Characterisation of antioxidant compounds in sweet bell pepper (Capsicum annuum L.) under organic and conventional growing systems

BACKGROUND: Sweet red bell pepper is one of the best sources of ascorbic acid and carotenoids as well as phenolic compounds important in the human diet. There have been some studies showing a higher level of bioactive compounds in organic bell pepper fruits compared with conventional fruits, but not all studies have been consistent in this respect. The levels of carotenoids and phenolics are very variable and may be affected by ripeness, genotype and cultivation. RESULTS: The results obtained in this study showed that an organic growing system affected the level of bioactive compounds (carotenoids and polyphenols) in sweet bell pepper fruits cultivated in Poland. Organic bell pepper fruits contained significantly more dry matter, vitamin C, total carotenoids, β‐carotene, α‐carotene, cis‐β‐carotene, total phenolic acids (as well as individual gallic and chlorogenic acids) and flavonoids (quercetin D ‐glucoside, quercetin and kaempferol) compared with conventional fruits. The bell pepper variety also affected the level of antioxidant compounds in fruits. CONCLUSION: Organic growing increased the level of antioxidant compounds such as carotenoids, phenolic compounds and vitamin C in sweet bell pepper. The second significant factor affecting the antioxidant compound content of sweet bell pepper was variety. It would be necessary to continue this study as a long‐term experiment in order to eliminate the influence of seasonality. Copyright © 2012 Society of Chemical Industry     

Nutritional constituents,phytochemical profiles, <Emphasis Type="Italic">in vitro</Emphasis> antioxidant and antimicrobial properties,and gas chromatography–mass spectrometry analysis of various solvent extracts from grape seeds (<Emphasis Type="Italic">Vitis vinifera</Emphasis> L.)

The present study revealed that the nutritive value of grape seeds (Vitis vinifera L.) was 383.55±0.13 Kcal/100 g, with magnesium as the most abundant mineral element (70.44±0.88 mg/L). The maximum phenolic (392.58±1.70mg of GAE/g), flavonoid (256.16±1.60 mg of QE/g), and tannin (30.95±0.17mg of CE/g) contents were also found in the ethanol, dichloromethane, and hexane extracts, respectively. The major phytochemical compounds in the ethyl acetate extract were identified via gas chromatography–mass spectrometry (GC–MS) analysis. The ethanol extract has the highest antioxidant activity (IC₅₀=140±1.20 μg/mL for DPPH, 145.28±0.45mg α-tocopherol/g for total antioxidant capacity, and EC₅₀=80±1.41 μg/mL for ferric-reducing power assays). For β-carotene test, the highest antioxidant activity was obtained in the hexane extract. A satisfactory antimicrobial activity was found against a panel of microorganisms with the ethyl acetate extract as the best antimicrobial agent. Additionally, it was found that the bactericidal concentration required for the grape seed extract to kill Listeria monocytogenes should be less than 12.50 mg/mL (minimum inhibitory concentration=4).     

Nutritional improvement of bhujia by incorporating colored bell peppers

The present study aimed at improving phytonutritional profile of traditional snack (bhujia) by incorporating variety bell pepper. The bell peppers were dried at 50°C which resulted in 4.94%–8.16% increase in total phenols whereas, retained approximately 92.49% total carotenoids and 91.36% of the antioxidant activity in terms of DPPH radical scavenging activity. Gram flour at 5.0% (w/w) level of bell pepper powders was optimized for developing bhujia which significantly (p ≤ 0.05) increased bulk density, minerals, phytonutritional profile, and sensory attributes of bhujia. Total phenols of developed bhujia increased by approximately 11% and antioxidant activity was found 3.5 times as compared to control. Fourier-transform infrared spectroscopy showed the presence of various phytochemicals compounds in the prepared products compared to control. Storage studies (at 25–30°C/50%–87% RH) revealed that the physicochemical parameters remained unaffected except moisture which increased significantly. However, peroxide value and free fatty acids remained well within maximum permissible limits.     

玫瑰红景天醇提物不同溶剂萃取物的生物活性

以无水乙醇为溶剂,用索氏提取器对玫瑰红景天粉末进行回流提取,回收乙醇后将乙醇提取物分散和溶解在水相中,依次用环己烷、氯仿、乙酸乙酯、正丁醇分别萃取,得到不同溶剂萃取物。用比色法测定不同溶剂萃取物和水相物中总酚和总黄酮含量,DPPH·法、Fenton法、普鲁士蓝法评价其抗氧化活性以及测试最小抑菌浓度(MIC)和最小杀菌浓度(MBC)。结果表明,乙酸乙酯萃取物中总酚和总黄酮含量最高,分别为(469.32±1.15),(338.57±0.92)mg/g萃取物;不同萃取物和水相物对DPPH·、·OH有不同程度的清除作用且有还原能力,其中乙酸乙酯萃取物和正丁醇萃取物有相对较好的抗氧化活性;总酚和总黄酮含量与抗氧化活性呈显著相关性(P<0.05);对选用的9种菌株均有抑制和灭活作用,MBC值在0.28~16.94mg/mL,对金黄色葡萄球菌株灭活作用更为显著,其中氯仿萃取物和乙酸乙酯萃取物的抗菌效果相对较好。玫瑰红景天乙醇提取物的不同溶剂萃取物及水相物均有抗氧化活性和抗菌活性,有潜在的应用价值。     

覆盆子醇提物及其不同极性部位抗氧化活性研究

以覆盆子醇提物及其不同极性部位的总酚、黄酮含量和抗氧化活性为研究目的,采用还原力,1,1-二苯基-2-苦基肼(DPPH)和OH自由基清除能力抗氧化体系来评价它们的抗氧化活性,研究结果表明:乙酸乙酯相的总酚和黄酮含量最高,分别为(328.33±13.75)mg/g和(298.25±25.64)mg/g(p<0.05);该相在不同抗氧化体系中的抗氧化活性也最强,清除DPPH和OH的能力显著强于BHT(p<0.05)。覆盆子醇提物及其不同极性部位中的总酚含量与还原力,DPPH和OH清除能力呈正相关,相关系数分别为0.9197、0.9321和0.9808,这表明总酚是覆盆子提取物的主要抗氧化活性成分。     

Variation of antioxidant activity and the levels of bioactive compounds in lipophilic and hydrophilic extracts from hot pepper (Capsicum spp.) cultivars

Peppers (Capsicum spp.) are a rich source of diverse bioactive compounds with potential health-promoting properties. This study investigated the extraction efficiency of five solvents on antioxidant activities from cayenne (CA408 and Mesilla), jalapeño (Ixtapa) and serrano (Tuxtlas) pepper cultivars. Freeze-dried peppers were extracted using a Soxhlet extractor with five solvents: hexane, ethyl acetate, acetone, methanol, and methanol:water (80:20). The levels of specific bioactive compounds (phenolics, capsaicinoids, carotenoids and flavonoids) were determined by HPLC and antioxidant activities were assayed by three methods. For all pepper cultivars tested, hexane extracts had the highest levels of capsaicinoids and carotenoids, but methanol extracts had the maximum levels of flavonoids. Hexane extracts showed higher 2,2-diphenyl-1-pricrylhydrozyl (DPPH) radical-scavenging activity and higher reducing power, and acetone extracts (from Mesilla pepper) had a high reducing power. All pepper extracts, except hexane, were effective in preventing deoxyribose degradation, and the inhibition was increased by high concentrations of extracts. The results of the present study indicated that, among the different measures of antioxidant activity, DPPH radical-scavenging activity was strongly correlated with total bioactive compounds (capsaicinoids, carotenoids, flavonoids and total phenolics) in pepper cultivars.     

Air-dried capsicum annuum var. acuminatum medium and big: Determination of bioactive constituents,antioxidant activity and carbohydrate-hydrolyzing enzymes inhibition

In the present study the total phenols, flavonoids, carotenoids and capsaicinoids content, the in vitro antioxidant and hypoglycemic activities of extracts of air-dried fruits from two Capsicum annuum cultivars were investigated. A different composition between the two cultivars was evidenced. C. annuum var. acuminatum medium extract presented a major content of phenols, carotenoids, capsaicin and dihydrocapsaicin while C. annuum var. acuminatum big extract is characterized by the highest quercetin, luteolin and kaempferol content with 68.0, 87.6 and 29.7 μg/g dried weight, respectively, analyzed by HPLC. Medium pepper showed the highest radical scavenging activity in DPPH assay (IC₅₀ of 85.3 μg/ml) while big pepper have an interesting activity in ABTS assay (IC₅₀ of 16.4 μg/ml) and the highest inhibition of linoleic acid oxidation with an IC₅₀ value of 1.2 μg/ml after 30 min of incubation. A selective inhibitory activity against α-amylase was demonstrated for C. annuum var. acuminatum big lipophilic fraction (IC₅₀ values of 8.7 μg/ml). The obtained results suggest that C. annuum cultivars could be used as valuable flavor with functional properties for foods.     

Optimization of Microwave-Assisted Extraction of Polyphenolic Compounds from <Emphasis Type="Italic">Ocimum basilicum</Emphasis> by Response Surface Methodology

Microwave-assisted extraction (MAE) was optimized by response surface methodology in order to enhance the extraction of polyphenols from basil (Ocimum basilicum L). Box–Behnken experimental design on three levels and three variables was used for optimization. Influence of ethanol concentration (50, 70, and 90%); microwave power (400, 600, and 800 W); and extraction time (15, 25, and 35 min) on each response were investigated. Experimental results were fitted to a second-order polynomial model, and multiple regression analysis and analysis of variance were used to evaluate model fitness and optimal conditions. Considering the maximum content of extracted total phenols, total flavonoids, and antioxidant activity, the optimal conditions for all investigated response were ethanol concentration of 50%, microwave power of 442 W, and extraction time of 15 min. Under the optimal conditions, obtained basil liquid extract contained 4.299 g gallic acid equivalents/100 g dry weight (DW) of total polyphenols, 0.849 g catechin equivalents/100 g DW of total flavonoids, and IC₅₀ and EC₅₀ values of 9.602 and 82.889 μg/mL, respectively. The development of simultaneous MAE procedure for extraction of total phenols, total flavonoids, and potential antioxidants from basil, represented valorization of basil as valuable source of bioactive compounds.     

The effect of washing on physicochemical changes in packaged, sliced green peppers

Whole green bell peppers (Capsicum annuum L.) were obtained through a local fresh‐cut company. They were washed in a 100 ppm chlorine solution, dried and then sliced into 0.5‐cm wide strips. A bulk sample of slices was divided into four treatments: (1) no wash, (2) one wash in fresh distilled water, (3) two sequential washes in fresh distilled water, and (4) three sequential washes in fresh distilled water. Retention of firmness of the pepper slices during storage at 7 °C improved with the number of washes after cutting. The modification of package atmosphere was less in all wash treatments than in the ‘no wash’ control. The sliced tissues of ‘no wash’ controls had higher levels of acetaldehyde and ethyl acetate. Analysis of the wash water revealed that sequential washes with water removed incremental amounts of acetaldehyde and soluble phenols from the cut surfaces of the tissue. These results show that washing has a dramatic effect on physicochemical measures of quality in green pepper slices, and it is likely that this effect is mediated by the removal of stress‐related compounds produced during the cutting operation. While acetaldehyde and total phenolics were the two stress‐related compounds measured in the wash water, it may be that other compounds removed in the wash water could have contributed to the beneficial effects on quality reported in this study.     

蜂胶乙酸乙酯提取物对意大利青霉菌的抑制作用及稳定性研究

本实验以青霉属的意大利青霉菌(Penicillium italicum)为研究材料,研究蜂胶不同溶剂提取物对意大利青霉菌的抑制作用及其对温度和pH 值的稳定性的影响。结果表明,乙酸乙酯提取物和乙醇提取物活性最高,氯仿提取物次之,石油醚提取物和水提取物活性最弱。提取物的抑菌活性与提取物中的黄酮含量和总酚呈显著正相关。乙酸乙酯提取物对意大利青霉的孢子萌发具有同样的抑制作用。蜂胶乙酸乙酯提取物溶液分别经过25、35、50、70、100℃的温度处理后其抑菌活性没有明显差异;在pH3.6～7.6 的范围内,随着pH 值的升高,提取物的抑菌活性先升高后降低,于pH5.2 时抑制率最高,pH4.4 时次之。这表明该蜂胶提取物能够有效的抑制意大利青霉的生长,在采后柑橘的防腐保鲜中具有良好的应用前景。     

Design of Sonotrode Ultrasound-Assisted Extraction of Phenolic Compounds from <Emphasis Type="Italic">Psidium guajava</Emphasis> L. Leaves

Psidium guajava L. has gained a special attention as health plant due to the presence of phenolic compounds. Box-Behnken design (BBD) has been applied for the extraction of target compounds from guava leaves via sonotrode ultrasound-assisted extraction (UAE). Different extraction times (5, 30, and 55 min), ratios of ethanol/water (50, 75, and 100% (v/v)), and ultrasound (US) power (80, 240, and 400 W) were tested to find their effect on the sum of phenolic compound (SPC), flavonols and flavan-3-ols via HPLC-ESI-QqQ-MS, and antioxidant activity (DPPH and TEAC assays). The best process conditions were as follows: 40 min, 60% ethanol/water (v/v), and 200 W. Established method has been used to extract phenolic compounds in two guava leaves varieties (pyrifera and pomifera). Pyrifera var. showed greater values of the SPC via HPLC-ESI-QqQ-MS (49.7 mg/g leaf dry weight (d.w.)), flavonols (12.51 mg/g d.w.), flavan-3-ols (7.20 mg/g d.w.), individual phenolic compounds, and antioxidant activity (8970 ± 5 and 465 ± 6 μmol Trolox/g leaf d.w, respectively) than pomifera var. Conventional extraction showed lower amounts of phenolic compounds (7.81 ± 0.03 and 4.64 ± 0.01 mg/g leaf d.w. for flavonols and flavan-3ols, respectively) in comparison to the ultrasound-assisted ones.     

Functional components in Luffa cylindrica and their effects on anti-inflammation of macrophage cells

The objectives of this study were to determine the distribution of functional components in peel and pulp of Luffa cylindrica and evaluate their anti-inflammatory activity on RAW 264.7 murine macrophage cells. Phenolics and flavonoids were present in abundant amounts in aqueous extract of peel, but in ethyl acetate extracts of peel, oleanolic acid, carotenoids and chlorophylls dominated. Both ethanol and ethyl acetate extracts in peel and pulp decreased production of nitric oxide in LPS-induced RAW 264.7 cells, whereas the ethanol extract mitigated secretion of prostaglandin E(2). Furthermore, all the extracts significantly inhibited IL-6 production, but remained ineffective in retarding generation of IL-1β and TNF-α. Ethyl acetate extract of peel reduced expression of inducible nitric oxide synthase, but enhanced expression of cyclooxygenase 2. Both ethyl acetate extracts of peel and pulp mitigated expression of p-IκBα, while the latter attenuated expression of p-ERK, and all the extracts failed to inhibit JNK phosphorylation.     

Antimicrobial, antioxidant and phytochemical investigations of sea buckthorn (Hippophaë rhamnoides L.) leaf, stem, root and seed

The antimicrobial and antioxidant activities of crude ethanolic extract from Hippophaë rhamnoides L. (Elaeagnaceae) leaf, stem, root and seed, and their respective fractions, obtained by liquid-liquid extraction (LLE) using hexane (HF), ethyl acetate (EAF) and water (WF), were investigated. The crude extract was obtained by Pressurised Liquid Extraction (PLE), using ethanol at 100 bar and 60 °C. Antimicrobial activity was tested against food-borne and clinical microorganisms. Antioxidant activity was measured using the DPPH-radical scavenging and the ferric reducing antioxidant power (FRAP) assays. The phytochemical contents were examined by colorimetric methods. The results showed that crude extracts were active against Gram − and + strains, and that seed and root extracts were better radical scavengers than leaf and stem extracts. For all organs, the two activities tested were found to be higher in WF. These activities were correlated with the presence of phenolic compounds in active fractions. High Performance Thin Layer Chromatography (HPTLC) fingerprints confirmed presence of phenolic compounds in active extracts and fractions.     

苦丁茶提取物的分离纯化、鉴定及不同萃取部位活性分析

以苦丁茶为原料，对其乙醇提取物和不同溶剂萃取部位的抗氧化活性、抗补体活性、抑制癌细胞活性进行探究，并对活性最佳的萃取部位进一步分离纯化，分析鉴定出单体化合物。抗氧化活性以总还原力、清除1,1-二苯基-2-三硝基苯肼自由基和超氧阴离子自由基的能力为指标，通过溶血实验评价抗补体活性，并采用MTT法测定对人乳腺癌细胞MCF-7的存活率，结合多种分离技术获得不同单体化合物，通过对质谱、核磁共振波谱的数据分析鉴定其化学结构。结果表明，苦丁茶乙醇提取物及各部位均具有良好的抗氧化效果，其中乙酸乙酯部位不仅在实验质量浓度范围内有较强的抗氧化活性（0.8 mg/mL均达到90%以上），还具有良好的抗补体活性（79.67±0.99）%，能很好抑制人乳腺癌MCF-7细胞增殖活性（54.8±0.26）%，对乙酸乙酯部位进行分离纯化，总共分离得到11 个单体化合物。由此可见，苦丁茶乙醇提取物和各部位均具有抗氧化、抗补体活性和人乳腺癌MCF-7细胞抑制活性，乙酸乙酯作为萃取剂时活性最佳。分离的单体化合物鉴定后多为酚类、黄酮类物质。     

红豆越橘不同溶剂萃取物组成及抗氧化相关性

以矮丛红豆越橘为研究对象,用体积分数95%乙醇提取后,分别用石油醚、乙酸乙酯、正丁醇进行萃取,评价乙醇粗提取物和不同溶剂萃取物中总酚、总黄酮、总花色苷、齐墩果酸含量及体外抗氧化能力(1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基、2,2’-联氮双(3-乙基苯并噻唑啉-6-磺酸)二铵盐自由基(2,2’-azinobis-(3-ethylbenzthiazoline-6-sulphonate),ABTS~+·)清除能力)。红豆越橘粗提取物及不同溶剂萃取物均具有一定的抗氧化活性,其中乙酸乙酯、正丁醇萃取物的抗氧化活性较强,乙酸乙酯萃取物具有最好的DPPH自由基清除能力(半抑制浓度(50%inhibitory concentration,IC_(50))为0.27 mg/m L)与ABTS+·清除能力(IC_(50)为0.05 mg/m L)。不同溶剂萃取物的抗氧化活性与总黄酮和总酚的含量具有较强的相关性。     

On-line HPLC-ABTS•+ evaluation and HPLC-MS n identification of bioactive compounds in hot pepper peel residues

In this study, bioactive compounds were extracted with aqueous ethanol from hot pepper peel residues, and the crude extract was divided into four fractions with ethyl ether, ethyl acetate and n-butanol in turn. The total phenolics (TP) and total flavonoids (TF) in the extract were analyzed, and the n-butanol fraction contained the highest TP and TF content, which was 13.45 mg gallic acid equivalents/g and 3.39 mg rutin equivalents/g, respectively. The antioxidant activity of the extract was evaluated by radical [2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 1,1-diphenyl-2-picrylhydrazyl] scavenging assays. The results of the correlation analysis showed that the antioxidant activity was well correlated with the content of TP and TF (R ² > 0.890). The antioxidant activity of individual antioxidant compound in the extract was evaluated using on-line HPLC-ABTS^?+ assay, and seven antioxidant compounds were identified using HPLC-DAD-MS ⁿ analyses. The main antioxidants identified were naringenin-7-glucoside, procyanidin dimer type B, quercetin-3-O-rhamnoside dimer, kaempferol-3-O-glucoside, kaempferol-3-O-rutinoside, quercetin-3-rutinoside and caffeic acid glycoside dimer. The results showed that hot pepper peel residues contained a certain amount of antioxidant compounds and had a potential application in food products.     

Antioxidant and Cytotoxic Activities of Lipophilic and Hydrophilic Fractions of Mentha Spicata L. (Lamiaceae)

Total antioxidant activity (TAA) and cytotoxic effect of four solvent fractions of ethanol extract of Mentha spicata L. were estimated. Relative antioxidant activity (RAA) was also determined relative to quercetin and L-ascorbic acid. Polyphenolics (phenolics and flavonoids) and pigments (chlorophylls and carotenoids) were quantitated and expressed as mg/g of the ethanol fraction. The ABTS/HRP/H₂O₂ decoloration method was used to estimate the total antioxidant activity. Cytotoxic effect on human prostate cancer cell line (PC-3) was assessed by MTT assay. The TAA was highest for ethyl acetate fraction (83%) followed by aqueous (75%), chloroform (51%) and hexane (47%) fractions. RAAs of ethyl acetate and aqueous fractions were equal to quercetin and ascorbic acid but less in hexane and chloroform fractions. Phenolics and flavonoids were higher in ethyl acetate (54 and 22 mg/g), aqueous (32 and 24 mg/g) and chloroform (30 and 16 mg/g) fractions compared to the hexane (14 and 15 mg/g) fraction. Chlorophyll and carotenoids were higher in chloroform fraction (29 and 7 mg/g) than in ethyl acetate (13 and 5 mg/g), hexane (14 and 3 mg/g) and aqueous (5 and 0.9 mg/g) fractions. Cytotoxic effect against PC-3 cell line was found to be highest for the chloroform fraction and lower for the aqueous fraction. Polyphenolic content and TAAs of the ethanol fractions were positively correlated. Similarly pigment content and cytotoxic effect of PC-3 cells were positively correlated.     

Green ultra-high pressure extraction of bioactive compounds from Haematococcus pluvialis and Porphyridium cruentum microalgae

Microalgae are considered prolific sources of bioactive compounds that can be useful for nutraceuticals. In this study, the potential of ultra-high pressure extraction (UHPE) for the simultaneous cell disruption and extraction of bioactives from two microalgae species, Haematococcus pluvialis and Porphyridium cruentum, was evaluated. The variables studied to extract carotenoids for H. pluvialis were pressure (100–600 MPa) and number of cycles (1 and 3 cycles) whereas the variables studied to obtain bioactives such as B-phycoerythrin, carotenoids, and PUFAs for P. cruentum were pressure (100–600 MPa) and different extraction solvents (water, ethanol, ethyl acetate or ethanol/d-limonene), generally recognized as safe (GRAS). The UHPE results showed significant increase on the extraction of carotenoids (109.74–119.34 mg per g extract) from H. pluvialis using 1 cycle of 20 min regardless of the pressure used. For P. cruentum, an UHPE with water provided extracts enriched in B-phycoerythrin (up to 144.43 mg per g extract), while subsequent UHPE using ethanol, ethyl acetate or ethanol/d-limonene 1:1 (v/v) provided extracts enriched in carotenoids (up to 65.05 mg per g extract) and polyunsaturated fatty acids (mainly eicosapentanoic acid and linoleic acid). Therefore, UHPE proved to be a viable green alternative for the recovery of bioactives from microalgae biomass.Industrial relevance: Microalgae are promising sources of bioactives such as B-phycoerythrin, carotenoids and polyunsaturated fatty acids. The potential of ultra-high-pressure extraction (UHPE) has been demonstrated as a fast and viable eco-friendly alternative using GRAS solvents (water, ethanol, ethyl acetate or ethanol/d-limonene) for the simultaneous cell disruption and extraction of these bioactives from Haematococcus pluvialis and Porphyridium cruentum. The bioactives obtained with one step or two step-UHPE process can be used in an array of food, cosmetic and pharmaceutical applications.     

Changes in the antioxidant capacity and phenolic compounds of <Emphasis Type="Italic">maesil</Emphasis> extract during one-year fermentation

This study aimed to identify the effects of soaking time and fermentation temperature and period on the total phenolics, total flavonoids, and antioxidant activity of maesil extract. Green maesil fruits were fermented with brown sugar at 15 or 25°C for one year. After soaking maesil for 90 days, the fruits were removed and the remaining liquid was further ripened for 275 days, whereas other samples continued to ferment with maesil until 365 days. Total phenolics, total flavonoids, and antioxidant activities of the extracts fermented with maesil for one year were higher compared with those wherein the fruits were removed at day 90. The total phenolic and total flavonoid contents were relatively higher at 15°C, whereas the ABTS and ferric-reducing antioxidant power (FRAP) activities were significantly higher at 25°C. The total phenolic and total flavonoid contents highly correlated with the antioxidant activities. These results show that fermentation temperature plays a critical role in enhancing the phenolic compounds and antioxidant activity of maesil extract.     

蜂胶不同溶剂萃取物组成和抗氧化性的研究

以蜂胶为原料,分别以甲醇、乙醇、氯仿、蒸馏水为溶剂进行萃取,测定各萃取物总酚与黄酮类物质的含量,通过测定还原能力,清除DPPH 自由基能力的测定来比较4 种不同萃取物的抗氧化性。结果表明：甲醇萃取物具有较强的抗氧化性。甲醇萃取物浓度为0.25mg/ml 时还原力高达1.162,且浓度为0.05mg/ml 时对DPPH 自由基清除率为64.676%。乙醇萃取物通过石油醚、氯仿、乙酸乙酯、丙酮依次分级萃取后所得到4 种萃取物各项指标测定结果表明,氯仿萃取了蜂胶乙醇萃取物中主要成分,但乙酸乙酯和丙酮萃取物的还原能力及清除DPPH 自由基清除能力较佳,在浓度为0.05mg/ml 时还原力分别为2.087 和1.798,DPPH自由基清除率达87.724% 和88.013%。