Chemical Profiling of Lentil (Lens culinaris Medik.) Cultivars and Isolation of Compounds

A high-performance liquid chromatography method was developed to obtain fingerprints of secondary metabolites of 12 lentil cultivars grown under the same environmental condition. Extracts (100% methanol and methanol-water (1:1)) were analyzed by RP-HPLC. Full photodiode array (191-360 nm) data were collected and used for cluster analysis. Methanol and methanol-water extracts showed slightly different clustering patterns. In the dendogram of methanol extracts, CDC Richlea appeared as an isolated group, whereas Indianhead was the isolated group in methanol-water extracts. The cultivar CDC Milestone was selected for further evaluation because of the presence of three peaks (8.9, 16.7, and 32.7 min) that were absent in other cultivars or present in very small amounts. Chromatographic separations of the methanol extract afforded several compounds including the novel 4-chloro-1H-indole-3-N-methylacetamide (13) as well as itaconic acid (3), arbutin (5), gentisic acid 5-O-[beta-d-apiofuranosyl-(1-->2)-beta-d-xylopyranoside] (9), and (6S,7Z,9R)-9-hydroxymegastigma-4,7-dien-3-one-9-O-beta-d-apiofuranosyl-(1-->2)-beta-d-glucopyranoside (14), which are described for the first time from lentils. Structures were determined by high-resolution NMR experiments.