Quantitative Analysis of Bioactive Carbazole Alkaloids in Murraya koenigii (L.) from Six Different Climatic Zones of India Using UPLC/MS/MS and Their Principal Component Analysis

Murraya koenigii (L.) Spreng (Curry leaf) is a commercially important medicinal plant in South Asia, containing therapeutically valuable carbazole alkaloids (CAs). Thus, the quantitative evaluation of these compounds from different climatic zones of India are an important aspect for quality assessment and economic isolation of targeted compounds from the plant. In this study, quantitative estimation of CAs among 34 Indian natural populations of M. koenigii was assessed using UPLC/MS/MS. The collected populations represent the humid subtropical, tropical wet & dry, tropical wet, semi-arid, arid, and montane climatic zones of India. A total of 11 CAs viz. koenine-I, murrayamine A, koenigine, koenimbidine, koenimbine, O-methylmurrayamine A, girinimbine, mahanine, 8,8''-biskoenigine, isomahanimbine, and mahanimbine were quantified using multiple reaction monitoring (MRM) experiments within 5.0 min. The respective range for natural abundance of CAs were observed as 0.097-1.222, 0.092-5.014, 0.034-0.661, 0.010-1.673, 0.013-7.336, 0.010-0.310, 0.010-0.114, 0.049-5.288, 0.031-1.731, 0.491-3.791, and 0.492-5.399 mg/g in leaves of M. koenigii. The developed method shown linearity regression coefficient (r2 >0.9995), LOD (0.003-0.248 ng/mL), LOQ (0.009-0.754 ng/mL), and the recovery was between 88.803-103.729 %. The bulk of these CAs were recorded in their highest concentrations in the humid subtropical zone, followed by the tropical wet & dry zones of India. Further, principal component analysis (PCA) was performed which differentiated the climatic zones according to the dominant and significant CAs contents within the populations. The study concludes that the method established is simple, rapid, with high sample throughput, and can be used as a tool for commercial purposes and quality control of M. koenigii.