Bioactive components and antimutagenic and antioxidant activities of two Echeveria DC. species

Abstract

In order to preserve plant biodiversity by its sustainable use, valuable plant products must be identified to induce the field production of specific species. Echeveria is the most representative genus from Crassulaceae of Mexico because its high endemism, historical–cultural significance and role in arid ecosystems of the country. Echeveria species have important biological activities, but their compounds have not been identified. The objective of the study was to determine biological activities (i.e., antimutagenic and antioxidant) and chemical composition by GC–MS of Echeveria kimnachii (EK) and Echeveria subrigida (ES) leaves. Methanol extracts of leaves were liquid–liquid partitioned to get the hexane (HF), ethyl acetate (EAF), and aqueous (AqF) fractions and they were analyzed. Methanol extracts and their fractions (500μg/plate) showed mutagenicity inhibition (>45%) in the Ames assay using Salmonella Typhimurium YG1024 and 1-nitropyrene (200ng/plate), and the most active fractions were HF-EK (91.8%) and EAF-ES (97.6%). The highest antioxidant activities (AA) were for EAFs by DPPH (inhibition %: EK=67.5 and ES=95.1) and β-carotene-bleaching (AA %: EK=57.1 and ES=41.6) methods. GC–MS profiles showed clear differences among EK and ES, hopenone b was specific for EK and brassicasterol and germanicol for ES. The high content of phenolics (i.e., isorhamnetin and gallic acid for ES) and organic acids (i.e., syringic and malic for EK) was associated with the highest antioxidant activities of the EAFs, and with the highest antimutagenic activity of EAF-ES. By contrast, HF-EK is high in sterols (i.e., lupenone, hopenone b and γ-sitosterol) which could be responsible of its strong antimutagenicity. Moreover, both Echeveria showed other secondary metabolites (e.g., phytosterols, terpenes and fatty acids) with published remarkable biological activities. Thus, E. kimnachii and E. subrigida could be sources of biological active compounds for pharmaceutical and nutraceutical industries.