Anti-HIV activity of flavonoids from Croton sphaerogynus Baill

Since the early days of medicine natural products have been used in treating various diseases. Products derived from plants have dominated the pharmacopoeias for thousands of years, providing an inexhaustible source of medicinal resources. Important physiological and ecological functions, such as radiation protection and attraction of pollinators, are attributed to flavonoids and other phenolic substances. For humans, these substances have medicinal uses, acting as anti-inflammatory, antiviral, antioxidant and antimicrobial agents [1]. Croton L. is the second largest genus of Euphorbiaceae, comprising of about 1300 trees, shrubs or herbaceous species, distributed in tropical and subtropical regions of the New and Old World. This study aimed to investigate the flavonoid composition of C. sphaerogynus and its anti-HIV1 potential. The leaf material was collected in the city of Itanhaém, São Paulo, dried at 40 °C for a week, powdered and 1 kg was subjected to maceration in ethanol for seven days at room temperature in the dark. The crude extract was fractionated using methanol and hexane. The methanol fraction was subjected to Sephadex® LH column chromatography, resulting on five subfractions (FP, F1, F2, F3 e F4). F3 was subjected to HPLC-prep, resulting in subfractions S1 and S2. All samples were dissolved in DMSO 10% to achieve concentrations of 200, 500 and 1000 µg/ml for anti-HIV1 assay (Roche®). Foscarnet (3 µg/ml) was used as a positive control. The sample that showed the highest percentage of RT inhibition at 1000 µg/mL was F1 (44.22%) followed by FP (42.10%), F4 (35.10%), F3 (34.70%), S1 (29.72%), F2 (23.67%) and S2 (18.66%). Predominating flavonols in all samples like quercetin 3-O-dimethyl ether and kaempferol 3-O-methyl ether were purified and also tested. According to the results, C. sphaerogynus is a no promising species for the exploitation of phenolic compounds with anti-HIV1 activity.

Acknowledgements: FAPESP (Fundação de Amparo à Pesquisa do estado de São Paulo) for financial support (2012/10079 – 0), and CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nivel Superior) for master scholarship of KPS.

Keywords: Euphorbiaceae, Croton, Anti-HIV1.

References:

[1] Kumar S, Pandey AK. Chemistry and biological activities of flavonoids: an overview. The Scientific World Journal 2013; 162750.