrullus colocynthis ; chemistry ; Free Radical Scavengers ; chemistry ; pharmacology ; Oxidation-Reduction ; drug effects ; Picrates ; chemistry ; Plant Extracts ; chemistry ; pharmacology ; Seeds ; chemistry

OBJECTIVETo develop a simple, reliable approach for evaluating the quality of Huangqin (Scutellaria baicalensis).

METHODTo determine the DPPH free radical scavenging activity and assay of four bioactive components: baicalin, baicalein, wogonin and wogonin-7-O-glucuronide by HPLC.

RESULTThe correlative relationship between DPPH free radical scavenging activity and baicalin content was obtained.

CONCLUSIONBioassay of DPPH free radical scavenging activity could be used as one of the methods for quality evaluation of Chinese drug Huangqin.

Biphenyl Compounds ; Flavanones ; Flavonoids ; chemistry ; isolation & purification ; pharmacology ; Free Radical Scavengers ; pharmacology ; Free Radicals ; Molecular Structure ; Picrates ; Plant Roots ; chemistry ; Plants, Medicinal ; chemistry ; Quality Control ; Scutellaria baicalensis ; chemistry

OBJECTIVETo study the rubrofusarin glucosides from whole plants of Berchemia polyphylla var. leioclada, and their scavenging activities for 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical.

METHODThe chemical constituents were isolated and purified via repeated silica gel and Sephadex LH-20 column chromatography. Their structures were elucidated by spectral analysis and the compounds were tested for their scavenging activities on DPPH radical.

RESULTThree rubrofusarin glucosides compounds were isolated and identified as rubrofusarin-6-O-beta-D-glucopyranoside (1), rubrofusarin-6-O-beta-D-(6'-O-acetyl) glucopyranoside (2), rubrofusarin-6-O-alpha-L-rhamnosyl-(1-6) -O-beta-D-glucopyranside (3). Three isolated compounds showed strong scavenging activities on DPPH radical, the concentration of half elimination ratio( micromol x L(-1)) of VitC and Compounds 1-3 were 18.2, 40.5, 23.3 and 13.6, respectively.

CONCLUSIONCompounds 1-3 were isolated from this plant for the first time and compound 2 was a new compound. They showed significant antioxidant activity, and the scavenging activity of compound 3 was a little stronger than that of VitC.

Biphenyl Compounds ; metabolism ; Free Radical Scavengers ; chemistry ; pharmacology ; Glucosides ; chemistry ; pharmacology ; Nuclear Magnetic Resonance, Biomolecular ; Picrates ; metabolism ; Pyrones ; chemistry ; pharmacology ; Rhamnaceae ; chemistry

The contents of total phenolics and extractable condensed tannins in the leaves, twigs and stem bark of Canarium album were determined. The structural heterogeneity of condensed tannins from stem bark was characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and nuclear magnetic resonance (NMR) analyses. The results show the predominance of signals representative of procyanidins and prodelphinidins. In addition, epicatechin and epigallocatechin polymers with galloylated procyanidin or prodelphinidin were also observed. The tannins were screened for their potential antioxidant activities using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) model systems. Tannins extracted from leaves, twigs and stem bark all showed a very good DPPH radical scavenging activity and ferric reducing power.
Antioxidants ; analysis ; chemistry ; pharmacology ; Burseraceae ; chemistry ; Free Radical Scavengers ; pharmacology ; Magnetic Resonance Spectroscopy ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Tannins ; analysis ; chemistry ; pharmacology