Determinación de la actividad fotoprotectora in vitro de los extractos de Chenopodium murale.

Abstract

The photoprotection, the sun protection factor (SPF) and the C4 photosynthesis ofChenopodium muralegrowing in extreme radiation zones were determined in this research.New alternatives against ultraviolet-B (UVB) radiation are being investigated because theincidence of skin cancer has increased in Ecuador. To determine the plant efficiency, ultravioletB radiation-induced cell death inEscherichia coli ATCC 25922 using ethanol extracts ofChenopodium muraleat 20 ppm, 200 ppm and 2 000 ppm was done. Bacterial suspensions of E.coli using Mcfarland 0.5 turbidity standards in quartz tubes were prepared and experimentalunits were established. The bacteria were exposed to UVB radiation in seven replicates. Aftereach replicate, a bacterium growth observing-nutrient agar was sowed. The number of colonyforming units (CFU) surviving was turned into percentage of viable cell and it was comparedwith Octyl-methoxycinnamate(OMC) and Pamidate. The SPF was calculated usingspectrophotometry and applying Mansur equation. A thin-layer chromatography (TLC) ofextracts was used to identify the compounds responsible for the photoprotection. Finally, theethanol extract of Chenopodium murale prepared at 200 ppm showed the highestphotoprotection with a viable cell rate of 10.75%. The ethanol extract SPF of Chenopodiummuraleat 20 ppm was 1.12. Kaempferol-3-O-gentobioside, kaempferol-3,7-O-di-rhamnosideand isorhamnetin-3-O-glucoside compounds responsible for photoprotection were found. Weconclude that Chenopodium muraledid not show the expected photoprotection according to themethod posed by Ávila Acevedo. We recommend to standardize the induced cell death forfurther studies of photoprotection.