Molecules 2013, 18, 6092-6100; doi:10.3390/molecules18056092 OPEN ACCESS molecules ISSN 1420-3049 www.mdpi.com/journal/molecules Article Low-Density Lipoprotein (LDL)-Antioxidant Biflavonoids from Garcinia madruno Edison Osorio 1,*, Julián Londoño 1 and Jaume Bastida 2 1 Grupo de Investigación en Sustancias Bioactivas, Facultad de Química Farmacéutica, Universidad de Antioquia, Carrera 53 n 61-30., A.A. 1226, Medellín, Colombia; E-Mail:
[email protected] 2 Departament de Productes Naturals, Facultat de Farmàcia, Universitat de Barcelona, Avn. Joan XXIII s/n, Barcelona 08028, Spain; E-Mail:
[email protected] * Author to whom correspondence should be addressed; E-Mail:
[email protected]; Tel./Fax: +574-219-65-90. Received: 3 March 2013; in revised form: 25 April 2013 / Accepted: 10 May 2013 / Published: 22 May 2013 Abstract: Six biflavonoids were isolated from G. madruno, one of which, 7''-O-(6''''-acetyl)-glucoside of morelloflavone, is a new compound identified on the basis of 1D, 2D NMR (HMQC and HMBC) spectroscopic methods and chemical evidence. The antioxidant activity of the biflavonoids against low-density lipoprotein (LDL) peroxidation induced with Cu2+, was studied by means of a TBARS assay. The antioxidant potential of a biflavonoid fraction (BF) was also evaluated and correlated with its biflavonoid content. The flavanone-(3→8'')-flavone biflavonoids displayed antioxidant activity, particularly morelloflavone, which was significantly more potent than quercetin, with a CE50 of 12.36 μg/mL. Lipid peroxidation, was also significantly reduced in the presence of the BF (EC50 = 11.85 μg/mL). These results suggest that the BF is an excellent antioxidant.