Melilotus albus and Dorycnium herbaceum extracts as source of phenolic compounds and their antimicrobial,antibiofilm, and antioxidant potentials

Melilotus albus Medic. and Dorycnium herbaceum Vill. (Fabaceae) acetone, ethyl acetate, and ethanol extracts were investigated for their in vitro antimicrobial, antibiofilm, and anti-oxidant activity with quantification of phenolic compound contents. In general, D. herbaceum extracts showed better antibacterial and antioxidant activity than M. albus extracts. Bacteria Bacillus subtilis, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa, and Proteus mirabilis were the most susceptible with the minimum inhibitory concentrations (MICs), determined by microdilution method, between 1.25–10 mg/mL. Antifungal activity was lower with the detectable MICs at 10 mg/mL and 20 mg/mL. The plant extracts, using the crystal violet assay, inhibit P. aeruginosa biofilm formation in concentration range from 5 mg/mL to 20 mg/mL whereas the effect on mature bacterial biofilm was lower. The antioxidant activity was evaluated using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radicals scavenging and reducing power model systems. The intensity of DPPH radicals scavenging activity, expressed as half maximal effective concentration (EC₅₀) values, was from 84.33 μg/mL to >1000 μg/mL. The extracts demonstrated reduced power in a concentration-dependent manner, with ethanol extract as the most active. The total phenols, flavonoids, and proanthocyanidins were determined spectrophotometrically while total extractable tannins were obtained by precipitation method. The phenolic compounds showed differences in their total contents depending on solvents polarities and plant species. Although the plants M. albus and D. herbaceum have not yet been fully explored, these results contribute better understanding of their biotic properties and potential application as antimicrobial and antioxidant agents.     

Antimicrobial and antioxidant effects of phenolic constituents from Klainedoxa gabonensis

Bioassay-guided fractionation of the methanol extract of the stem bark of Klainedoxa gabonensis Pierre ex Engl. (Irvingiaceae) afforded 12 compounds, namely, ellagic acid (1), ellagic acid 3,3′-dimethylether (2), gallic acid (3), methyl gallate (4), lupeol (5), β-amyrin (7), erythrodiol (8), oleanolic acid (9), betulinic acid (6), hederagenin (10), bayogenin acid (11), and stigmasterol-3-O-β-d-glucopyranoside (12). Compounds 1-3 and 7-12 were isolated for the first time from this genus. The structures were established on the basis of 1D/2D NMR experiments and mass spectrometric data. Crude extract, fractions (A, B, C and D) and pure compounds were tested for their antimicrobial activity using paper disk agar diffusion assay. The test delivered a range of low to high activities for phenolic compounds 1-4, low or missing activities for terpenoid compounds 5-11, and impressive very high antibacterial/antifungal values for two fractions C and D probably due to synergistic effects of compounds. The broth microdilution assay revealed MICs of 15.4-115.1?μg/mL for phenolic compounds, MICs higher than 1?mg/mL for terpenoids and MICs of 4.5-30.3?μg/mL for fractions C and D. The determination of the radical scavenging activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay gave high antioxidant values for the methanol extract and fraction D (IC₅₀ 10.45 and 5.50?μg/mL) as well as for the phenolic compounds 1-4 (IC₅₀ 45.50-48.25?mM) compared to the standard 3-t-butyl-4-hydroxyanisole (BHA) (IC₅₀ 44.20?mM).     

Effects of blending wheatgrass juice on enhancing phenolic compounds and antioxidant activities of traditional kombucha beverage

Traditional kombucha is a fermented black tea extract and sugar. Sweetened black tea (10% w/v) and wheatgrass juice (WGJ) were mixed in various ratios and used as fermentation substrate for enhancing phenolic compounds and antioxidant activity. Starter, comprising of yeast (Dekkera bruxellensis) and acetic acid bacteria (Gluconacetobacter rhaeticus and Gluconobacter roseus), was inoculated at 20% (v/v), and fermented statically at 29 ± 1°C for 12 days. The results showed that the total phenolic and flavonoid contents and antioxidant activity of the modified kombucha were higher than those of traditional preparations. All WGJ-blended kombucha preparations were characterized as having higher concentrations of various phenolic compounds such as gallic acid, catechin, caffeic acid, ferulic acid, rutin, and chlorogenic acid as compared to traditional ones. Addition of WGJ resulted in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability of kombucha being > 90%, while the oxygen radical absorbance capacity increased from 5.0 μmol trolox equivalents/mL to 12.8 μmol trolox equivalents/mL as the ratio of WGJ increased from 0% to 67% (v/v). The highest antioxidant activity was obtained using a 1:1 (v/v) black tea decoction to WGJ ratio and 3 days of fermentation, producing various types of phenolic acids. These results suggest that intake of fermented black tea enhanced with wheatgrass juice is advantageous over traditional kombucha formulas in terms of providing various complementary phenolics and might have more potential to reduce oxidative stress.     

Antioxidant capacity of hesperidin from Citrus peel using electron spin resonance and cytotoxic activity against human carcinoma cell lines

Context: Hesperidin is a flavonoid that has various pharmacological activities including anti-inflammatory, antimicrobial and antiviral activities.

Objective: The aim of the study is the isolation of hesperidin from the peel of Citrus sinensis L. (Rutaceae), and the evaluation of its antioxidant capacity and cytotoxicity against different human carcinoma cell lines.

Materials and methods: In the present work, hesperidin is identified and confirmed using chromatographic and spectral analysis. To correlate between hesperidin concentration and antioxidant capacity of peel extracts, extraction was carried out using 1% HCl-MeOH, MeOH, alkaline solution, the concentration of hesperidin determined qualitatively and quantitatively using high performance thin layer chromatography (HPTLC), high performance liquid chromatography (HPLC) analysis, in vitro antioxidant capacity of hesperidin and the extracts against free radical diphenylpicrylhydrazyl (DPPH?) performed using an electron spin resonance spectrophotometer (ESR). Cytotoxic assay against larynx, cervix, breast and liver carcinoma cell lines was performed.

Results: Hesperidin was found to be moderately active as an antioxidant agent; its capacity reached 36%. In addition, the results revealed that hesperidin exhibited pronounced anticancer activity against the selected cell lines. IC₅₀ were 1.67, 3.33, 4.17, 4.58 µg/mL, respectively.

Discussion and conclusion: Orange peels are considered to be a cheap source for hesperidin which may be used in the pharmaceutical industry as a natural chemopreventive agent. Hesperidin and orange peel extract could possess antioxidant properties with a wide range of therapeutic applications.     

Characterization of bioactive compounds from raw and ripe Mangifera indica L. peel extracts

Mango is one of the important tropical fruits in the world. As it is a seasonal fruit, it is processed for various products. During its processing, peel is one of the major byproducts, which is being wasted. Bioactive conserves were extracted using 80% acetone from peels of raw and ripe mango fruits and subjected to acid hydrolysis. The prominent phenolic compounds identified by HPLC were protocatechuic acid, gentisic acid and gallic acid. The phenolic acid derivatives present in acetone extracts of raw and ripe peels were tentatively identified by LC–MS. Gallic acid, syringic acid, mangiferin, ellagic acid, gentisyl-protocatechuic acid, quercetin were the phenolic compounds identified in both raw and ripe peels, while raw peel showed the presence of glycosylated iriflophenone and maclurin derivatives also. β-Carotene was the major carotenoid followed by violaxanthin and lutein. Thus, both raw and ripe mango peel extracts have different phenolic compounds and carotenoids, which will have various pharmaceutical applications.     

柚的化学与药理研究进展

对芸香科植物柚的化学成分及药理研究进行了综述 ,认为该种植物在调节血压、抗凝、抑菌等方面有较好的开发价值     

The protective effects of polyphenols from jujube peel (Ziziphus Jujube Mill) on isoproterenol-induced myocardial ischemia and aluminum-induced oxidative damage in rats

This study was aimed to evaluate the preventive effect of the polyphenols from Chinese jujube peel (Ziziphus jujube Mill. cv. Dongzao) against myocardial injury (MI) induced by isoproterenol (ISO) and biotoxicity of aluminum in rats. The free phenols from jujube peel (JPFP) and the bond phenols from jujube peel (JPBP) were administered to rats by gastric gavage. The results showed that prior administration of JPFP or JPBP remarkably inhibited increases in levels of malondialdehyde (MDA) and activities of Ca²⁺-ATPase and Mg²⁺-ATPase, reductions in activities of superoxide dismutase (SOD), glutathione peroxidase, creatine kinase, lactate dehydrogenase and Na⁺/K⁺-ATPase in the rats induced by ISO. The abnormal changes in morphology of heart muscle and in electrocardiograph induced by ISO treatment were also significantly prevented by the JPFP or JPBP. Treatment with aluminum chloride could cause a significant oxidative damage, including a significant increase in MDA level and decreases in glutathione-S- transferase and SOD activities in brain of the rats, the study showed that gavage with JPFP or JPBP could remarkably alleviate the toxic responses of the rats to aluminum chloride. In summary, our study showed that jujube phenolics can prevent ISO-induced myocardial injury and reduce aluminum toxicity in rats.     

Antioxidant and antiacetylcholinesterase activities of Sorbus torminalis (L.) Crantz (wild service tree) fruits

In this study, the antioxidant and antiacetylcholinesterase activities of Sorbus torminalis (L.) Crantz fruits were evaluated. Total phenolic and flavonoid compounds, 2,2′-azino-bis (3-ethylbenzothioazoline-6-sulfonic acid), 2,2′-diphenyl-1-picrylhydrazyl, and superoxide anion radicals scavenging activities and ferric-reducing antioxidant power of water, ethyl acetate, acetone, and methanol extracts were determined for the measurement of the antioxidant activity. Quercetin and α-tocopherol were used as standard antioxidants. The inhibitory effect of the water extract on acetylcholinesterase (AChE) was evaluated using the Ellman method and galantamine was used as a standard. Water extract had the highest total phenolic concentration and the strongest antioxidant activity followed by ethyl acetate and acetone extracts whereas methanol extract has the lowest phenolics and weakest antioxidant activity. Moreover, water extract showed moderate ability to inhibit AChE. It was concluded that fruits of S. torminalis have antioxidant and anti-AChE activities and that the plant might be a natural source of antioxidants and AChE inhibitors.     

低功率超声醇提薄荷总黄酮工艺优化及抗氧化活性研究

目的 优选乙醇提取薄荷总黄酮的最佳工艺,并考察薄荷总黄酮的抗氧化活性.方法 采用低功率超声法(50℃,100 W)提取薄荷总黄酮,在单因素试验基础上,采用响应面分析法优选最佳薄荷总黄酮醇提工艺;采用Fetion反应考察薄荷总黄酮的抗氧化活性.结果 最佳提取工艺为乙醇体积分数41.14％,液料比21.57:1(mL/g)...     

大规模提取罗汉果叶和藤及其多种生物活性的研究

目的大规模制备罗汉果叶和藤提取物并研究其抗菌、抗氧化和促进胰岛素分泌的多种活性。方法制备罗汉果叶和藤提取物,并通过离子交换树脂进一步分离。通过活性测试对提取物和各馏分进行抗菌、抗氧化和促进胰岛素分泌的试验。结果罗汉果叶和藤提取物以及分离得到的馏分表现出抗菌、抗氧化和促进胰岛素分泌的活性。结论罗汉果叶和藤提取物具有抗菌、抗氧化和促进胰岛素分泌的活性。罗汉果叶和藤具有开发为药物和功能性食品的潜力。     

Comparing ultrasonic- and microwave-assisted methods for extraction of phenolic compounds from Kabkab date seed (Phoenix dactylifera L.) and stepwise regression analysis of extracts antioxidant activity

This study aimed to extract bioactive compounds (phenolics and flavonoids and condensed tannins) from roasted date seed (Phoenix dactylifera L. cv Kabkab) using various solvent systems (W: water, AE: aqueous-ethanol, AA: aqueous-acetone) and extraction method (ultrasonic-assisted (UAE), microwave-assisted (MAE) and the combination of these two methods (UMAE) maceration (ME) and Decoction-Infusion (DIE) Extraction). Moreover, the feasibility of antioxidant activity prediction was investigated based on stepwise regression analysis and phytochemical properties. Extraction yield, Total phenolic content (TPC), total flavonoid content (TFD) and antioxidant activity (DPPH*, ABTS*⁺, FRAP and averaged antioxidant activity: AAA) of the extracts were evaluated. The main effect of solvent systems and extraction methods on phytochemical compounds and antioxidant activity were significant (P < 0.01). Water and aqueous-ethanol solvents extracted higher phytochemical compounds than aqueous-acetone (P < 0.05). Although the highest extraction performance was observed for the ME method, the novel methods show an acceptable result in a much shorter time. Among novel methods, the highest and lowest performances were recorded for UAE and MAE. There was no significant difference between novel-green methods (e.g., UAE and UMAE). Although the lowest phytochemical yield was obtained for MAE, this performance was obtained in less than 5 min. The highest and lowest correlation between the phytochemical compositions and antioxidant activity parameters were for DPPH* and AAA, respectively. Stepwise-regression analysis showed the weakest and strongest prediction models for AAA (10-fold S = 0.098 and 10-fold R² = 87.07) and ABTS*⁺ (10-fold S = 0.129 and 10-fold R² = 78.25), respectively.     

In vitro Antioxidant and Pharmacognostic Studies of Leaf Extracts of Cajanus cajan (L.) Millsp

Cajanus cajan (L.) Millsp is one of the second most dietary legume crops. The leaf extracts may be used as a potential source of natural antioxidant. The ash values, extractive values, total phenolic and flavonoid content, in vitro antioxidant activity of various leaf extracts as well as anatomical investigation of Cajanus cajan were carried out. Physicochemical parameters such as total, acid-insoluble and water-soluble ash values and moisture content of the leaf powder of C. cajan were found to be 9.50%, 1.40 g/100 g, 4.15 g/100 g drug and 6.72%, respectively. Percent yield of acetone, aqueous, ethanol, ethyl acetate and chloroform leaf extracts were 9.0, 10.6, 13.75, 8.7 and 5.8 g/100 g, respectively. Significant amount of phenolic and flavonoid content were observed. The results of the antioxidant activity were found to be concentration-dependent. The IC₅₀ values for DPPH assay determined for aqueous and ethanol extracts were 0.69 and 0.79 mg/ml, respectively. Reducing power is increased with increasing amount of concentration in both aqueous and ethanol leaf extracts. The highest hydroxyl radical scavenging activity reached up to 83.67% in aqueous and 78.75% in ethanol extracts and in phosphomolybdenum assay the aqueous extract showed strong antioxidant capacity up to 55.97 nM gallic acid equivalents/g. It was found that the aqueous extract possessed highest antioxidant activity in all the assays tested. The antioxidant characteristics of leaf extracts are possibly because of the presence of polyphenols. Microscopic study showed the presence of collenchyma, fibres, xylem, phloem, epidermis, trichomes, palisade tissue, basal sheath, pith and cortex in leaf, petiole and pulvinus.     

Comparative antihemolytic and radical scavenging activities of strawberry tree (Arbutus unedo L.) leaf and fruit

The present study reports the antioxidant properties of Arbutus unedo L. leaf and fruit extracts using different in vitro assays including (i) reducing power, (ii) scavenging effect on DPPH free radicals, and (iii) inhibitory effect on AAPH-induced hemolysis and lipid peroxidation in human erythrocytes. All assays demonstrated antioxidant efficiency for A. unedo L. aqueous extracts, being consistently higher in the leaf. EC₅₀ values for reducing power and DPPH radical scavenging activities were, respectively, 0.318 ± 0.007 and 0.087 ± 0.007 mg/mL for leaf, and 2.894 ± 0.049 and 0.790 ± 0.016 mg/mL for fruit extracts. Under the oxidative action of AAPH, A. unedo leaf and fruit extracts protected the erythrocyte membrane from hemolysis (IC₅₀ of 0.062 ± 0.002 and 0.430 ± 0.091 mg/mL, respectively) and decreased the levels of malondialdehyde, a breakdown product of lipid peroxidation (IC₅₀ of 0.075 ± 0.014 and 0.732 ± 0.452 mg/mL, respectively). In accordance with antioxidant activity, phenolic content was found to be significantly higher in leaf extract. To our knowledge, this is the first time that the antioxidant activity of A. unedo species is evaluated using human biological membranes. Overall, our results suggest that A. unedo leaves are a promising source of natural antioxidants with potential application in diseases mediated by free radicals.     

Analysis of volatile compounds in fresh healthy and diseased peppers (Capsicum annuum L.) using solvent free solid injection coupled with gas chromatography-flame ionization detector and confirmation with mass spectrometry

The characteristic volatile flavor compounds in healthy peppers (Capsicum annuum L.) were evaluated using a solvent-free solid injector coupled with a-gas chromatography-flame ionization detector (SFSI-GC-FID) and the results of evaluation were confirmed using GC-mass spectrometry (GC-MS). These compounds were compared with those obtained from peppers that were naturally infected or artificially inoculated with Colletotrichum spp. Parameters influencing the vaporization efficiency, including the injector temperature, pre-heating time and holding time, were optimized to improve the analytical efficiency. A total of 96 compounds (excluding eight capillary compounds), 17 of which were identified in healthy peppers, 49 of which were found in naturally infected peppers, and 61 of which were identified in artificially inoculated peppers, were separated and identified under the optimal conditions of an injector temperature of 250 degrees C and 7-min preheating and holding times. Acetic acid and 2-furanmethanol were the major compounds detected in the volatiles of the healthy and diseased peppers. The major compound detected in both the healthy and naturally infected peppers was 3-hydroxypyridine, while hexadecanoic acid was the primary compound identified in the artificially inoculated peppers. Indole derivatives (1H-indole, 4-methylindole and 1-ethylindole) were suggested to be the key factors contributing to the pepper infection caused by Colletotrichum spp. We conclude that SFSI in combination with GC is a suitable approach for distinguishing between healthy and diseased peppers by the investigation of their volatile compounds. It does not require the use of solvents and complicated equipment.     

内蒙古香青兰总黄酮提取工艺优化及其抗氧化活性成分分析

目的 优化内蒙古香青兰总黄酮提取工艺,并对抗氧化活性成分进行分析。方法 采用单因素试验法结合响应面法优化提取工艺,并通过清除DPPH自由基试验、ABTS自由基清除试验、抑制羟基自由基试验和抑制超氧阴离子自由基试验筛选提取物的抗氧化活性成分,用高效液相色谱-电喷雾离子源-离子阱-飞行时间质谱联用技术(LC-MS-IT-TOF)对抗氧化活性成分进行分析。结果 内蒙古香青兰总黄酮最佳制备条件为提取温度67℃、乙醇体积百分数63%、料液比 1:58,提取物中总黄酮含量4.77%。香青兰总黄酮抗氧化活性成分为乙酸乙酯活性成分,主要包含迷迭香酸、迷迭香酸甲酯、木犀草素、芹菜素、芹菜素-7-O-b-D-葡萄糖苷等化学成分。结论 首次建立内蒙古香青兰总黄酮制备方法,该方法简单易操作,提取物总黄酮含量丰富,乙酸乙酯活性成分是香青兰总黄酮抗氧化活性成分,含有多种黄酮类化合物。     

Antioxidant, α‐Glucosidase and Xanthine Oxidase Inhibitory Activity of Bioactive Compounds From Maize (Zea mays L.)

Chemical investigations into maize (Zea mays L.) kernels yielded phenolic compounds, which were structurally established using chromatographic and spectroscopic methods. The isolated phenolic compounds from maize kernel were examined in vitro for their antioxidant abilities by DPPH (2,2‐diphenyl‐1‐picryl hydrazine) radical, OH radical scavenging activity, and reducing ability, along with α‐glucosidase and xanthine oxidase (XO) inhibition. The isolated maize phenolics revealed significant xanthine oxidase and α‐glucosidase inhibitory activity to that of allopurinol and acarbose in vitro and in vivo, respectively. The kinetics study with xanthine oxidase revealed competitive type of inhibition by isolated maize vanillic acid ( M2 ), ferulic acid ( M5 ), 3′‐methoxyhirsutrin ( M7 ), and peonidin‐3‐glucoside ( M10 ) as compared to control allopurinol. Overall, with few exceptions, all the phenolic compounds from maize kernel revealed significant biological activities with all parameters examined. Also, the phenolic compounds from maize were found to be more reactive toward DPPH radical and had considerable reducing ability and OH radical scavenging activity. These findings suggest that maize kernel phenolic compounds can be considered as potential antioxidant, α‐glucosidase, and XO inhibitory agents those might be further explored for the design of lead antioxidant, antidiabetic and antigout drug candidates using in vivo trials.