白芨活性成分的抗氧化和对α-淀粉酶的抑制作用

Antioxidant and α-Amylase Inhibitory Effects of Bioactive Components of Bletilla striata

采用甲醇回流提取、梯度萃取得到5个不同极性萃取物(正己烷萃取物、二氯甲烷萃取物、乙酸乙酯萃取物、正丁醇萃取物和水萃取物),分析萃取物中的总酚、总黄酮含量,以还原能力、对1,1-二苯基-2-三硝基苯肼(DPPH)和2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐(ABTS)自由基清除能力及α-淀粉酶抑制作用为评价指标研究其体外抗氧化和降血糖活性,并运用气相色谱-质谱联用(GC-MS)法对甲醇粗提物的化学成分进行鉴定。结果显示:白芨不同极性萃取物中的总酚和总黄酮含量存在显著性差异,二氯甲烷萃取物表现出最高的总酚含量(311.27±0.96 mg/g)和总黄酮含量(22.19±1.47 mg/g)。各萃取物具有较强的抗氧化活性,其还原能力和对DPPH、ABTS自由基清除能力与其浓度呈现良好的线性依赖关系。白芨不同极性萃取物对α-淀粉酶具有一定的抑制作用,以二氯甲烷萃取物的抑制效果最显著,其IC50值为15.75 mg/m L。总酚含量与抗氧化及α-淀粉酶抑制活性呈显著正相关,表明多酚类物质是白芨发挥作用的物质基础。GC-MS分析了甲醇粗提物并鉴定出15个化合物,占总峰面积量的93.13%,主要化学成分为酯类(53.01%)、芳香族类(28.68%)、有机酸类(8.97%)化合物,表明芳香族类化合物中的多酚类物质是主要的活性成分,酯类、有机酸可能是潜在的活性成分。研究表明,白芨萃取物的生物活性成分含量丰富,具有较好的抗氧化和α-淀粉酶抑制活性,为白芨的进一步开发利用提供依据。

Bletilla striata extracts were prepared by methanol circumfluence extraction. Five fractions of B. striata were achieved by extraction with different polar solvents including n-hexane,dichloromethane,ethyl acetate,n-butanol and water. The fractions were detected by the contents of total phenolics and total flavonoids,reducing power,scavenging DPPH and ABTS free radicals and α-amylase inhibitory activities. Gas chromatography-mass spectrometry（ GC-MS） was used to identify the main constituents of the methanol crude extract. The results showed that there were significant differences in the contents of total phenolics and total flavonoids among different polarity fractions. Dichloromethane fraction exhibited the highest contents of total phenolics（ 311. 27 ± 0. 96 mg/g） and total flavonoids（ 22. 19 ± 1. 47 mg/g）. All the fractions had strong antioxidant capacity such as reducing power,and DPPH,ABTS free radical scavenging abilities.There was a good linear dependence between the antioxidant capacity and the concentration. The fractions also exerted the inhibitory effects on α-amylase. The dichloromethane fraction presented the best α-amylase inhibitory effect with IC50 value of 15. 75 mg/m L. Total phenolics demonstrated positive correlations with antioxidant and α-amylase inhibitory activities,indicating that polyphenols were the bioactive components of B. striata. The methanol crude extract was analyzed by GC-MS,and fifteen compounds representing 93. 13% of the total constituents were identified. Esters（ 53. 01%）,aromatic series（ 28. 68%）,and organic acids（ 8. 97%） were the main components,among which,polyphenols were themajor bioactive components,while esters,organic acids might be potential bioactive components. In conclusion,B. striata fractions contained high content of bioactive compounds,showed potent antioxidant and α-amylase inhibitory activities.This research was profitable for the study and use of the B. striata.