Study On The Chemical Components Of Plantago Virginica And The Enrichment Process Of Verbascoside

Objectives: To study the chemical components of Plantago virginica systematically,the enrichment process of verbascoside,and evaluate the antioxidant capacity in vitro of Plantago virginica.Methods: The whole dried Plantago virginica extracted by refluxing with an aqueous ethanol solution and then successively extracted with petroleum ether and ethyl acetate.The extracts were separated by column chromatography,semi-preparative liquid phase and other separation methods to separate compounds.Combining the physical and chemical properties of the separated compounds,using spectroscopy techniques and other means and referring to the relevant literature to identify the compound structure.The content of some chemical components in Plantago virginica were determined by HPLC and UV.The optimal extraction scheme of verbascoside from Plantago virginica was determined by orthogonal test,and the optimal enrichment process of verbascoside was determined by macroporous resin chromatography.By studying the DPPH scavenging effect of different extract parts of plantain in Plantago virginica and crude verbascoside,the superoxide anion free radical scavenging ability to evaluate its antioxidant capacity.Results: Six compounds were isolated and identified from the ethanol extract of Plantago virginica as stigmasterol(1),β-sitosterol(2),ursolic acid(3),oleanolic acid(4),plantamajoside(5)and Geniposidic acid(6).The content of Plantamajoside was 0.53-0.64 mg/g,the content of verbascoside was 34.76-36.88 mg/g,the content of isoacteoside was 3.27-3.82 mg/g,the content of oleanolic acid was 0.25-0.45 mg/g,the content of ursolic acid was 1.31-1.79 mg/g and the content of total flavonoids was 44.53-53.48 mg/g,in 3 different periods.The results showed that the best reflux extraction process for verbascoside in Plantago virginica: 80% ethanol,15 mL/g material-liquid ratio,and the reflux time is 2 h,twice.The best enrichment process of verbascoside in Plantago virginica: the n-butanol part is passed through X-5 macroporous resin column,which is first eluted with water and 10% ethanol to remove impurities,and then elute with 50% ethanol at a flow rate of 2 BV/h,eluent volume is 6 BV.Each part of the same concentration has the ability to scavenge DPPH and scavenge superoxide anion free radicals,crude verbascoside > n-butanol > ethyl acetate > petroleum ether.Conclusion: Six compounds were isolated and identified from the ethanol extract of Plantago virginica.The content of verbascoside,isoacteoside and total flavonoids in Plantago virginica are higher than that reported in the literature.The experiment determined the best enrichment process of verbascoside.DPPH scavenging and superoxide anion free radical scavenging experiments show that Plantago virginica has certain antioxidant capacity in vitro.