从甜菊叶中提取和精制甜菊苷的方法

本实验用１５００ｍｌ８０℃热水从１００ｇ甜菊干叶中萃取菊苷，用Ｃａ（ＯＨ）２和聚合硫酸铁作絮凝剂，在８０℃温度下去除萃取液中的杂质和素，再吸吸附树脂处理后于９８％的乙醇中结晶提纯，可得８．９６ｇ纯度为９６．２％的甜菊苷，文中对影响提取和精制的因素如温度，水量，絮凝剂和树脂种类以及乙醇浓度等进行探讨，结果表明，本方法可大大提高结晶的收率和纯度。     

Interactions of Stevioside and Steviol with Renal Organic Anion Transporters in S2 Cells and Mouse Renal Cortical Slices

Purpose Our previous studies have shown that both stevioside and steviol inhibited transepithelial transport of para-aminohippurate (PAH) in isolated rabbit renal proximal tubules by interfering with organic anion transport system. The current study examined the direct interactions of stevioside and steviol with specific organic anion transporters.Methods S2 cells expressing human organic anion transporters (hOAT1, hOAT2, hOAT3, and hOAT4) and an intact renal epithelium were used to determine the inhibitory effect of stevioside and steviol on organic anion transport.Results Stevioside at 0.5–1 mM showed no interaction with any OAT. In contrast, steviol markedly inhibited substrate uptake in all S2hOAT cells. Steviol had low IC₅₀ for hOAT1 (11.4 M) and hOAT3 (36.5 M) similar to that of probenecid, whereas IC₅₀ for hOAT2 (1000 M) and hOAT4 (285 M) was much higher. Results obtained in mouse renal cortical slices were very similar; that is, stevioside was without inhibitory effect and steviol was a potent inhibitor of PAH and estrone sulfate (ES) transport.Conclusions Stevioside has no interaction with human or mouse OATs. In contrast, steviol interacts directly with human OATs, in particular, hOAT1 and hOAT3, with a potency approximating probenecid, suggesting that the inhibition of OAT-mediated transport by steviol could alter renal drug clearance.     

反相高效液相法测定甜叶菊中莱鲍迪苷A和甜菊糖苷的含量

目的建立反相高效液相色谱法（RP．HPLC）测定甜叶菊中莱鲍迪苷A（RA）和甜菊糖苷（ST）的含量。方法采用welchMaterials XB—C18柱（250mm×4．6mm,5μm）,以乙腈．10mmol·L^-1磷酸酸钠缓冲液（pH=2．67,35：65,v～）为流动相,流速0．7mL·min^-1,检测波长210nm,柱温30℃,进样量5此。结果以外标法定量,RA和sT均在O．25～2．50mg·mL^-1与峰面积线性关系良好,r〉0．9995。RA回收率为100．3％,RSD为2．3％（n=6）,ST回收率为101．0％,RSD为2．5％（n=6）。结论本方法快捷、准确、可靠,易操作,可用于甜叶菊及相关产品中RA和ST含量测定。     

甜叶菊化学成分和药理作用的研究进展及其质量标志物（Q-Marker）预测

甜叶菊Stevia rebaudiana是一种应用广泛的菊科植物,具有降血糖、抗肿瘤、抗氧化、抗炎、降血压、调血脂等多种药理作用,其化学成分主要包括二萜类、黄酮类、多酚类、多糖等。基于甜叶菊化学成分和药理作用的研究进展,从植物亲缘性和化学成分特有性、成分可测性、成分有效性及传统药性等方面对甜叶菊质量标志物（quality marker,Q-Marker）进行预测分析,初步预测甜菊苷、莱鲍迪苷A、莱鲍迪苷C、黄酮苷、绿原酸等可作为甜叶菊的主要Q-Marker,为完善甜叶菊质量评价体系提供参考。     

甜菊总甙苦味组分对小鼠免疫功能的影响

甜叶菊(Stevia rebaudiana Bertoni),原产于南美,当地作为甜茶饮用。以甜菊的叶子作原料提炼的甜菊精,已作为高甜度、低热量的天然健康糖料应用于食品工业。在提炼甜菊精的过程中,有一种带苦味的副产品,为了充分利用甜叶菊资源,我们研究了此苦味副产品对动物免疫功能的影响,发现它有一定的免疫抑制作用。现报道如下。     

Investigation of the antihypertensive effect of oral crude stevioside in patients with mild essential hypertension

The antihypertensive effect of crude stevioside obtained from the leaves of Stevia rebaudiana (Bertoni) Bertoni (Compositae) on previously untreated mild hypertensive patients was examined. Patients with essential hypertension were submitted to a placebo phase for 4 weeks. The volunteers selected in this phase were randomly assigned to receive either capsules containing placebo during 24 weeks or crude stevioside 3.75 mg/kg/day (7 weeks), 7.5 mg/kg/day (11 weeks) and 15.0 mg/kg/day (6 weeks). All capsules were prescribed twice a daily (b.i.d.), i.e. before lunch and before dinner. After the placebo phase and after each dose of crude stevioside, body mass index, electrocardiogram and laboratory tests were performed. During the investigation blood pressure (BP) was measured biweekly and the remaining data were collected at the end of each stevioside dose step. All adverse events were prospectively recorded but no major adverse clinical effects were observed during the trial. Systolic and diastolic BP decreased (p < 0.05) during the treatment with crude stevioside, but a similar effect was observed in the placebo group. Therefore, crude stevioside up to 15.0 mg/kg/day did not show an antihypertensive effect. Moreover, the results suggest that oral crude stevioside is safe and supports the well-established tolerability during long term use as a sweetener in Brazil.     

ent-贝壳杉烯类化合物的合成及其抗肿瘤活性

目的:以甜菊苷为原料合成ent-贝壳杉烯类目标化合物。方法:构造了以exo-亚甲基环戊酮为特征的药效基团结构,同时对C-4位的羧基进行了修饰,以改善目标化合物的活性,并通过MTT法检测目标化合物的体外抗肿瘤活性。结果和结论:合成的13个ent-贝壳杉烯类目标化合物结构经1HNMR、ESI-MS和FT-IR确认。MTT法显示部分目标化合物对肿瘤细胞BEL-7402,HO-8910,MCF-7和HL-60有较好的抑制活性。