1H NMR-based fingerprinting of eleven Mexican Capsicum annuum cultivars.

Affiliation

Centro de Nanociencias y Micro y Nanotecnologías, Instituto Politécnico Nacional, Av. Luis Enrique Erro S/N, Unidad Profesional Adolfo López Mateos, Zacateco, Delegación Gustavo A. Madero, Ciudad de México 07738, México. Electronic address: [Email]

Abstract

Approximately 90% of the chili peppers consumed in the world are harvested in Mexico. The present article describes the untargeted 1H NMR-based metabolomic profiling of 11 cultivars of Capsicum annuum species which are routinely consumed worldwide. The metabolomic fingerprinting detected via 1H NMR contained 44 metabolites including sugars, amino acids, organic acids, polyphenolic acids and alcohols which were identified by comparison with the literature data, with Chenomx database and by 2D NMR. Statistical approaches based on principal component analysis (PCA) and linear discriminant analysis (LDA) were used to classify the Capsicum annuum cultivars according to their metabolite profile. LDA revealed metabolomic differences and similarities among Capsicum annuum cultivars, whereas hierarchical cluster analysis (HCA) significantly separated the cultivars according to the phylogenetic trees obtained. Substantial endogenous levels of free amino acids and carbohydrates were detected in all the studied cultivars but interestingly, Capsicum annuum cv. mirasol and C. annuum cv. chilaca contained almost three-fold more endogenous levels of vitamin C than the other cultivars. Considering that this antioxidant was found in crude aqueous extracts, its abundance could be directly proportional to its bioavailability for human nutrition. The results suggest that 1H NMR is an effective method to determine differences among cultivars of the Capsicum annuum species.

Keywords

Biomarkers,Capsicum spp.,Cultivars,Linear discriminant analysis (LDA),Metabolomic fingerprinting,Nuclear magnetic resonance spectroscopy,Principal component analysis (PCA),