Macrolobin: A new unusual C-glycoside chromone from Macrolobium latifolium and its anticholinesterase and antimicrobial activities

Abstract

Abstract This work describes the chemical and biological investigations of leaves and stems of Macrolobium latifolium (Vogel). The DCM, EtOAc soluble fractions obtained by liquid-liquid partition the crude methanolic extract of this species were submitted to usual chromatographic techniques which permitted to isolate an unusual 5,7-dihydroxychromone-3α- d -C-glucoside, named macrolobin, along with the known compounds identified as β-taraxerol, friedelin, stigmasterol, β-sitosterol, campesterol, and apigenin. The structures of all compounds were elucidated by 1H, 13C, HSQC and HMBC NMR spectra, IR spectra data analysis, and MS. Furthermore, the chemical profile from fatty acids and/or triglycerides fraction was also determined after transesterification. The reaction products were subjected to GC-FID and GC–MS permitted to detected methyl palmitate as the main fatty acid derivate present in the oil and, lauric (7.52 %), octadecanoic (17.15 %), docosanoic (5.36 %), tricosanoic (11.83 %) and tetracosanoic as minor methyl esters. Concerning the biological activities, the organic soluble fractions and macrolobin displayed antimicrobial activity against Salmonella enterica, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli (MIC values 125−1000 μg.mL−1) and, macrolobin exhibited significant acetylcholinesterase inhibition (IC50 0.8 μM). These findings indicate M. latifolium can contribute with the development of new bioactive compounds, especially the AChE inhibition.