Seasonal influence on phenolic-mediated antihyperglycemic properties of Canadian sugar and red maple leaves using in vitro assay models

Red and sugar maple leaves collected in the summer and fall from Canada, were evaluated for phenolic content, antioxidant, α-glucosidase, and α-amylase inhibitory activities variation. The phenolic contents of summer red maple leaves (RML-S) and summer sugar maple leaves (SML-S) were higher than red and sugar maple leaves collected in fall (RML-F and SML-F, respectively). HPLC analyses showed differences in phenolic compounds present in the SML samples compared to the RML samples. The extracts were assayed for yeast and rat α-glucosidase inhibitory activities. Both results showed that SML-S extracts had the highest inhibitory activity which could possibly be attributed to the unique phenolics present therein. Milder effects were observed in terms of α-amylase inhibitory activity, with RML-F having the highest inhibitory activity. These results suggest that maple tree leaf extracts may have potential for phenolic-mediated α-glucosidase inhibition, relevant to type 2 diabetes management, with SML-S extract having the highest bioactivity.     

几种原花青素的降血糖作用及与常见食品原料的结合研究

以4种不同来源的原花青素为研究对象,利用高通量淀粉浊度法测定其对α-淀粉酶和α-葡萄糖苷酶活力的抑制效果,研究其与常见食物原料之间的相互作用,为进一步开发降血糖主食提供理论依据。结果表明:葡萄籽与高粱麸皮原花青素对α-淀粉酶和α-葡萄糖苷酶活力抑制效果相对较好,蔓越莓与苹果原花青素对α-淀粉酶和α-葡萄糖苷酶活力抑制效果相对较差;食物中的主要成分与原花青素结合后会影响其对酶活力的抑制效果,常见食物中糯米、散装大米、高粱米等与葡萄籽原花青素结合明显,降低其对碳水化合物消化酶活力抑制效果,但玉米淀粉、木薯粉、马铃薯粉、生粉、米粉、小西米、小黄米、玉米片、红薯粉、黑米及黑豆与葡萄籽原花青素之间几乎不结合,是适宜发挥原花青素对碳水化合物消化酶活力抑制作用的食品原料。     

Inhibitory properties of polyphenols in Malus “Winter Red” crabapple fruit on α-glucosidase and α-amylase using improved methods

To explore the inhibitory activity of polyphenols on α-glucosidase and α-amylase, 16 polyphenols were isolated, identified, and quantified in an edible Malus “Winter Red” crabapple fruit. The limitations of two traditional methods for α-glucosidase and α-amylase activity assay in vitro were assayed. An improved method based on an HPLC assay for α-glucosidase and a colorimetric method coupled with a custom-made mini-column for α-amylase were established. Compared with positive controls, acarbose and miglito, most polyphenols, especially the four aglycones (cyanidin, quercetin, phloretin, and 3-hydroxyphloretin) showed higher inhibition rates on α-glucosidase. None of the polyphenols showed higher inhibition rates on α-amylase than acarbose, but most, especially the four aglycones, showed higher inhibition rates on α-amylase than miglito. The Malus Winter Red fruit has great potential for postprandial blood glucose management as a potential diet therapy for diabetic patients.     

Metabolite profiling,antioxidant activity,and glycosidase inhibition property of the mesocarp tissue extracts of sugar date palm [Phoenix sylvestris (L.) Roxb.] fruits

Phoenix sylvestris is an underutilized seasonal fruit in West Bengal, India. Methanol extract and extracts after alkaline hydrolysis of the mesocarp tissue of full-mature edible fruits of P. sylvestris were analyzed by GC-MS following a metabolomics approach. The fractions were tested for their antioxidant and inhibitory properties against the two key enzymes involved in diabetes, α-amylase, and α-glucosidase. Total 71 metabolites belonging to organic acids, amino acids, sugars, sugar alcohols, fatty acids, and phenols were identified in the methanol extract and in fractions after saponification. All the extracts and fractions showed high antioxidant, α-glucosidase, and α-amylase inhibitory activities. Sugars like raffinose (IC₅₀ = 0.36 μM), sucrose (IC₅₀ = 0.51 μM), trehalose (IC₅₀ = 0.85 μM), and phenols like taxifolin (IC₅₀ = 0.31 μM), benzoic acid (IC₅₀ = 2.74 μM) inhibited only the enzyme α-amylase. Phenolic components which inhibited both the enzymes were caffeic acid (IC₅₀ = 1.42 μM for α-amylase and IC₅₀ = 1.8 μM for α-glucosidase), 3, 4-dihydroxy benzoic acid (IC₅₀ = 0.23 μM for α-amylase and IC₅₀ = 2.58 μM for α-glucosidase), and quinic acid (IC₅₀ = 4.91 μM for α-amylase and IC₅₀ = 4.95 μM for α-glucosidase). Ferulic acid (IC₅₀ = 0.52 μM) and 4-hydroxycinnamic acid (IC₅₀ = 0.23 μM) inhibited only α-glucosidase. This study suggested that the metabolites present in the fruit mesocarp tissue showed the potential antioxidant activity and properties to inhibit the enzymes α-amylase and α-glucosidase. Further in vivo study is to be carried out to prove the efficacy of the fruits.

Abbreviations: FM: crude methanol extract; SI: ethyl acetate extract after alkaline hydrolysis step I; SII: ethyl acetate extract after alkaline hydrolysis step II     

银耳多糖对淀粉消化酶的抑制作用及其机理研究

目的:研究银耳多糖对胰α-淀粉酶和α-葡萄糖苷酶的抑制作用及机制。方法:以干银耳为原料,分别采用碱法提取、酶法脱蛋白和柱层析分离,得到总糖含量为92.45%的银耳多糖（Tremella fuciformis polysaccharide,TP）,采用可见光分光光度法分析了TP对胰α-淀粉酶和α-葡萄糖苷酶的抑制作用,采用荧光光谱法和圆二色谱法表征了TP对该两种酶结构的影响。结果:TP能抑制该两种酶的活性,其对胰α-淀粉酶的抑制作用明显高于α-葡萄糖苷酶,对该两种酶的半抑制浓度（IC₅₀）分别为7.6835和16.9306 mg/mL。TP通过与该两种淀粉消化酶发生相互作用抑制其活性。TP与胰α-淀粉酶相互作用明显,可静态猝灭此酶,改变其二级结构;TP与α-葡萄糖苷酶相互作用微弱,不能改变其二级结构。结论:TP通过与淀粉消化酶发生相互作用抑制其活性。     

桑叶黄酮类和多糖类化合物的提取及其降血糖作用研究

从桑叶中提取总黄酮和多糖,并测定其对α-葡萄糖苷酶和猪胰液α-淀粉酶的抑制作用以评估其降血糖功能。结果表明,桑叶中提取的黄酮类和多糖类化合物对这两种酶都有较好的抑制作用,并且总黄酮和多糖对α-葡萄糖苷酶及猪胰液α-淀粉酶的抑制存在协同作用,两者混合对两种酶的抑制作用更强。     

Screening of Possible In Vitro Neuroprotective,Skin Care,Antihyperglycemic, and Antioxidative Effects of Anchusa undulata L. subsp. hybrida (Ten.) Coutinho from Turkey and Its Fatty Acid Profile

The aim of this work was to determine antioxidant capacities, neuroprotective, skin care, antidiabetic effects, and fatty acid composition of Anchusa undulata subsp. hybrida. The antioxidant activity was screened by four different test systems including total antioxidant, antiradical, reducing power, and metal chelating activities. Neuroprotective potential was determined by anticholinesterase inhibitor assay. Tyrosinase inhibitory activity was tested to detect skin care effect. Antidiabetic effects were evaluated with α-amylase and α-glucosidase inhibitory assays. Inhibitory activities on acetycholinesterase, butyrylcholinesterase, tyrosinase, α-amylase, and α-glucosidase enzymes were observed as 2.238 and 1.239 μmol GALAEs/g, 0.339 mmol KAEs/g, 0.193, and 0.219 mmol ACEs/g extract, respectively. Amount of total phenolics and flavonoids were found as 80.34 μg GAEs/mg and 25.09 μg QEs/mg in the extract, respectively. Twenty-three fatty acids were found in the aerial parts, being oleic acid (24.30 g/100 g of total fatty acids) the most abundant, followed by linoleic (21.19 g/100 g of total fatty acids) and palmitic acids (17.50 g/100 g of total fatty acids).     

糙米多酚对淀粉消化酶的抑制作用及机理

本研究将糙米多酚(brown rice polyphenols,BRP)经过提取和C₁₈固相柱纯化后,研究了BRP对α-淀粉酶和α-葡萄糖苷酶的抑制作用及其机理。液相色谱-质谱联用技术(UPLC-DAD-ESI-Q-TOF-MS)分析结果表明,BRP中大部分多酚以糖苷的形式存在,包括1种酚醛、2种酚酸酰胺、4种酚酸糖苷、6种酚酸、6种酚酸酯和8种黄酮糖苷。BRP对α-葡萄糖苷酶显示出剂量依赖型酶抑制活性,当浓度为2 mg/mL时,抑制率最高可达到39.37%,而BRP对α-淀粉酶无明显抑制作用。此外,荧光光谱和热力学研究结果表明,BRP能与α-葡萄糖苷酶发生疏水相互作用,对α-葡萄糖苷酶的内源荧光具有动态猝灭作用。以上结果表明,BRP主要通过与α-葡萄糖苷酶发生疏水相互作用抑制α-葡萄糖苷酶的活性,从而延缓碳水化合物的水解。本文为改善餐后血糖提供一定的参考。     

1-脱氧野尻霉素对α-葡萄糖苷酶的抑制作用机制

运用紫外光谱法、荧光光谱法和圆二色光谱法,研究桑叶提取物1-脱氧野尻霉素（1-deoxynojirimycin,DNJ）对α-葡萄糖苷酶的作用。结果发现：DNJ与α-葡萄糖苷酶反应的半抑制浓度为0.297 μg/mL,作用类型为竞争型抑制;其与α-葡萄糖苷酶主要通过静电吸引力相互作用形成基态复合物,并使α-葡萄糖苷酶的内源荧光猝灭;DNJ与α-葡萄糖苷酶相互作用形成复合物的过程是熵驱动的吸热反应,静电吸引力是两者结合反应的主要驱动力。不同温度（273、298、310 K）条件下荧光猝灭常数（Ksv）分别为1.48×104、1.29×104、1.12×104 L/mol。DNJ使α-葡萄糖苷酶的构象发生变化,且使其二级结构重新排列;诱导酶活性口袋关闭,不利于底物结合到活性位点,推测这可能是DNJ抑制α-葡萄糖苷酶活性从而降低血糖水平的机理。     

桑叶多酚的鉴定及其抗氧化、抗α-淀粉酶活性分析

目的:桑树叶片在传统医学中被用作降糖和降血压的药物,其作用机理与活性成分含量有关。评价桑叶提取物不同生物活性,包括生物活性物质含量、抗氧化活性和抗α-淀粉酶活性。方法:采用SPE（固相萃取技术）将多酚粗提液分离纯化为花色苷、非花色苷多酚和水层三个组分,采用HPLC-PDA和HPLC-ESI/MS2对桑叶中的多酚物质进行系统地定性和定量。利用DPPH（1,1-二苯基-2-三硝基苯肼自由基清除能力）、ABTS（2,2’-联氮-双（3-乙基苯并噻唑啉-6-磺酸））和FRAP（铁离子还原能力）三种方法测定不同提取物的抗氧化活性,并采用福林酚法、pH差异法和比色法测定桑叶提取物总酚、总花色苷和总原花青素含量。结果:桑叶中共鉴定出6种花色苷、42种非花色苷多酚,其中,矮牵牛素-3-葡萄糖苷和原花青素衍生物含量很高;桑叶中总酚、总花色苷和总原花青素的含量分别为14.09 mg GAE/g DW、0.17 mg C3G/g DW和17.24 μg PA2/g DW;多酚粗提液、花色苷、非花色苷多酚和水层对α-淀粉酶活性的IC₅₀（半抑制浓度）分别为8.31、13.70、0.25和12.00 mg/mL,由此看出非花色苷多酚的抗α-淀粉酶活性最高。结论:桑叶具有较强的抗氧化活性,其中花色苷显示出最高的抗氧化活性。这些数据可以为蒙古桑叶用作功能食品提供重要参考。     

野生蓝果忍冬多酚鉴定及其抗氧化、降血糖活性

目的：对野生蓝果忍冬进行多酚成分鉴定和抗氧化、抗淀粉酶活性研究。方法：以我国小兴安岭地区的野生蓝果忍冬果实为材料,通过固相萃取技术分离纯化得到花色苷和非花色苷分离液,测定分离液中的化学成分,并测定多酚粗提液中总酚和总花色苷含量,抗氧化活性（1,1-二苯基-2-三硝基苯肼自由基清除能力、铁离子还原能力、2,2’-联氮-双(3-乙基苯并噻唑啉-6-磺酸)阳离子自由基清除能力、氧自由基吸收能力）,抗α-淀粉酶、α-葡萄糖苷酶活性和脂肪酶活性。结果：野生蓝果忍冬果实中含有丰富的花色苷和非花色苷多酚,尤其是矢车菊素-3-葡萄糖苷和山柰酚-3-芸香糖苷含量很高;蓝果忍冬多酚粗提液中总酚含量为82.7 mg/100 g,总花色苷含量为49.8 mg/100 g,具有较强的抗氧化活性;对α-淀粉酶、α-葡萄糖苷酶活性的半抑制质量浓度分别为0.39 mg/mL和0.933 mg/mL,对脂肪酶活性的半抑制质量浓度为12.31 mg/mL,说明蓝果忍冬可以作为一种有前景的淀粉酶抑制剂。     

黑加仑果实降解多糖理化特性、结构及体外降血糖活性

本实验以微波辅助溶剂法提取的黑加仑果实多糖为原料，采用超声辅助Fe2＋-VC-H2O2降解，经Sepharose 6B柱层析法分离，得到两种多糖（DP-1和DP-2）。经液相色谱测定DP-1和DP-2分子质量分别为1.29×106 Da和1.07×106 Da；气相色谱测定结果表明，DP-1和DP-2由相同的6 种单糖构成，但组成比例不同。傅里叶变换红外光谱、高碘酸氧化及核磁共振分析结果表明，DP-1和DP-2糖链上都含有α-、β-吡喃环，且主要是由6 种糖残基构成。功能特性测定结果显示DP-1和DP-2具有一定的吸湿性、保湿性及热稳定性。活性实验结果证实多糖DP-1和DP-2对α-葡萄糖苷酶和α-淀粉酶具有显著的抑制活性，质量浓度为2.0 mg/mL时，对α-葡萄糖苷酶抑制率最高，分别为（67.45±3.45）%和（73.22±0.48）%；对α-淀粉酶抑制率也最高，分别为（64.74±2.08）%和（73.28±2.52）%。此外，两种多糖对α-淀粉酶的抑制属于可逆竞争型。本研究可为黑加仑果实多糖的进一步利用提供理论参考。     

富硒蓝莓全果果酒体外消化特性研究

为分析富硒蓝莓全果果酒的体外消化特性,以非富硒酵母发酵蓝莓全果果酒为对照,对两种果酒在模拟胃肠液消化前后的总多酚含量、抗氧化活性、α-葡萄糖苷酶抑制活性及酚酸含量进行测定。结果表明,两种果酒在模拟胃肠液消化后总多酚含量、抗氧化活性、α-葡萄糖苷酶抑制活性均有所下降,3.0 h模拟胃液及1.0 h模拟肠液消化后富硒蓝莓全果果酒中总多酚含量是对照的1.28倍,对1,1-二苯基-2-三硝基苯肼（DPPH）、2,2’-联氮双（3-乙基苯并噻唑啉-6-磺酸）二铵盐（ABTS）、超氧阴离子（O2-）自由基清除率及对α-葡萄糖苷酶抑制活性分别是对照的1.27倍、1.85倍、1.07倍、1.18倍。富硒蓝莓全果果酒经模拟胃肠液消化后主要的酚酸为没食子酸（0.98μg/mL）、绿原酸（0.11μg/mL）、芦丁（0.17μg/mL）。富硒蓝莓全果果酒较对照在模拟胃肠液消化后具有更高的抗氧化、抑制α-葡萄糖苷酶活性,具有更强的生物活性。     

Biological activity of rice extract and the inhibition potential of rice extract,rice volatile compounds and their combination against α-glucosidase, α-amylase and tyrosinase

Rice is produced for consumption and traditional medicine. Rice is also used as an ingredient in cosmetic products. In this study, the author investigated the biological activity and inhibition potential against α-glucosidase, α-amylase and tyrosinase activity of rice extract (black rice [BR], red rice [RR] and white rice [WR]), rice volatile compounds, rice extract combined with volatile compounds, rice extract combined with standard inhibitors and volatile compounds combined with standard inhibitors. The results revealed that the free-radical scavenging capacity of rice extract is related to the phenolic content and flavonoids. BR showed the highest potential to inhibit α-glucosidase and α-amylase activity, whereas WR showed the highest potential to inhibit tyrosinase activity. Among rice volatile compounds, vanillin and vanillyl alcohol had the highest inhibition potential against α-glucosidase and α-amylase, respectively, whereas guaiacol had the highest inhibitory activity against tyrosinase. Molecular docking supported by the high binding efficiency was also obtained from vanillin and guaiacol when located at the active site of these enzymes. The combination of RR with acarbose (AB) had the highest inhibition potential and showed a synergic effect on both α-glucosidase and α-amylase. Interestingly, the combination of rice extract (BR, RR and WR) and vanillin and vanillyl alcohol had a synergic effect on α-amylase. Moreover, the combination of WR and vanillyl alcohol had the highest inhibition potential and showed a synergic effect on tyrosinase, whereas rice volatile compounds had a synergic effect on tyrosinase obtained from 2-pentylfuran/kojic acid (KA), vanillin/KA and vanillyl alcohol/KA.     

低糖枇杷桑葚复合果酱配方优化

针对传统高糖果酱的缺陷,以枇杷和桑葚为主要原料研制低糖复合果酱.通过单因素实验对枇杷占复合果浆添加比、柠檬酸添加量、白砂糖添加量和果胶添加量进行筛选,根据感官评分,采用Box-Benhnken中心组合设计试验,优化低糖枇杷桑葚复合果酱的配方.结果 表明,最佳配方参数为:枇杷占复合果浆添加比为32％,柠檬酸添加量为0.1...     

Chemical composition and bioactivities of the polyphenolic-rich extract of Ormenis africana Jord. and Fourr

Ormenis africana is an endemic North African species used in folk medicine because of its hypoglycemic property. In this study, the α-amylase and α-glucosidase inhibition and antioxidant activities of the polyphenolic-rich extract from O. africana were determined. The chemical composition was made using liquid chromatography with photodiode array and electrospray ionization mass spectrometry method and the identification of phenolics was assessed by comparing their retention times and ultraviolet and mass spectra with those of the standards and/or reported in the literature. The total phenolic content was estimated by the Folin–Ciocalteu method. The antidiabetic potential was estimated by the determination of α-amylase and α-glucosidase inhibition in vitro. Four assays were used for the evaluation of antioxidant activity of the extracts. Seventeen phenolic compounds were detected. The major peaks are chlorogenic acid, 5-O-di-caffeoylquinic acid, and apigenin and luteolin derivatives. The polyphenolic-rich extract showed remarkable α-amylase and α-glucosidase inhibition activity in a concentration dependent manner. Furthermore, the extract also demonstrated high antioxidant activities. O. africana can serve as a potential natural source for the development of a novel α-amylase and α-glucosidase inhibitory agents against diabetic complications.     

Anti-diabetic activity peptides from albumin against α-glucosidase and α-amylase

The objectives of this study were to identify novel peptides from albumin, and to evaluate and validate the anti-diabetic activity of peptides against α-glucosidase and α-amylase. In the research, albumin hydrolysate was purified and identified, tandem MS was adapted to characterise the amino acid sequences of peptides from the hydrolysate. In addition, anti-diabetic effects of the peptides with α-glucosidase and α-amylase inhibitory activity have been performed. The present work found eight novel peptides from albumin. Results also suggested that peptide KLPGF had α-glucosidase inhibitory activity with an IC(50) of 59.5±5.7μmoll(-1) and α-amylase inhibitory activity with an IC(50) of 120.0±4.0μmoll(-1). In conclusion, the results revealed that the peptide KLPGF was a potential anti-diabetic inhibitor.     

驼乳制品中抑制α-淀粉酶和α-葡萄糖苷酶活性乳酸菌的筛选及益生特性研究

目的:本研究以新疆阿勒泰地区的驼乳制品为研究对象,筛选对α-淀粉酶和α-葡萄糖苷酶有抑制活性的优良乳酸菌。方法:采用稀释涂布法分离纯化菌株,DNS和pNPG法筛选对α-淀粉酶和α-葡萄糖苷酶有抑制活性的菌株,通过耐酸性、耐胆盐、模拟胃肠道环境耐受性、抑菌性、抗氧化活性实验评价菌株的益生特性。结果:从驼乳制品中共计获得34株菌株,其中6株对α-淀粉酶和α-葡萄糖苷酶有抑制活性,经过形态学和16S rRNA分子鉴定,确定有4株为植物乳杆菌Lactiplantibacillus plantarum,2株为副干酪乳杆菌Lactiplantibacillus paracasei。6株乳酸菌对α-淀粉酶的抑制活性都达到50%以上,其中X34对α-淀粉酶的抑制率最高达到88.59%。本实验中筛选的乳酸菌对α-葡萄糖苷酶的抑制率在11%~16%之间,X31抑制率最高为15.43%。6株乳酸菌在不同pH（1.0、2.0、3.0）和不同浓度胆盐（1、2、3 g/L）的培养基中均可存活。6株乳酸菌在模拟胃液和肠液中的存活率分别达到83%和90%以上。对羟自由基和超氧阴离子自由基的清除率超过90%以上,其中X29对羟自由基的清除率最高为92.43%,对超氧阴离子自由基清除率最强的是X33清除率达到94.04%。6株乳酸菌对大肠杆菌、沙门氏菌和金黄色葡萄球菌有一定的抑制作用,其中X31对大肠杆菌的最大抑菌圈直径为19.63 mm,X23对沙门氏菌抑菌圈最大达到19.85 mm,菌株X33对金黄色葡萄球菌的抑菌圈直径最大为19.17 mm。结论:从驼乳制品中筛选到6株具有潜在降糖活性的乳酸菌,对强酸、胆盐和胃肠液有一定的耐受性,抗氧化能力较强,具有抑制致病菌的效果,为后期研发功能性降糖饮品提供益生菌株。     

Physicochemical properties, α-amylase and α-glucosidase inhibitory effects of the polysaccharide from leaves of Morus alba L. under simulated gastro-intestinal digestion and its fermentation capability in vitro by human gut microbiota

The investigation aimed at determining the impact of sequential simulated digestion on the physicochemical properties and digestive enzymes inhibitory effects of the polysaccharides fraction (MLP-2) of Morus alba L. leaves as well as its in vitro fermentation behaviours. After artificial salivary, gastric and intestinal digestions, the chemical components and microstructure of MLP-2 were altered with significantly (P < 0.05) decreased molecular weight. The α-amylase and α-glucosidase inhibitory activities of MLP-2 were significantly (P < 0.05) improved throughout simulated digestion. MLP-2I, the intestinal digested fraction of MLP-2, could significantly (P < 0.05) decrease the pH value of fermented culture and increase the short-chain fatty acids (SCFA) concentrations, especially acetic, propionic and butyric acids. In conclusion, MLP-2 could be gradually degraded under simulated digestion with altered physicochemical properties and enhanced α-amylase and α-glucosidase inhibitory effects, and further utilised by human gut microbiota to decrease pH value and promote SCFA production.     

番石榴不同部位乙醇提取物的抗氧化、降血糖及酪氨酸酶抑制活性

目的:比较研究番石榴不同部位(根、茎、叶、果实)乙醇提取物抗氧化、降血糖和抑制酪氨酸酶活性.方法:分别采用ABTS法和DPPH法、pNPG法和DNS法、L-DOPA法评价番石榴不同部位抗氧化活性、降血糖活性和酪氨酸酶抑制活性.结果:番石榴不同部位乙醇提取物均具有一定的体外抗氧化、降血糖和酪氨酸酶抑制活性,并呈现一定的量...