Evaluation of antioxidant capacity of phenolic compounds from Eryngium alternatum

Abstract

In Mexico, the main causes of death are type two diabetes and obesity. Due to the fact that the treatment against diabetes is highly expensive, the use of medicinal plants is a more affordable option and among Mexicans is common practice since prehispanic times, due to its great variety of medicinal plants. Unfortunately, there is not a serious regulation in the use, classification, dosage and preparation of herbal remedies. The Eryngium spp. has 69 endemic species and is mostly used to treat diabetes and dyslipidemia. The most reported species and that are present in the Mexican pharmacopoeia are Eryngium heterophyllum and Eryngium carlinae, but there are very few studies regarding the rest of the plants that belong to this family. In the present study, we worked with Eryngium alternatum a species that is common to find in drugstores or “tianguis” but there is very little information about it. What gives the Eryngium spp. its medicinal properties are the phenolic compounds, specifically caffeic, chlorogenic, rosmarinic acids, rutin, kaempferol, quercetin and coumarin which are in charge of its antioxidant activities. A proximal analysis was made and it was compared to Eryngium heterophyllum, as well a Box-Behnken surface analysis was made to evaluate the type of solvent (water, Ethanol, 50/50), the type of concentration (1:5 w/v, 1:10 w/v, 1:15 w/v) and the type of temperature (20°C, 40°C, 60°C) needed for polyphenol extraction, a 2.2-diphenyl-1picrylhydrazyl radical (DPPH) analysis was made in order to determine the antioxidant activity of the plant and the phenolic determination was made with the use of HPLC-DAD and UPLC-MS. At the end of the study, it was determined that the best treatment for polyphenol extraction and antioxidant activity was 50/50, 60°C, 1:15 w/v. The main polyphenols present with antioxidant activity, were chlorogenic acid (2300.91 ± 40.16 µg/g), Kaempferol-3-O-glucoside (1644.29 ± 40.28 µg/g), Rosmarinic acid (6128.79 ± 75.59 µg/g) and Quercetin-3-glucoside (322.75 ± 2.76 µg/g).