La gestión del riesgo de mercado en las entidades de depósito. Introducción a la metodología VARÂ

[ES] El propósito de este artículo es suministrar al lector los primeros pasos para la comprensión de la metodología Value at Risk (Var). La necesidad de comprender esta metodología está justificada por el acuerdo de Basilea y la Directiva sobre los requerimientos de capital impuesta por la Unión Europea. Ambos proponen los métodos VaR para determinar el capital mínimo de los bancos comerciales en su operativa pero, ¿Qué es el riesgo exactamente?. El riesgo puede ser definido como la volatilidad de los resultados esperados.

Phenolic Constituents, Antioxidant and Preliminary Antimycoplasmic Activities of Leaf Skin and Flowers of Aloe vera (L.) Burm. f. (syn. A. barbadensis Mill.) from the Canary Islands (Spain)

[EN]The methanol extracts of leaf skins and flowers of Aloe vera from the Canary Islands were analyzed for their phenolic profiles and screened for their antioxidant and antimycoplasmic activities. The use of reversed phase high performance liquid chromatography (RP-HPLC) allowed the identification of 18 phenolic constituents. Leaf skin extracts were characterized by the abundance of catechin, sinapic acid and quercitrin. Gentisic acid, epicatechin and quercitrin were the most prominent phenolic compounds of the flowers. The in vitro antioxidant activities determined by using the 1,1-diphenyl-2- picrylhydrazyl (DPPH) and ferric antioxidant reducing power (FRAP) assays revealed that both extracts exhibited antioxidant activity, being the leaf skin extract the most active fraction. The leaf skin extract was also found to be active against the microbial strains tested. Therefore, A. vera extracts from leaf skin and flowers can be considered as good natural antioxidant sources.