Free radical scavenging activity of different extracts and some constituents from the leaves of Ligustrum vulgare and L. delavayanum

The free radical scavenging activity of the water infusions, different organic solvent extracts and some constituents from Ligustrum vulgare and Ligustrum delavayanum leaves was assessed with the aid of DPPH radical. Among the samples screened, water infusions had the strongest free radical scavenging capacity. From the tested compounds scavenging active flavonoid aglycones are present in the most active chloroform fractions from both leaves samples.     

Radical scavenging capacity of Agrimonia eupatoria and Agrimonia procera

The antioxidant activity of Agrimonia eupatoria (Agrimony) and Agrimonia procera (Fragrant agrimony) extracts was assessed by measuring in DPPH radical scavenging and ABTS(+) radical decolourisation reaction systems. Radical scavenging capacity of agrimony extracts varied in a wide range (9.1-97.5% in DPPH reaction and 6.7-79.5% in ABTS reaction) depending on the polarity of the solvent used to obtain the extract.     

Apoptotic and free radical scavenging properties of the methanolic extract of Gentianella alborosea

Gentianella alborosea ("Hercampure") is a Peruvian species used in folk medicine for the treatment of a variety of health disorders. We tested the free radical scavenging (DPPH) and induction of apoptosis on a human uterus tumor cell line (HeLa) by its methanolic extract. The results showed a noticeable radical scavenging activity and a dose-dependent apoptotic effect.     

Antimicrobial and free radical scavenging activities of Teucrium montanum

The antimicrobial and free radical scavenging activities of petroleum ether, chloroform, ethyl acetate, n-butanol and water extracts of Teucrium montanum were investigated. Ethyl acetate, chloroform and n-butanol extracts expressed a wide range of inhibiting activity against both Gram (+) and Gram (-) bacteria. n-Butanol extract possessed potent DPPH free radical scavenging activity.     

12个楸树无性系叶片多酚含量与抗氧化活性

自由基具有强氧化性,机体衰老及多种疾病如肿瘤、炎症、神经退行性疾病、动脉粥样硬化等的诱发促进机制都与自由基有关[1]。自由基的减少,不仅要靠自身的清除系统,还需要外部抗氧化剂的协助。近年来,关于合成抗氧化剂的副作用受到人们更多的关注,因此,寻找安全、高效的植物源类抗氧化剂,已成为食品领域研究的热点。楸树(Catalpa bungei C.A.Mey.)为紫葳科(Bignoniaceae)梓属植物,落叶乔木,《本草纲目》记载楸树树皮、叶具有药     

Evaluation of Pluchea carolinensis extracts as antioxidants by the epinephrine oxidation method

Many methods have been used to evaluate synthetic and natural products as hydroxyl radical scavengers. In this study a spectrophotometric method to evaluate the scavenger activity of the hydroxyl radical produced in Fenton reaction is proposed. The oxidation of l-epinephrine to adrenochrome permitted the detection of the hydroxyl radical by spectrophotometry and its possible scavenging by hydroquinone, a well known antioxidant. The method was used to evaluate the antioxidant activity of Pluchea carolinensis leaves.     

A new flavonoid glycoside from the leaf of Cephalotaxus koreana

A new flavone glycoside, apigenin 5-O-alpha-L-rhamnopyranosyl-(1-->3)-beta-D-glucopyranoside (1), along with four known flavonol glycosides (2-5), were isolated from the leaf of Cephalotaxus koreana. The new glycoside 1 showed inhibitory activity in superoxide radical scavenging assay with IC(50) value of 13.0 microM, while it showed weak activity in 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay. Compounds 2-5 exhibited antioxidant activity in scavenging DPPH and superoxide radicals with IC(50) values ranging from 5.7 to 22.3 microM.     

In vitro antioxidant activity of Argyreia cymosa bark extracts

The Argyreia cymosa bark extracts were subjected to in vitro antioxidant activity with different methods. The petroleum ether extract has shown antioxidant activity in ABTS, nitric oxide, hydroxyl radical (by p-NDA) and lipid peroxidation methods. The ethyl acetate extract has shown antioxidant activity in DPPH, H(2)O(2) and hydroxyl radical (by deoxyribose) scavenging methods.     

Antioxidant activity of nine Fabaceae species growing in Serbia and Montenegro

The aim of this study was to investigate antioxidant capacity of nine Fabaceae species collected on the mountains of Serbia and Montenegro. Antioxidant assays with various reaction mechanisms were used, including total phenolic content by Folin-Ciocalteu, DPPH radical scavenging capacity, Trolox equivalent antioxidant capacity (TEAC) values by ABTS radical cation and inhibition of liposome peroxidation. The investigated plants exhibited strong antioxidant capacity in all the tested methods, and among them, Lathyrus binatus, Trifolium pannonicum, and Anthyllis aurea were found to be the most active.     

Effect of Garcinia mangostana on inflammation caused by Propionibacterium acnes

The present study was aimed to investigate the activity of Thai medicinal plants on inflammation caused by Propionibacterium acnes in terms of free radical scavenging and cytokine reducing properties. P. acnes have been recognized as pus-forming bacteria triggering an inflammation in acne. Antioxidant activity was determined by DPPH scavenging and NBT reduction assay. The result showed that Garcinia mangostana possessed the most significant antioxidant activity and reduced reactive oxygen species production. Houttuynia cordata, Eupatorium odoratum, and Senna alata had a moderate antioxidant effect. In addition, Garcinia mangostana extracts could reduce the TNF-alpha production as determined by ELISA. Garcinia mangostana was highly effective in scavenging free radicals and was able to suppress the production of pro-inflammatory cytokines. This study has identified the promising source of anti-inflammatory agent which could be useful in treatment of acne vulgaris.     

Antioxidant activity of Cassia auriculata flowers

The ethanol and methanol extracts of Cassia auriculata flowers were screened for antioxidant activity. The antioxidant activity was determined by an improved assay based on the decolorization of the radical monocation of 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method. The ethanol and methanol extracts of C. auriculata flowers showed antioxidant activity in both assays.     

Four new prenylated flavonoids and xanthones from the root bark of Artocarpus nobilis

Chemical investigation of the n-butanol extract from the methanol extract of the root bark of Artocarpus nobilis furnished four new prenylated flavonoids together with artonin E 2'-methylether (4), isoartonin E 2'-methylether (5), dihydroisoartonin E 2'-methylether (6), artonin V 2'-methylether (7), artobiloxanthone (1), artonin E (2) and cycloartobiloxanthone (3). All these compounds showed strong radical scavenging properties towards DPPH radical.     

Radical scavenging activity and composition of raspberry (Rubus idaeus) leaves from different locations in Lithuania

Raspberry (Rubus idaeus) leaves, collected in different locations of Lithuania were extracted with ethanol and the extracts were tested for their antioxidant activity (AA) by using ABTS(.)(+) decolourisation and DPPH(.) scavenging methods. All extracts were active, with radical scavenging capacity at the used concentrations from 20.5 to 82.5% in DPPH(.) reaction system and from 8.0 to 42.7% in ABTS(.)(+) reaction. The total amount of phenolic compounds in the leaves varied from 4.8 to 12.0 mg of gallic acid equivalents (GAE) in 1 g of plant extract. Quercetin glucuronide, quercetin-3-O-glucoside and rutin were identified in the extracts.     

Antioxidant and 15-lipoxygenase inhibitory activity of rotenoids, isoflavones and phenolic glycosides from Sarcolobus globosus

From Sarcolobus globosus, two rotenoids (villosinol and 6-oxo-6a,12a-dehydrodeguelin), one isoflavone (genistin) and four phenolic glycosides (vanillic acid 4-O-beta-d-glucoside, glucosyringic acid, tachioside and isotachioside) were identified for the first time from this species. Extracts and compounds from S. globosus were evaluated for their DPPH radical scavenging and 15-lipoxygenase (15-LO) inhibitory activities. All tested rotenoids were found to inhibit 15-LO, while they lacked DPPH radical scavenging effect.     

Phytochemical and antioxidant analysis of eight Hypericum taxa from Central Italy

Eight taxa of the Hypericum spp. growing in Central Italy (Appennino Umbro-Marchigiano) were analyzed by HPLC-DAD for constituents quantitation, for antioxidant and free radical scavenging activities. H. perforatum subsp. veronense was the richest in phenolic compounds and hyperforin was detected for the first time in H. hircinum subsp. majus. Significant values of antioxidant activity were found in the investigated Hypericum taxa.     

Scavenging effect and antispasmodic activity of the essential oil of Cyclotrichium niveum

The radical scavenging and the spasmolitic activity of Cyclotrichium niveum essential oil were evaluated in vitro. It showed an IC(50) of 1750 microg/ml on DPPH method and dose dependently (0.1, 0.5 and 1 mg/ml) inhibits the contraction induced by carbachol on rabbit bladder from 15 to 100%. Moreover, it was able to inhibit the rat ileum muscle by 30 to 100%.     

DPPH radical scavenging activity of two flavonol glycosides from Aconitum napellus sp. lusitanicum

The DPPH radical scavenging activity of two flavonol glycosides obtained from ethanolic extracts of Aconitum napellus sp. lusitanicum was studied. The results showed a high DPPH antiradical activity of compound 1 (quercetin 3-O-(6-trans-caffeoyl)-beta-glucopyranosyl-(1-->2)-beta-glucopyranosyl-7-O-alpha-rhamnopyranoside) when compared with compound 2 (quercetin-3-sophoroside-7-rhamnopyranoside), rutin and ascorbic acid. The relationship between the caffeoyl and rhamnopyranoside groups in the flavonol glycosides structures and the DPPH antiradical activity was also discussed.     

Antioxidant activity of Filipendula hexapetala flowers

The antioxidant activity of the methanol extract of Filipendula hexapetala flowers was assessed by the assay for ferric-reducing antioxidant power (FRAP), the assay for DPPH free radical scavenging ability (DPPH) and the assay for the influence of lipid peroxidation in liposomes, induced by Fe(2+)/ascorbate system and measured by the TBA test (LP). The activity of the investigated extract in all test-systems was found to be significant. The principal constituent responsible for the observed effects was isolated and identified as spiraeoside.     

香椿叶提取物清除DPPH自由基能力的测定方法

建立了以分光光度法测定天然抗氧化剂清除2,2-二苯基-1-苦肼基(DPPH)自由基能力的方法。通过测定芦丁、檞皮素、抗坏血酸、没食子酸的DPPH自由基清除率曲线,提出以IC50值作为评价试样清除DPPH自由基能力的指标,并将此应用于测定香椿叶提取物清除DPPH自由基的能力。通过测定香椿叶提取物与DPPH溶液反应后,DPPH溶液在517 nm处的吸光度的变化,确定了测定香椿叶提取物清除DPPH自由基能力的条件。即:测定波长517 nm,反应时间50 m in。在此条件下测得的以总黄酮计的香椿叶提取物清除DPPH自由基的IC50值为22.026。     

Tannins from barks of Pinus caribaea protect Escherichia coli cells against DNA damage induced by gamma-rays

This work was aimed to evaluate genotoxicity and antigenotoxicity activity against gamma-rays of a tannin fraction obtained from barks of Pinus caribaea, as well as to elucidate the antigenotoxic mechanisms involved in radioprotection by using different approaches as pre-, co- and post-irradiation cell treatments with plant extract. The tannin fraction was not genotoxic to Escherichia coli cells in experiments using different exposure times. This extract was antigenotoxic against gamma-rays when the cells were pre- or co-treated with this extracts, but not during post-irradiation treatments, suggesting a possibly antigenotoxic action through free radical scavenging mechanisms. The results are discussed in relation to the chemopreventive and therapeutic potential of the studied plant species.