Antioxidant and hepatoprotective activity of ethanolic extract of leaves of Solidago microglossa containing polyphenolic compounds

The antioxidative and hepatoprotective potential of Solidago microglossa D.C, a widely used medicinal plant from Brazil was investigated. The leaf extract showed inhibition against thiobarbituric acid reactive species (TBARS) induced by different prooxidants (10 μM FeSO₄ and 5 μM sodium nitroprusside SNP) in rat liver, brain and phospholipid homogenates from egg yolk. Moreover, the free radical scavenging activities of the extract was evaluated by the scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH) (IC_50, 3.8 ± 0.5 μg/ml) and hydroxyl radical on benzoic acid hydroxylation (IC_50, 32.3 ± 1.3 μg/ml) and deoxyribose (IC_50, 39.1 ± 2.4 μg/ml) assays. The ethanolic extract showed significant hepatoprotective activity against paracetamol (250 mg/kg) induced liver damage in mice in a dose dependent manner. The phenolic composition and their quantification by high performance liquid chromatography (HPLC) resulted in the identification of gallic acid and flavonoids: quercetrin (quercetin-3-O-rhamnoside), rutin (quercetin-3-O-rutinoside) and quercetin.     

Chemical composition and antioxidant activity of the essential oil of Clinopodium vulgare L.

This study was designed to examine the chemical composition and in vitro antioxidant activity of the essential oil of Clinopodium vulgare. GC–MS analysis of the oil resulted in the identification of 40 compounds, representing 99.4% of the oil; thymol (38.9%), γ-terpinene (29.6%) and p-cymene (9.1%) were the main components. The samples were subjected to a screening for their possible antioxidant activity by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene-linoleic acid assays. In the first case, IC₅₀ value of the C. vulgare essential oil was determined as 63.0 ± 2.71 μg/ml. IC₅₀ value of thymol and γ-terpinene, the major compounds of the oil, was determined as 161 ± 1.3 μg/ml and 122 ± 2.5 μg/ml, respectively, whereas p-cymene did not show antioxidant activity. In β-carotene-linoleic acid system, C. vulgare essential oil exhibited 52.3 ± 1.19% inhibition against linoleic acid oxidation. In both systems, antioxidant capacities of BHT, curcumine and ascorbic acid were also determined in parallel experiments.     

Antioxidant,anticholinesterase and antimicrobial constituents from the essential oil and ethanol extract of Salvia potentillifolia

The essential oil of Salvia potentillifolia was analysed by GC and GC–MS. Totally, 123 components were detected in both hydrodistilled and steam-distilled oils, α- and β-pinenes being major compounds. The antioxidant activities were determined by using complementary tests, namely, DPPH radical-scavenging, β-carotene-linoleic acid and reducing power assays. The ethanol extract also showed better activity (IC₅₀ = 69.4 ± 0.99 μg/ml) than that of BHT in the DPPH system, and showed great lipid peroxidation inhibition in the β-carotene-linoleic acid system (IC₅₀ = 30.4 ± 0.50 μg/ml). The essential oil showed meaningful butyrylcholinesterase activity (65.7 ± 0.21%), and α-pinene showed high acetylcholinesterase inhibitory activity (IC₅₀ = 86.2 ± 0.96 μM) while β-pinene was inactive. Antimicrobial activity was also investigated on several microorganisms, and the essential oil showed high activity against Bacillus subtilis and B. cereus. It also exhibited remarkable anticandidal activity against Candida albicans and C. tropicalis with MIC values of 18.5 and 15.5 μg/ml, respectively, while α- and β-pinenes showed moderate activity.     

Rosmarinic acid,scutellarein 4′-methyl ether 7-O-glucuronide and (16S)-coleon E are the main compounds responsible for the antiacetylcholinesterase and antioxidant activity in herbal tea of Plectranthus barbatus (“falso boldo”)

Plectranthus barbatus, known as “falso boldo” in Brazil, is used in herbal tea or cooked as a vegetable. Infusions and decoctions of leaves from P. barbatus were analysed for their inhibition of acetylcholinesterase and their antioxidant activity. The decoction showed high inhibition activity (31% inhibition with 0.5 mg of extract/ml) and also high antioxidant activity (IC₅₀ = 45.8 ± 0.5 μg of dry extract/ml in the DPPH test; IC₅₀ = 69.8 ± 3.1 μg of dry extract/ml in the β-carotene–linoleic acid test). Rosmarinic acid, scutellarein 4′-methyl ether 7-O-glucuronide and (16S)-coleon E were the main constituents identified. These compounds have antiacetylcholinesterase activity. Rosmarinic acid and the scutellarein derivative have IC₅₀ = 440 μg/ml and 1 mg/ml, respectively. One milligram per millilitre of (16S)-coleon E showed 61% inhibition of the enzyme. Other Plectranthus species, P. ecklonii, P. fructicosus, P. lanuginosus and P. verticillatus, were also analysed and the results obtained correlated with the content in rosmarinic acid.     

Antioxidant, antiacetylcholinesterase and antimicrobial activities of Cymbopogon schoenanthus L. Spreng (lemon grass) from Tunisia

Aqueous extract, proanthocyanidin rich extract, and organic extracts of Cymbopogon schoenanthus L. Spreng (lemon grass) shoots from three different locations in South Tunisia were screened for their antioxidant, acetylcholinesterase and antimicrobial activities. In addition to the evaluation of these activities, the contents of flavonoids and total phenolic compounds were determined.Antioxidant activity measured by DPPH assay showed that the proanthocyanidin extract exhibited higher antioxidant activity than the aqueous extract. Extract concentration providing 50% inhibition (IC₅₀) ranged from 16.4 ± 6.8 μg/mL to 26.4 ± 6.8 μg/mL. The antioxidant activity was also determined using the β-carotene/linoleic acid bleaching test. The best results (IC₅₀ = 0.11 ± 0.10 mg/mL) were obtained with the proanthocyanidin extract of the plants collected from the desert region (Dhibat).The greatest acetylcholinesterase inhibitory activity (IC₅₀ = 0.23 ± 0.04 mg/mL) was exhibited by the ethyl acetate and methanol extracts of the plants collected from the mountainous region. It seems that extracts obtained with more polar solvents gave better results.The proanthocyanidin extracts showed a good antimicrobial activity against Streptococcus sobrinus at low concentration (MIC = 4 mg/mL). Therefore, these extracts could be used to prevent carious lesions by inhibiting S. sobrinus growth.     

Iron-chelating ability and antioxidant properties of phycocyanin isolated from a protean extract of Spirulinaplatensis

The invitro scavenger activities of different reactive oxygen species (superoxide radical, hydroxyl radical, hydrogen peroxide, hypochlorous acid and peroxyl radical), the effects on lipid peroxidation and the iron-chelating ability of a Spirulinaplatensis protean extract and the biliprotein, phycocyanin, isolated from this microalga were studied. S. platensis protean extract inhibited the generation of hydroxyl radical (IC₅₀ = 537 μg/ml for the system with EDTA and 1500 μg/ml without EDTA), the production of peroxyl radical (IC₅₀ = 230 μg/ml), and the lipid peroxidation process (IC₅₀ = 2320 μg/ml for the enzymatic system and 2180 μg/ml for the non-enzymatic system). Besides, phycocyanin inhibited hydroxyl and peroxyl radicals and the lipid peroxidation process. The iron ions decreased the maximum fluorescence emission spectra of S. platensis protean extract and phycocyanin and it was an indicator of the metal-chelating activity. The antioxidant properties of S. platensis and phycocyanin may arise from both radical-scavenging and metal chelation. Our results suggest that S. platensis could be used as a dietary supplement to prevent some diseases where free radicals are involved.     

Composition and antioxidant and antimicrobial activity of the essential oil and extracts of Stachys inflata Benth from Iran

Composition and antioxidant and antimicrobial activities of essential oil and methanol extract polar and nonpolar subfractions of Stachys inflata were determined. GC and GC/MS analyse of the essential oil showed 45 constituents representing 95.46% of the oil, the major components linalool (28.55%), α-terpineol (9.45%), spathulenol (8.37%) and (2E)-hexenal (4.62%) constituted 50.99% of it. Essential oil and extracts were also tested for their antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene/linoleic acid assays. In the DPPH test, IC₅₀ value for the polar subfraction was 89.50 μg/ml, indicating an antioxidant potency of about 22% of that of butylated hydroxytoluene (IC₅₀ = 19.72 μg/ml) for this extract. In β-carotene/linoleic acid assay, the best inhibition belonged to the nonpolar subfraction (77.08%). Total phenolic content of the polar and nonpolar extract subfractions was 5.4 and 2.8% (w/w), respectively. The plant also showed a week antimicrobial activity against three strains of tested microorganisms. Linalool and α-terpineol were also tested as major components of the oil and showed no antioxidant but considerable antimicrobial activities.     

Standardised Mangifera indica extract is an ideal antioxidant

The standardised ethanolic and aqueous extracts of Mangifera indica leaf were prepared and analysed for their free radicals scavenging activity. The IC₅₀ values using the DPPH assay were 0.17 ± 0.02 and 0.49 ± 0.4 mg/ml, respectively. Standardised ethanolic extracts of the M. indica leaf had a solid content of 9.1 ± 0.7%, mangiferin concentration of 73 ± 0.17 mg/g of dry weight of the extract, free radical scavenging activity (IC₅₀) of 0.17 ± 0.02 mg/ml and total phenolic content of 590 ± 48 mg/g of extract. The protection exhibited by these extracts against lipid peroxidation was superior to butylated hydroxytoluene (BHT) and commercial grape seed extract. These extracts at higher concentration did not exhibit pro-oxidant activities when compared to vitamin C. Our findings also show that the aqueous and ethanolic extracts of M. indica leaf protect NIH/3T3 cells from oxidant-induced cell death.     

Antioxidant potential of meso-zeaxanthin a semi synthetic carotenoid

Semi synthetic carotenoid meso-zeaxanthin was evaluated for its antioxidant potential in vitro and in vivo. Meso-zeaxanthin was found to scavenge superoxide radicals, hydroxyl radicals and inhibited in vitro lipid peroxidation. Concentrations needed for 50% inhibition (IC₅₀) were 27.0, 3.5 and 3.2 μg/ml, respectively. It scavenged 2,2-azobis-3-ethylbenzthiozoline-6-sulphonic acid and 2,2-diphenyl-1-picryl hydrazyl radicals and IC₅₀ were 46.5, 6.25 μg/ml, respectively. It also scavenged nitric oxide radicals and IC₅₀ was found to be 2.2 μg/ml. Oral administration of meso-zeaxanthin inhibited superoxide radicals generated in macrophages by 25.2%, 50.1% and 67.2% at doses of 50, 100 and 250 mg/kg b.wt., respectively. One month oral administration of meso-zeaxanthin to mice significantly increased catalase, superoxide dismutase, glutathione and glutathione reductase levels in blood and liver. Levels of glutathione peroxidase and glutathione-S-transferase were also found to be increased in the liver, in a dose dependent manner. These results showed that meso-zeaxanthin has significant antioxidant activity in vitro and in vivo.     

Anti-oxidant,anti-proliferative and anti-inflammatory activities of the extracts from black raspberry fruits and wine

The purpose of the study was to determine polyphenols, anthocyanins and ascorbic acid in the extracts of black raspberry fruits and wine, along with their anti-oxidant, anti-proliferative and anti-inflammatory activities. Black raspberry fruits without or with seeds crushed were blended in 60% ethanol (FE and FES, respectively) or in water (FW and FWS, respectively). Black raspberry wine without or with seeds crushed (W and WS, respectively) were prepared. Polyphenol content was the highest in the FES (8.25 mg/g fruit). Generally the ethanol extracts with seeds crushed showed higher anti-oxidant activities with the lowest DPPH IC₅₀ (130 μg/ml (freeze-dried extract/reaction solution)) for the FES and the lowest ABTS IC₅₀ (198 μg/ml) for the WS. Cell viabilities were reduced by 13–70% when treated with 100 μg/ml (freeze-dried extract/medium) for HT-29 cells and 1000 μg/ml for LNCaP cells. The FES most actively suppressed nitric oxide production in LPS-stimulated RAW264.7 cells (p < 0.05). Superoxide dismutase and glutathione peroxidase activities treated with the extracts were higher than the control (p < 0.05).     

Chemical composition,antioxidative activity and cell viability effects of a Siberian pine (Pinus sibirica Du Tour) extract

Siberian pine (Pinus sibirica Du Tour) seeds, commonly known as cedar nuts, are ascribed a number of medicinal properties. In this study, we report the qualitative–quantitative composition, antioxidant activity and cell viability-related properties of a defatted aqueous-acetone-soluble P. sibirica seed extract. The total phenolic and total tannin contents were estimated at 266 ± 3.9 mg gallic acid/g and 115 ± 7.8 mg tannic acid/g, respectively. Reverse-phase chromatographic analysis of the crude extract indicated the presence of a chromatographic hump indicative of the presence of proanthocyanidins. After acid hydrolysis, the presence of hydroxylated benzoic and cinnamic acids, flavanones and flavan-3-ols was confirmed. After thiolysis, (+)-catechin was identified as more abundant than (−)-epicatechin, suggesting that this molecule was the main terminal unit of the proanthocyanidins within this extract. The extract demonstrated iron(III)-reductive (AscAE = 650 ± 5.10 μmol ascorbic acid/g) and iron(II) chelating (EC₅₀ = 20.1 ± 2.1) activities and the ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (IC₅₀ = 257 ± 2.36 μg/ml) and hydroxyl (IC₅₀ = 338 ± 6.49 μg/ml) free radicals. When the effects of P. sibirica extract were assessed in a tumourigenic SH-SY5Y neuroblastoma cell line, it was found that the cell viability was diminished in the presence of P. sibirica extract (0.2–1.0 mg/ml), as indicated by decreased membrane integrity (LDH assay) and mitochondrial metabolic activity (MTT assay), but the level of p53 protein was not changed (Western blot).     

Screening of antioxidative properties of the methanolic extracts of Pelargonium endlicherianum Fenzl., Verbascum wiedemannianum Fisch. & Mey., Sideritis libanotica Labill. subsp. linearis (Bentham) Borm., Centaurea mucronifera DC. and Hieracium cappadocicum Freyn from Turkish flora

Five extracts from five plants, of which four are endemic to Turkish flora, were screened for their possible in vitro antioxidant activities by two complementary test systems, namely DPPH free radical-scavenging and β-carotene/linoleic acid. In the first case, Pelargonium endlicherianum extract exerted greater antioxidant activity than those of other plant extracts studied with an IC₅₀ value of 7.43 ± 0.47 μg/ml, followed by Hieracium cappadocicum (30.0 ± 0.14 μg/ml). When compared to the synthetic antioxidant BHT (18.0 ± 0.40 μg/ml), the methanolic extract of P. endlicherianum exhibited more than two fold greater antioxidant activity. In the β-carotene/linoleic acid test system, the most active plant was P. endlicherianum with 72.6% ± 2.96 inhibition rate, followed by H. cappadocicum (55.1% ± 2.33) and Verbascum wiedemannianum (52.5% ± 3.11). Antioxidant activities of curcumin and ascorbic acid were also determined as positive controls in parallel experiments.     

The protective ability of Mediterranean dietary plants against the oxidative damage: The role of radical oxygen species in inflammation and the polyphenol,flavonoid and sterol contents

Ten hydroalcoholic extracts of edible plants from the Calabria region (Italy) were evaluated for their in vitro antioxidant and antiradical properties and in vivo topical anti-inflammatory activity. All the extracts had radical-scavenging and/or antioxidant properties, the most active plants being hawkweed oxtongue and viper’s bugloss. The best free radical (DPPH·)-scavenging activity was found in hawkweed oxtongue and chicory leaves extracts (IC₅₀ = 25 and 26 μg/ml, respectively). Hawkweed oxtongue, poppy and viper’s bugloss extracts showed the greatest inhibition of linoleic acid oxidation (IC₅₀ = 3 μg/ml). Viper’s bugloss and hawkweed oxtongue extracts had the greatest antioxidant effect on bovine brain peroxidation (IC₅₀ = 11 and 22 μg/ml). All the extracts also showed an anti-inflammatory effect: 300 μg/cm² provoked oedema reductions ranging from 18% to 43%. Cress was the most active plant. Chicory leaves contained the highest amount of phenolics (190 mg/g) whilst Rush crimps contained the highest amount of flavonoids (32.9 mg/g), followed by hawkweed oxtongue (15.8 mg/g). Cress contained the highest number of sterols. Among them, γ-sitosterol (12.2%) and ergost-5-en-3-ol (3β) (4.5%) were found to be the major constituents. Moreover, three of the identified molecules (stigmasta-5,23-dien-3β-ol, stigmasta-5,24(28)-dien-3-ol (3β,22E) and 9,19-cyclolanost-24-en-3-ol (3β)) were found in this plant only.     

In vitro activity of the essential oils of Origanum vulgare, Satureja montana and their main constituents in peroxynitrite-induced oxidative processes

The essential oil obtained from aerial parts of Satureja montana L. and Origanum vulgare L. (Labiatae) along with four of its main components, p-cymene, carvacrol, thymol and γ-terpinene were tested in models of in vitro peroxynitrite-induced formation of both 3-nitrotyrosine and malondialdehyde, two biomarkers of the oxidative stress of recognised pathological and toxicological significance. The essential oils showed a significant activity, thus decreasing 3-nitrotyrosine formation (IC₅₀ values of 43.9 μg/ml for S. montana and 19.2 μg/ml for O. vulgare), and also inhibited the peroxynitrite induced malondialdehyde formation (IC₅₀ values of 27.2 μg/ml and 17.0 μg/ml respectively). Thymol and carvacrol inhibited 3-nitrotyrosine formation (IC₅₀ values of 81.3 μM and 106.3 μM; ascorbic acid IC₅₀ = 400 μM) and reduced malondialdehyde formation (IC₅₀ values of 43.9 μM and 70.1 μM respectively; trolox IC₅₀ = 240 μM). On the contrary, p-cymene and γ-terpinene were completely inactive in both assays under the concentration of 300 μg/ml. These results support, in particular for origanum, the nutraceutical value of these spices and the potential of thymol and carvacrol in preventing the formation of toxic products by the action of reactive nitrogen species.     

Antimicrobial and human cancer cell cytotoxic effect of synthetic angiotensin-converting enzyme (ACE) inhibitory peptides

Four peptides with high angiotensin-converting enzyme (ACE) inhibitory effect were separated from beef sarcoplasmic protein hydrolysates using commercial enzymes. They were identified as GFHI, DFHING, FHG, and GLSDGEWQ and their 50% inhibition concentration (IC₅₀) values against ACE were 117, 64.3, 52.9, and 50.5 μg/ml, respectively. These peptides were synthesised and further biological activities of these four peptides were measured, including antimicrobial, cytotoxic effect against cancer cells, and macrophage-stimulating effect. Peptide GLSDGEWQ showed growth inhibition on Salmonella Typhimurium, Bacillus cereus, Escherichia coli, and Listeria monocytogenes at a 100 ppm level but not on Staphylococcus aureus and Pseudomonas aeruginosa. Peptide GFHI showed higher inhibition activity on the growth of E. coli and P. aeruginosa at concentrations of 200 and 400 μg/ml. However, peptide FHG inhibited only P. aeruginosa at 200 and 400 μg/ml. The effect of separated peptides on breast cancer (MCF-7), lung cancer (A549), and stomach cancer (AGS) cell viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Peptide GFHI showed a slight decrease of MCF-7 cell viability in a dose dependent manner. When 400 μg/ml of peptide GFHI was applied to the AGS cell, its viability was decreased by 75%. However, peptide DFHINQ seemed to act as a nutrient to AGS cell because it increased its viability. None of the four peptides had a cytotoxic effect on A549 cells. Nitric oxide (NO) production of peptide GFHI by stimulation of macrophage was investigated at 100, 300, and 1000 μg/ml concentration. NO was not produced in all treatments. From these results it is expected that the ACE inhibitory peptides identified from beef sarcoplasmic protein hydrolysates have both antimicrobial and cancer cell cytotoxic effects.     

Antioxidant and free radical scavenging activities of wild bitter melon (Momordica charantia Linn. var. abbreviata Ser.) in Taiwan

Momordica charantia Linn. var. abbreviata Ser. (Cucurbitaceae), also known as “Shan Ku Gua”, is a wild variety of bitter melon (BM) in Taiwan. The size of its fruits is only about one-fifth of the commonly seen BM. It is commonly consumed as vegetable and also used as a popular folk medicine. In this study, the antioxidant and free radical scavenging activities of BM aqueous (BM-H₂O) and ethanol (BM-EtOH) extracts were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), metal chelation, cytochrome c and xanthine oxidase inhibition (XOI) assays, as well as FeCl₂-ascorbic acid induced lipid peroxidation (thiobarbituric acid reactive substances, TBARS) assay in rat liver homogenates in vitro. Total flavonoid and phenol contents of BM extracts were also analyzed. Results showed that both BM-H₂O (IC₅₀=129.94 μg/ml) and BM-EtOH (IC₅₀=156.78 μg/ml) possess potent DPPH radical scavenging activity, which was better than vitamin E (IC₅₀=172.21 μg/ml). These extracts also showed better iron chelating activity than vitamin E. However, they were weaker than vitamin E in free radical scavenging, xanthine oxidase inhibitory and anti-lipid peroxidation activities. With the exception of XOI activity [IC₅₀=7.90 μg/ml (BM-H₂O) vs. 7.69 μg/ml (BM-EtOH)], BM-H₂O showed a lower IC₅₀ value in free radical scavenging [IC₅₀=6.15 μg/ml (BM-H₂O) vs. 7.08 μg/ml (BM-EtOH)] and anti-lipid peroxidation [IC₅₀=53.72 μg/ml (BM-H₂O) vs. 88.51 μg/ml (BM-EtOH) for liver; 82.53 μg/ml (BM-H₂O) vs. 91.83 μg/ml (BM-EtOH) for brain] activities than BM-EtOH. Both BM extracts showed a weak anti-lipid peroxidation activity in plasma. BM-H₂O (62.0 mg/g) possessed a significant higher concentration of total flavonoids than BM-EtOH (44.0 mg/g), but was lower in the total phenol content (BM-H₂O: 51.6 mg/g vs. BM-EtOH: 68.8 mg/g). In conclusion, BM extracts possess potent antioxidant and free radical scavenging activities. These antioxidant activities could have contributed, at least partly, to the therapeutic benefits of the certain traditional claims of wild BM.     

Screening of the antioxidant potentials of six Salvia species from Turkey

This study was designed to examine the in vitro antioxidant activities of the methanol extracts of six Salvia species [Salvia caespitosa Montbret & Aucher ex Bentham (ENDEMIC), Salvia hypargeia Fisch. & Mey. (ENDEMIC), Salvia euphratica subsp. euphratica Montbret & Aucher ex Bentham (ENDEMIC), Salvia sclarea L., Salvia candidissima subsp. candidissima Montbret & Aucher ex Bentham and Salvia aethiopis L.] from Turkey. The extracts were screened for their possible antioxidant activities by two complementary test systems, namely DPPH free radical-scavenging and β-carotene/linoleic acid systems. Non-polar subfractions of the methanol extracts of Salvia species studied did not show any antioxidant activity in both test systems. In the first case, the most active plant was S. euphratica subsp. euphratica, an endemic species, with an IC₅₀ value of 20.7 ± 1.22 μg/ml, followed by S. sclarea (IC₅₀ = 23.4 ± 0.97 μg/ml) among the polar subfractions. In the β-carotene/linoleic acid test system, polar extract of S. hypargeia was superior to the polar extracts of other Salvia species studied (69.2% ± 1.90%). This activity was followed by S. sclarea with 63.5% ± 4.24% inhibition rate. The inhibition rate of the synthetic antioxidant, buthylated hydroxytoluene (BHT), was also determined to be 96%. Since the polar extracts of Salvia species dealt with here exhibited excellent antioxidant activities when compared to BHT, it seems possible to keep perishable fat-containing food longer by direct addition of an extract of sage.