Determinación de la actividad fotoprotectora in vitro de Zea mays.

Abstract

The objective was to determine the in vitro photoprotctive activity of lyophilized hydroalcoholic extract of the Zea mays leaves which were analyzed at concentrations of 2000, 200, 20 ppm. The conditioning and quality control of the raw drug was carried out.Phytochemical screening showed the presence of flavonoids and phenolic compounds in the Zea mays leaves. The extract used in all tests was obtained by lyophilization from the previously concentrated hydroalcoholic extract on a rotary evaporator.By thin layer chromatography, the possible presence of flavone compounds type glycosidic was evidenced. The content of total flavonoids, total phenols, and capacity to attract some free radicals were determined by spectrophotometric methods. The sun protection factor was obtained by applying the Mansur equation. In vitro photoprotective activity was evaluated by the cell death method induced by UVB radiation on Escherichia coli. Surviving colony forming units (CFUs) were detected in a 30 minute intervals for 3 hours. The contents of total phenols and flavonoids were 158.41 mg QE / 100 g lyophilized extract and 128.22 mg GAE / 100 g of lyophilized extract, respectively. The capacity of free radicals obtained a value of 29.4%.The extract from the Zea mays leaves concentration 20 ppm showed an SPF of 6.8 in contrast to ethylhexyl methoxycinnamate and octyldimethyl-PABA controls which obtained values of 16.88 and 14.59, respectively. A greater photoprotective character on Escherichia coli with respect to the ethylhexyl methoxycinnamate and octyldimethyl-PABA positive controls tested at the same concentration,was shown in a Zea mays extract at a concentration of 2000 ppm,this is verified by the presence of CFU in the case of extract up to 150 min and in controls up to 120 min. It is recommended the toxicology study of Zea mays leaves for further investigations.