Antioxidant Activity of Ipomoea batatas L. Lam. Leaf Grown in Continental Croatia and Its Effect on Glutathione Level in Glucose-Induced Oxidative Stress

Ethanolic and aqueous extract of Ipomoea batatas (L.) Lam. leaf grown in Croatia were prepared. Antioxidant activity of the extracts, as well as their effect on intracellular glucose-induced oxidative stress, was determined. Antioxidant activity was assayed by DPPH radical scavenging activity, reducing power, activity in β-carotene-linoleic acid assay, and superoxide dismutase-like activity. In addition to being richer in phenols and flavonoids than aqueous extract, ethanolic extract also demonstrated superior antioxidant activity in all the assays. In a concentration of 10 μg/ml, both extracts were able to significantly increase intracellular glutathione levels.     

Evaluation of the antioxidant potential of Pittosporum dasycaulon Miq. stem bark

The in vitro antioxidant properties of methanol and aqueous extracts of stem bark from Pittosporum dasycaulon Miq. were investigated. Fractions were screened for total antioxidant capacity, ferric reducing power, and radical scavenging activities. The total phenolic, flavonoid, and tannin contents of the methanol and aqueous extracts were also determined. The aqueous extract exhibited a stronger scavenging effect than the methanol extract against the DPPH free radical, the nitric oxide radical, and the superoxide radical. The methanol extract exhibited a stronger total antioxidant activity and reducing power than the aqueous extract. The free radical scavenging effect of P. dasycaulon stem bark extracts was comparable to an ascorbic acid reference antioxidant while the reducing power of the methanol extract was greater than ascorbic acid. P. dasycaulon stem bark is a potential source of natural antioxidant compounds.     

In vitro evaluation of the antioxidant activities in the differentially processed seeds from underutilized legume, Bauhinia vahlii Wight & Arn

Antioxidant potential and total phenolics content of 70% acetone extracts of the raw and processed seeds of Bauhinia vahlii were evaluated. The extract of raw seeds contained higher levels of total phenolics (30.8 g/100 g) and tannins (19.6 g/100 g) compared to dry heated and soaking followed by autoclaving seed extracts. Extracts were screened for antioxidant and free radical scavenging activities using various chemical and in vitro model systems. In all the models, except DPPH radical scavenging activity, the extract from raw seeds manifested the strongest antioxidant activity than that from processed seeds. In β-carotene/linoleic acid emulsion system and superoxide scavenging activity, the raw seed extract registered more activity when compared to the standards (butylated hydroxyanisole and α-tocopherol). Whereas, the extract from dry heated seed exhibited higher DPPH^· scavenging activity (IC₅₀ 70.77 μg/mL) than the raw seeds (IC₅₀ 74.4 μg/mL). This study has to some extent validated the antioxidant potential of the seeds of B. vahlii.     

Inflorescences of Brassicacea species as source of bioactive compounds: A comparative study

Two Brassica oleracea varieties (B. oleracea L. var. costata DC and B. oleracea L. var. acephala) and Brassica rapa L. var. rapa inflorescences were studied for their chemical composition and antioxidant capacity. Phenolic compounds and organic acids profiles were determined by HPLC–DAD and HPLC–UV, respectively. B. oleracea var. costata and B. oleracea L. var. acephala inflorescences presented a similar qualitative phenolic composition, exhibiting several complex kaempferol derivatives and 3-p-coumaroylquinic acid, while B. rapa var. rapa was characterized by kaempferol and isorhamnetin glycosides and several phenolic acids derivatives. B. oleracea L. var. costata and B. rapa var. rapa showed the highest phenolics content. The three Brassica exhibited the same six organic acids (aconitic, citric, pyruvic, malic, shikimic and fumaric acids), but B. oleracea L. var. acephala presented a considerably higher amount. Each inflorescence was investigated for its capacity to act as a scavenger of DPPH radical and reactive oxygen species (superoxide radical, hydroxyl radical and hypochlorous acid), exhibiting antioxidant capacity in a concentration dependent manner against all radicals. These samples were also studied for its antimicrobial potential against Gram-positive and Gram-negative bacteria and fungi, displaying antimicrobial capacity only against Gram-positive bacteria.     

Antioxidant and tyrosinase inhibitory activities of different parts of guava (<Emphasis Type="Italic">Psidium guajava</Emphasis> L.)

The antioxidant and the tyrosinase inhibitory activities of 4 different solvents (acetone, ethanol, methanol, and water) for preparation of extracts from guava (branch, fruit, leaf, and seed) were evaluated by measuring total phenolic contents (TPC), DPPH radical scavenging activity, ABTS radical scavenging activity, reducing power (RP), and tyrosinase inhibitory activity. The extracts of branch and leaf showed relatively higher antioxidant properties than those of fruit and seed. The highest TPC (141.28 mg/g gallic acid equivalents), DPPH radical scavenging activity (IC₅₀=34.01 μg/mL), ABTS radical scavenging activity (IC₅₀=3.23 μg/mL), and RP (IC₅₀= 75.63 μg/mL) were found in acetone extract of leaf, while water extract of seed had the lowest antioxidant activity. The tyrosinase inhibitory activity of ethanol extract from guava leaf was 69.56%, which was the highest activity among the extracts. These results indicate that useful bioactive substances exist in the guava branch as well as leaf extracts.     

Antioxidant Capacities,Phenolic Contents,and GC/MS Analysis of Rhodiola imbricata Edgew. Root Extracts from Trans‐Himalaya

Our aim was to assess the antioxidant capacities and phenolic constituents of methanol and aqueous extracts of Rhodiola imbricata Edgew. root from Trans‐Himalayan cold desert of Ladakh. The 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) and 2,2′‐azinobis‐(3‐ethylbenzothiazoline‐6‐sulfonic acid (ABTS) radical scavenging capacity of the root extracts increased in a dose‐dependent manner (up to 0.1 mg/mL) and root extract concentrations required for 50% inhibition of radical scavenging effect (IC₅₀) were recorded as 0.013 and 0.014 mg/mL (for DPPH) and 0.016 and 0.017 mg/mL (for ABTS) for methanol and aqueous extracts, respectively. The total antioxidant power of the extract was determined by ferric reducing antioxidant power (FRAP) assay. Total polyphenol and phenolic acid content of methanol and aqueous extracts were 112.24, 59.06, 39.02, and 16.95 mg gallic acid equivalent/g of extract, respectively. Total flavonoid and flavonol contents were estimated to be 30.2, 17.67, 20.68, and 7.38 mg quercetin equivalent/g of extract, respectively. In all antioxidant capacity assays, the methanol extract exhibited significantly higher antioxidant capacity than that of aqueous extract due to the presence of significantly higher amount of vital phytoconstitiuents, viz. polyphenol, phenolic acid, and flavonol. GC/MS analysis showed that phytosterols, alkyl halide, phenols, and fatty acid esters were major phytochemical clusters. On the other hand, monoterpenes, fatty acids, tocopherols, aliphatic hydrocarbons, and ethers were found to be present in comparatively less amount in the methanol extract. Hence, our study signifies that this high‐altitude medicinal herb could be used as the natural source of antioxidants and supports its use in traditional system of medicine to ameliorate oxidative stress and high‐altitude maladies.     

Optimization of Conditions for the Extraction of Antioxidants from Leaves of <Emphasis Type="Italic">Syzygium cumini</Emphasis> L. Using Different Solvents

The aim of the present study was to find out the best method for extracting antioxidants from Syzygium cumini L. leaves. The extraction was done by three different methods: sequential cold percolation extraction method, decoction extraction method, and maceration extraction method. Antioxidant activity, total phenol, and flavonoid content were determined in all different extracts of various extraction methods of S. cumini L. leaves. Antioxidant activity was tested by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical, superoxide anion radical and hydroxyl radical scavenging activities, and reducing capacity assessment. Sequential cold percolation extraction method proved to be the best extraction method. The acetone extract had maximum phenol and flavonoid content and showed best DPPH free radical scavenging activity and reducing capacity assessment. Ethyl acetate extract showed best superoxide radical scavenging activity, while aqueous extract showed best hydroxyl radical scavenging activity. It can be concluded that sequential cold percolation extraction method is the best method of extracting leaf antioxidants for this plant at least.     

Antioxidant activities of red pepper (Capsicum annuum) pericarp and seed extracts

In this study, we examined the antioxidant activities of red pepper (Capsicum annuum, L.) pericarp and red pepper seed extracts. The extracts were evaluated by various antioxidant assays, including 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging, superoxide anion radical scavenging, hydroxyl radical scavenging, [2,2′‐azino‐bis(3‐ethylbenzthiazoline‐6‐sulphonic acid)] (ABTS) radical scavenging, ferrous chelating activity, superoxide dismutase (SOD) activity and reducing power, along with the determination of total phenolic and flavonoid contents. All the extracts showed strong antioxidant activity by the testing methods. The red pepper pericarp extract exhibited strong ferrous chelating activity and high scavenging activity against free radicals, including both the hydroxyl and DPPH radicals, but it exhibited weaker scavenging activity for the superoxide anion radical and for SOD. In contrast, the red pepper seed extract exhibited strong SOD activity and high scavenging activity against the superoxide anion radical, but showed weaker ferrous chelating activity, hydroxyl radical scavenging, and DPPH radical scavenging. We observed that the reducing power level and ABTS radical scavenging activity of the red pepper seed were higher than those of the red pepper pericarp at the highest tested concentration. Most of the test results for the red pepper seed and red pepper pericarp extracts increased markedly with increasing concentration; however, the metal chelating, SOD and ABTS radical scavenging activities did not increase with the concentration. Highest total phenolic and flavonoid contents were obtained from the red pepper pericarp extracts. Overall, the red pepper seed and red pepper pericarp extracts were highly effective for the antioxidant properties assayed, with the exceptions of ferrous chelating activity, hydroxyl radical scavenging and SOD activity.     

Screening of medium composition for the free radical‐scavenging properties by Antrodia cinnamomea

The effects of nutritional conditions on the scavenging capacity on superoxide anion radical and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) free radical of ethanolic extracts from filtrates of Antrodia cinnamomea were investigated in shake‐flask cultures. Culture medium significantly affected inhibition of superoxide anion generation and DPPH free radical scavenging activity. In contrast, both scavenging capabilities on superoxide anion radical and DPPH free radical were found to be greatly affected by varying the carbon source, the nitrogen source, the growth factors or the trace elements. The maximal inhibition of superoxide anion generation could be obtained when the culture medium compositions were: xylose, ammonium oxalate, nicotinic acid, NaH₂PO₄ and CuSO₄; while a maximal DPPH free radical scavenging activity could be achieved when the medium composition setting as: fructose, peptone, nicotinic acid, KH₂PO₄ and CaCl₂ (the scavenging effects on superoxide anion radical and DPPH free radical were increased to 96.3 ± 0.3% and 29.0 ± 1.0%, respectively). We proved that controlling the culturing conditions and modifying the composition of the medium can dramatically enhance the scavenging ability on superoxide anion radical and DPPH free radical of A. cinnamomea.     

Antioxidant and free radical scavenging activities of pigments extracted from molasses alcohol wastewater

The pigments from molasses alcohol wastewater were extracted by the macroporous resin adsorption method. The antioxidant and free radical scavenging activities of these pigments were also investigated. The adsorptive characteristics of five macroporous resins including HPD-600, HPD-500, D301-R, NKA-II and D296-R were studied and the results showed that the macroporous resin HPD-600 was most appropriate for extracting the pigments from molasses alcohol wastewater. The antioxidant and free radical scavenging activities of pigments extracted from alcohol wastewater were evaluated using nitrate, hydroxyl radical, superoxide anion radical and 1,1-diphenyl-2-picrylhydrazyl (DPPH) in vitro model systems. The pigment extract exhibited a concentration-dependent radical scavenging activity in all the systems. Meanwhile, scavenging activity of pigment extract in the DPPH system was found to be significantly (P < 0.05) higher than that in other systems and the 50% inhibitory concentration (IC₅₀ value) was about 0.07 mg/ml. The scavenging effect of pigment extract on superoxide anion radical was very weak with IC₅₀ value greater than 10 mg/ml.     

Antioxidant potency of cumin varieties—cumin, black cumin and bitter cumin—on antioxidant systems

Cumin is one of the commonly used spices in food preparations. It is also used in traditional medicine as a stimulant, a carminative and an astringent. In this study, we characterized the antioxidant activity of three commercially available cumin varieties, viz., cumin (Cuminum cyminum), black cumin (Nigella sativa) and bitter cumin (C. nigrum). The antioxidant capacity of cumin varieties was tested on Fe²⁺ ascorbate induced rat liver microsomal lipid peroxidation, soybean lipoxygenase dependent lipid peroxidation and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging methods. The total phenolic content of methanolic extracts of cumin varieties ranged from 4.1 to 53.6 mg g^–1 dry weight. Methanolic extracts of all the three varieties of cumin showed higher antioxidant activity compared with that of the aqueous extract. Among the cumin varieties, bitter cumin showed the highest antioxidant activity followed by cumin and black cumin in different antioxidant systems. IC₅₀ values of the methanolic extract of bitter cumin were found to be 0.32, 0.1 and 0.07 mg dry weight of cumin seeds on the lipoxygenase dependent lipid peroxidation system, the DPPH radical scavenging system and the rat liver microsomal lipid peroxidation system, respectively. The data also show that cumin is a potent antioxidant capable of scavenging hydroxy, peroxy and DPPH free radicals and thus inhibits radical-mediated lipid peroxidation. The high antioxidant activity of bitter cumin can be correlated to the high phenolic content among the three cumin varieties. Thus, bitter cumin with a high phenolic content and good antioxidant activity can be supplemented for both nutritional purposes and preservation of foods.     

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 and antimicrobial activity of legume hulls

Antioxidant activity of aqueous hull extracts of commonly consumed legumes in India namely Vigna radiata (mung bean), Cicer arietinum (Bengal gram) and Cajanus cajan (pigeon pea) was studied by several in vitro assays. The extracts showed high phenolic content and excellent DPPH scavenging activity (75-85%) at very low concentration. The IC₅₀ values for superoxide radical scavenging activity was also low (85-150 ??g/ml). The antioxidant activity coefficient as determined by ??-carotene bleaching assay was very high (828-1086). The hull extracts also exhibited high reducing power indicating good antioxidant potential. Of the extracts studied pigeon pea hull extract had the highest antioxidant activity. It also exhibited good antibacterial activity against Bacillus cereus. This study indicated that legume hulls have good antioxidant potential comparable to the synthetic antioxidant butylated hydroxy toluene and could therefore have application in food, cosmetic and pharmaceutical industry.     

Compositions, antioxidant and antimicrobial activities of Helichrysum (Asteraceae) species collected from Turkey

The methanolic extracts of 16 Helichrysum species were investigated for their in vitro antioxidant, radical scavenging and antimicrobial activities. All the extracts showed strong antioxidant and radical scavenging activity. The highest total antioxidant capacity as ascorbic acid equivalents (AAE) of 194.64 mg/g dry extract was obtained for Helichrysum noeanum in the phosphomolybdenum assay. The highest IC₅₀ value (7.95 μg/ml) was observed for the extract of Helichrysum stoechas subsp. barellieri in the DPPH assay. The total phenolic contents of the extracts ranged from 66.74 to 160.63 mg gallic acid equivalents (GAE)/g dry extract. The major component present in the extracts was identified as chlorogenic acid followed by apigenin-7-glucoside and apigenin by HPLC analysis. All the extracts showed significant antimicrobial activity against microorganisms containing 13 bacteria and two yeasts in the agar diffusion method.     

Evaluation of antioxidant and antimicrobial potential of strawberry tree (<Emphasis Type="Italic">Arbutus Unedo</Emphasis> L.) leaf

In present study, antioxidant and antimicrobial activities of strawberry tree (Arbutus unedo L.) leaves were investigated. Antioxidant activity was determined by methods of DPPH scavenging, β-carotene bleaching, reducing power, metal chelating, superoxide anion scavenging, and hydrogen peroxide scavenging activity. Total phenolic content were determined to be 197.16±1.43 mg GAE/g extract in aqueous extract. The EC₅₀ value of methanolic extracts was found to be 0.423 mg/mL. The extracts of leaves showed nearly 1/4 metal chelating capacity of standard EDTA, high reducing power, superoxide anion scavenging, and hydrogen peroxide scavenging activities. While the strawberry tree leaves exhibited antibacterial activity against Staphylococcus aureus, there was no inhibitory effect against Escherichia coli and Salmonella enteritidis. The strawberry tree leaves exhibited antifungal effect against 2 aflatoxigenic molds namely Aspergillus parasiticus NRRL 2999 and NRRL 465. These results suggest that the strawberry tree leaves may be used as an antioxidant source for pharmaceutical application, nutraceutical and functional food industries.     

Antioxidative Activity and Safety of 50% Ethanolic Red Bean Extract (Phaseolus radiatus L. var. Aurea)

ABSTRACT: This study evaluated the antioxidative activities of 50% ethanolic extract from red bean (Phaseolus radiatus L. var. Aurea). The antioxidative activities, including α,α‐diphenyl‐β‐picryl‐hydrazyl (DPPH) radicals scavenging effects, Fe²⁺‐chelating ability, and reducing power, were studied in vitro. The antioxidative activity was found to increase with the concentration of the extract to a certain extent and then level off as the concentration further increased. Compared with commercial antioxidants, the red bean extract showed less scavenging effect on the DPPH radical and less reducing power than α‐Tocopherol and BHT, but better Fe²⁺‐chelating ability. No mutagenic effect toward any tester strains was found in the 50% ethanolic extract of red bean.     

丝瓜花不同溶剂提取物抗氧化活性及其酚类成分分析

以无水乙醇、70%乙醇、40%乙醇和水分别对丝瓜花进行提取,并测定各提取物中总酚、总黄酮含量,采用DPPH·清除能力、超氧化物自由基清除能力、FRAP抗氧化能力和亚铁离子螯合能力等方法评价其抗氧化活性,通过HPLC分析其中酚类成分。结果表明,70%和40%乙醇提取物总酚及总黄酮含量较高,而且DPPH·清除活性、FRAP还原力最强,40%乙醇提取物、水提物分别具有最强的超氧阴离子自由基清除活性和亚铁离子螯合能力。总酚含量与DPPH·清除活性之间存在较强的相关性(R²=0.8688)。HPLC分析检出提取物中9种酚类化合物,其中含量最高的为杨梅素。试验结果说明,70%乙醇、40%乙醇可能是丝瓜花抗氧化性物质提取的较好溶剂。结果表明丝瓜花是一种较好的抗氧剂资源。     

Metabolite profiling and inhibitory properties of leaf extracts of Ficus benjamina towards α-glucosidase and α-amylase

The use of antioxidant-rich medicinal plants having the potential to reduce oxidative stress and postprandial hyperglycemic pressure is one of the most promising option for the management of diabetes. This study presents information on metabolite profiling and in vitro anti-diabetic effects of leaf extracts of Ficus benjamina. The DPPH (2, 2-diphenyl-1-picrylhydrazyl radicals) assay was performed to determine the in vitro antioxidant potential of the plant extracts. The anti-diabetic effects were investigated by evaluating inhibitory properties of F. benjamina leaf extracts towards carbohydrate hydrolyzing enzymes, i.e., α-glucosidase and α-amylase, whereas ¹H NMR and UHPLC-QTOF-MS/MS analytical methods were employed for metabolite profiling of F. benjamina leaf extracts. Among 40, 60, 80, and 100% ethanolic leaf extracts of F. benjamina, 80% ethanolic extract exhibited the highest antioxidant activity based upon its DPPH radical scavenging ability (IC₅₀ value: 63.71 ± 2.66 µg/mL). The 80% ethanolic leaf extract of F. benjamina also proved to be the most efficient α-glucosidase and α-amylase inhibitor with IC₅₀ values of 9.65 ± 1.04 µg/mL and 13.08 ± 1.06 µg/mL, respectively; these values were even better than acarbose with α-glucosidase inhibition activity (IC₅₀ = 116.01 ± 3.83 µg/mL) and α-amylase inhibition activity (IC₅₀ = 152.66 ± 7.32 µg/mL). Moreover, a total of 31 metabolites were identified in F. benjamina leaf extract, which may have the potential to contribute to its antioxidant and inhibitory properties against carbohydrate hydrolyzing enzymes. The findings of this study depict F. benjamina leaf extracts as a promising α-glucosidase and α-amylase inhibitor, and therefore, can be utilized for the development of anti-diabetic functional diets/nutra-pharmaceuticals.     

Antioxidant activity of the differentially processed seeds of Jack bean (<Emphasis Type="Italic">Canavalia ensiformis</Emphasis> L. DC)

Antioxidant activity of 70% acetone extracts of raw and processed seeds of Jack bean (Canavalia ensiformis L. DC) was evaluated by various in vitro antioxidant assays, including total antioxidant, free radical scavenging, reducing power, metal ion chelating, β-carotene/linoleic acid bleaching, and antihemolytic activities. The total phenolics and tannin contents were higher in the extract of seeds processed by autoclaving with 1% ash solution (3.2 and 1.6 g/100 g extract, respectively). In general, all the extracts of processed seeds exhibited higher activity in various antioxidant systems, when compared to raw seeds but significant differences were noticed between processing methods. The extract of seeds autoclaved with 1% sugar solution showed higher DPPH radical scavenging activity (IC₅₀ 10.6 mg/mL). Interestingly, the extract of dry heated seeds registered higher inhibition of hemolysis (76.1%) compared to standards butylated hydroxyanisole (BHA) (66.2%) and α-tocopherol (59.3%) at the concentration of 500 μg/mL.