CHEMISTRY STUDY OF Distictella elongata AND EVALUATION OF THE LIPOXYGENASE INHIBITORY ACTIVITY AND CYTOTOXICITY

Abstract

Purpose: Distictella elongata belongs to the Bignoniaceae, which is distributed in tropical regions of South America and Africa. Phytochemical studies with several species of Bignoniaceae revealed the presence of lignans, flavonoids, iridoids, triterpenes, cinnamic and benzoic acids, and naphthoquinones. The aims of this work were the evaluation of the lipoxygenase (LOX) inhibitory and the cytotoxic activities and also chemical analysis of crude extracts and fractions. Methods: The cytotoxicity was measured using the in vitro Roche Diagnostics Toxicology assay kit. The 15-LOX inhibitory activity was evaluated using an in vitro Cayman Chemical enzyme assay kit. The leaves of D. elongate were triturated and extracted with ethanol. The extract (30 g) was dissolved in methanol-water (8:2 v/v) and submitted to a liquid-liquid partition with hexane, and EtOAc. The EtOAc fraction was purified by solid phase extraction using silica ODS and methanol-water as eluent. Results: The crude extract showed LOX inhibitory activity of 31.6 ± 3.2 % at 25 μg/mL, and when assayed against normal human lung fibroblasts cell line (GM07492A) the extract displayed IC 50 of 159.8 ± 3.3 µg/mL. Thus, the extract was considered not cytotoxic. Partition of the bioactive extract furnished three fractions. The EtOAc fraction afforded the best result; the percentage of inhibition was 40.8 at 25 µg/mL. Chromatographic purification of this fraction yielded five fractions. The EtOAc fraction also exhibited weak cytotoxic activity IC 50 of 111.7 ± 11.4 µg/mL. Conclusion: The ethanol extract allowed the obtention of a bioactive fraction, and then five fractions, which are under purification process.