Determinación de la actividad fotoprotectora in vitro de Passiflora mixta.

Abstract

The photoprotective activity in vitro of the hydroalcoholic extract of Passiflora mixta var. mixta by UV-B induced cell death method on a strain of Escherichia coli ATCC 25922. The extract was prepared using 70% (v/v) ethanol as an extractive solvent and dynamic maceration for 72 h in darkness; the mixture was vacuum filtered, concentrated under controlled conditions in order to remove the organic solvent and finally lyophilized. Phytochemical screening demonstrated the presence of secondary metabolites such as; phenolic compounds, flavonoids, pyrophoretic type tannins, alkaloids, lactone compounds, triterpenes, steroids, reducing sugars, quinones and anthocyanins. Flavonoids, especially of the C-glycosides type, were recorded as thin layer chromatography; vitexin 2-O-rhamnoside, isovitexin 2-O-glucoside, quercetin-3-rutinoside and quercetin-3-O-glucoside. The total phenol content determined by the Folin-Ciocalteu method was 325 ± 7.07 mg GAE/g of lyophilisate; While the total flavonoid content was 629.04 ± 6.23 mg QE / g lyophilized. The antioxidant activity evaluated with the DPPH* radical of the Passiflora mixta extract in terms of IC50 was achieved at a lyophilized extract concentration of 5.43 (μg mL xvi

-1 ) dissolved in methanol. The sun protection factor (SPF) of the extract of P. mixta. calculated at a concentration of 20 ppm, after applying the Mansur equation and the spectrophotometric method for the recording of absorbances obtained a value of 7.00 ± 0.08. The number of surviving colony forming units of E. coli after exposure to UV-B radiation were transformed into area under a curve. The results indicate that the extracts at 2000 ppm and 200 ppm of P. mixta have higher photoprotective activity compared to the octyl dimethyl PABA and 2ethylhexyl 4-methoxycinnamate (OMC) positive controls at the same concentration. Testing

to ensure safety is recommended.