Studies On The Terpenoids From Three Medicinal Plants And Their Biological Activities

Terpenoids are widely distributed in plants,insects,fungi,and marine organisms.They have diverse skeleton types,chiral centers,substituents,and rearrangements and exhibit a variety of biological activities.Thus,terpenoids have attracted widespread attentions from synthetic chemists and pharmacologists.Some of the terpenoids isolated from medicinal plants have been used as natural drugs for the treatment of various diseases due to their remarkable biological activities,such as paclitaxel as anticancer drug,artemisinin as antimalarial drug,and rographolide as antibiotics.As part of a program to search for unique and significant bioactive terpenoids,the isolation,structural characterization,and biological activities of the terpenoids from three medicinal plants,Euphorbia hylonoma Hand.-Mazz.,Salvia miltiorrhiza Bunge,and Abies chensiensis Tiegh.,were investigated.A total of 150 compounds were obtained from the above three medicinal plants using various chromatographic techniques,and their structures were identified by the spectroscopic data analysis?NMR,HRESIMS,IR,UV?,single-crystal X-ray diffraction,electronic circular dichroism?ECD?data,calculation of ECD data and specific optical rotations using the TDDFT method at B3LYP/dgdzvp or B3LYP/6 31+G?d,p?levels,and the comparison of their spectroscopic data with the reported literature values.Among them,terpenoids were mainly obtained,including 3 tetraterpenoids,28 triterpenoids,105 diterpenoids,and 2 sesquiterpenoids,as well as 12 other type compounds.63 compounds were isolated from the roots of Euphorbia hylonoma,including 58diterpenoids with various skeleton types,of which 25 compounds?Eh-1-Eh-7,Eh-9-Eh-20,Eh-25-Eh-28,Eh-32,and Eh-35?were new,2 triterpenoids,2 steroids,and1 cytochalasin;31 abietane diterpenoids?8 new ones Sm-1-Sm-4,Sm-16,Sm-20,Sm-30,and Sm-31?and 1 oleanane triterpenoid were obtained from Salvia miltiorrhiza;55compounds were identified from the bark of the branches of Abies chensiensis,including 3 new tetraterpenoids Ac-26-Ac-28,25 triterpenoids?10 new cycloartane triterpenoids Ac-1,Ac-2,Ac-4,Ac-7,Ac-8,Ac-12,Ac-15,Ac-17,Ac-18,and Ac-21?,16 abietane diterpenoids?1 new compound Ac-38?,2 eremophilane sesquiterpenoids,and 9 lignans.Among them,tetraterpenoids are a class of characteristic and rare compounds from the genus Abies,which are formed via a[4+2]Diels-Alder cycloaddition between a lanostane triterpenoid and a monoterpenoid.Currently,only12 tetraterpenoids with this skeleton type were isolated from this genus.In addition,some of terpenoids were evaluated for their biological activities,including anti-inflammatory activity,cytotoxic activity,antifungal and antibacterial activities,phytotoxic activity,and immunomodulatory activity.The biological evaluation results showed that compounds Eh-8 and Eh-33 could significantly inhibit the NO production with their IC₅₀ values being 7.12 and 12.73?M,respectively,which were lower than that of the positive control(indomethacin IC₅₀=41.41?M).Then,the effects of compounds Eh-8 and Eh-33 on the iNOS protein expression were also evaluated.Compound Ac-8 was the most active against Bacillus subtilis with MIC value of 5?g/mL.The morphological alterations of B.subtilis on treatment with Ac-8were observed by scanning electron microscopy,showing that the cells were irregular,wrinkled,and disrupted.Compound Eh-30 had a selective phytotoxic activity against different plant seedlings.Compounds Sm-3,Sm-17,Sm-19,and Sm-23 showed significant immunomodulatory activity at the test concentrations.In this paper,the diterpenoids with phytotoxic and plant-growth regulatory activities,which were isolated from plants and microorganisms,and the effects caused by these compounds on the test plants were summarized.It is hoped that this review will provide a reference for the development of natural herbicides and plant-growth regulators and prompt readers to pay a continued attention to such bioactive compounds.Our research results could further enrich the natural product library of terpenoids and provide relevant bases on the study of the active constituents from the medicinal plants and their structure-activity relationships,on the discovery of active lead compounds,and on the screening of potential new drugs.In addition,all studies could also provide assistances and thoughts for the research and development of traditional Chinese medicine.