Study On Chemical Constituents And Biological Activity Of Aleuritopteris Anceps

Aleuritopteris anceps is a plant of the genus Aleuritopteris,family Pteridaceae.It is less commonly distributed in nature,although the whole herb can be used as folk medicine,with heat diuresis,cough,phlegm,blood stasis effect.Previously,there is no research report on the chemical composition of Aleuritopteris anceps,and its biological activities remain unknown.Thus,this study is dedicated to investigate the chemical composition and biological activities of A.anceps,and the results of the study are as follows:1.Extraction and identification of volatile oil components:The volatile oil of A.anceps was extracted and its volatile components and their contents were initially analyzed by GC-MS,and the total ion flow spectrum of the volatile oil components of Aleuritopteris anceps was obtained,and 40 compounds were detected and identified within 60 minutes.2.Extraction,separation,and structure identification of chemical constituent of A.anceps:the crude extracts of A.anceps were obtained with solvents of different polarity,and further purified by various techniques such as silica gel column,MCI,MPFC,Sephadex LH-20 and other technologies.The structures of isolated compounds were identified by ¹H NMR,¹³C NMR and 2D NMR,combined with single-crystal X-ray structure diffraction.A total of ten compounds were obtained from the whole plant of A.anceps:5-hydroxy-3,7,4’-trimethoxyflavone（1）、（17Z）-13,19-epoxycheilanth-1,17-diene-2-ol-3-one（2）、β-sitosterol（3）、5-hydroxy-7,4’-dimethoxyflavone（4）、3,7,3’,4’-tetramethyl-quercetin（5）、compound6（structure to be determined）,5,4’-dihydroxy-3,7-dimethoxyflavone（7）、kaempferol（8）、daucosterol（9）and quercetin-3-O-β-D-glucopyranoside（10）.Among these compounds,compound 2 is a new cheilanthane-type sesterterpene,and compound 6 is also a previously unknown sesterterpene whose structure needs to be further determined.The above ten compounds were isolated from Aleuritopteris anceps for the first time.3.Determination of antioxidant activity:Butyl Alcohol extract had strong scavenging ability on both DPPH and ABTS free radicals:The IC₅₀value of flavonoid kaempferol（compound 8）was 0.046 mg/mL,which was close to the positive drug(VC,IC₅₀value was 0.009 mg/mL).The scavenging IC₅₀value of ABTS free radical was 0.003 mg/mL,which was lower than that of positive drug(VC,IC₅₀value was 0.005 mg/mL),indicating the kaempferol（compound 8）had good antioxidant activity.4.Determination of anti-α-glucosidase activity:Among all crude extracts,the total ethanol extract,ethyl acetate extract and butyl alcohol extract had better inhibitory activity onα-glucosidase.In addition to that,two flavonoids compound,5-hydroxy-3,7,4’-trimethoxyflavone（compound 1）,5-hydroxy-7,4’-dimethoxyflavone（compound 4）,the terpenoids（17Z）-13,19-epoxycheilanth-1,17-diene-2-ol-3-one（compound 2）and daucosterol（compound 9）showed good inhibitory activity againstα-glucosidase,and compound 2 showed the most significant inhibitory effect with an IC₅₀value of 72.127±4.568μg/mL,which was much smaller than that of positive drug(acarbose,IC₅₀value was 485.275±5.132μg/mL).5.Determination of antitumor activity:Two terpenoids and five flavonoids isolated from A.anceps had strong inhibitory effect on A549 and MCF-7 cells,and all of their IC₅₀values were lower than positive drug cisplatin.Among these compounds,（17Z）-13,19-epoxycheilanth-1,17-diene-2-ol-3-one（compound2）and3,7,3’,4’-tetramethyl-quercetin（compound 5）showed good inhibitory activity against the two tumor cells.6.Determination of antibacterial activity:The antibacterial activity of crude extracts and the isolated pure compounds of A.anceps were investigated.The results showed that the all crude extracts and the isolated pure compounds showed no significant inhibitory activity against P.marginalis,P.carotovorum and S.aureus.DCM extract and 5-hydroxy-3,7,4’-trimethoxyflavone（compound 1）showed certain inhibitory activity against E.amylovora,while PE extract,BU extract and5,4’-dihydroxy-3,7-dimethoxyflavone（compound 7）showed certain inhibitory activity against E.coli.In conclusion,the detailed extraction and isolation of chemical components and the preliminary biological activities of A.anceps has been conducted.Two new sesterterpenes,with 8 known natural products were isolated from A.anceps for the first time.This study might be beneficial for the further development and utilization of A.anceps in the coming future.