Chemically modified extracts of Zinnia peruviana antioxidant and cytotoxic properties

SALINAS, A.; RETA, G. F.; DONADEL O. J.; TONN, C. E.; CIFUENTE, D. A.

San Luis

Congreso; XXXII Anual Meeting, Sociedad de Biología de Cuyo; 2014

Plants are potential sources of bioactive molecules. According to the Dictionary of Natural Products, around 84% of the bioactivecompounds contain at least a hydroxyl group or an amine group in their structure. Previously, we had investigated the antioxidantproperties of Zinnia peruviana (L.) L. (Asteraceae), and promising results were obtained. It is well-accepted that the antioxidant activityis markedly influenced by the presence of hydroxyl groups in a chemical structure. In this sense, in the present work we investigate theantioxidant properties and the cytotoxic activity of Z. peruviana extracts.Z. peruviana ?chinita del campo? is a traditional argentineanherb and antimalaric properties have been reported. A series of crude and modified extracts were prepared in order to study the changesin the bioactivities evaluated. Crude extracts were obtained from aerial parts of Z. peruviana using different organic solvents at roomtemperature. Modified extracts were prepared by chemical transformations. Acid hydrolysis was performed with HCl 2 M for 30-40 min.at 80º C and sulfonylation reaction was carried out with p-toluene sulfonyl chloride and K2CO3 in refluxing acetone for 24 hs. Thechanges produced were monitored by TLC. The radical scavenging activity was evaluated using DPPH assay. Chemosensitivity testswere performed using the SRB assay of the NCI. Significant changes in antioxidant properties and cytotoxic bioactivity were observed.These results show how a particular biological activity can be affected by chemical modification of an organic extract, and represent apossible alternative strategy for producing natural product-like libraries from natural products libraries.