Chromolaena tacotana (Klatt) R. M. King and H. Rob. Source of Flavonoids with Antiproliferative and Antioxidant Activity

Objetive: To determine the antioxidant and antiproferative activity of the flavonoids isolated from the leaves of Chromolaena tacotana. Methods: Extraction was carried out with dichloromethane (CH₂Cl₂) from the leaves by soxhlet, the flavonoids were isolated by column chromatography (Si gel G 60-200 microns 4 x 60cm) eluted with CHCl₃, mixtures of CHCl₃: MeOH and MeOH. The molecular structures were elucidated by 1HNMR, 13CNMR mono and 2D and UV spectroscopic methods with displacement reagents. Each flavonoid was evaluated for its antioxidant activity by the methods DPPH^● and ABTS^{● +} and the cytotoxic activity was evaluated by MTT analysis. Findings: These compounds were identified as 3,5,4’-trihydroxy-7- methoxyflavone (Ct1), 3,5,8-trihydroxy-7,4’dimethoxyflavone (Ct2), 5,4’-dihydroxy-7-methoxyflavanonol (Ct3) and 5, 7, 3’, 4’-tetrahydroxy-3-methoxyflavone (Ct4). The flavonoid that had the best response in antioxidant activity was Ct4 with and IC₅₀ of 2.51mg/L of DPPH^● and 2.13 mg/L of ABTS^●+. Antiproliferative potential showed that MDA-MB-231 breast cancer cells were the most sensitivity cell line to the flavonoids, and Ct2 is the flavonoid with better antineoplastic potential on majority of cells, except for the most resistant SiHa cervix cancer cells. Application: The high antioxidant activity of flavonoids isolated from Chromolaena tacotana and its antiproliferative activity on different cell lines, make the species a plant with pharmacological potential.