Hydrolysable Tannins and Biological Activities of <i>Meriania hernandoi</i> and <i>Meriania nobilis</i> (Melastomataceae)
Claudia Lorena Valverde Malaver,
Ana Julia Colmenares Dulcey,
Carlos Rial,
Rosa M. Varela,
José M. G. Molinillo,
Francisco A. Macías,
José Hipólito Isaza Martínez
Affiliations
Claudia Lorena Valverde Malaver
Department of Chemistry, Faculty of Natural and Exact Sciences, Universidad del Valle, GIPNA, Cali 760032, Colombia
Ana Julia Colmenares Dulcey
Department of Chemistry, Faculty of Natural and Exact Sciences, Universidad del Valle, GIPNA, Cali 760032, Colombia
Carlos Rial
Allelopathy Group, Instituto de Biomoléculas (INBIO), Department of Organic Chemistry, School of Sciences, Universidad de Cadiz, C/República Saharaui 7, 11510-Puerto Real (Cadiz), Spain
Rosa M. Varela
Allelopathy Group, Instituto de Biomoléculas (INBIO), Department of Organic Chemistry, School of Sciences, Universidad de Cadiz, C/República Saharaui 7, 11510-Puerto Real (Cadiz), Spain
José M. G. Molinillo
Allelopathy Group, Instituto de Biomoléculas (INBIO), Department of Organic Chemistry, School of Sciences, Universidad de Cadiz, C/República Saharaui 7, 11510-Puerto Real (Cadiz), Spain
Francisco A. Macías
Allelopathy Group, Instituto de Biomoléculas (INBIO), Department of Organic Chemistry, School of Sciences, Universidad de Cadiz, C/República Saharaui 7, 11510-Puerto Real (Cadiz), Spain
José Hipólito Isaza Martínez
Department of Chemistry, Faculty of Natural and Exact Sciences, Universidad del Valle, GIPNA, Cali 760032, Colombia
A bio-guided study of leaf extracts allowed the isolation of two new macrobicyclic hydrolysable tannins, namely merianin A (1) and merianin B (2), and oct-1-en-3-yl β-xylopyranosyl-(1„-6’)-β-glucopyranoside (3) from Meriania hernandoi, in addition to 11 known compounds reported for the first time in the Meriania genus. The structures were elucidated by spectroscopic analyses including one- and two-dimensional NMR techniques and mass spectrometry. The bioactivities of the compounds were determined by measuring the DPPH radical scavenging activity and by carrying out antioxidant power assays (FRAP), etiolated wheat coleoptile assays and phytotoxicity assays on the standard target species Lycopersicum esculentum W. (tomato). Compounds 1 and 2 exhibited the best free radical scavenging activities, with FRS50 values of 2.0 and 1.9 µM, respectively.
