Evaluation of antioxidant properties of medical plants using microbial test systems

The antioxidant activities of extracts from leaves of the medicinal plants growing in Siberia were examined. Total antioxidant activity was determined using in vitro methods including DPPH (2,2-diphenyl-1-picrylhydrazyl radical) free radical scavenging assay, chelating capacity assay with ferrozine, evaluation of capacity to protect plasmid DNA against oxidative damage, measurement of H₂O₂ production, and measurement of total flavonoid and tannin content as well. Using in vivo experiments, we also evaluated capacities of the plant extracts to protect bacteria Escherichia coli against bacteriostatic and bactericidal effects of H₂O₂, and influence of the plant extracts on expression of antioxidant gene katG, encoding catalase. The extracts from Chamerion angustifolium, Filipendula vulgaris and Pyrola rotundifolia indicated the highest levels of antioxidant activity both in vivo and in vitro. Our data suggest that the extracts of the tested plants may provide antioxidant effects on bacteria simultaneously through different pathways, including direct radical scavenging, iron chelation and induction of genes encoding antioxidant enzymes.     

Antioxidant Properties of Selected <Emphasis Type="Italic">Boletus</Emphasis> Mushrooms

Considering the growing interest for mushrooms and the demand search of natural antioxidants sources, the aim of this study was to investigate the antioxidant properties of two edible widely used Boletus species, Boletus edulis, and Boletus auranticus, collected from Istra region in Croatia in late summer 2007. To evaluate the antioxidant properties and content of antioxidant compounds, scavenging capacity on DPPH˙, OH˙, and O₂˙⁻ radicals, reducing power and capacity to inhibit lipid peroxidation has been investigated. It is determined that content of total phenols (41.82 ± 0.08 mg gallic acid equivalent per gram of dry extract) was higher for B. edulis. Using high performance liquid chromatography/diode array detector analysis, the main antioxidant compound, variegatic acid, has been detected and quantified. 1,1-Diphenyl-2-picryl-hydrazyl-hydrate assay was used as a preliminary free radical–scavenging evaluation. By this assay, it has been found that B. edulis dry mushroom extract exhibits 50% of inhibition value at the extract concentration of 0.016 ± 0.0003 mg/ml. The extracts were capable of reducing iron(III) and, thus, are capable of donating electrons. Using electron paramagnetic resonance spin-trapping and spin-probing techniques, activity against relevant reactive species, ˙OH and O₂˙⁻ radical, was analyzed for both mushroom extracts. Both investigated extracts are determined as good inhibitors for ˙OH radical reduction, and both exhibited significant capacity for scavenging O₂˙⁻ radical and for that could help to prevent or meliorate oxidative damage. Only B. edulis extract prevents lipid peroxidation. Investigated mushroom extracts could represent easily accessible natural antioxidant resource.     

Evaluation of in-vitro antioxidant and antibacterial properties of Commelina nudiflora L. extracts prepared by different polar solvents

The study explored on the commonly available weed plant Commelina nudiflora which has potential in-vitro antioxidant and antimicrobial activity. The different polar solvents such as ethanol, chloroform, dichloromethane, hexane and aqueous were used for the soxhlet extraction. The extracts were identified pharmacologically as important bioactive compounds and their potential free radical scavenging activities, and antimicrobial properties were studied. C. nudiflora extracts were monitored on their in-vitro antioxidant ability by DPPH and ABTS radical scavenging assay. Aqueous extract shows significant free radical scavenging activity of 63.4 mg/GAE and 49.10 mg/g in DPPH and ABTS respectively. Furthermore, the aqueous crude extract was used in antibacterial studies, which shows the highest inhibitory activity against Pseudomonas aeruginosa, Escherichia coli and Salmonella typhi. Among all the extracts, aqueous extract of C. nudiflora has significant control over free radical scavenging activity and inhibition of the growth of food pathogenic bacteria. Also, the aqueous extract contains abundance of phenolics and flavonoids higher than other extracts. This study explored weed plant C. nudiflora as a potential source of antioxidant and antibacterial efficacy and identified various therapeutic value bioactive compounds from GC–MS analysis.Abbreviations: ABTS, 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid), DPPH, 2,2-diphenyl-1-picrylhydrazyl, GAE, gallic acid equivalent, GC–MS, gas chromatography and mass spectrometry     

Antioxidant activity of aqueous methanol extracts from the lucanid beetle,Serrognathus platymelus castanicolor Motschulsky (Coleoptera: Lucanidae)

The objective of this study was to evaluate the antioxidant properties of extracts of the lucanid beetle, Serrognathus platymelus castanicolor Motschulsky, obtained at different growth stages. The antioxidant activities of six different extracts were determined using 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), and singlet oxygen (¹O₂). The activity level of pupal methanol extracts (PME) was higher in the DPPH and ABTS radical scavenging assays, whereas that of the water extracts was weaker in all assays. The ¹O₂ quenching ability of the PME was comparable to that of ascorbic acid (effective concentration of 50% ¹O₂ quenching: EC₅₀ = 0.184 mg/ml^-1 and 0.167 mg/ml^-1, respectively). The free radical scavenging antioxidant ability of the extracts significantly altered phenolic contents, important factors in the potency of antioxidant capacity. Our results suggest that these extracts may reduce oxidative stress in living organisms and reduce oxidative damage in insects under unfavorable conditions.     

Lipid and Phenolic Constituents from Seeds of Hypericum perforatum L. and Hypericum tetrapterum Fr. and their Antioxidant Activity

Seeds of Hypericum perforatum and H. tetrapterum were extracted with dichloromethane and methanol and investigated by chromatographic and mass spectrometric methods. Both species yielded a fatty oil fraction amounting to 30.5% and 18.0% of the seed weight, respectively. Linoleic acid (C18:2n‐6) was shown to be the predominant fatty acid constituent. Moreover, xanthone derivatives, i.e. tetrahydroxyxanthones (THX), xanthone‐glycosides and xanthone‐sulfonates, were assigned in methanolic extracts. For structure elucidation, one representative xanthone, namely 1,3,6,7‐THX, was synthesized and analyzed via HPLC‐DAD/MSⁿ and GC/MS. Total THX contents were quantitated applying a validated HPLC‐DAD method, resulting in 1.25 g/kg (H. perforatum) and 0.27 g/kg (H. tetrapterum), respectively. Moreover, the free radical scavenging capacity of the methanol extracts was tested using the DPPH antioxidant assay. Both, H. perforatum (IC₅₀ = 8.7 mg/l) and 1,3,6,7‐THX (IC₅₀ = 3.0 mg/l), exhibited good DPPH free radical scavenging activity compared to Trolox (IC₅₀ = 6.6 mg/l).     

In Vitro and In Vivo Antioxidant Activity of <Emphasis Type="Italic">Bifidobacterium animalis</Emphasis> 01 Isolated from Centenarians

Several studies reported the antioxidant activity of bifidobacteria using assays in vitro. In present study, the in vitro and in vivo antioxidant activity of Bifidobacterium animalis 01 was investigated. Culture supernatant, intact cells, and intracellular cell-free extracts of B. animalis 01 were involved in this study. The antioxidant assays in vitro included lipid peroxidation assay, 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, hydroxyl radical ( ^• OH) assay and superoxide anion ( \textO₂ ^- {\text{O}}_{2}^{ - } ) assay. The antioxidant assays in vivo were conducted using mice model. Activities of antioxidative enzymes, malondialdehyde (MDA) content in serums and livers of aging mice were evaluated. Monoamine oxidase (MAO) activity and lipofuscin level in brains of aging mice were also characterized. Results showed that culture supernatant, intact cells and intracellular cell-free extracts of B. animalis 01 could effectively scavenge free radicals, significantly enhance mice’s activities of antioxidative enzymes and reduce mice’s MDA content, lipofuscin level and MAO activity. Our results indicated that B. animalis 01 has the potential to be developed into a dietary antioxidant supplements.     

Evaluation of Antioxidant Activities of Ampelopsin and Its Protective Effect in Lipopolysaccharide-Induced Oxidative Stress Piglets

The aim of this study was to investigate the antioxidant potential of ampelopsin (APS) by using various methods in vitro, as well as to determine effects of APS on LPS-induced oxidative stress in piglets. The results showed that APS exhibited excellent free radical scavenging by DPPH, ABTS, O₂•⁻, H₂O₂ and ferric reducing antioxidant power. Ampelopsin also protected pig erythrocytes against AAPH-induced apoptosis and hemolysis, decreased total superoxide dismutase activity, and increased lipid peroxidation. Furthermore the results demonstrated that APS enhanced the total antioxidant capacity and decreased the malondialdehyde and protein carbonyl contents in LPS-treated piglets. The results of the present investigation suggest that APS possesses a strong antioxidant activity and alleviates LPS-induced oxidative stress, possibly due to its ability to prevent reactive oxygen species.     

Evaluation of Nutritional and Antioxidant Status of Lepidium latifolium Linn.: A Novel Phytofood from Ladakh

Lepidium latifolium Linn. (perennial pepperweed) is one of the preferred phytofoods among cold arid region of Ladakh, India and its leaves contribute significantly to people''s diet. This study was conducted to determine its nutritive value and antioxidant activity. Plant samples from three different locations were selected in the present study. Results showed that this plant is an excellent source of glucosinolates, notably sinigrin that is present in very high amount (∼70–90%). Its value ranged from 149 to 199 µg per g fresh weight. Fatty acid composition analysis showed that its leaves were abundant in unsaturated fatty acids, specifically linolenic acid (18∶3) whose percentage is about 50%. Higher glucose and crude protein along with higher nitrogen to sulfur ratio, supplements the nutritive value of this plant. Based on total phenol, flavanoids, free radical scavenging activity and DNA protective activity showed that this ecotype of perennial pepperweed contains high antioxidant properties. The percentage inhibition for O₂ ⁻ scavenging activity ranged from 41.3% to 83.9%. Higher content of phenols (26.89 to 50.51 mg gallic acid equivalents per g dry weight) and flavanoids (38.66 to 76.00 mg quercetin equivalents per g dry weight) in leaves could be responsible for the free radical scavenging activity of this plant. Depending upon the location of the plants, variations were observed in different activities. Based on the systematic evaluation in this study, preparations of Lepidium latifolium from Ladakh can be promoted as substitute to dietary requirements.     

Antioxidant,Anti-Skin-Aging,Anti-Inflammatory,and Anti-Acetylcholinesterase Activities of Rourea oligophlebia Extracts

The objective of this study was to evaluate the antioxidant, anti-skin-aging, anti-inflammatory, and anti-acetylcholinesterase activities of the hexane (n-hex), AcOEt, BuOH, MeOH, and aqueous extracts from R. oligophlebia roots. The total phenolic and flavonoid contents (TPC and TFC) were determined using Folin-Ciocalteu and AlCl₃ colorimetric assays. The antioxidant capacity was examined by reducing power (RP), ferric reducing antioxidant power (FRAP), ABTS⋅⁺, and DPPH⋅⁺ radical cation assays. All extracts potentially exhibited antioxidant activity with IC₅₀ values ranging from 2.93 to 5.73 μg/mL for ABTS⋅⁺ and from 5.69 to 7.65 μg/mL for DPPH⋅⁺ except the n-hex extract. The BuOH, MeOH, and aqueous extract possess promising anti-skin-aging activities, as observed by an attenuation of UV-A toxicity on human keratinocytes. We proposed that these anti-skin-aging properties are possibly due to direct scavenging activity against reactive oxygen species and upregulate cellular antioxidant machinery. Moreover, we found that the antioxidant capacity was well correlated with anti-inflammatory capacity against nitric oxide (NO) production in terms of the n-hex, AcOEt, and BuOH extracts with IC₅₀ values from 23.21 to 47.1 μg/mL. In contrast, these activities were found to be poorly correlated with AchE activity. To the best of our knowledge, this is the first report of the antioxidant, anti-skin-aging, anti-inflammatory, and anti-acetylcholinesterase activities of the extracts of R. oligophlebia roots. These findings indicated that this species could be a potential source of natural antioxidant, anti-aging, and anti-inflammatory agents. Consequently, it may be suggested as a medicinal plant that prevents diseases related to oxidative stress and inflammatory responses.     

Phytochemical characteristics of aerial part of Cissus quadrangularis (L) and its in-vitro inhibitory activity against leukemic cells and antioxidant properties

Background and ObjectivesCissus quadrangularis Linn, is a rich bioresource for folk and traditional medicines from ancient times till date. The present study aimed to investigate the free radical scavenging and anticancer efficacy in vitro of the ethanolic and methanolic extract from the aerial parts of Cissus quadrangularis (L).Material and MethodsIn vitro cell-free antioxidant analyses were performed for the ethanolic extract of Cissus quadrangularis (L). (EECQ) and methanolic extract of Cissus quadrangularis (L). (MECQ) using different free radical scavenging assays includes DPPH, nitric oxide, superoxide, metal chelation, and hydrogen peroxide radical scavenging assays. In vitro leukemic cytotoxic assessment by MTT assay was performed both EECQ and MECQ extract against HL-60 cell lines.ResultsStrong antioxidant effects were recorded in EECQ and MECQ in all the cell-free models. The ethanolic extract exhibited a significant dose-dependent free radical activity in comparison with methanolic extracts. The EECQ and MECQ possess pronounced anticancer efficacy against leukemic cells HL-60 with an IC₅₀ value of 36 μg/mL and 40 μg/mL respectively.ConclusionPresent data indicates the presence of marked antioxidant and anticancer behaviors in the extracts of aerial portions of Cissus quadrangularis (L). extracts. Thus, Cissus quadrangularis (L). poses as a promising safe chemopreventive plant to combat cancer.     

Antioxidant activity of mycosporine-like amino acids isolated from three red macroalgae and one marine lichen

Several standard in vitro assays were performed in order to determine the potential antioxidant capabilities of purified aqueous extracts of the mycosporine-like amino acids (MAAs), porphyra-334 plus shinorine (P-334 + SH), isolated from the red alga Porphyra rosengurttii, asterina-330 plus palythine (AS-330 + PNE), from the red alga Gelidium corneum, shinorine (SH), from the red alga Ahnfeltiopsis devoniensis, and mycosporine -glycine (M-Gly), isolated from the marine lichen Lichina pygmaea. The scavenging potential of hydrosoluble radicals (ABTS⁺ decolorization method), the antioxidant activity in lipid medium (β-carotene/ linoleate bleaching method) and the scavenging capacity of superoxide radicals (pyrogallol autooxidation assay) were evaluated. In terms of scavenging of hydrosoluble radicals, the antioxidant activity of all MAAs studied was dose-dependent and it increased with the alkalinity of the medium (pH 6 to 8.5). M-Gly presented the highest activity in all pH tested; at pH 8.5 its IC₅₀ was 8-fold that of L-ascorbic acid (L-ASC) followed by AS-330 + PNE while P-334 + SH and SH showed scarce activity of scavenging of hydrosoluble free radicals. AS-330 + PNE showed high activity for inhibition of β-carotene oxidation relative to vitamin E and superoxide radical scavenging whilst the activity of P-334 +SH and SH were moderate. According to these results, the potential of MAAs in photoprotection can be considered high due to a double function: (1) UV chemical screening with high efficiency for UVB and UVA regions of the solar spectrum, and (2) their antioxidant capacity.     

Superoxide dismutase activity of the captopril-iron complex

With an assay that generates superoxide anion radicals without the intervention of metal ions we investigated the antioxidant properties of captopril, an angiotensin-converting enzyme inhibitor with a sulfhydryl group. Under these conditions, increasing concentrations of the drug were seen not to scavenge O· ₂ ^– directly. However, a combination of captopril and iron could bring about the breakdown of the superoxide anion; a result that may help to understand the free radical-scavenging properties of captopril.     

Antioxidant properties of <Emphasis Type="Italic">Galium verum</Emphasis> L. (Rubiaceae) extracts

The antioxidant properties of methanol extracts of Lady’s Bedstraw (Galium verum L., Rubiaceae) herb from two different localities in Serbia were evaluated. Antioxidant activity was assessed in four different model systems. Free radical scavenging capacity (RSC) was examined by measuring the scavenging activity of extracts on 2,2-diphenyl-1-pycrylhydrazil (DPPH) and hydroxyl radical (OH), as well as on hydrogen peroxide. In addition, the protective effects of lipid peroxidation (LP) in corn oil were evaluated by the TBA-assay using the Fe²⁺/ascorbate system of induction. The amount of dried extract, the content of total phenolics, flavonoids and chlorophylls was also determined. Extracts from both locations expressed very strong scavenger activity, reducing the DPPH^⊙ (IC₅₀=3.10 μg/mland 8.04 μg/ml) and OH radical formation (IC₅₀=0.05 μg/ml and 0.54 μg/ml) and neutralising H₂O₂ (IC₅₀=4.98 μg/ml and 3.80 μg/ml), in a dose dependant manner. Also, examined extracts showed notable inhibition of LP (IC₅₀=11.69 μg/ml and 19.47 μg/ml). The observed differences in antioxidant activity could be partially explained by the levels of phenolics (2.44–4.65 mg and 4.57–5.16 mg gallic acid equivalents/g dry extract), flavonoids (6.38–10.70 μg and 15.56–17.96 μg quercetin equivalents/g dry extract) and chlorophylls in the investigated Lady’s Bedstraw extracts.     

In vitro antioxidant properties,free radicals scavenging activities of extracts and polyphenol composition of a non-timber forest product used as spice: Monodora myristica

Background

Excessive production of free radicals causes direct damage to biological molecules such as DNA, proteins, lipids, carbohydrates leading to tumor development and progression. Natural antioxidant molecules from phytochemicals of plant origin may directly inhibit either their production or limit their propagation or destroy them to protect the system. In the present study, Monodora myristica a non-timber forest product consumed in Cameroon as spice was screened for its free radical scavenging properties, antioxidant and enzymes protective activities. Its phenolic compound profile was also realized by HPLC.

Results

This study demonstrated that M. myristica has scavenging properties against DPPH^•, OH^•, NO^•, and ABTS^• radicals which vary in a dose depending manner. It also showed an antioxidant potential that was comparable with that of Butylated Hydroxytoluene (BHT) and vitamin C used as standard. The aqueous ethanol extract of M. myristica barks (AEH); showed a significantly higher content in polyphenolic compounds (21.44 ± 0.24 mg caffeic acid/g dried extract) and flavonoid (5.69 ± 0.07 quercetin equivalent mg/g of dried weight) as compared to the other studied extracts. The HPLC analysis of the barks and leaves revealed the presence of several polyphenols. The acids (3,4-OH-benzoic, caffeic, gallic, O- and P- coumaric, syringic, vanillic), alcohols (tyrosol and OH-tyrosol), theobromine, quercetin, rutin, catechine and apigenin were the identified and quantified polyphenols. All the tested extracts demonstrated a high protective potential on the superoxide dismutase (SOD), catalase and peroxidase activities.

Conclusion

Finally, the different extracts from M. myristica and specifically the aqueous ethanol extract reveal several properties such as higher free radical scavenging properties, significant antioxidant capacities and protective potential effects on liver enzymes.     

Lipase-catalysed synthesis of esters of ferulic acid with natural compounds and evaluation of their antioxidant properties

Lipases from Candida antarctica (Novozyme 435^®), Candida rugosa, Chromobacterium viscosum and Pseudomonas sp. were used to perform transesterifications of vinyl ferulate with hydroxyl-steroids and p-arbutin. The antioxidant activity of the products was evaluated using the free radical 2,2′-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) free radical quenching antioxidant assays, and inhibition of the oxidation of low-density lipoprotein, LDL. Arbutin ferulate was found to possess a 19% higher antiradical activity against the ABTS free radical than its precursor ferulic acid, and it also inhibited the oxidation of LDL more efficiently (by 10%) than its precursors. All of the biocatalytically synthesised products exhibited higher antioxidant activity than Trolox, the well known commercial benchmark antioxidant, and their precursor, ferulic acid.     

Antioxidant properties and phenolic profiling by UPLC-QTOF-MS of Ajwah,Safawy and Sukkari cultivars of date palm

Date palm (P. dactylifera) plays a vital role in ethnomedicinal practices in several parts of the world. There are over 2000 cultivars of date palm that differ in chemical composition and extent of bioactivity. The present study was undertaken to comparatively evaluate the antioxidant potential of three cultivars of date palm (Ajwah, Safawy and Sukkari) from Saudi Arabia and analyze their phenolic constituents in order to draw a rationale for their activity. Antioxidant activities of the date cultivars were evaluated by different quantitative methods including 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical scavenging assay, total antioxidant capacity, reducing power, total phenolic (TPC), flavonoid (TFC) and tannin content (TTC), while qualitative phenolic composition was determined using ultra performance liquid chromatography coupled to quadropole time of flight mass spectrometry (UPLC-QTOF-MS). All the three date extracts showed good DPPH radical scavenging (IC₅₀ 103–177 μg/mL) and hydroxyl radical scavenging (IC₅₀ 1.1–1.55 mg/mL) activity and total antioxidant capacity (IC₅₀ 87–192 μg/mL). The reducing power was also comparable to that of ascorbic acid, used as standard in above experiments. All the three samples contain significant amount of major antioxidant components (phenolic, flavonoid and tannin) that successfully correlates with the results of radical scavenging assays. UPLC-QTOF-MS revealed a total of 22 compounds in these date cultivars classified into common phenolics, flavonoids, sterols and phytoestrogens. Significant variation in the degree of antioxidant activity of these three date cultivars can be attributed to the difference in the content and composition of phenolic compounds.     

Antioxidant activities of cultured <Emphasis Type="Italic">Armillariella mellea</Emphasis>

This study aimed to evaluate the antioxidant activities of a cultured medicinal fungus—Armillariella mellea (Vahl. ex Fr.) Karst. (AM). Three antioxidant assay systems, namely cytochrome c, xanthine oxidase inhibition, and FeCl₂-ascorbic acid stimulated lipid peroxidation in rat tissue homogenate tests, were used. Total flavonoid and phenol contents of AM extracts were also analyzed. Results showed that both aqueous (AM-H₂O) and ethanolic (AM-EtOH) extracts of solid state cultured AM showed antioxidant activities in a concentration-dependent manner. At concentrations 1–100 μg/ml, the free radical scavenging activity was 73.7–92.1% for AM-H₂O, and 60.0–90.8% for AM-EtOH. These extracts also showed an inhibitory effect on xanthine oxidase activity, but with a lesser potency (IC₅₀ is 9.17 μg/ml for AM-H₂O and 7.48 μg/ml for AM-EtOH). In general, AM-H₂O showed a stronger antilipid peroxidation activity on different rat’s tissues than AM-EtOH. However, both AM extracts displayed a weak inhibitory effect on lipid peroxidation in plasma. Interestingly, the antilipid peroxidation activity of AM-H₂O (IC₅₀–6.66 μg/ml) in brain homogenate was as good as IC₅₀–5.42 μg/ml. AM-H₂O (80.0 mg/g) possessed a significantly higher concentration of total flavonoids than AM-EtOH (30.0 mg/g), whereas no difference was noted in the total phenol content between these two extracts. These results conclude that AM extracts possess potent free radical scavenging and antilipid peroxidation activities, especially the AM-H₂O in the brain homogenate. Published in Russian in Prikladnaya Biokhimiya i Mikrobiologiya, 2007, Vol. 43, No. 4, pp. 495–500. The text was submitted by the authors in English.     

The importance of lipid solubility in antioxidants and free radical generating systems for determining lipoprotein peroxidation

The oxidative modification of low-density lipoprotein (LDL) plays an important role in atherosclerosis. Protecting LDL from oxidation has been shown to reduce the risk of coronary heart disease. In this study, we compared the protective effects of two lipophilic antioxidants (vitamin E and lazaroid) with two hydrophilic antioxidants (trolox and vitamin C) in the presence of several different free radical generating systems. Vitamin E (IC₅₀ = 5.9 μM) and lazaroid (IC₅₀ = 5.0 μM) were more effective in inhibiting lipid peroxidation caused by a Fe-ADP free radical generating system than vitamin C (IC₅₀ = 5.2 × 10³ μM) and trolox (IC₅ = 1.2 × 10³ μM). Preincubation of lipoproteins with a lipophilic antioxidant increased the protective effect against various free radicals. Preincubation with hydrophilic antioxidants did not have an effect. We also tested the efficacy of the antioxidants when the free radicals were generated within the lipid or the aqueous environment surrounding the LDL. For this purpose, we used the peroxyl generating azo-compounds AMVN (2,2′-azobis(2,4-dimethylvaleronitrile)) and AAPH (2,2′azobis (2-amidinopropane) dihydrochloride). All of the antioxidants tested were more effective against free radicals generated in a water soluble medium than they were against free radicals generated in a lipid environment. In conclusion, our data demonstrate that lipid solubility is an important factor for both the antioxidant and the free radical generating systems in determining the extent of lipid peroxidation in LDL. Our data also demonstrate that antioxidant efficacy in one set of experimental conditions may not necessarily translate into a similar degree of protection in another set of conditions where lipophilicity is a variable.     

Metabolomic profiling and antioxidant activity of some Acacia species

Metabolomic profiling of different parts (leaves, flowers and pods) of Acacia species (Acacia nilotica, Acacia seyal and Acacia laeta) was evaluated. The multivariate data analyses such as principal component analysis (PCA) and partial least square-discriminant analysis (PLS-DA) were used to differentiate the distribution of plant metabolites among different species or different organs of the same species. A.nilotica was characterized with a high content of saponins and A.seyal was characterized with high contents of proteins, phenolics, flavonoids and anthocyanins. A.laeta had a higher content of carbohydrates than A. nilotica and A. seyal. On the basis of these results, total antioxidant capacity, DPPH free radical scavenging activity and reducing power of the methanolic extracts of studied parts were evaluated. A.nilotica and A.seyal extracts showed less inhibitory concentration 50 (IC₅₀) compared to A.laeta extracts which means that these two species have the strongest radical scavenging activity whereas A. laeta extracts have the lowest radical scavenging activity. A positive correlation between saponins and flavonoids with total antioxidant capacity and DPPH radical scavenging activity was observed. Based on these results, the potentiality of these plants as antioxidants was discussed.     

Phytochemical,antioxidant and mineral composition of hydroalcoholic extract of chicory (Cichorium intybus L.) leaves

The phytochemical, antioxidant and mineral composition of hydroalcoholic extract of leaves of Cichorium intybus L., was determined. The leaves were found to possess comparatively higher values of total flavonoids, total phenolic acids. The phytochemical screening confirmed the presence of tannins, saponins, flavonoids, in the leaves of the plant. The leaf extract was found to show comparatively low value of IC₅₀ for 2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibition. The IC₅₀ value of chicory leaves extract was found to be 67.2 ± 2.6 μg/ml. The extracts were found to contain high amount of mineral elements especially Mg and Zn. Due to good phytochemical and antioxidant composition, C. intybus L., leaves would be an important candidate in pharmaceutical formulations and play an important role in improving the human health by participating in the antioxidant defense system against free radical generation.