Evaluación de la actividad antioxidante de 5 especies de rubiaceae del Ecuador (Palicourea pilosa, palicourea amethystina, palicourea sulphurea, psychotria stenostachya y cinchona sp)

Abstract

The aim of the research was to determine the presence or absence of antioxidant activity in the plants: Palicourea pilosa, Palicourea amethystina, Palicourea sulphurea, Psychotria stenostachya and Cinchona sp, to do that, it was necessary the collection, drying and extraction of metabolites of the plant previously treated with hydroalcoholic method. The DPPH method which aims to identify the free radical scavenging capacity of the antioxidant substances that can be found in the extracts of the plants previously mentioned, where the nitrogen will have an electron that will be reduced by receiving a hydrogen atom of the antioxidant and thus the result will be a compound called hydrazine. After the mentioned reaction the violet color that characterizes the DPPH* reagent will turn into a yellow color which will determine if there is antioxidant activity, after performing this test and verifying that the question is positive, the quantification of its activity, thanks to a pattern which in our case was ascorbic acid, is carried out by measuring in the spectrophotometer at 517nm. Once the affirmative results of the DPPH* assay is obtained, the process continues to perform an extraction of total alkaloids in order to determine the antioxidant activity specifically with the application of the NADH/phenazine methosulfate/NBT method whose fundamental mechanism is based on the reduction of phenazine methosulfate (PMS) by the coenzyme NADH, which causes the generation of superoxide radical whose electrons are transferred to the tetrazolium salt as a final acceptor producing a purple formazan insoluble in water, and consequently measuring its activity at 560nm. Finally, determining the antioxidant activity of the 5 extracts, the tabulation and application of one-way ANOVA at 95% confidence level is necessary to determine the significant differences.