Antipromastigote and cytotoxic activities of some chemical constituents of Hypericum lanceolatum Lam. (Guttifereae)

Phytochemical investigation of the ethanol extract of the stem bark of Hypericum lanceolatum Lam. (Guttifereae)afforded eight known compounds including 2,2ʹ,5,6ʹ-tetrahydroxybenzophenone (1), 5-hydroxy-3-methoxyxanthone(2), 3-hydroxy-5-methoxyxanthone (3), betulinic acid (4), hydroquinone (5) 6,7-dihydroxy-1,3-dimethoxyxanthone(6), calophyllumin A (7), and 1,3,5,6-tetrahydroxy-4-prenylxanthone (8). Compound 1 was submitted to acetylationreaction to give 5-acetoxy-2,2ʹ,6ʹ-trihydroxybenzophenone (9), a new hemisynthetic derivative. Compounds 5 and8 were isolated for the first time from this plant. The structures were established by extensive analysis of their massspectrometry and nuclear magnetic resonance (NMR) spectroscopic data and comparison with those from the literature.The isolated compounds (1, 2, 4, 5, and 8) and the derivative of benzophenone (9) were tested for their antipromastigoteand cytotoxic activities against visceral leishmaniasis parasite Leishmania donovani and macrophage RAW 264.7 cellline, respectively. Compound 9 was the most active with an IC50 value of 6.1 µg/ml, while compounds 1, 2, 4, and 8were moderately active with IC50 values ranging from 11.4 to 34.8 µg/ml against L. donovani and were not cytotoxicexcept compound 5 that was very toxic and not active. The findings of the present study suggested that compounds 1,2, 4, and 8 could be considered as a potential source of therapeutic medicine for the treatment of leishmaniasis.

Chenopodium ambrosioides induces an endothelium-dependent relaxation of rat isolated aorta / 中西医结合学报

OBJECTIVE@#This study aims to evaluate the vasodilatory effect of Chenopodium ambrosioides on the isolated rat aorta, and to explore its mechanism of action.@*METHODS@#The vasorelaxant effect and the mode of action of various extracts from the leaves of C. ambrosioides were evaluated on thoracic aortic rings isolated from Wistar rats. In addition, ethyl acetate and methanol fractions were analyzed, using thin-layer chromatography and high-performance liquid chromatography techniques, for their polyphenolic content.@*RESULTS@#The various active extracts of C. ambrosioides at four concentrations (10, 10, 10 and 1 mg/mL) relaxed the contraction elicited by phenylephrine, in a concentration-dependent manner. This effect seems to be endothelium-dependent, since the vasodilatory effect was entirely absent in denuded aortic rings. The vasorelaxant effect of the methanol fraction (MF) of C. ambrosioides at 1 mg/mL was also inhibited by atropine and tetraethylammonium. This effect remained unchanged by Nω-nitro-l-arginine methyl ester hydrochloride and glibenclamide. The preliminary phytochemical analysis showed that the leaves of C. ambrosioides are rich in phenolic and flavonoid derivatives.@*CONCLUSION@#These results suggest that the MF of C. ambrosioides produces an endothelium-dependent relaxation of the isolated rat aorta, which is thought to be mediated mainly through stimulation of the muscarinic receptors, and probably involving the opening of Ca-activated potassium channels.

Antioxidant capacity and polyphenolic content of the Echinocystis lobata [Michx.] Torr. et A.Gray flowers

Echinocystis lobata [Michx.] Torr. et A.Gray is a spontaneous species in the Romanian flora, lesser studied by scientific literature, but which has proved significant activities in traditional medicine. The present study is aimed to provide data on the polyphenolic compounds in the composition of the flowers of this species and to test their biological potential. Polyphenols were identified and quantified using an HPLC-MS method. Tested biological activities were the cytotoxic, anti-plasmodial and antioxidant ones. Methods used for testing the antioxidant activity were the DPPH, CUPRAC, FRAP, TEAC, EPR and SNPAC assays. Cytotoxic activity was tested on cancerous and healthy cell lines and anti-plasmodial activity was assesed on two strains of Plasmodium falciparum. Ethanolic extracts of the flowers of E. lobata proved to contain isoquercitrin, rutin, quercitrin, kaempferol, p-coumaric and ferulic acid. No cytotoxic and antiplasmodial activity was found, but antioxidant assays showed an important antioxidant capacity. The obtained results show that flowers of E. lobata are important sources of antioxidant compounds. It is the first approach of the kind on the flowers of this species and it offers a new perspective on possible sources of antioxidant compounds