黄色洋葱皮不同溶剂多酚提取物的总酚、总黄酮含量及抗氧化活性

以黄色洋葱皮为原料,分别利用70%甲醇、70%乙醇和70%丙酮作为提取溶剂进行多酚类物质提取。测定提取物中的总酚含量、总黄酮含量并研究其抗氧化活性(DPPH自由基清除能力、ABTS自由基清除能力以及铁还原能力)。研究结果显示:利用甲醇作为提取剂所得的多酚类物质提取率最高(12.35%),并且提取物中总酚和总黄酮含量最高,分别为83.17、34.31 mg/g。同时,甲醇提取物对DPPH自由基和ABTS自由基的半抑制浓度IC₅₀分别为0.059和0.031 mg/mL,低于抗坏血酸而高于乙醇提取物和丙酮提取物。     

Isolation and Identification of Phenolic Antioxidants in Black Rice Bran

Black rice bran contains phenolic compounds of a high antioxidant activity. In this study, the 40% acetone extract of black rice bran was sequentially fractionated to obtain 5 fractions. Out of the 5 fractions, ethyl acetate fraction was subfractionated using the Sephadex LH‐20 chromatography. The antioxidant activity of phenolic compounds in the extracts was investigated by 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical assay, 2,2‐azino‐bis‐(3‐ethylenebenzothiozoline‐6‐sulfonic acid) (ABTS) radical cation assay, reducing power. The subfraction 2 from ethyl acetate fraction had the highest total phenolic contents (TPC) (816.0 μg/mg) and the lowest EC₅₀ values (47.8 μg/mL for DPPH radical assay, 112.8 μg/mL for ABTS radical cation assay, and 49.2 μg/mL for reducing power). These results were 3.1, 1.3, and 2.6 times lower than those of butylated hydroxytoluene (BHT), respectively. At a concentration of 100 μg/mL, the antioxidant activity and TPC of various extracts was closely correlated, with correlation coefficients (R²) higher than 0.86. The major phenolic acid in subfraction 2 was identified as ferulic acid (178.3 μg/mg) by HPLC and LC‐ESI/MS/MS analyses. Our finding identified ferulic acid as a major phenolic compound in black rice bran, and supports the potential use of black rice bran as a natural source of antioxidant.     

凤眼果壳多酚的抗氧化和抗人肺癌细胞A549增殖活性

本研究以凤眼果壳为原料,提取凤眼果壳游离态和结合态多酚,通过不同极性有机溶剂萃取游离态多酚获得四相提取物,分别是正己烷相(HF),乙酸乙酯相(EAF),正丁醇相(BF)和水相(AqF).测量游离态、结合态和萃取后的四相提取物的总多酚和总黄酮含量,结果表明游离态的多酚和黄酮含量均比结合态高.萃取后的四相提取物中,EAF的...     

黑脉羊肚菌多酚分级制备及其抗氧化活性

以黑脉羊肚菌为原料,采用不同极性溶剂提取多酚,分别得到乙酸乙酯相、甲醇相和水相多酚提取物,通过高效液相色谱分析其组分,测定其对1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除能力、2,2’-联氨-(3-乙基苯并噻唑啉-6-磺酸)二铵盐(2,2’-azinobis-(3-ethylbenzthiazoline-6-sulphonate),ABTS)自由基清除能力和抗氧化能力指数(oxygen radical absorbance capacity,ORAC)值,并探讨该多酚提取物含量与抗氧化相关性。结果表明,黑脉羊肚菌总酚含量为20.109 mg/g,其中水相组分多酚含量最高(14.478 mg/g),甲醇相次之(5.443 mg/g),乙酸乙酯相组分多酚含量最低(0.188 mg/g)。3种溶剂的多酚提取物组成中,荭草素含量均为最高。水相组分清除DPPH自由基能力最强,甲醇相组分清除ABTS~+·能力最强,乙酸乙酯相组分具有较高的ORAC值。多酚含量与DPPH自由基清除率、ORAC值具有显著相关性(P0.05)。     

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.     

Phenolic contents and antioxidant activities from different tissues of <Emphasis Type="Italic">Baekseohyang</Emphasis> (<Emphasis Type="Italic">Daphne kiusiana</Emphasis>)

The aim of this research was to investigate the levels of phenolic compounds and antioxidant activities in different tissues including leaves, stems, and roots from baekseohyang (Daphne kiusiana). The highest contents of total phenolics (43.59 mg gallic acid equivalent, GAE/g) and flavonoids (15.73 mg rutin equivalents, RE/g) were observed in the 75% methanol extract of leaves. Moreover, this extract had the predominant antioxidant capacity, DPPH (85.91%) and ABTS (92.57%) radical scavenging activities as well as reducing power (7.20%) at a concentration of 5 mg/mL. The highest content of phenolic compounds was also exhibited in this extract with an increasing order in leaves, roots, and stems and their major components were vanillic acid (6.37 mg/g), tannic acid (1.91 mg/g), and p-hydroxybenzoic acid (3.96 mg/g). Thus, the strong antioxidant activities of the 75% methanol extract are correlated with high phenolic compound contents. This study suggests that baekseohyang leaves may potentially be used as an accessible source of natural antioxidants.     

Oregano: chemical analysis and evaluation of its antimalarial, antioxidant, and cytotoxic activities

Abstract: GC‐FID and GC‐MS analysis of essential oil from oregano leaves (Origanum compactum) resulted in the identification of 46 compounds, representing more than 98% of the total composition. Carvacrol was the predominant compound (36.46%), followed by thymol (29.74%) and p‐cymene (24.31%). Serial extractions with petroleum ether, ethyl acetate, ethanol, and water were performed on aerials parts of Origanum compactum. In these extracts, different chemical families were characterized: polyphenols (gallic acid equivalent 21.2 to 858.3 g/kg), tannins (catechin equivalent 12.4 to 510.3 g/kg), anthocyanins (cyanidin equivalent 0.38 to 5.63 mg/kg), and flavonoids (quercetin equivalent 14.5 to 54.7 g/kg). The samples (essential oil and extracts) were subjected to a screening for antioxidant (DPPH and ABTS assays) and antimalarial activities and against human breast cancer cells. The essential oil showed a higher antioxidant activity with an IC₅₀= 2 ± 0.1 mg/L. Among the extracts, the aqueous extract had the highest antioxidant activity with an IC₅₀= 4.8 ± 0.2 mg/L (DPPH assay). Concerning antimalarial activity, Origanum compactum essential oil and ethyl acetate extract showed the best results with an IC₅₀ of 34 and 33 mg/mL, respectively. In addition, ethyl acetate extract (30 mg/L) and ethanol extract (56 mg/L) showed activity against human breast cancer cells (MCF7). The oregano essential oil was considered to be nontoxic.     

Phenolic Profiles,Antioxidant Activities,and Neuroprotective Properties of Mulberry (Morus atropurpurea Roxb.) Fruit Extracts from Different Ripening Stages

The present work investigated the phenolic profiles (including nonanthocyanin and anthocyanin phenolics), antioxidant activities, and neuroprotective potential of mulberry fruit (MF) (Morus atropurpurea Roxb.) grown in China at different ripening stages. High‐performance liquid chromatography‐tandem mass spectrometry method (HPLC‐MS/MS) was used to identify and quantify the phenolic compounds. The antioxidant capacity, total phenolic content (TPC), total flavonoid content (TFC), and total monomeric anthocyanin content (TAC) were determined using spectrophotometric methods. The neuroprotective effects of MFs at different ripening stages were investigated using Aβ_25‐35‐treated PC12 cells as the cellular model of Alzheimer's disease. Of the 19 phenolic compounds characterized from the MF extracts, the contents of rutin and anthocyanins increased and that of chlorogenic acid decreased significantly with maturity. At the fully ripened stage, MF extracts showed the highest amounts of TPC (11.23 mg gallic acid equivalents/g fresh weight), TFC (15.1 mg rutin equivalents/g fresh weight), and TAC (1177 mg cyanidin 3‐O‐glucoside equivalents/100 g fresh weight). Meanwhile, antioxidant activity of MF extracts at this stage was highest according to ABTS (an IC50 value of 4.11 μg/mL) and DPPH (an IC50 value of 10.08 μg/mL) assays. Cellular assays revealed increased cell viability in cells treated with the ripe MF extracts; compared with the control groups, the ripening fruits also increased the antioxidant enzyme levels in PC12 cells. Together, these results suggest that the antioxidant activities and neuroprotective properties of ripening MFs are related to the contents and types of phenolic compounds that are present in the fruits.     

The antioxidant activity and stability of the phenolic fraction of green olives and extra virgin olive oil

The antioxidant activity of phenolic extracts from olives and olive oil has been assessed by scavenging of 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radicals and by studying the effects on the stability of stripped olive oil in the absence and presence of ferric chloride. The olive extracts contained a much higher concentration (1940–5800 mg kg^?1) of phenolic components than the olive oil extract (180 mg kg^?1). Some olive extracts were more effective than the olive oil extract in scavenging DPPH radicals, but the three varieties of olives examined showed relatively large differences in both polyphenol concentration and antioxidant activity of extracts. α‐Tocopherol and extracts from both olives and olive oil were effective antioxidants in stripped olive oil at 60 °C. Ferric chloride reduced the stability of stripped olive oil, but the olive extract studied was significantly more effective as an antioxidant in the presence of the metal salt than the olive oil extract or α‐tocopherol. Ferric ions catalysed the oxidation of caffeic acid, oleuropein and phenolic components of the olive and olive oil extracts in aqueous solution (pH 5.4). The olive extract oxidised more rapidly than the olive oil extract in aqueous solution. © 2001 Society of Chemical Industry     

水生蔬菜提取物的抗氧化活性分析及其对菜籽油的抗氧化作用

研究七种常见水生蔬菜不同部位提取物的抗氧化活性以及对油脂抗氧化的效果。采用ABTS自由基清除法、DPPH自由基清除法检测菱角、芡实、莲藕、水芋头、茭白、荸荠和慈姑不同部位的醇提物、水提物的抗氧化活性,烘箱法测定对菜籽油过氧化值的影响。在30种提取物中DPPH自由基清除能力较强的三种提取物IC50值分别为:芡实壳醇提物(0.03 mg/mL)芡实壳水提物(0.04mg/m L)=菱角壳醇提物(0.04mg/m L);ABTS自由基清除能力较强的三种提取物Trolox含量分别为芡实壳醇提物(1.42g/g)芡实壳水提物(1.41 g/g)菱角壳醇提物(1.15 g/g);添加0.1%浓度的五种提取物第7 d的POV值分别为23.86 meq/kg、24.06 meq/kg、23.53meq/kg、24.43 meq/kg、22.40 meq/kg,五种提取物的油脂抗氧化效果均不如0.1%浓度的BHA。30种水生蔬菜提取物中,芡实壳和菱角壳的醇提物、水提物DPPH自由基清除能力最强,芡实壳醇提物、水提物ABTS自由基清除能力最强;芡实壳水提物、芡实壳醇提物、菱角壳水提物、菱角壳醇提物以及藕节醇提物对菜籽油有一定抗氧化的效果,但效果弱于相同剂量的BHA。     

Phenolic composition,antioxidant, antibacterial,larvacidal against Culex pipiens,and cytotoxic activities of Hyacinthella lineata steudel extracts

This study reports the phenolic composition, antioxidant, antibacterial, larvacidal, and cytotoxic activity of methanol and acetone extracts of Hyacinthella lineata leaves and bulbs. The phenolic composition of H. lineata was determined by HPLC. The most abundant component was gallic acid (421.9µg/g). The β-carotene/DPPH/ABTS/FRAP decoloration method was used to estimate the total antioxidant activity. The total antioxidant activity was the highest for bulb-methanol fraction (65.41 ± 0.05%). The total phenolic content for leaves-methanol extract of the plant was determined as 6.56 ± 4.027mg/mL gallic acid equivalents. Analysis of the antibacterial activity showed that the methanolic-bulb extract are efficient against gram positive and gram negative bacteria. The cytotoxic effect on Artemia salina was assessed by Brine shrimp assay. Brine shrimp lethality assay showed that LC₅₀ values of HBM were obtained as 4.105 ± 2.42μg/ml. The bulb extract of H. lineata showed the highest larvicidal activity against Cx pipiens with value LC₅₀ (64.3275μg/ml). This study suggested that H. lineata may be used as a potential source of antioxidant, and for their biological activity, cytotoxic and antimicrobial properties.     

In vitro antioxidant activity of different cultivars of banana flower (Musa paradicicus L.) extracts available in India

Abstract: Six different cultivars of banana flowers (Musa paradicicus) (Kathali, Bichi, Shingapuri, Kacha, Champa, and Kalabou) were analyzed for the content of polyphenol expressed as gallic acid equivalent and flavonoid expressed as quercetein equivalent, and the in vitro total antioxidative activities of the flower extracts were compared with standard and expressed as trolox equivalent. The reducing power, 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) and 2,2‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonic acid) radical cation (ABTS?⁺) scavenging activities, inhibition of lipid peroxidation in a linoleic acid emulsion system, and liposome peroxidation system were measured and compared with respective standard antioxidants. Iron‐mediated Fenton reaction was carried out to evaluate the protective effect of the extract of banana flower (Kacha cultivar) against H₂O₂‐induced DNA damage. The Kacha variety contains the maximum amount of polyphenol (11.94 ± 0.03 mg of gallic acid equivalent/g of dry weight) and flavonoid (0.174 ± 0.001 g of quercetin equivalent/g of polyphenol). It also has the highest total antioxidant capacity, DPPH radical scavenging activity, and ABTS?⁺ radical scavenging activity with a least EC₅₀ value of 0.051 mg/mL. Hepatic cell damage in iron‐mediated Fenton reaction caused by free radicals is reduced by the banana flower extract. On the basis of the results obtained, the banana flowers are found to be a potential source of natural antioxidants. This is the first report on the antioxidant properties of the extracts from banana flowers. The study suggests that the flowers of M. paradicicus that are found in India and consumed as vegetable can provide valuable functional ingredients that help in the prevention of oxidative stress.     

Antioxidative activities of grape (Vitis vinifera) seed extracts obtained from different varieties grown in Turkey

In this study, total phenolic contents and antioxidant activities of grape seed extracts obtained from twelve different grape seeds from common varieties grown in Turkey were determined. Grape seeds were extracted with 70% acetone and extraction yield of grape seed were calculated. The total phenolic content of grape seed extracts were determined by the Folin‐Ciocalteu procedure and ranged from 33 945 to 58 730 mg per 100 g extract as gallic acid equivalent. Antioxidant activities of grape seed extracts with two different free radical scavenging methods, ABTS [2,2/‐azinobis (3‐ethylbenzothiazoneline‐6‐sulfonic acid)] and DPPH (2,2‐diphenyl‐picrylhydrazyl) assays, using Trolox equivalent as standards, were investigated. Grape seed extracts exhibited antioxidant activities 2.46–4.14 and 3.55–5.76 [Trolox equivalent antioxidant capacities (TEAC) mg^?1 extracts] in ABTS and DPPH assays, respectively. Compared with varieties, Muskule extracts exhibited the lowest total phenolic content, TEAC_ABTS and TEAC_DPPH value while Narince extracts had the highest total phenolic content and TEAC_DPPH value, and Alphonse Lavalleé had the highest TEAC_ABTS value. Total phenolic content showed that there is a significant correlation with TEAC_DPPH (r = 0.7974, P ≤ 0.001) and TEAC_ABTS values (r = 0.4860, P ≤ 0.05).     

Antioxidant activities and phenolic compounds of pigmented rice bran extracts

This study was carried out to investigate the antioxidant activities and phenolic compounds of pigmented rice (black, red, and green rice) and brown rice brans. Antioxidant activity was determined by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical assay, 2,2-azino-bis-(3-ethylenebenzothiozoline-6-sulfonic acid) (ABTS) radical cation assay, reducing power, and chelating ability. Phenolic compounds were measured by using HPLC. Pigmented rice brans were extracted by using aqueous mixtures of acetone, ethanol, and methanol to determine the most effective extraction solvent. Of all solvents examined, extract from 40:60 acetone-water mixtures (v/v) provided the highest DPPH radical assay as well as the highest total phenolic and flavonoid content. We finally selected 40% acetone as an extraction solvent for antioxidant study of pigmented rice bran. Antioxidant activities of 40% acetone extracts of pigmented rice bran, measured in the range of 0 to 1500 μg/mL. At 500 μg/mL concentration, red rice bran, which had the highest total phenolic (259.5 μg/mg) and total flavonoid (187.4 μg/mg) contents, showed the highest antioxidant activity: 83.6%, 71.5%, 1.2%, and 16.4% for DPPH radical assay, ABTS radical cation assay, reducing power, and chelating ability, respectively. Red rice bran showed a lower EC(50) value (112.6 μg/mL) than that of butylated hydroxytoluene (144.5 μg/mL) from the DPPH radical assay. The major phenolic acids of red rice bran were ferulic, vanillic and p-coumaric acids. The results indicated pigmented rice bran might be used as a natural antioxidant. PRACTICAL APPLICATION: The present study revealed black and red rice bran shows high antioxidant activities and they contain high amount of phenolic compounds. Indeed, black and red rice bran could be better raw materials for manufacturing the food with high antioxidant activity.     

Antioxidant Activities of Polyphenolic Compounds Isolated from Antidesma thwaitesianum Müll. Arg. Seeds and Marcs

ABSTRACT: Antidesma thwaitesianum Müll. Arg. or mao is widely used as commercial products of juice and wine in Thailand. As a result, waste products from the mao plant, such as mao seeds (MS) and mao marcs (MM), are plentiful. We aimed to purify and analyze polyphenolic content in both MS and MM and to investigate the radical scavenging activities of these polyphenolics against 1,1‐diphenyl‐2‐picryl‐hydrazyl (DPPH) and 2,2′‐Azinobis (3‐ethylbenzothiazoline 6‐sulphonate) (ABTS) radicals and thiobarbituric acid reactive products (TBARP). The results showed MS and MM to be an abundant source of polyphenols (97.32 to 130 mg gallic acid equivalents [GAE]/g) and proanthocyanidins. The radical scavenging activities of MS/MM against DPPH and ABTS radicals (IC₅₀ of 0.85 to 1.21 μg/mL) were significantly higher (P < 0.05) than that of standard trolox (IC₅₀ of 5.05 μg/mL). Activity of MS/MM extracts were 3.74 and 3.80 μg/mL trolox eq/g f.w. for the DPPH and ABTS assays, respectively. The oxidation of erythrocyte membranes using 2‐thiobarbituric acid demonstrated that the protective effect of MS/MM on lipid peroxidation is as strong as grape seed proanthocyanidin extract. These findings suggest that polyphenolic compounds and proanthocyanidins isolated from these mao extracts had much higher antioxidant activities than those of standard trolox and exhibited similar antioxidant potential to grape seed proanthocyanidin extract. These findings may also increase value of mao waste products and allow development of commercial health products.     

Phenolic Content and Antioxidant Activity of Raspberry and Blackberry Cultivars

ABSTRACT: Raspberry (Aksu Kırmızısı, Rubin, Newburgh, Hollanda Boduru, Heritage) and blackberry (Bursa 1, Bursa 2, Jumbo, Chester) cultivars were assayed for antioxidant activity (determined as 2,2-azino-di-[3-ethylbenzothialozine-sulphonic acid][ABTS], 2,2-diphenyl-1-picrylhydrazyl radical [DPPH], and cupric ion reducing antioxidant capacity [CUPRAC]), total phenol, total flavonoid, and total anthocyanin contents. In addition, 10 anthocyanins and anthocyanidins were determined in raspberry and blackberry by liquid chromatography-mass spectrometry (LC-MS/MS). Raspberry and blackberry had the highest ABTS, DPPH, CUPRAC, total phenol, and total flavonoid contents in methanol extracts, whereas total anthocyanin contents were the highest in water extracts. The antioxidant activity of the raspberry and blackberry was directly related to the total amount of phenolic compounds detected in the raspberry and blackberry. All antioxidant activity values were highly correlated with anthocyanin content in blackberry (0.93 ≤ r ≤ 0.99, P = 0.05). On the other hand, high correlation between total flavonoid content and antioxidant activity was recorded in water extract of blackberry (0.91 ≤ r ≤ 0.93, P = 0.05). ABTS value was highly correlated with total flavonoid content in methanol extract (r = 0.90), whereas total flavonoid content was relatively less correlated with DPPH (r = 0.85) and CUPRAC (r = 0.89).     

Radical scavenging activities,endogenous oxidative enzymes and total phenols in edible mushrooms commonly consumed in Europe

Edible mushrooms are a good source of antioxidants. Methanol extracts of mushrooms such as Pleurotus sp., Agaricus bisporus, Morchella esculenta, Boletus edulis (approx. 2 mg mL^?1) showed a high 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) scavenging activity close to 90%. Water extracts showed even higher antioxidant activity. In this case, B. edulis, Lentinus edodes and Amanita cesarea showed the highest 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid (ABTS) scavenging activity at approx. 0.14 mg mL^?1. Other mushrooms such as Lactarius deliciosus and Cantharellus cibarius showed lower antioxidant activity in both extracts. Oxidative enzymes (peroxidases and polyphenol oxidases) present in the water fractions reduced their antioxidant activity by different extents since the phenols responsible for the antioxidant activity were not only those substrates of the oxidative enzymes. Other phenolic compounds and low‐molecular‐weight compounds were also involved in the antioxidant activity and differed depending on mushroom species. Copyright © 2007 Society of Chemical Industry     

牡丹花水提物对肾素和ACE的双重抑制作用

研究了牡丹花水提物对肾素-血管紧张素系统中两种关键酶肾素和血管紧张素转化酶(ACE)的抑制作用,选取典型的牡丹花色品种,并与芍药进行比较,考察了样品水提物的肾素和ACE抑制活性及抗氧化能力,并分析酚类及黄酮类物质的含量与其功能活性的相关性。结果表明,红色系的牡丹和芍药花水提物具有优良的肾素和ACE抑制活性,而白色系的牡丹花水提物抑制肾素和ACE活性的能力则很弱。其中活性最高的样品水提物抑制肾素的IC50值为0.08 mg/mL,抑制ACE的IC50值为0.23 mg/mL;此外,红色系的牡丹和芍药花水提物的ABTS自由基清除能力为115.89~121.75mgTE/gDW,DPPH自由基清除能力为192.67~200.46mg TE/g DW,铁离子还原能力为119.86~208.94 mg TE/g DW,总酚含量为99.29~122.45 mg GAE/g DW,白色牡丹花水提物的抗氧化能力及总酚含量均远低于红色系样品水提物。相关性分析表明,不同样品水提物的肾素和ACE抑制活性及DPPH、ABTS自由基清除能力和铁离子还原能力与总酚含量显著正相关(p<0.01),相关系数分别为0.99、0.91、0.99、0.99和0.98。本研究指出深色系的牡丹花水提物倾向于表现出更强的肾素和ACE抑制活性,其中酚类化合物是潜在的重要活性物质,这可为探讨新型血压调控因子及实现不同品系牡丹花的高值化利用提供更丰富的基础理论支撑。     

Antioxidant and antigenotoxic activities of ethanol extracts from Rhus chinensis Mill leaves

Ethanol extracts were obtained from Rhus chinensis Mill (RCM) leaves and used for antioxidant and antigenotoxic activity assays. IC₅₀ values in DPPH assays were 15.96, 18.83, 20.43, 27.93, 37.43, 46.21, and 141.84 μg/mL for TPP, IPE, LLE, Vc, CE, BHT, and Trolox. Similar results were obtained using ABTS and FRAP assays. In vivo testing showed strong antioxidant activities that were positively correlated with polyphenol contents. Leaf tissue contained abundant polyphenols, and more than 10 phenolic compounds were detected in extracts. Quantitative results showed that quercetin-3-rhamnoside (26.4±0.76 mg/g of extract) was the most abundant ingredient, followed by hyperoside (15.2±0.42 mg/g of extract), quercetin (1.5±0.07mg/g of extract), and kaempferol (0.48±0.05 mg/g of extract). This study increases the knowledge for possible uses of forest by-products as a substitute for gallnuts.     

Antioxidant effects of solvent extracts from the dried jujube (Zizyphus jujube) sarcocarp,seed, and leaf via sonication

Antioxidant effects of extracts from sarcocarp, seed, and leaf of dried jujube (Zizyphus jujube) were investigated. The highest amount of flavonoids and polyphenol was found in 80% methanol leaf extract at value of 43.04±0.34 and 324.75±6.01 mg/g, respectively. For 2,2′-azino-bis-3-ethylbenzo-thiazoline-6-sulfonic acid (ABTS) radical scavenging activity analysis at a concentration of 1,000 μg/mL, 70% ethanol seed extract (94.76±0.23%), and 80% methanol leaf extract (95.46±0.14%) were observed to have higher activity than those of controls, such as butylated hydroxyl anisole (BHA) (89.60±0.00%), butylated hydroxyl toluene (BHT) (84.07±0.50%), vitamin C (89.27±0.12%), and vitamin E (88.53±0.12%). All solvent extracts from leaf showed higher ABTS radical scavenging activity (over 98%) than those of controls with their activity values around 94% (500 g/mL). All extracts from sarcocarp and seed showed superoxide dismutase (SOD)-like activity of 24.46–34.84% on the concentrations (100–1,000 g/mL), and 80% methanol leaf extract showed the highest activity (43.66±0.37%) among samples. These results indicate that sarcocarp, seed of dried jujube are all excellent antioxidants, and especially leaf showed higher antioxidant effect than those of vitamin C and E.