Drought increase antioxidant activity of Bauhinia sp and Solanum sp
Judá Ben-Hur de Oliveira1, Suiany Gervásio1, Jean Carlos Vencioneck Dutra1, Mirieli Bernardes Xavier1, Maria do Carmo Pimentel Batitucci1
1Centro de Ciências Humanas e Naturais - UFES, Departamento de Ciências Biológicas, Laboratório de Genética Vegetal e Toxicológica, Vitória, ES, Brasil. *[email protected]
Bauhinia (camel’s foot tree) and Solanum (jurubeba) are genera of plants commonly used as anti-diabetic in popular Brazilian medicine. Secondary metabolites of medicinal plants have been related to its antioxidant activity and the amount of secondary metabolites can variate due to environmental conditions, such as seasonal variations (dry and rainy seasons). This study was aimed in evaluate the interference of seasonality on the anti-oxidant activity of Bauhinia sp and Solanum sp collected in dry and rainy seasons in the years of 2015 and 2016. Bauhinia sp and Solanum sp leaves were collected in dry season (2015) and rainy season (2016) at the Horto da Prefeitura Municipal de Vitória-ES, Brazil. The plant material was dried at room temperature, pulverized in an electric grinder, macerated in ethanol (100%) for 7 days, filtered and the solvent was evaporated under low pressure to obtain the crude extracts. The comparative evaluation of antioxidant activity of the extracts was performed by spectrophotometry methodologies: evaluation of the sequestering activity of stable free radical 2,2-diphenyl-1-picryl-hydrazyl (DPPH) and 2,2’-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS). The extracts were diluted at the concentrations of 500.00, 250.00, 125.00, 62.50, 31.25 and 15.63 μg.mL-1 and the antioxidant activity was expressed as a percentage of the free radical inhibition. Following the DPPH test, Bauhinia sp collected in the dry season (2015) reached 12.24-89.79% and in the rainy season (2016) reached 2.03-46.02% of DPPH inhibition and in ABTS test in the dry season (2015) reached 8.62-92.87% and in the rainy season (2016) reached 2.07-77.97% of ABTS inhibition. In DPPH test, Solanum sp collected in the dry season (2015) reached 13.42-90.66% and in the rainy season (2016) reached 5.79-73.59% of DPPH inhibition and in ABTS test in the dry season (2015) reached 18.20-91.74% and in the rainy season (2016) reached 5.60-77.02% of ABTS inhibition. In DPPH and ABTS test, Bauhinia sp and Solanum sp extracts showed strong antioxidant activity and better antioxidant performance was observed in the year of 2015 in both specimens. Drought have been reported as a stress able to induce the increase of some plant secondary metabolites production and 2015 was characterized as a year of extreme drought on Espírito Santo. Our results suggest that the extreme drought and hydric stress induced an increase in the production of plant secondary metabolites, such as phenolic compounds (flavonoids and tannins), which can be related to the results of antioxidant activity.
Financial support: UFES