ABSTRACT
Introduction: The Vismia genus belongs to the Hypericaceae family and comprises around 57 species of which 17 have been located in Venezuela. Previous investigations have been carried out in extracts as well as pure isolated compounds, revealing antimicrobial, antioxidant and anti-HIV, among other, biological activities. Objective: This investigation aims to determine the cytotoxic activity of essential oils from leaves of Vismia baccifera Triana & Planch (VBJ and VBV) and Vismia macrophylla Kunth (VM) collected in three different locations of the Venezuelan Andean region. Methods: Essential oils obtained by hydrodistillation were analyzed using gas chromatography-mass spectrometry (GC-MS) and their cytotoxic activity was analyzed following the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay. Human tumor cell lines from SKBr3, MCF-7 and PANC-1, two breast carcinomas and one pancreatic adenocarcinoma of ductal type, were tested with the oil samples and human dermis fibroblasts were used as non-tumor cells. Results: β-caryophyllene and trans-caryophyllene were present as major components in VBJ and VBV, respectively, while γ-bisabolene was the main component in the VM sample. Anticancer activity was observed on V. baccifera essential oil against SKBr3, MCF-7 and PANC-1. The selectivity index showed that VBV is highly selective against the SKBr3 cell line and has no activity against non-tumor cells. Conclusions: These results are considered a contribution to natural products research and may provide supportive data for future studies on cancer.
Introducción: El género Vismia pertenece a la familia Hypericaceae y comprende alrededor de 57 especies de las cuales 17 han sido ubicadas en Venezuela. Se han realizado investigaciones previas tanto en extractos como en compuestos puros aislados revelando actividad antimicrobiana, antioxidante y anti-VIH, entre otras actividades biológicas. Objetivo: El propósito de esta investigación es determinar la actividad citotóxica de los aceites esenciales de las hojas de Vismia baccifera Triana & Planch (VBJ y VBV) y Vismia macrophylla Kunth (VM) recolectadas en tres localidades de la región andina venezolana. Métodos: Aceites esenciales obtenidos por hidrodestilación fueron analizados por cromatografía de gases-espectrometría de masas y su actividad citotóxica fue analizada siguiendo el método MTT (bromuro de 3-[4,5-dimetiltiazol-2-il]-2,5-difeniltetrazolio). Los aceites esenciales fueron ensayados frente a células tumorales humanas SKBr3, MCF-7 y PANC-1, dos carcinomas de mama y un adenocarcinoma pancreático del tipo ductal, usando cultivos primarios de fibroblastos de dermis humana como células no tumorales. Resultados: β-cariofileno y trans-cariofileno estuvieron presentes como compuestos mayoritarios en VBJ y VBV, respectivamente, mientras que γ-bisaboleno fue el componente principal en la muestra VM. El aceite esencial de V. baccifera mostró actividad anticancerígena frente a SKBr3, MCF-7 y PANC-1. El índice de selectividad reveló que VBV es altamente selectivo frente a la línea celular SKBr3 y no presenta actividad contra las células no tumorales. Conclusiones: Estos resultados se consideran una contribución a la investigación de los productos naturales y los datos pueden ser de utilidad en futuras investigaciones sobre el cáncer.
ABSTRACT
Abstract Lepechinia mutica (Benth.) Epling, Lamiaceae, and Vallea stipularis L.f., Elaeocarpaceae, are the object of the present study. These plants are endemic to the Andean region and have attracted our attention on the basis of interesting results obtained in a preliminary anticholinesterase screening. Actually, carnosol and tiliroside, isolated from L. mutica and V. stipularis, respectively, have shown a promising selective inhibitory activity against butyrylcholinesterase. Specifically, the anti-butyrylcholinesterase activity of carnosol was 5.15 µM and that of tiliroside was 52.9 µM, compared to 8.568 ± 0.570 µM of the positive control Donepezil. Carnosol and tiliroside were purified chromatographically from the ethyl acetate extract of L. mutica and V. stipularis, respectively. Spectrophotometric methods were used for enzymatic studies.
ABSTRACT
Aqueous extract of the stem barks of Croton cuneatus Klotz (Euphorbiaceae) was investigated for hypoglycaemic activity in streptozotocin(STZ)-induced diabetic rats. Increasing doses of aqueous extract (6.5, 13, 26 and 52 mg/kg i.p.) were separately administered to groups of fasted normal and diabetic rats. Plasma glucose concentration, cholesterol and changes in body weight were evaluated. The chronic intraperitoneal (i.p.) administration of the extract for 22 days was found to induce significant reduction in blood glucose level. A comparison was made between the action of the aqueous extract of C. cuneatus and the reference standard drug glibenclamide. The results of this experimental animal study indicate that this plant has an antidiabetic activity in hiperglycaemic rat models.
A ação hipoglicemiante do extrato aquoso das cascas do caule de Croton cuneatus Klotz (Euphorbiaceae) foi investigada em ratos com diabetes induzida pela estreptozotocina (STZ). Doses crescentes do extrato aquoso (6,5, 13, 26 e 52 mg/kg i.p.) foram administradas separadamente a grupos de animais normais e diabéticos em jejum. Foram avaliadas as concentrações plasmáticas de glicose e colesterol, assim como mudanças no peso corporal. A administração crônica intraperitoneal (i.p.) do extrato durante 22 dias induziu uma redução significativa nos níveis de glicose sanguínea. Foi feita uma comparação entre o extrato aquoso de C. cuneatus e a droga de referência glibenclamida. Os resultados desse experimento indicam que esta planta possui atividade antidiabética em modelo com animais hiperglicêmicos.