Biosynthesis of pentacyclic triterpenoids in leaves of Ilex aquifolium L.

Ilex leaves can utilize sucrose and mevalonate for the synthesis of triterpene esters. Mevalonate is also used for the synthesis of free triterpenoid alcohols, but sucrose is not. The selectivity of precursor utilization indicates separate sites for triterpenol and triterpenol-ester synthesis. The sites of synthesis are not found at the main locations of accumulation of triterpenols (the epicuticular wax) or triterpene esters (the cytoplasmatic lipid globules). Transport from the site of synthesis to the lipid globules, and especially towards the epicuticular wax, is slow.Abbreviations MVA mevalonic acid lactone - TLC thin layer chromatography     

板桥党参最佳采收期的研究

研究了二年生、三年生板桥党参(Codonopsis tangshenO liv.)的产量、多糖含量以及总皂苷含量的动态变化。结果表明:二年生、三年生党参产量在8~10月份都较高,与相同月份之间存在极显著差异(p<0.01);二年生、三年生党参多糖含量在7~9月份都较高,与相同月份之间不存在显著差异(p>0.05);二年生的党参总皂苷含量在11月份最高(1.11%),6月份次之(0.90%),9月份最低(0.77%);三年生的党参总皂苷含量在6月份最高(1.07%),8、9、10月份之间差异不显著(P>0.05),7月份最低(0.72%)。综合考虑产量、多糖及总皂苷含量,板桥党参于栽培第三年8、9月份采收比较合理。     

番茄中皂苷类成分研究进展

皂苷因其在人体中具有重要的生理及药理活性一直是人们研究的热点.番茄是我们日常生活中最常食用的蔬菜,其主要活性物质除了人们熟知的番茄红素外尚含有含量并不低的水溶性番茄皂苷,目前国内有关番茄皂苷的研究报导较少.本文主要对上世纪70年代以来国外研究人员在番茄皂苷研究方面所取得的进展进行综述.     

培养基中有机物组份对人参细胞生长及其皂甙,多糖含量的影响

本文研究了培养基中肌醇、烟酸、甘氨酸、维生素Ｂ＿６、维生素Ｂ＿１等有机物组份对人参细胞生长及其皂甙、多糖含量的影响。结果表明,只有维生素Ｂ＿１是人参细胞生长必需的,缺少其他有机物组份对其皂甙、多糖含量无不利影响。     

Transformations of Glycyrrhizic Acid: XV. Synthesis of Triterpene Saponins with Monosaccharide Residues Attached through Ester Bonds

Triterpene saponins, glycoside analogues of glycyrrhizic acid with a modified carbohydrate chain containing monosaccharide residues attached through ester bonds, were synthesized. To this end, peracetylated glycyrrhizic acid or its 30-methyl ester were glycosylated by 2,3,4,6-tetra-O-acetyl--D-gluco- or --D-galactopyranosyl bromide in dichloroethane in the presence of Ag₂CO₃. Glycerrhetinic acid saponin with D-Galp residues exhibited a higher antiulcer activity than glycyrrhizic acid in rats at a dose of 25 mg/kg.     

Structure characterization and identification steroidal saponins from Ophiopogon japonicus Ker-Gawler (Liliaceae) by high-performance liquid chromatography with ion trap mass spectrometry

Introduction – Steroidal saponins are the main active constituents in Ophiopogon japonicus Ker‐Gawler (Liliaceae). However, because of their high polarity, non‐chromophores and low content in plants, steroidal saponins are difficult to be isolated from O. japonicus by conventional phytochemical methods. Objective – To develop a sensitive and rapid approach towards the structural analysis of steroidal saponins using HPLC/ESI‐MSⁿ. Methodology – The fragmentation behaviors of six known steroidal saponins in negative ESI‐MSⁿ were used to deduce their mass spectral fragmentation mechanisms. By using HPLC/ESI‐MSⁿ, the important structural information on aglycone types, sugar types and saccharide sequences can be obtained. Results – According to the HPLC retention behaviour, the molecular structural characteristics provided by multistage mass spectrometry spectra and the literature, a total of 8 steroidal saponins were tentatively identified or characterized in O. japonicus rapidly. Conclusion – This work has shown that HPLC‐ESI‐MSⁿ may be used as an effective and rapid method for the characterization and identification of steroidal saponins from O. japonicus. Copyright © 2010 John Wiley & Sons, Ltd.     

Cytotoxic triterpenoid saponins acylated with monoterpenic acids from fruits of Gleditsia caspica Desf.

Four bisdesmosidic triterpenoid saponins named caspicaosides A-D, were isolated from the fruits of Gleditsia caspica Desf. Their structures were determined by NMR spectroscopy including HOHAHA, ¹H-¹H COSY, ROE, HMQC, HMBC experiments and HRFAB-MS as well as acid hydrolysis. The four 3,28-O-bisdesmosidic triterpenoid saponins comprised echinocystic acid as the aglycone and common oligosaccharide moieties at C3 and C28. The saccharide moiety at C-3 was identified as β-d-xylopyranosyl-(1 → 2)-α-l-arabinopyranosyl-(1 → 6)-β-d-glucopyranosyl while that at C-28 was determined as β-d-xylopyranosyl-(1 → 3)-β-d-xylopyranosyl-(1 → 4)-α-l-rhamnopyranosyl-(1 → 2)-[α-l-rhamnopyranosyl-(1 → 6)-]β-d-glucopyranosyl. The pentasaccharide moiety linked to C-28 was acylated with monoterpenic acid and or monoterpene-arabinoside moieties at C-2 or C-2 and C-3 of the terminal rhamnose unit. The isolated saponins were assayed for their in vitro cytotoxicities against the three human tumor cell lines HepG2, A549 and HT29 using MTT method. The results showed that caspicaosides B and C bearing two and three monoterpene units, respectively, exhibited significant cytotoxic activities against the used cell lines with IC₅₀ values 1.5-6.5 μM. Caspicaosides A and D with one monoterpene unit exhibited significant cytotoxic activities on HepG2 cell line with IC₅₀ values equal to 4.5 and 5.4 μM, respectively, and IC₅₀ values >10 μM against the other two cell lines. The number of monoterpene units seems to play a main role in determining the activity.     

三七总皂苷对大鼠脑缺血再灌注损伤后脑组织的凋亡抑制作用

目的:探讨三七总皂苷(PNS)对大鼠脑缺血再灌注损伤后大脑皮层细胞的凋亡抑制作用.方法:采用大脑中动脉栓塞再通法建立脑缺血再灌注模型,将大鼠随机分为假手术组、缺血再灌注组和三七总皂苷治疗组;根据再灌注时间不同分为再灌注10h、12 h、24h组,缺血时间为90 min.大鼠脑缺血再灌注10h、12h和24h不同时间点进行神经功能评分,采用原位末端标记法检测神经细胞凋亡情况,同时用免疫组化法检测抑制凋亡蛋白XIAP和促凋亡蛋白Smac阳性细胞数.结果:缺血再灌注组神经细胞凋亡数明显增加,XIAP蛋白的表达呈先高后低的变化(P＜0.05),Smac蛋白的表达明显上升(P＜0.05);PNS治疗组能明显减少脑皮层组织神经细胞凋亡数(P＜0.05),增加XIAP蛋白表达(P＜0.05),减少Smac蛋白表达(P＜0.05).结论:PNS可能通过促进抑制凋亡蛋白XIAP的表达和抑制促凋亡蛋白Smac的表达,减少脑组织缺血再灌注损伤后的神经细胞凋亡,进而对再灌注后脑组织具有抑制脑细胞凋亡的作用.     

A triterpenoidal saponin and sphingolipids from Pteleopsis hylodendron

From the stem bark of Pteleopsis hylodendron, a triterpenoidal saponin bellericagenin [B 3-O-[beta-D-glucopyranosyl-(1-->2)-alpha-D-glucopyranoside] (1) (Pteleopsoside)] and two sphingolipids, hylodendroside-I (2), and hylodendroside-II (3) were isolated, along with a synthetically known compound, [2alpha, 3beta, 23-triacetoxy-19alpha-hydroxyolean-12-en-28-oic acid (4)]. Other known compounds, friedelin (5), beta-carotene (6), lupeol (7), sitosterol (8), and stigmasterol (9), were also obtained. Their structures were deduced with the help of detailed spectroscopic studies.