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DOI: 10.1055/s-0036-1596193
Investigation of an edible TCM bitter melon (Momordica charantia): metabolite profiling, differentiation and characterization
Publication History
Publication Date:
14 December 2016 (online)
Obesity is a worldwide chronic energy expenditure disorder associated with a vast number of diseases and disabilities. As a rich source of developing new drugs, Traditional Chinese Medicine (TCM) has a long history of usage for treating obesity.
Bitter melon (Momordica charantia, Cucurbitaceae) is an edible medicinal plant, which has been worldwide used as a botanical dietary supplement for the treatment of diabetes and obesity. Our previous studies provided a detailed investigation of the chemical constituents of bitter melon and proved the anti-diabetic effect of cucurbitane-type triterpenoid constituents for the first time. Meanwhile, we also observed that these constituents could enhance fatty acid oxidation and control weight gain [1,2]. In order to assess if bioactive metabolite composition changes significantly along with the hybrids or habitat of bitter melon, an UHPLC-TOF metabolomic study was carried out.
In this study, an optimized method for qualitative analysis of triterpenoids was set up based on UHPLC-TOF MS. The metabolites of over 50 seed samples of bitter melon collected in different parts of China were profiled, and the data were analysed with various multivariate statistical methods. The non-targeted PCA and HCA provided a good discrimination of these samples, which interestingly reveals the presence of two chemotypes of bitter melon. Biomarkers of each chemotypes were identified by comparing spectroscopic data with isolated compounds, or putatively elucidated based on fragmentation pattern of mass spectra based on HRMSn data.
In addition, the annotation was confirmed using innovative MS/MS molecular network analysis from data dependent UHPLC-HRMSn profiling. The network showed the two bitter melon chemotypes highlighted by PCA mainly differ in their richness either in cucurbitane or oleanane triterpenoids. Our finding will be helpful to clarify the correlations between compound distribution and effects of different bitter melons.
Acknowledgements: We are thankful for the financial support of the Sino-Swiss Science and Technology Cooperation (SSSTC) program (No. EG 08 – 032014).
Keywords: Metabolomics, bitter melon, Momordica charantia, PCA, UHPLC-TOF MS, triterpenoids, molecular networking.
References:
[1] Tan M-J, Ye J-M, Turner N, Hohnen-Behrens C, Ke C-Q, Tang C-P, Chen T, Weiss H-C, Gesing E-R, Rowland A, James DE, Ye Y. Antidiabetic activities of triterpenoids isolated from bitter melon associated with activation of the AMPK pathway. Chem Biol 2008; 15: 263 – 273
[2] Iseli TJ, Turner N, Zeng X-Y, Cooney GJ, Kraegen EW, Yao S, Ye, Y, James DE, Ye J-M. Activation of AMPK by Bitter Melon Triterpenoids Involves CaMKKβ. PLoS ONE 2013; 8: e62309