In vitro antioxidant activity of Diospyros malabarica Kostel bark

Antioxidant activity of defatted methanol extract of D. malabarica bark was studied for its free radical scavenging property on different in vitro models e.g. 1,1-diphenyl-2-picryl hydrazyl (DPPH), nitric oxide, superoxide, hydroxyl radical and lipid peroxide radical model. The extract showed good dose-dependent free radical scavenging property in all the models except in hydroxyl radical inhibition assay. IC50 values were found to be 9.16, 13.21, 25.27 and 17.33 microg/ml respectively in DPPH, nitric oxide, superoxide and lipid peroxidation inhibition assays. In hydroxyl radical inhibition assay 1000 microg/ml extract showed only 10% inhibition with respect to the control. Measurement of total phenolic compounds by Folin-Ciocalteu's phenol reagent indicated that 1 mg of the extract contained 120.7 microg equivalent of pyrocatechol. The results indicate that the antioxidant property of the extract may be due to the high content of phenolic compounds. However, the underlying mechanism may not involve hydroxyl radical scavenging property.     

Lipase inhibitory activity of ethyl acetate fraction from Ecklonia cava extracts

Obesity is a key contributing risk factor to cardiovascular disease, certain cancers, and diabetes. Much effort has being made to investigate potential inhibitors against lipase from natural products. The ethyl acetate (EA) extract of Ecklonia cava (EC) were tested for their ability to inhibit pancreatic lipase activity in vitro. The 22 sub-fractions from EA extract were separated using silica gel column chromatography. Among the sub-fractions, the EA6 sub-fraction exhibited the highest inhibitory activity. Dieckol compound was isolated from the EA6 sub-fraction, which inhibited the lipase activity in a concentrationdependent manner with IC₅₀ value at 0.26 mg/mL. These results suggest that EC has potential as a natural antiobesity agent.     

Chemical composition,antioxidant and antimicrobial activities of the essential oil and methanolic extract of Ferulago bernardii Tomk. & M. Pimen of Iran

The aim of the study was to investigate chemical composition, antioxidant, antibacterial and antifungal activities of the essential oil (EO), polar and nonpolar sub-fractions of methanolic extract of Ferulago bernardii. The chemical constituent of the EO was identified by means of GC–MS. The antimicrobial activities of the EO, polar and nonpolar extracts were evaluated by micro-dilution and agar disc diffusion assays. The antioxidant activity was measured by 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) free radical scavenging activity assay. The main components of the EO were α-pinene (35.03%), z-β-ocimene (14.24%) and bornyl acetate (11.64%). Bacillus cereus and Salmonella typhimurium were the most susceptible and resistant to the antibacterial activity of the essential oil and extract, respectively. The free radical scavenging activities of all extracts and the essential oil were in the order: polar > non-polar > EO. Our findings indicate that F. bernardii essential oil and methanolic extract has a potential to be applied as antimicrobial and antioxidant agent.     

Antioxidant potentials and rosmarinic acid levels of the methanolic extracts of Salvia virgata (Jacq), Salvia staminea (Montbret & Aucher ex Bentham) and Salvia verbenaca (L.) from Turkey

This study was designed to examine the in vitro antioxidant activities and rosmarinic acid levels of the methanol extracts of Salvia virgata, Salvia staminea and Salvia verbenaca. The extracts were screened for their possible antioxidant activity by two complementary test systems, namely DPPH free radical scavenging and beta-carotene/linoleic acid systems. In the first case, the most active plant was S. verbenaca (14.30+/-1.42 microg mg(-1)), followed by S. virgata (65.70+/-2.12 microg mg(-1)). S. staminae exhibited the weakest antioxidant activity in this test system of which IC(50) value is 75.40+/-0.57 microg mg(-1). In beta-carotene/linoleic acid test system, S. verbenaca extract was superior to the other extracts studied (inhibition value is 77.03%+/-0.42). Antioxidant activities of BHT, ascorbic acid, curcumin and alpha-tocopherol were determined in parallel experiments. Activity of rosmarinic acid was also screened for better establishing the relationship between rosmarinic acid level and antioxidant activity for the plant extracts. According to the results obtained by spectrophotometric analysis and further supported by HPLC, S. verbenaca has the highest rosmarinic acid level with a value of 29.30+/-0.24 microg mg(-1). Our results showed that the rosmarinic acid and its derivatives are more likely to be responsible for most of the observed antioxidant activities of Salvia species.     

In vitro antioxidant activity of banana (Musa spp. ABB cv. Pisang Awak)

The methanolic extract of Musa ABB cv Pisang Awak was investigated for the polyphenolic contents and antioxidant activity. The total phenol and flavonoid contents of the fruit extract were found to be 120 mg gallic acid equivalents (GAE) and 440 mg quercetin equivalents (QE)/100 g of sample dry weight, respectively. The antioxidant activity of the Pisang Awak methanol extract (PAME) (20-500 microg/ml) was determined using 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity, reducing capacity, 2-2'-azinobis-3-ethylbenzothiozoline-6-sulfonic acid (ABTS) radical cation decolourization and hydroxyl radical scavenging capacity (OH*). The EC50 values of DPPH, ABTS and OH* activities of the PAME and butylated hydroxy toluene (BHT) were found to be 65 and 9 microg/ml, 29 and 6 microg/ml, 36 and 42 microg/ml respectively. The reducing capacity increased with increasing concentration (31.5-1000 mg/ml) of the fruit extract and the activity was comparable with the standard BHT. The high performance thin layer chromatography (HPTLC) analysis of the extract revealed the presence of polyphenols. The strong and positive correlations were obtained between total phenol/flavonoid contents (R2 = 0.693-1.0) and free radical scavenging ability was attributed to the polyphenols as the major antioxidants.     

A comparison of HIV-1 integrase inhibition by aqueous and methanol extracts of Chinese medicinal herbs

The aqueous and methanol extracts of twenty herbs traditionally used in Chinese medicine were screened for anti-HIV-1 integrase activity in a non-radioactive ELISA-based HIV-1 integrase assay. The screening was performed at an herb extract concentration of 50 microg/ml. It was found that most of the aqueous and methanol herb extracts could elicit strong inhibition of HIV-I integrase activity. The inhibition was most likely due to tannins or polyphenolics in the herb extracts. In most of the herb extracts, 40-80% of the anti-HIV-1 integrase activity could be removed after passing through a minicolumn of polyamide resin. After removal of polyphenolic compounds, the methanol extract of Paeonia suffruticosa still exerted potent inhibition of HIV-1 integrase (EC50 = 15 microg/ml) and the aqueous extract of Prunella vulgaris caused moderate inhibition (EC50 = 45 microg/ml). The results support the view that herbs represent a rich source of anti-HIV compounds.     

Anti-genotoxic and free-radical scavenging activities of extracts from (Tunisian) Myrtus communis

The effect of extracts from leaves of Myrtus communis on the SOS reponse induced by Aflatoxin B1 (AFB1) and Nifuroxazide was investigated in a bacterial assay system, i.e. the SOS chromotest with Escherichia coli PQ37. Aqueous extract, the total flavonoids oligomer fraction (TOF), hexane, chloroform, ethyl acetate and methanol extracts and essential oil obtained from M. communis significantly decreased the SOS response induced by AFB1 (10 microg/assay) and Nifuroxazide (20 microg/assay). Ethyl acetate and methanol extracts showed the strongest inhibition of the induction of the SOS response by the indirectly genotoxic AFB1. The methanol and aqueous extracts exhibited the highest level of protection towards the SOS-induced response by the directly genotoxic Nifuroxazide. In addition to anti-genotoxic activity, the aqueous extract, the TOF, and the ethyl acetate and methanol extracts showed an important free-radical scavenging activity towards the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. These results suggest the future utilization of these extracts as additives in chemoprevention studies.     

Antioxidant and antimicrobial activities of essential oil and extracts of Saurauia lantsangensis hu root

Antioxidant and antimicrobial activities of the essential oil and n-hexane (HEE), chloroform (CHE), ethyl acetate (EAE), and methanol (MEE) extracts, respectively, from the root of Saurauia lantsangensis Hu were investigated. The GC-MS analysis revealed 39 compounds representing 96.41% of the oil containing T-muurolol (13.85%), acetophenone (7.46%), alpha-cadinol (6.26%), methyl palmitate (5.36%), n-hexadecanoic acid (4.31%), torreyol (3.69%), and isospathulenol (3.48%) as major components. Antioxidant activities determined by three various testing systems, i.e., DPPH radical scavenging, superoxide anion radical scavenging, and reducing power assay, increased in the order: HEE < CHE < oil < MEE < EAE. CHE, EAE, MEE and oil exhibited a promising antimicrobial effect determined as the diameter of zones of inhibition (13.3-16.2, 16.5-20.4, 13.5-16.6, and 16.5-22.7 mm), respectively, along with their respective MIC values (500-1000, 125-500, 250-500, and 250-500 microg/ml) against Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli), Gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus), and a yeast (Hansenula anomala).     

Screening of the antioxidative properties and total phenolic contents of three endemic Tanacetum subspecies from Turkish flora

Methanolic extracts of three different Tanacetum subspecies [Tanacetum densum (Lab.) Schultz Bip. subsp. sivasicum Hub-Mor and Grierson, Tanacetum densum (Lab.) Schultz Bip. subsp. eginense Heywood and Tanacetum densum (Lab.) Schultz Bip. subsp. amani Heywood] which are endemic to Turkish flora were screened for their possible antioxidant activities by two complementary test systems namely DPPH free radical scavenging and beta-carotene/linoleic acid. In DPPH system, the most active plant was T. densum subsp. amani with an IC(50) value of 69.30+/-0.37 microg/ml. On the other hand, T. densum subsp. sivasicum exerted greater antioxidant activity than those of other subspecies in beta-carotene/linoleic acid system (79.10%+/-1.83). Antioxidant activities of BHT, curcumine and ascorbic acid were also determined as positive controls in parallel experiments. Total phenolic constituents of the extracts of Tanacetum subspecies were performed employing the literature methods involving Folin-Ciocalteu reagent and gallic acid as standard. The amount of total phenolics was highest in subsp. sivasicum (162.33+/-3.57 microg/mg), followed by subsp. amani (158.44+/-2.17 microg/mg). Especially, a positive correlation was observed between total phenolic content and antioxidant activity of the extracts.     

Antioxidant activity of 50% aqueous--ethanol extract from Acantholippia deserticola

The antioxidant properties oí Acantholippia deserticola, a herb used in traditional northern Chilean medicine was studied using free radical-generating systems. The 50% aqueous-ethanol extract oí Acantholippia deserticola protected against non-enzymatic lipid peroxidation in microsomal membranes of rat, induced by an Fe++-ascorbate system and measured spectrophotometrically by the TBARS test, and had strong free radical scavenging capacities on stable ABTS and DPPH radicals. The results shows that the IC50 value of the 50% aqueous-ethanolic extract of A.deserticola is 18 +/- 0.5 microg/mL in DPPH radical-scavenging, 15 +/- 0.8 microg/mL in lipid peroxidation , Total Antioxidant Activity (TAA) is 0.95 mM of Trolox per mg/mL of extract. The total phenolics content of extract is 725 +/- 12 mg of gallic acid equivalent per g of dried extract. The results indicate that the 50% aqueous-ethanol extract of Acantholippia deserticola clearly has antioxidant properties.     

Free-radical scavenging by Ouratea parviflora in experimentally-induced liver injuries

The antioxidant potential of crude extracts and fractions from leaves of Ouratea parviflora, a Brazilian medicinal plant used for the treatment of inflammatory diseases, was investigated in vitro through the scavenging of radicals 2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH), hydroxyl radical (HO*), superoxide anion (O2*-), and lipid peroxidation in rat liver homogenate. The crude extract (CEOP) and hydro-alcoholic fraction (OP4) showed strong inhibitory activity toward lipid peroxidation induced by tert-butyl peroxide (IC50 = 2.3 +/- 0.2 and 1.9 +/- 0.1 microg/ml, respectively). The same products exhibited a strong concentration-dependent inhibition of deoxyribose oxidation (14.9 +/- 0.2 and 0.2 +/- 0.1 microg/ml, respectively), and also showed a considerable antioxidant activity against O2*- (87.3 +/- 0.1 and 73.1 +/- 0.4 microg/ml, respectively) and DPPH radicals (55.4 +/- 0.3 and 38.3 +/- 0.4 microg/ml, respectively). The protective effects of CEOP and OP4 were also studied in mouse liver. CCl4 significantly increased (by 90%) levels of lipid hydroperoxides, carbonyl protein content (64%), DNA damage index (133%), aspartate aminotransferase (261%), alanine aminotransferase (212%), catalase activity (23%), and also caused a decrease of 60% in GSH content. The results showed that CEOP and OP4 exerted cytoprotective effects against oxidative injury caused by CCl4 in rat liver, probably related to the antioxidant activity showed by the in vitro free radical scavenging property.     

Antioxidant potential of n-butanol fraction from extract of Jasminum mesnyi Hance leaves

Methanolic extract of Jasminum mesnyi Hance leaves having antidiabetic activity was subjected to fractionation to obtain antioxidant and antihyperglycemic rich fraction. Different concentrations of ethyl acetate and n-butanol fractions were subjected to antioxidant assay by DPPH method, nitric oxide scavenging activity and reducing power assay. The fractions showed dose dependent free radical scavenging property in all the models. IC50 values for ethyl acetate and n-butanol fractions were 153.45 +/- 6.65 and 6.22 +/- 0.25 microg/ml, respectively, as compared to L-ascorbic acid and rutin (as standards; IC50 values 6.54 +/- 0.24 and 5.43 +/- 0.21 microg/ml, respectively) in DPPH model. In nitric oxide scavenging activity, IC50 values were 141.54 +/- 9.95 microg/ml, 35.12 +/- 1.58 microg/ml, 21.06 +/- 0.95 microg/ml and 29.93 +/- 0.32 microg/ml for ethyl acetate, n-butanol fractions, L-ascorbic acid and rutin, respectively. n-Butanol fraction showed a good reducing potential and better free radical scavenging activity as compared to ethyl acetate fraction. Potent antioxidant n-butanol fraction showed better oral glucose tolerance test (antihyperglycemic) at par with metformin (standard drug), n-Butanol fraction contained secoiridoid glycosides which might be responsible for both antioxidant and antihyperglycemic activity.     

印度块菌提取物抗氧化活性的研究

对印度块菌Tuber indicum子实体的提取物,包括55%乙醇粗提物(ECE)、石油醚提取物(PEF)和乙酸乙酯提取物(EAF)的清除DPPH自由基和羟基自由基能力、铁离子鳌合能力以及各提取物的总酚含量等进行了研究和测定,结果显示,3种提取物的清除自由基能力和铁离子鳌合能力具有显著差异(P0.05);ECE对DPPH自由基的清除活性最高,其EC50值为1.61g/L;EAF对羟基自由基及铁离子表现出较强的清除或螯合的能力,其EC50值分别为3.31g/L和0.70g/L;EAF的总酚含量(2.964mg GAE/g提取物)最高,其次是ECE,总酚含量为(2.618mg GAE/g提取物);PEF的清除自由基和铁离子鳌合能力较差,其总酚含量也最低(1.124mg GAE/g提取物);总酚含量与印度块菌提取物清除自由基以及鳌合铁离子的能力密切相关。     

In vitro antioxidant studies in leaves of Annona species

Antioxidant potential of leaves of three different species of Annona was studied by using different in vitro models eg., 1,1-diphenyl-2-picryl hydrazyl (DPPH), 2,2-azinobis-(3-ethylbenzothizoline-6-sulphonate) (ABTS), nitric oxide, superoxide, hydroxy radical and lipid peroxidation. The ethanolic extract of A. muricata at 500 microg/ml showed maximum scavenging activity (90.05%) of ABTS radical cation followed by the scavenging of hydroxyl radical (85.88%) and nitric oxide (72.60%) at the same concentration. However, the extract showed only moderate lipid peroxidation inhibition activity. In contrast, the extract of A. reticulata showed better activity in quenching DPPH (89.37%) and superoxide radical (80.88%) respectively. A.squamosa extract exhibited least inhibition in all in vitro antioxidant models excepting hydroxyl radical (79.79%). These findings suggest that the extracts of A. muricata possess potent in vitro antioxidant activity as compared to leaves of A. squamosa and A. reticulata suggesting its role as an effective free radical scavenger, augmenting its therapeutic     

黄连抗氧化活性研究

利用DPPH、FRAP和ABTS三种抗氧化活性分析方法对黄连植物不同部位的有机溶剂提取部分进行抗氧化评价,将所测定结果与Trolox进行比较,发现黄连植物不同部位抗氧化活性不同。其中,黄连须根的抗氧化活性最高;同一部位中,乙酸乙酯和甲醇提取物抗氧化活性一般要高于石油醚提取物。在三种方法中,黄连不同部位的提取物清除自由基的能力均随浓度增大而增大;三种方法之间有很好的相关性,以FRAP法与DPPH法相关性最好(r=0.9261,P<0.01)。     

Evaluation of antioxidant properties of root bark of Hemidesmus indicus R. Br. (Anantmul).

Hemidesmus indicus R. Br. (Asclepiadaceae) is a well known drug in Ayurveda system of medicine. In the present study, antioxidant activity of methanolic extract of H. indicus root bark was evaluated in several in vitro and ex vivo models. Further, preliminary phytochemical analysis and TLC fingerprint profile of the extract was established to characterize the extract which showed antioxidant properties. The in vitro and ex vivo antioxidant potential of root bark of H. indicus was evaluated in different systems viz. radical scavenging activity by DPPH reduction, superoxide radical scavenging activity in riboflavin/light/NBT system, nitric oxide (NO) radical scavenging activity in sodium nitroprusside/Greiss reagent system and inhibition of lipid peroxidation induced by iron-ADP-ascorbate in liver homogenate and phenylhydrazine induced haemolysis in erythrocyte membrane stabilization study. The extract was found to have different levels of antioxidant properties in the models tested. In scavenging DPPH and superoxide radicals, its activity was intense (EC50 = 18.87 and 19.9 microg/ml respectively) while in scavenging NO radical, it was moderate. It also inhibited lipid peroxidation of liver homogenate (EC50 = 43.8 microg/ml) and the haemolysis induced by phenylhydrazine (EC50 = 9.74 microg/ml) confirming the membrane stabilization activity. The free radical scavenging property may be one of the mechanisms by which this drug is effective in several free radical mediated disease conditions.     

Inhibition of p38/CREB phosphorylation and COX-2 expression by olive oil polyphenols underlies their anti-proliferative effects

We investigated the anti-proliferative effects of an olive oil polyphenolic extract on human colon adenocarcinoma cells. Analysis indicated that the extract contained hydroxytyrosol, tyrosol and the various secoiridoid derivatives, including oleuropein. This extract exerted a strong inhibitory effect on cancer cell proliferation, which was linked to the induction of a G2/M phase cell cycle block. Following treatment with the extract (50 microg/ml) the number of cells in the G2/M phase increased to 51.82+/-2.69% relative to control cells (15.1+/-2.5%). This G2/M block was mediated by the ability of olive oil polyphenols (50 microg/ml) to exert rapid inhibition of p38 (38.7+/-4.7%) and CREB (28.6+/-5.5%) phosphorylation which led to a downstream reduction in COX-2 expression (56.9+/-9.3%). Our data suggest that olive oil polyphenols may exert chemopreventative effects in the large intestine by interacting with signalling pathways responsible for colorectal cancer development.     

Anti-inflammatory and antioxidant effects of Croton celtidifolius bark.

Croton celtidifolius Baill commonly known as "sangue-de-adave" is a tree found in the Atlantic Forest of south of Brazil, mainly in Santa Catarina. The bark and leaf infusions of this medicinal plant have been popularly used for the treatment of inflammatory diseases. In this study we evaluated the anti-inflammatory and antioxidant properties of crude extract (CE), aqueous fraction (AqF), ethyl acetate fraction (EAF), butanolic fraction (BuF) and catechin, gallocatechin and sub-fractions, 19SF, 35SF and 63SF that contained a mixture of proanthocyanidins and were derived from the EAF fraction. The CE, AqF, EAF, BuF, catechin and sub-fractions 35SF and 63SF reduced paw edema induced by carrageenan. The CE, fractions, sub-fractions and isolated compounds showed antioxidant properties in vitro, all were able to scavenge superoxide anions at a concentration of 100 microg ml(-1). The EAF, catechin and gallocatechin were most effective in the deoxyribose assay, IC50 0.69 (0.44-1.06), 0.20 (0.11-0.39), 0.55 (0.28-1.08) microg x ml(-1) respectively. The CE and other fractions and sub-fractions inhibited deoxyribose degradation up to 1 microg x ml(-1). In the hydrophobic system only AqF did not show lipid peroxidation inhibition. The CE, other fractions, sub-fractions and isolated compounds inhibited lipidid peroxidation only at a concentration of 100 microg x ml(-1). In summary, this study demonstrates that Croton celtidifolius bark has significant anti-inflammatory and antioxidant activity.     

杜仲内生球毛壳菌的抗氧化活性研究

本文研究了分离自杜仲叶片的内生真菌球毛壳菌菌株No.173发酵液提取物的抗氧化活性,采用铁氰化钾还原力测定法、β-胡萝卜素/亚油酸模型和光照核黄素体系评价了发酵液提取物的抗氧化作用,并采用Folin-Ciocalteu法测定杜仲内生球毛壳菌发酵液提取物总多酚含量。结果表明,其抗氧化能力与Vc基本相当;清除超氧阴离子的能力优于芦丁;多酚含量为255.53±1.38mg/g,是其主要的抗氧化活性成分。     

Chemical composition, antioxidant and antimicrobial properties of the essential oils of three Salvia species from Turkish flora

Essential oils of three different Salvia species [Salvia aucheri var. aucheri (endemic), Salvia aramiensis and Salvia pilifera (endemic)] were screened for their possible antioxidant and antimicrobial properties as well as their chemical compositions. According to the gas chromatography (GC)/EIMS (gas chromatography/electron impact mass spectrum) analysis results; 41 (97.2%), 51 (98.5%) and 83 compounds (98.2%) were identified, respectively. While 1,8-cineole (30.5%), camphor (21.3%) and borneol (8.50%) are the major compounds for S. aucheri var. aucheri oil, beta-pinene (10.3%), was the main constituent for S. aramienesis together with 1,8-cineole (46.0%) and camphor (8.7%). In the case of S. pilifera oil, alpha-thujene (36.1%) and alpha-pinene (13.8%) determined as the major compounds. Antioxidant activity was employed by two complementary test systems namely 2,2'-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging and beta-carotene/linoleic acid systems. Antioxidant activity of S. aramiensis was found to be higher than those of the others for the both systems (12.26+/-1.09 and 92.46%+/-1.64 microg mg(-1), respectively). Additionally, antioxidant activities of BHT, curcumin, ascorbic acid and alpha-tocopherol were determined in parallel experiments. In the case of antimicrobial activity, similar activity pattern was obtained (both in disc diffusion and MIC tests). Antimicrobial activity of S. aramiensis was followed by S. aucheri var. aucheri and S. pilifera, respectively. In these experiments, the most sensitive microorganism Acinetobacter lwoffii was followed by Candida albicans.