Effect of Home-Cooking Methods on Phenolic Composition and Antioxidant Activity of Sweetpotato (<i>Ipomoea batatas</i>(L.) Lam.) Cultivars Grown in Egypt

Four sweetpotato (Ipomoea batatas (L.) Lam.) cultivars grown in Alexandria, Egypt, including Monofya 6, Monofya 66, Abeeis, and Beauregard were cooked using four different home-cooking methods (boiling, baking, microwaving, and deep-frying). The antioxidant contents (total phenolics by Folin-Denis, and individual phenolic acids by HPLC) as well as the antioxidant activity determined by reducing power (RP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2’-azinobis(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) were measured in this study. Results indicated that total phenolic contents of raw flesh tissue by Folin-Denis ranged from 0.53 to 0.87 mg chlorogenic acid equivalent (mg ChAE)/g dry weight basis (dw). The RP ranged between 0.1 and 0.25 mg ChAE/g dw, DPPH and ABTS radical scavenging activities varied from 1.10 to 1.72 and 0.85 to 1.51 μmol trolox equivalent (TE)/g dw, respectively. Thermal processing significantly (P ≤ 0.05) increased the total phenolic content, as well as individual phenolic acids and antioxidant capacity of all the cultivars under study. In this respect, deep-frying exhibited the highest increment among the four processing methods. The most abundant individual phenolic acids in processed flesh roots tissues were chlorogenic acid followed by 3,5-dicaffeoylquinic acid. Total phenolic contents were highly correlated with RP, DPPH, and ABTS, also the correlation between the DPPH and ABTS values were significantly high.

Phenolic Contents and Antioxidant Activity of Various Date Palm (<i>Phoenix dactylifera </i>L.) Fruits from Saudi Arabia

The present study aimed to estimate the individual and total phenols and antioxidant activity of the aqueous and alcoholic extracts of three premium quality date varieties (Khalas, Sukkari and Ajwa) from Saudi Arabia. In general, water extract has shown significantly higher contents of total phenols than alcoholic, especially in Ajwa (455.88 and 245.66 mg/100 g respectively). However, phenolic profile indicated that Sukkari contained the highest rutin concentration (8.10 mg/kg), whereas, catechin was approximately the same in Sukkari and Ajwa (7.50 and 7.30 mg/kg respectively). Khalas was the highest variety content of caffeic acid (7.40 mg/kg). A significant difference has indicated among extracts and varieties in suppressing lipid peroxidation. Sukkari and Ajwa have reduced the oxidation with 50% at lower concentration in water extract than alcoholic (0.63, 0.70 and 1.60, 1.43 mg/ml respectively). Furthermore, high positive linear correlation was found between total phenols in water (r = 0.96) and alcohol (r = 0.85) extracts and inhibition of lipid oxidation activity. The compounds responsible for the activity were catechin (r = 0.96), and rutin (r = 0.74) in water extract, whereas this correlation decreased in alcoholic extract (r = 0.66) for catechin and very weak (r = 0.38) for rutin. No correlation was found between caffeic acid and lipid peroxidation in both extracts. Similar significant results were obtained with DPPH test, except with Sukari, which has shown no difference between aqueous and alcoholic extracts (4.30, 4.10 mg/ml respectively).

Comparison among Cornelian Cherry and <i>Prunus cerasus</i>According to Phenolic Content and Antioxidant Capacity by Three Various Methods of Extraction

Cornelian cherry and Prunus cerasus with red pigments possess precious source of flavonoids and phenolic acids which have various applications in treatment of various health problems. This study is conducted to compare different methods of extraction (shaking incubator, soxhelet, ultrasonic) were applied in order to identify the best method which shows the highest rate of antioxidant capacity by DPPH and ferric reducing antioxidant power (FRAP) methods and total phenolic compounds via Folin-Ciocalteu procedure, p-coumaric acid content of fruits were evaluated by high performance liquid chromatography (HPLC). As a result, cornelian cherry with 1313.13 mg/Kg average TPC score exhibits higher total phenolic content than Prunus cerasus with 1270 mg/Kg. It’s notice worthy that there was a slight difference among antioxidant activity in two fruits. Consequently, DPPH revealed nearly stronger antioxidant activity for Prunus cerasus while cornelian cherry had a little more potent antioxidant activity according to FRAP Test. p-coumaric acid content was almost twice in Prunus cerasus (10.8 mg/ml) than cornelian cherry (5.6 mg/ml). In addition, both shaking incubator and ultrasonic extraction procedures were more efficient than soxhelet in two fruits.

Biochemical changes in phenols,flavonoids,tannins,vitamin E,β-carotene and antioxidant activity during soaking of three white sorghum varieties

Objective:To investigate the changes in total phenols,flavonoids,tannins,vitamin E, β-carotene and antioxidant activity during soaking of three white sorghum varieties.Methods: The changes in total phenols,total ilavonoids,tannins,phenolic acids compounds,flavonoid components,vitamin E,P-carotene and antioxidant activity during soaking of sorghum grains were determined.Results:Total phenols,total flavonoids,tannins,vitamin E,P-carotene and antioxidant activity in raw sorghum were ranged from 109.21 to 116.70,45.91 to 54.69,1.39 to 21.79 mg/100 g,1.74 to 5.25,0.54 to 1.19 mg/kg and 21.72%to 27.69%and 25.29%to 31.97%,respectively. The above measured compounds were significantly decreased after soaking.p-Hydroxybenzoic acid,vanillic acid,syringic acid and cinnamic acid represent the major phenolic acids in Dorado variety.While ferulic acid,p-coumaric acid,gallic acid and caffeic acid represent the major phenolic acids in Shandaweel-6.On the other hand,protocatechuic acid represents the major phenolic acids in Giza-15.Regarding flavonoids components,Dorado was the highest variety in kampferol and naringenin while Shandaweel-6 was the highest variety in luteolin, apigenin,hypersoid,quercelin and christen.Finally,Giza-15 was the highest variety in catechin. Phenolic acids,flavonoid compounds and antioxidant activities were decreased after soaking. Conclusions:Sorghum varieties have moderate quantities from total phenols,total flavonoids, tannins,phenolic acids compounds,flavonoid components,vitamin E,P-carotene and antioxidant activity which decreased after soaking.

Changes of Polyphenols in Tobacco Leaves During the Flue-Curing Process and Correlation Analysis on Some Chemical Components

The changes of polyphenols in tobacco leaves during the flue-curing process and correlation analysis on some chemical components were studied. Leaf samples were taken from different tobacco-producing regions in Henan Province, China. The results indicated that the content of total phenols increased during the first 24 h of curing, and then decreased. It reached the lowest value at 72 h of curing and increased rapidly after that. The content of chlorogenic acid also increased during 0-24 h of curing. But the lowest point occurred at 60 or 72 h of curing and then it increased till the end of the curing process. The content of mtin generally increased with curing, and showed little fluctuations. The changes of PPO and POD activity were the opposite. Rutin was found to have a highly significant positive correlation with total sugar （r=0.822^＊＊）, but a highly significant negative correlation with starch, nicotine, and protein.

The Effects of Salicylic Acid on Helianthus annuus L. Exposed to Quizalofop-P-Ethyl

Herbicides adversely affect both the target plant and its environment. In this study, Helianthus annuus L. cv. “Oliva CL” was treated post-emergence with 0.3 to 3.1 mM quizalofop-p-ethyl. The peroxidase activity (POD), ascorbate peroxidase activity (APX), lipid peroxidation, pigment sys tem and total phenolic content were then determined on the 1st, 5th, 10th and 15th days following treatment. The POD activity increased on all application days, and the APX activity increased on the 5th day and decreased on the 10th and 15th days. In addition, the malondialdehyde (MDA) content was increased on the 1st, 5th, 10th and 15th days, except for the in H. annuus plants treated with 1.6 to 3.1 mM quizalofop-p-ethyl. The total chlorophyll, carotenoid and total phenolic content were important and changed in a time dependent manner. In the present study, we also investigated the possible role of salicylic acid (SA) in protecting H. annuus seedlings from herbicide toxicity. The plants were first treated with 0.5 mM SA pre-emergence and then treated with 0.3 to 3.1 mM quizalofop-p-ethyl herbicide post-emergence. In general, increases in the POD activity and MDA content were observed in the treatment groups on all application days. In the treated groups, the APX activity increased until the 15th day. In the SA pre-treated plants, the total phenollic, total chlorophyll and carotenoid content were also important in a time dependent manner.

真空预冷对采后娃娃菜流通及货架品质的影响

为优选娃娃菜真空预冷的处理条件,维持采后娃娃菜的新鲜品质,在分析不同真空预冷终温(0、2和4℃)和不同真空预冷终压(400、600、800和1000 Pa)对采后娃娃菜预冷效果的基础上,进行了二因素三水平的中心复合响应面试验。结果显示,与不经预冷处理的对照和终温0℃的预冷组相比,在终压600 Pa条件下,2~4℃的预冷终温处理可更好地维持采后娃娃菜的外观品质,抑制其呼吸速率和丙二醛(MDA)含量的升高。在终温2℃条件下,与不经预冷处理的对照和终压1000 Pa的预冷组相比,400~800 Pa的预冷终压处理可更好地维持采后娃娃菜的外观品质,抑制其呼吸速率及MDA含量的升高。进一步的中心复合响应面试验结果显示,采后娃娃菜的真空预冷最优条件为终温4.0℃、终压600 Pa,该真空预冷条件不仅可维持采后娃娃菜的较好品质,而且可使活性物质可溶性蛋白、总酚和抗坏血酸的含量分别提高18.78%、18.47%和33.23%。因此,适宜的真空预冷处理是一种极具潜力的商品化处理技术,能有效维持采后娃娃菜在流通及货架期间的良好品质。

狗脊总酚酸的提取工艺优化及抗氧化活性

目的采用Box-Behnken设计-响应面法优化狗脊总酚酸的提取工艺,并评价其体外抗氧化活性。方法以液料比、乙醇浓度和提取温度为影响因素,总酚酸提取率为评价指标,在单因素考察的基础上,运用三因素三水平的Box-Behnken设计-响应面法优化狗∶脊总酚酸的最佳提取工艺。测定狗脊总酚酸提取物对ABTS·^(+)和DPPH·的清除效果。结果狗脊总酚酸最佳提取工艺为:乙醇浓度55%、提取温度88℃、液料比602 mg/mL和1 mg/mL时,对ABTS·^(+)、DPPH·的清除率分别为92.76%和88.66%。结论响应面优化法试验理论值与实测值较一致,得到的狗脊总酚酸提取工艺简便可行,狗脊总酚酸提取物具有良好的体外抗氧化活性。

石刁柏真伪的红外快速鉴别与总皂苷、总酚酸含量测定及抗氧化活性分析

使用傅里叶红外光谱法对石刁柏样品进行定性研究,并对石刁柏进行总皂苷、总酚酸、DPPH+清除率及抗氧化活性测定。结果显示14批石刁柏样品的红外图谱峰型一致,相似度系数均在98.7%以上,可断定均为正品石刁柏;证明红外光谱技术可快速鉴别石刁柏的真伪。14批石刁柏样品的总皂苷、总多酚含量稳定,最高分别为6.340 mg·g^(-1)、2.0450 mg·g^(-1);各批次石刁柏对DPPH+均有清除作用,最佳IC50为4.57mg·mL^(-1),代表石刁柏总抗氧化能力的Vc浓度最大为2.4110 mg·mL^(-1);对测定结果进行pearson相关性分析和聚类分析,可将14批石刁柏分为5类;总皂苷、总酚酸与石刁柏的总抗氧化能力密切相关,相关系数值具有非常显著的正相关性,石刁柏具有较好的抗氧化能力。本研究为控制石刁柏药材质量、保证其安全使用和后期开发利用提供理论支持。

2个桑树品种果实不同发育时期营养物质的变化

【目的】有针对性地对桑葚品质进行遗传改良,了解果实发育过程中营养物质组成的动态变化。【方法】对桑葚鲜质量进行测量,使用渗透计测定果实硬度,采用便携式糖度计测定桑葚可溶性固形物含量,采用NaOH滴定法测定可滴定酸含量,采用NaNO2-Al(NO3)3比色法测定总黄酮含量,采用福林-酚比色法测定总酚含量,采用气相色谱串联质谱法测定可溶性糖和有机酸含量,使用荧光定量PCR分析糖代谢相关基因表达水平。【结果】通过对安葚和桂花的形态及营养物质分析发现,与安葚相比,桂花的单果质量较大,果实硬度较小。2个品种桑葚的总酚和总黄酮含量存在显著差异,安葚的总酚和总黄酮含量不断积累,桂花的积累量则较少。此外,葡萄糖和果糖在2个品种桑葚中具有相似的积累趋势,但二者蔗糖的积累存在显著差异。安葚和桂花桑葚中的有机酸主要为苹果酸,其次是琥珀酸和酒石酸。随着果实发育,2个品种桑葚糖酸比逐渐增大,糖酸比在7.99~81.06之间,且在各个不同发育时期,安葚糖酸比大于桂花。蔗糖代谢相关基因表达分析表明,中性转化酶1(INV1)基因在10~30 DAP桂花中的表达量显著高于安葚,桂花中蔗糖磷酸酶(SPP)基因表达量显著高于安葚,蔗糖合酶2(SUS2)基因在安葚40~50 DAP间表达量较高且显著高于桂花。【结论】在河北承德的生长条件下,桂花果实的蔗糖、苹果酸和可溶性固形物含量高于安葚,安葚果实的总黄酮、总酚和可滴定酸含量高于桂花。此外,INV1、SPP与SUS2基因在桑葚糖代谢中发挥重要的调控作用。研究结果为不同颜色桑葚成熟过程中营养成分动态变化的研究提供了信息,为桑葚果实品质形成研究奠定了基础。

槐米的红外快速鉴别与总黄酮、总酚酸、还原糖含量测定

研究槐米内总成分含量,使用傅里叶红外光谱法对槐米样品进行定性研究;采用硝酸铝显色法、福林酚法、DNS对槐米进行总黄酮、总酚酸、还原糖进行测定。14批槐米的红外图谱的峰型一致,各批次槐米的一维红外光谱都存在表征酚酸类、黄酮类和糖类成分的特征吸收峰;在其二阶导数红外图谱,进一步确认黄酮类化合物的存在。含量测定发现其富含总黄酮、总多酚、还原糖。槐米富含酚酸、黄酮类、还原糖成分,一维红外光谱和二阶导数光谱的结合,可以为不同批次槐米的识别分析提供科学数据,有助于槐米的整体质量控制以及有效成分定性分析研究。本研究为后期开发利用槐米提供理论支持,也为控制槐米的药材质量,保证其安全使用提供参考。

3种测定广式酱油中总糖含量的方法比较

该研究通过比较直接滴定法、苯酚硫酸法、蒽酮硫酸法3种方法测定广式酱油总糖含量的差异,并对这3种方法进行方法学验证,以期筛选出一种适合广式酱油总糖含量测定的方法。结果显示,直接滴定法、苯酚硫酸法和蒽酮硫酸法分别在0.50~8.00、0.00~0.08和0.00~0.08 mg/mL范围内线性关系良好。直接滴定法、苯酚硫酸法和蒽酮硫酸法的精密度试验的RSD值分别为1.07%、0.05%、0.05%,重现性试验的RSD值分别为0.88%、3.93%、3.24%,直接滴定法在24 h内显色稳定,苯酚硫酸法和蒽酮硫酸法在1 h内显色稳定。而在加标回收率试验中,蒽酮硫酸法的平均加标回收率较高,为168.04%,RSD值为2.97%,直接滴定法的平均加标回收率为104.67%,RSD值为2.07%,苯酚硫酸法的平均加标回收率为103.85%,但其RSD值为8.04%,蒽酮硫酸法测定酱油总糖含量的准确度低于其他两种方法。因此,直接滴定法和苯酚硫酸法的精密度、重现性、稳定性良好,理论上均具有可行性,蒽酮硫酸法不适合用于广式酱油总糖含量的测定。酱油中总糖含量是反映酱油品质的基本指标之一,筛选出适合酱油总糖含量的检测方法,对实际酱油生产监控和产品加工过程的品质控制都有重要意义,同时也为酱油总糖含量测定方法标准的制定提供一定的实验参考。

食叶草不同部位营养成分分析

研究旨在比较食叶草的叶、根、茎和种子的营养成分及抗营养因子含量,对食叶草不同部位进行初步营养价值评价。选取不同批次食叶草样品,分别测定叶、根、茎和种子4个部位的常规营养成分、氨基酸、矿物质元素、生物活性成分及抗营养因子含量。结果显示:食叶草不同部位(叶、根、茎和种子)的干物质、粗蛋白、粗脂肪、粗灰分、粗纤维含量均存在极显著差异(P<0.01),其中叶的粗蛋白、粗脂肪、粗灰分含量最高,达到30.15%、3.71%、13.78%。食叶草矿物质元素种类丰富,叶、根、茎和种子4个部位的钙、磷、锰、铁、铜、硒含量均存在极显著差异(P<0.01),锌含量差异不显著(P>0.05)。其中叶的锰、铁、铜、硒含量最高,分别为170.06、921.92、11.31、0.33 mg/kg。种子部位的锌含量最高,为6.95 mg/kg。在食叶草叶、根、茎和种子中均检测出了17种氨基酸,包括7种必需氨基酸,2种半必需氨基酸,8种非必需氨基酸;通过比较可知,叶、根、茎和种子4个部位的17种氨基酸均存在极显著差异(P<0.01),其中叶中的天门冬氨酸、谷氨酸、半光氨酸、蛋氨酸、亮氨酸、精氨酸含量均高于其他部位。食叶草叶、根、茎和种子4个部位的总黄酮和总酚酸含量均存在极显著差异(P<0.01),其中叶的总黄酮含量最高,为19.8 mg/g;种子中的总酚酸含量最高,为4.48 mg/g。食叶草叶、根、茎和种子4个部位的草酸和植酸含量均存在极显著差异(P<0.01),单宁含量存在显著差异(P<0.05),其中叶的草酸含量和植酸含量最高,为103.22、67.52 mg/g,单宁含量最高在种子部位,为2.79 mg/g。与7种常见饲料相比,食叶草叶中CP含量高于2种能量饲料和3种粗饲料,粗纤维含量高于2种能量饲料和2种蛋白饲料,低于粗饲料;粗灰分含量均高于其他7种常见饲料,Fe、Mn元素含量均高于7种常见饲料。综上所述,食叶草叶具有较高的营养价值,与7种常见饲料相比,部分营养成分含量较高,在蛋白源饲料原料资源开发方面具有较大潜力。

基于总糖、可溶性蛋白和酚酸含量的新疆蔷薇果实营养品质评价

【目的】深入挖掘新疆地区的蔷薇果实种质资源,了解其主要营养成分差异,为蔷薇果品质改良及开发利用提供参考依据。【方法】以单叶蔷薇、密刺蔷薇、宽刺蔷薇和弯刺蔷薇等10种新疆蔷薇果为试验材料,测定果实中总糖、可溶性蛋白和酚酸的含量并进行方差分析、相关性分析及聚类分析,运用隶属函数法对10种新疆蔷薇果实进行差异分析和营养品质综合评价。【结果】单叶蔷薇果实的总糖和酚酸含量最高,分别为125.54、9.09 mg·g^(-1),现代月季‘天山祥云’果实的总糖和酚酸含量最低,分别为102.90、4.78 mg·g^(-1);可溶性蛋白含量最高的是‘天山祥云’,为46.68 mg·g^(-1),最低的是宽刺蔷薇,为28.51 mg·g^(-1)。相关性分析表明,蔷薇果的酚酸与总糖含量呈极显著正相关,可溶性蛋白与酚酸和总糖均呈现极显著负相关。聚类分析结果显示,10种新疆蔷薇果可分为3个类群,第1类是弯刺蔷薇、疏花蔷薇1、宽刺蔷薇、托木尔蔷薇和尖刺蔷薇;第2类是单叶蔷薇;第3类包括疏花蔷薇2、‘天山祥云’、密刺蔷薇和伊犁蔷薇,可根据不同需求和目标选择相应的果实类群。平均隶属函数值可排序为:单叶蔷薇>密刺蔷薇>弯刺蔷薇>伊犁蔷薇>托木尔蔷薇>尖刺蔷薇>疏花蔷薇1>宽刺蔷薇>疏花蔷薇2>‘天山祥云’。【结论】蔷薇属果实具有较高的食用价值和药用价值,但不同蔷薇果中总糖、可溶性蛋白和酚酸含量差异较大,该研究结果可为蔷薇属果实的开发利用提供一定的参考依据和理论支撑。

双丹膏中总酚的含量测定

以没食子酸为对照,采用福林酚比色法在761 nm波长下测定6个不同批次双丹膏中总酚的含量。研究发现,没食子酸在1.76~4.40μg/mL范围内线性关系良好,平均加样回收率为99.19%,RSD为1.22%。6批次双丹膏总酚含量由低到高依次为18.44、18.62、18.72、18.73、18.76、18.95 mg/g。结果表明,该方法简便、准确,具有良好的精密度、稳定性、重复性,可用于双丹膏中总酚的含量测定,为双丹膏的质量控制提供理论依据。

Nitrogen mineralization in the oldest climax communities in the eastern Mediterranean region

In this study,we investigated how tree species affect N mineralization in connection to some soil properties and seconder metabolite levels of litter,in the soil of the old-est native forest communities.In the oldest pure communi-ties of Pinus nigra(PN),Fagus orientalis(FO),and Abies bornmuelleriana(AB)in the mountain range of Mount Uludağ,Bursa,Turkey,annual net yield and N mineraliza-tion in the 0-5-and 5-20-cm soil layers were determined in a field incubation study over 1 year.Sampling locations were chosen from 1300 to 1600 m a.s.l.,and moisture content(%),pH,water-holding capacity(%),organic C,total N,and C/N ratio,and annual net mineral N yield of the soil and hydro-lyzed tannic acid and total phenolic compounds in litter were compared for these forest communities.F.orientalis had the highest annual net Nmin yield(43.9±4.8 kg ha^(-1) a^(-1)),P.nigra the lowest(30.5±4.2 kg ha^(-1) a^(-1)).Our findings show that in the oldest forest ecosystems,the seasonal soil moisture content and tree species play an essential role in N cycling and that hydrolyzed tannic acids and total phenolic compounds effectively control N turnover.Tannic acid and total phenolics in the litter were found to inhibit nitrification,but total phenolics were found to stimulate ammonification.

黄蜀葵花药材总多糖含量测定方法研究

目的:建立黄蜀葵花药材中总多糖的含量测定方法,为其质量控制提供依据。方法:以葡萄糖为对照,用苯酚-硫酸法对样品显色,采用紫外-可见分光光度法在485 nm波长处测定总多糖的含量,并对方法学进行研究。结果:总多糖在2.270~13.620μg/mL范围内呈良好线性关系;其回归方程为Y=0.0612186X-0.0178058(r=0.999),加样回收率为99.15%,RSD为0.66%(n=9)。结论:采用苯酚-硫酸法测定黄蜀葵花药材中总多糖的含量,方法稳定,精密度高,重复性好,适用于黄蜀葵花药材的多糖含量测定。

水芹总酚酸体外抗HIV-1的作用

目的探讨水芹总酚酸体外抑制人类免疫缺陷病毒1型的作用。方法用不同稀释度的水芹总酚酸与TZM-bl细胞共同培养,使用MTT法检测活细胞的数量,观察水芹总酚酸对TZM-bl细胞的毒性作用;用人类免疫缺陷病毒1型实验室适应株SF33、BAL分别感染TZM-bl细胞,基于TZM-bl细胞的荧光素酶检测体系,采用荧光素酶活性检测方法检测水芹总酚酸抗人类免疫缺陷病毒1型的活性。结果水芹总酚酸对TZM-bl细胞表现出较低的细胞毒性,半数细胞毒浓度>1600μg·ml^(-1)。水芹总酚酸对TZM-bl细胞HIV-1 SF33、HIV-1 BAL病毒的半抑制浓度平均值分别为38.93和24.25μg·ml^(-1),治疗指数分别为>41和>66。结论水芹总酚酸在体外具有抑制人类免疫缺陷病毒1型复制活性的作用。

Box-Behnken响应面法优化杠板归总酚酸的提取工艺

目的:采用Box-Behnken-响应面法优化杠板归总酚酸的提取工艺。方法:以液料比、乙醇浓度和提取时间为考察因素,以总酚酸含量为评价指标,设计Box-Behnken实验进行工艺优化确定杠板归总酚酸的最佳提取工艺。结果:杠板归总酚酸最佳提取工艺为料液比31、乙醇浓度63%、超声时间46 min,此条件下总酚酸含量3.69 mg/g。结论:本试验优化所得的提取工艺高效稳定、操作简易,可用于杠板归中总酚酸的提取。

Antioxidant Activity and Phytochemical Screening in Acacia rigidula Benth. Leaves

This study aimed to compare the total phenolic content (TPC) and antioxidant activities of A. rigidula extracts. It also aimed to identify phenolic acids present in the extracts. The 2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and ferric thiocyanate lipid peroxidation antioxidant assays were performed. High performance liquid chromatography was used to identify phenolic acids. There was no solvent effect on TPC nor on scavenging activities, and inhibition of lipid peroxidation (p > 0.05) among solvent extracts. On the other hand, 1:1:3 water: acetone: methanol extract (10.22 mg GAE/g sample) had significantly higher reducing potential than 50% ethanol extract (EE) (9.259 mg GAE/g sample) (p < 0.05);but EE was not significantly different from 80% methanol extract (9.781 mg GAE/g sample) (p > 0.05). Phenolic fraction designated as fraction 4 had the highest antioxidant activity (p < 0.05) with 69.49% ABTS scavenging activity and FRAP reducing potential, 22.26 mg of GAE/g sample. DPPH scavenging activities of fractions 4 (55.59%) and 5 (55.64%) were significantly higher than the other fractions (p A. rigidula extracts contain gallic, caffeic, vanillic, p-coumaric, salicylic acids and vanillin.