从桑枝皮醇提物萃取的不同组分及其体外生物活性

Various Constituents and in vitro Bioactivity of the Mulberry Branch Bark Ethanolic Extract

为了从桑枝皮中获取有效的药用功能性成分,以不同极性的有机溶剂石油醚、氯仿、乙酸乙酯、正丁醇进一步萃取并分离桑枝皮醇提物(MBBEE)中的活性成分,获得的正丁醇萃取组分(n-BuOH)和剩余水相组分(Res)占MBBEE总量的94.26%(其中Res组分得率达73.72%,n-BuOH组分得率为20.54%),石油醚、氯仿、乙酸乙酯3种萃取组分的得率总共不足2%。对各种样品的活性成分检测表明,MBBEE中含有的总黄酮、总多酚和总糖3种活性成分分别为39.99、56.24和16.37mg/g,而以上3种活性成分在n-BuOH组分中分别为74.25、107.49和14.21mg/g,在Res组分中分别为262.16、118.70和75.88mg/g。对各种样品的氨基酸组成分析表明,游离氨基酸含量为n-BuOH组分>MBBEE>Res组分。各种样品的体外生物活性试验显示,MBBEE、n-BuOH组分和Res组分均具有很强的DPPH自由基清除作用以及对酪氨酸酶和α-葡萄糖苷酶的抑制作用,其中:对DPPH自由基清除作用以Res组分最强,抑制中值(IC50)为100μg/mL;对酪氨酸酶抑制活性以n-BuOH组分最高,IC50为5.2μg/mL;对α-葡萄糖苷酶的抑制活性以Res组分最高,IC50为2.8μg/mL。试验结果表明,从桑枝皮醇提物中萃取的n-BuOH组分和Res组分是降血糖以及抗氧化、抗衰老、美白的功能性成分。

In order to obtain various functional components for drug uses from mulberry branch bark,the active constituents of the mulberry branch bark ethanolic extract （MBBEE） were further extracted with organic solvents of different polarities including petroleum ether,chloroform,ethyl acetate,and n-butanol （n-BuOH）.The obtained n-BuOH fraction and the residue water phase fraction （Res） accounted for 94.26% of the total MBBEE in which the yield of Res and n-BuOH fractions was 73.72% and 20.54% respectively while the total yield of petroleum ether,chloroform,and ethyl acetate was less than 2%.Active constituent analyses showed that,contents of total flavonoids,total polyphenolics and total sugar of MBBEE were 39.99,56.24 and 16.37 mg/g respectively.These three constituents in the n-BuOH fraction were 74.25,107.49 and 14.21 mg/g respectively,and those in the Res fraction were 262.16,118.70 and 75.88 mg/g respectively.Amino acid component analyses to various samples showed that the content of free amino acids was in the order of n-BUOH fraction〉 MBBEE 〉Res fraction.In vitro bioactivity assay results revealed that MBBEE,n-BuOH fraction and Res fraction had good scavenging activity to DPPH free radical and strong inhibitory activities against tyrosinase and α-glucosidase.The Res fraction had the strongest scavenging activity to DPPH free radical.Its inhibitory concentration 50% （IC50） was 100 μg/mL.The n-BuOH fraction had the strongest tyrosinase inhibitoryactivity,with an IC50value of 5.2 μg/mL.The Res fraction had the strongest α-glucosidase inhibitory activity,with an IC50 value of 2.8 μg/mL.The above results indicated that the n-BuOH and Res fractions extracted from MBBEE contain functional constituents with hypoglycemic,antioxidant,anti-aging and skin protection activities.