The Discovery Of New Diterpenoids In Broken Rice And Their Biological Activities

Objective:The chemical constituents in the plant of Isodon rubescens[Hemsl.]Hara.from Guiyang were studied and their activity was screened,in order to find novel monomer compounds with good activity and provide scientific basis for the rational development and utilization of the plant resources.Methods:The stems and leaves of Isodon rubescens,which were air-dried and powered,was extracted and concentrated with industrial methanol in cold leaching.After extraction with three different solvents and it was separated and purified by MCI,Silica gel column chromatography,Sephadex chromatography,Cis reverse phase column chromatography,recrystallizing and semi-prepared high performance liquid chromatography.Meanwhile,the analysis of spectrum data of IR,UV,MS,]H NMR,13C NMR,2D-NMR,and X-ray single crystal diffraction technology were used to illustrate and identify these compounds.In addition,most of the compounds in this study were screened for anti-tumo and bacteriostatic activities by MTT method,AGAR perforation method and Broth microdilution method.Results:Twenty-six compounds have been isolated and identified from the Isodon rubescens,including nine new compounds(1-9),and one new natural product diterpene(10),and sixteen known compounds(11-26).The types of compounds involved diterpenes,triterpenes,sesquiterpenes and steroids,among which diterpenes were also involved in the podocarpane type(the podocarpane type was isolated from this plant for the first time),abietane,and ent-kaurane.These 26 compounds are 9?-hydroxy-13-oxo-podocarpane-8,20-lactone(1);9?-hydroxy-13-oxo-podocarpane-8,20-lactone(2);abieta-8,11,13-trien-7,20-lactone(3);9a,12a-dihydroxy-abieta-13-en-8,20-lactone(4);13a,14a-dihydroxy-abieta-8-en-20-oic-acid(5);19-hydroxy-3-oxo-abieta-7,15-dien-17,14-olide(6);15?-hydroxy-6,7-seco-6,19:6,20-diepoxy-7,20-olide-ent-kaur-16-en(7);6?,7?,15?-trihydroxy-19-acetoxy-7?,20:11?,12?-diepoxy-ent-kaur-16-en(8);15?,19?-dihydroxy-6,7-seco-6,18-epoxy-7,20-olide-ent-kaur-16-en(9);dihydrolongirabdolactone(10);rubesanolide E(11);rubesanolide D(12);rubesanolide C(13);rubesanolide A(14);abiet-8,11,13-trien-20-oic-acid(15);ludongnin A(16);guidongnin A(17);guidongnin B(18);guidongnin H(19);16(R)-methoxy-11?-hydroxy-6,7-seco-6,19,7,20-diolide-ent-kaur-15-one(20);dihymacrocalyxofomin D(21);3?,27-dihydroxyluo-12-ene(22);ursolic acid(23);(-)-ledol(24);oplopanone(25);?-sitosterol(26).The activity showed when compound 7 was 1.00×10-4 mol/L,it had an inhibitory effect on human leukemia cells(HL-60),the inhibitory rate was 87.43±0.26%,but no inhibitory activity was found after the concentration continued to decrease;and compound 3 had inhibitory effect on T.rubrum,the inhibition rate was 31.15%at the concentration of 100 ug/mL.Other tested compounds had no inhibitory effect on the selected cell line or cell lines.Conclusion:Nine new diterpenes were isolated from the Isodon rubescens in Guiyang,which indicated that the region had a great influence on the chemical composition of the plant,indicating that there might be a large number of new diterpenes in the Isodon rubescens plants in guiyang,and the chemical composition of the Isodon rubescens plants in guiyang could be further studied.At the same time,from the experimental results,the 26 compounds isolated contain 21 diterpenoids,which to a certain extent indicates that this experimental route can be used as a targeted experiment technical route for the future study of diterpenoids in this plant.In addition,the preliminary activity screening also laid a good foundation for the subsequent development and utilization of this plant.