A new triterpene saponin from Panax japonicus C.A.Meyer var major(Burk.) C.Y.Wu et K.M.Feng

One new Iriterpene saponin was isolated from Panaxjaponicus C. A. Meyer var major （Burk.） C. Y. Wu et K. M. Feng, and established as oleanolic acid 3-O-[β-D-glucopyranosyl-（1 →2）-β-D-glucuronopyranosyl-6＇-O-n-butyl ester] which showed mod- erate antitumor activities against the A2780 cells and OVCAR-3 cells. Its structure was established by means of spectral data, particularly NMR, including HSQC and HMBC techniques.

Preparation and antiviral effects of polysaccharides from Panax japonicus

Water-soluble polysaccharides were prepared from Panax japonicus by hot water extraction and ethanol precipitation.The polysaccharides were further purified by ion exchange chromatography to obtain neutral and acidic polysaccharides.The neutral polysaccharide fraction mainly contained Glc(90.2%),which was a glucan fraction.The acidic polysaccharide fraction mainly contained GalA(43.6%),Gal(21.7%),and Ara(15.4%),with a degree of methyl-esterification of 20.3%,which was a pectic polysaccharide.The acidic polysaccharide of Panax japonicus could effectively inhibit the replication of human seasonal influenza virus H1N1 and canine influenza virus H3N2 in MDCK cells and A549 cells and significantly reduce the virus titer in infected cells.It also effectively inhibited the number of infected cells of the SARS-CoV-2 South Africa strain and the Omicron strain.The acid polysaccharide of Panax japonicus showed good efficacy against influenza virus and COVID-19 infection,which could be used as a potential antiviral candidate drug molecule in the future.

竹节参达玛烷合成酶基因的克隆和生物信息学分析

达玛烷合成酶(dammarenediol synthase,DS)是三萜类皂苷化合物进入达玛烷型皂苷合成途径的首个关键酶,对人参属植物三萜皂苷的生物合成具有重要的调控作用。本实验以6年生栽培种竹节参为实验材料,基于竹节参转录组数据,利用RT-PCR方法克隆得到DS基因的全长cDNA序列,命名为pjDS。该基因序列长度为2556 bp,其中包含一段完整开放阅读框,长达2310 bp,一共编码了769个氨基酸。经生物信息学分析后得出,该基因编码的蛋白质分子量为88.40 kD,理论等电点为5.84,为亲水性蛋白质,并含有跨膜区,具有56处磷酸化位点。其二级结构主要由α-螺旋(44.21%)和无规则线圈(34.72%)构成,并具有QW(QXXXXXW)和DCTAE这2种氧化鲨烯环化酶(OCS)家族的特征性保守基序。pjDS蛋白序列与人参(ACZ71036.1)、西洋参(AGK62449.1)、三七(AIK21788.1)、锡金三七(ANB82450.1)和越南人参(AGS16975.1)氨基酸序列的相似性分别为99%、99%、99%、99%和98%。实时荧光定量PCR的结果表明,pjDS基因在竹节参的根状茎、茎、叶和花等各器官组织均有所表达,进一步发现该基因在花中表达量最高,而在根状茎中的表达量最低。本研究为进一步研究竹节参中三萜皂苷生物合成机制提供理论依据。