RESUMO
BACKGROUND: Commelina benghalensis (CB) is a small plant whose fleshy stems are used in South Africa to treat skin conditions (e.g., cancerous skin outgrowths). This study was aimed at evaluating the effect of sub-fractions of acetone extracts of CB stems on growth-associated molecular events of apoptosis and cell division cycle of Jurkat-T (JT) cells. METHODS: Acetone extract of CB stems were subfractioned into n-hexane (F1) and dichloromethane (F2) fractions. After treatment of JT cells with these subfractions, cell proliferation, viability and apoptosis were determined using a haemocytometer, the trypan blue dye exclusion assay, and Hoechst 33258 staining, respectively. Cell division cycle distribution profiles were analysed using an Epics Alba Flow Cytometer and the expression of cell division cycle regulatory genes was analysed using RT-PCR, while immunoreactive proteins were detected on western blots. RESULTS: The F1 and F2 fractions inhibited the proliferation and viability of JT cells in a concentration- and time-dependent manner, with IC50 values of 32.5 µg/mâ and 56 µg/mâ, respectively. The observed cytotoxicity was established to be a consequence of apoptosis. as verified using Hoechst staining method. Both fractions induced a G1/S interphase arrest of the cell division cycle of JT cells.RT-PCR analyses showed an up-regulatory effect by the F1 fraction in the expression of cyclin B1, cdc2 and bax, with a down-regulatory effect in the expression levels of bcl-2. Fraction F1 also increased the protein expression levels of p53 and its downstream regulators, p21 and Cdc2. However, protein Bax and p21 and p53 transcripts were undetectable under the same experimental conditions. On the other hand, fraction F2 increased the mRNA expression levels of bax, bcl-2, cyclin B1 and cdc2. Concomitantly, fraction F2 showed an up-regulation in the protein expression levels of Cdc2, Bcl-2, Cyclin B1 and p21. Despite the up-regulation in protein expression levels by fraction F2, there was no observable expression levels of the p53 protein and p21 and p53 mRNAs under similar experimental conditions. CONCLUSION: These findings suggest that the F1 and F2 fractions of CB may provide a valuable lead for the development of novel and effective anti-neoplastic drug(s).
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Proteínas de Ciclo Celular/metabolismo , Commelina , Leucemia de Células T/metabolismo , Extratos Vegetais/farmacologia , Antineoplásicos Fitogênicos/uso terapêutico , Proteína Quinase CDC2 , Proteínas de Ciclo Celular/genética , Proliferação de Células/efeitos dos fármacos , Ciclina B1/genética , Ciclina B1/metabolismo , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Quinases Ciclina-Dependentes/genética , Quinases Ciclina-Dependentes/metabolismo , Humanos , Células Jurkat , Leucemia de Células T/tratamento farmacológico , Fitoterapia , Extratos Vegetais/uso terapêutico , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , RNA Mensageiro/metabolismo , África do Sul , Linfócitos T/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Regulação para Cima , Proteína X Associada a bcl-2/genética , Proteína X Associada a bcl-2/metabolismoRESUMO
Senna italica, a member of the Fabaceae family (subfamily Caesalpiniaceae), is widely used in South African traditional medicine to treat a number of disease conditions. Aqueous extracts of the plant are mainly used to treat sexually transmitted infections and intestinal complications. The roots of S. italica were ground to a fine powder and sequentially extracted with n-hexane, dichloromethane, acetone, and methanol using serial exhaustive extraction (SEE) method. Thin layer chromatography was used to analyse the phytochemical composition of the extracts and DPPH radical scavenging method to detect the presence of antioxidant compounds. The bioassay guided fractionation of the acetone fraction afforded an antioxidant compound with free radical scavenging activity. The isolated compound was subsequently identified as 3,4',5-trihydroxystilbene (resveratrol). This study represents the first report of the stilbene resveratrol in S. italica.