Comparación de la aplicabilidad de las técnicas DPPH (1,1-difenil-2-picril-hidrazilo) y Peróxidos para extractos resinosos y no resinosos en metanol y diclorometano

Abstract

In the present research, the antioxidant capacity present in methanol and di-chloro methane extracts obtained from leaves of Jungia rugosa Less and Desmodium molliculum was evaluated. Desmodium molliculum, a plant traditionally named “hierba del infante” was collected into the Azuay province and was botanically characterized at Herbarium Azuay (HA) into the Universidad del Azuay. Dried extracts were obtained by means of percolation, using methanol and dichloromethane as solvents for extraction. A fraction of those extracts was used for their phytochemical characterization using a general screening method based on Thin Layer Chromatography (TLC). Results show the presence of phenolic compounds (flavonols and flavone) and terpenoids as the more important compounds. To evaluate antioxidant activity, two different techniques were applied: discoloration of radical 2,2-diphenyl-1-picrilhidrazilo (DPPH) and the hydrogen peroxide scavenging assay, ascorbic acid was used as a standard, IC50 value for standard was determined as 2.68 ug/ml by the first method and 58.63 ug/ml by the second method. In the DPPH assay, IC50 value for methanolic extracts of Jungia rugose Less was between 40 – 129 µg/ml and for dichloromethane extracts was between 74 – 340 µg/ml. IC50 of Desmodium molliculum was 48 µg/ml in methanolic extract and 80 ug/ml in dichloromethane extract. When hydrogen peroxide assay was developed, the IC50 value of Desmodium molliculum methanolic extract was 61 µg/ml, and between 177 – 349 µg/ml for Jungia rugosa Less. Antioxidant activity of dichloromethane extracts was not evaluated by this technique due to incompatibility with the reagents used. The findings suggest that “Jungia” and “Desmodium” have antioxidant activity, which could be related to the presence of phenolic compounds.