In vivo and in vitro antimalarial activity of 4-nerolidylcatechol

4‐Nerolidylcatechol (4‐NC) isolated from Piper peltatum L. (Piperaceae) was evaluated for in vitro antiplasmodial activity against Plasmodium falciparum (cultures of both standard CQR (K1) and CQS (3D7) strains and two Amazonian field isolates) and for in vivo antimalarial activity using the Plasmodium berghei‐murine model. 4‐NC exhibits significant in vitro and moderate in vivo antiplasmodial activity. 4‐NC administered orally and subcutaneously at doses of 200, 400 and 600 mg/kg/day suppressed the growth of P. berghei by up to 63% after four daily treatments (days 1–4). Also, 4‐NC exhibited important in vitro antiplasmodial activity against both standard and field P. falciparum strains in which 50% inhibition of parasite growth (IC₅₀) was produced at concentrations of 0.05–2.11 μg/mL and depended upon the parasite strain. Interestingly, healthy (non‐infected) mice that received 4‐NC orally presented (denatured) blood plasma which exhibited significant in vitro activity against P. falciparum. This is evidence that mouse metabolism allows 4‐NC or active metabolites to enter the blood. Further chemical and pharmacological studies are necessary to confirm the potential of 4‐NC as a new antimalarial prototype. Copyright © 2011 John Wiley & Sons, Ltd.     

Antioxidant and Anti‐α‐glucosidase Compounds from the Rhizome of Peltiphyllum peltatum (Torr.) Engl

The antioxidant, anti‐α‐glucosidase and anticholinesterase effects of the alcohol extract of fresh underground rhizomes of Peltiphyllum peltatum were studied. A potent antioxidant activity accompanied by a selective α‐glucosidase effect was observed for the crude extract. Further activity‐guided fractionation (petroleum ether, chloroform, ethyl acetate, n‐butanol and water) resulted in the identification of the ethyl acetate fraction with the highest antioxidant effect. Gallic acid, methyl‐3‐O‐methyl gallate, catechin, gallocatechin, bergenin and 11‐O‐galloylbergenin were isolated from the ethyl acetate fraction. While all the isolated compounds did show a variable degree of radical scavenging effect, 11‐O‐galloylbergenin was identified as the selective α‐glucosidase inhibitor. The isolation, structural elucidation and biological effects of these compounds are discussed. Copyright © 2012 John Wiley & Sons, Ltd.     

星果草属药用植物的生药鉴别研究

目的 :对星果草属药用植物进行系统的生药鉴别研究 ,为该类药材质量控制提供依据。方法 :野外采集 ,市场调查 ,结合文献查阅 ,形态和组织学比较研究。结果 :对药材的性状 ,根、根茎、叶的显微特征进行了描述 ,绘图。结论 :本属植物根茎的组织特征和近缘的黄连属相似 ,但有明显不同 ,属内 2种在组织上能够有效区别。为本属生药的质量控制提供了形态组织学上的依据。     

Investigation on the hypoglycaemic effects of extracts of four Mexican medicinal plants in normal and alloxan-diabetic mice

The hypoglycaemic activities of four water ethanol extracts (WEE) prepared from Bidens pilosa L., Salvia officinalis L., Psacalium peltatum H.B.K. (Cass) and Turnera diffusa Willd. were investigated in healthy and alloxan-diabetic mice. The WEE of S. officinalis significantly reduced the blood glucose of fasting normal mice 120 (15.7%) and 240 min (30.2%) after intraperitoneal administration (p < 0.05). The WEE of P. peltatum and B. pilosa also significantly diminished glycaemia in healthy mice at 240 min (19.6% and 13.8%, respectively). In mildly diabetic mice, the WEE of P. peltatum lowered the basal blood glucose level 120 (16%) and 240 min (54%) after intraperitoneal administration (p < 0.05 and p < 0.01, respectively). The WEE of B. pilosa and S. officinalis also significantly diminished the hyperglycaemia in mildly diabetic mice at 240 mins (32.6% and 22.7%, respectively). The administration of these three extracts to animals with severe hyperglycaemia did not cause a significant decrease. The WEE of T. diffusa did not show any hypoglycaemic activity. Thus, three of the WEE studied conserved the hypoglycaemic activity originally detected in the traditional preparations of the studied antidiabetic plants. It appears that these extracts require the presence of insulin to show hypoglycaemic activity.     

裂叶星果草的性状及显微鉴别

对裂叶星果草进行了性状及组织显微鉴别,并与同属星果草进行比较,初步提出本属药用植物的形态组织学特征,为本属生药质量控制提供形态组织学上的依据.     

裂叶星果草生物碱的研究

目的：对裂叶星果草的化学成分进 行分离鉴定。方法：采用离子交换和色谱技术 进行分离,经IR,UV,1H-NMR和MS方法鉴定化合物。结果：分得4 个化合物,鉴定为小檗碱、小檗红碱、巴马汀、木兰碱。结论： 均为首次从该植物中得到。     

Anti-tumoral activities of dioncoquinones B and C and related naphthoquinones gained from total synthesis or isolation from plants

Dioncoquinones belong to a family of natural naphthoquinone products of interest due to their promising anti-tumoral and anti-infective activities. In particular, dioncoquinones A (5) and B (6) have been shown to be highly active against Leishmania major and multiple myeloma cells without any significant toxicity toward normal blood cells. Their effective concentrations against multiple myeloma cell lines were similar to those of melphalan, a well known DNA-alkylating agent used in a standard therapy against B cell lymphoma and multiple myeloma. We report on the first total synthesis of the highly oxygenated anti-tumoral agent dioncoquinone B (6) and the isolation of its new, even higher-oxygenated analogs, dioncoquinones C (7), D (8), and E (9), from cell cultures of Triphyophyllum peltatum. In addition, several derivatives of these compounds were synthesized, including dioncoquinone C (7), and a small library of naphthoquinones was created. Furthermore, the first structure-activity relationship (SAR) study on this class of compounds was conducted, showing that each of the three hydroxy groups, at C-3, C-5, and C-6, is required for improved anti-tumoral activities and decreased cytotoxicities.     

星果草的化学成分研究

首次从植物星果草中分离得到四种结晶,经化学及光谱分析鉴定为季铵型水溶性生物碱非洲防己碱,药根碱,棕榈碱及木兰花碱。