Extraction And Separation And Determination Of Active Components In Usnea Longissima Ach.

Usnea longissima Ach.,which contains several kinds of active substances such as usnic acid,diffrataic acid,barbatic acid,ramalic acid,belongs to Ascolichens Lecanorales Usneaceae Usnea and have high social and economic values.In this paper,the content of usnic acid in the 95%of alcohol extractives of usnea that was collected from Qinling mountain,Tibet,the Lesser Xingan Mountains in Hei Longiiang and Altai Mountains in Xinjiang was measured,the 1,1-diphenyl-2-picryl- hydrazyl(DPPH)free radical scavenging activity was also measured,then purification process of extractive from Usnea longissima Ach.in Tibet was taken after extracted the usnea by CHCl₃,meanwhile,the pure material from extractive-was identified.At last,the total antioxidation competence and antibacterial activities were measured and the minimum inhibitory concentration of pure substance extracted from Usnea longissima Ach.was also tested.The conclusion was made as follow:(1)The usnea was extracted twice by 95%alcohol in 80℃,the ultraviolet intake degree of extractive was measured in 284nm,the results showed that the Usnea longissima Ach.had high content of usnic acid,the usnic acid of usnea collected from northeast of China can achieved 5.71%and the collection from Tibet can achieved 5.66%,therefore,these two usnea was most suitable material for usnic acid extraction and had important value for massive development of usnic acid.(2)The 1,1-diphenyl-2-picryl- hydrazyl(DPPH)free radical scavenging activity of ascorbic acid in the alcohol extractive of usnea was measured,the IC₅₀which was a evaluate index to DPPH free radical scavenging activity was applied in measurement of DPPH free radical scavenging activity of the extractives from Usnea.The DPPH free radical scavenging activity of the extractives from all kinds of Usnea were low by compared with the activity of DPPH in ascorbic acid.(3)The usnea collection from Tibet was extracted successively by soxhlex in 75℃,96g extractive were extracted from 960g usnea collections.The extractive was taken gradient elution by Silica Gel Column Chromatography,then with many extraction methods used,5 pure substances were extracted.These five substance were 2-methyl-4-ethyoxyl-6-methoxyl phenylformic acid,barbertic acid,usnic acid,2-methyl-4-methoxyl-6-hydroxyl phenylformic acid,compound E.Among these substances,2-methyl-4-ethyoxyl-6-methoxyl phenylformic acid,2-methyl-4-methoxyl-6-hydroxyl phenylformic acid,compound E was firstly extracted from Usnea longissima Ach..(4)The total antioxidation competence of usnea extractive in acetone solution with the concentration of 5mg/ml was measured by total antioxidation competence measurement kits., the result showed that all extractives had the total antioxidation competence except F6B, among them,the total antioxidation competenceof F8 and F10 was much higher than ascorbic acid with the competence of 77.70 unit per milliliter.In addition,the total antioxidation competence F10 was highest among all extractives,the competence can achieved 86.21 unit per milliliter,it is indicated that the F10 had high total antioxidation competence and had a certain extent of value for application.(5)The antibacterial activities of usnea extractives in acetone solution with the concentration of 5mg per milliliter by using filter paper method were measured.The result showed that most of usnea extractives had inhibit effect on Escherichia coil.and Candida spp. but the activities were lower than penicillin.All the extractives can not inhibit the penicillinum spp.(6)the minimum inhibitory concentration of 5 kinds of substances extracted from Usnea longissima Ach.were tested under the concentration of 100,50,25,12.5,6.25,3.125μg per milliliter.The result indicated that all the substances had the inhibition effect on Escherichia coil except compound A,the antibacterial activities of usnic acid achieved 25μg per milliliter and was higher than any other substances.As to inhibition effect on Candida spp.,only usnic acid and F6A had the ability of inhibition.The usnic acid had high inhibition effect than compound B and the activity achieve 12.5μg per milliliter.All of the substances had,no inhibition effect on penicillinum spp..