Chemical Constituents From Petrosimonia Sibirica L. And Research On Its Antimicrobial And Antioxidant Activities

Petrosimonia sibirica L.(Petrosimonia), an annual and herbaceous plant that belongs tothe Chenopodiaceae family. P. sibirica is mainly distributed in Xinjiang, it is a characteristicplant of Xinjiang. It has been used in desert area as a high yield forage with good nutritionalproperties. Current studies on P. sibirica are majorly focused on genetics and ecology.However, to the best of our knowledge, reports of its chemical composition and activityresearch are less. This research evaluated the antioxidant activity of the different extracts fromP. sibirica. The chemical composition was separated from the chloroform extract and ethylacetate extract based on bioassay-guided separation. Then the compounds were evaluated bythe antibacterial, antioxidant activity. The main results are as follows.1. Total phenol and total flavonoid contents of various extracts of P. sibirica weredetermined. The DPPH free radical, O2-free radical scavenging ability and iron ion reductionability were used to evaluate the antioxidant activity of these extracts. The results revealed theethyl acetate extract was found to have the highest total phenolic and flavonoid contents,followed by the chloroform extract. The two extracrs also possessed the highest antioxidantactivity. This can be sepeculated that the ethyl acetate extract and chloroform extract couldcontain rich alkaloids, flavonoids, organic acids and other active ingredients.2. By bioassay-guided fractionation, thirteen compounds were isolated and purified byTLC, column chromatography on silica gel, and Sephadex LH-20column chromatographyfrom the chloroform extract and ethyl acetate extract of P. sibirica. Based on thespectrometric analysis of their1H-NMR,13C-NMR and MS data, the compounds wereidentified as n-hexadecanol (CMP-1),4-hydroxyphenethyl tetradecanoate (CMP-2),4-hydroxyacetophenone (CMP-3), loliolide (CMP-4), syringic acid (CMP-7), chrysoeriol(CMP-8), dibutyl phthalate (CMP-10), vanillic acid (CMP-11),4-hydroxy-3-methoxybenzene ethanol (CMP-12), N-[2-(3,4-dihydroxyphenyl)-2-hydroxyethyl]-3-(4-methoxyphenyl)prop-2-enamide (CMP-13), harmine (CMP-14), isorhamnetin-3-O-rutinoside (CMP-15),2,5-dimethoxy-benzoquinone (CMP-16). All of these compounds wereisolated form P. sibirica for the first time.3. Seven strains of bacteria and two strains of fungi were used as the test microorganism,and the MIC and IC50values were used to evaluate the antimicrobial activity of the sevencompounds isolated from P. sibirica. The results indicated that the antimicrobial activity ofCMP-7and CMP-15was better, CMP-7showed the best inhibitory activity against Bacillussubtilis with MIC value of0.05mg/mL, IC50value of0.0220mg/mL; CMP-15showed thebest inhibitory activity against Pseudomonas syringaw, Xanthomonas vesicatoria and Alternaria solani, with MIC value of0.2mg/mL,0.2mg/mL and0.1mg/mL, IC50value of0.1331mg/mL,0.1056mg/mL and0.0549mg/mL. CMP-12displayed the strongest inhibitoryactivity against Escherichia coli with MIC of0.05mg/mL, IC50value of0.0349mg/mL.CMP-13displayed the strongest inhibitory activity against Staphylococcus epidermidis withMIC of0.1mg/Ml and IC50of0.0426mg/mL.4. The antioxidant activity of the compounds was measured by DPPH and FRAP. Theresults showed that CMP-13exhibited the strongest activity to scavenging DPPH free radicalwith IC50of0.2452mg/mL. CMP-12exhibited the best reducing power with FRAP value of9.402mmol/g, it was stronger than AA.