Simultaneous quantitative determination of bioactive terpene indole alkaloids in ethanolic extracts of Catharanthus roseus (L.) G. Don by ultra high performance liquid chromatography–tandem mass spectrometry

Abstract

A rapid, sensitive and reproducible method using ultra-high-performance liquid chromatography coupled with electrospray ionization hybrid triple quadrupole-linear ion trap mass spectrometry (UHPLC-ESI-QqQLIT-MS/MS) in multiple reaction monitoring (MRM) mode was developed and validated for simultaneous quantitation of anticancer (vincristine, vinblastine, vindesine), antihypertensive (ajmaline, ajmalicine, reserpine), aphrodisiac (yohimbine), sedative (serpentine) agents, dietary supplement (vinpocetine, yohimbine) and precursor of vinblastine (vindoline) from crude extracts of Catharanthus roseus. The precursor to product ion transitions for these compounds were observed at m/z 327 → 144, 355 → 144, 754 → 355, 353 → 144, 349 → 317, 825 → 225, 811 → 224, 458 → 188, 351 → 280 and 609 → 195, respectively in positive ionization mode. Chromatographic separation of all targeted TIAs was performed on ACQUITY UPLC BEH™ C18 column (1.7 μm, 2.1 mm × 50 mm). The calibration curves were linear within the concentration range 0.5–1000 ng/mL and correlation coefficients (R2) were closer to 1. Limit of detection (LOD) and limit of quantitation (LOQ) ranged from 0.039–0.583 ng/mL and 0.118–1.767 ng/mL, respectively. The intra-day (0.23–2.71% RSD) and inter-day (0.40–2.90% RSD) precision, stability (0.69–3.45% RSD) and recovery (99.63–104.30% ± %RSD ≤ 3.03%) were acceptable indicating good accuracy of the developed method. The method was successfully applied in ethanolic extracts of 39 samples of C. roseus parts (leaf, stem and root) collected from five different locations in India. Serpentine was detected as one of the most abundant TIA. Principal component analysis (PCA) was able to successfully discriminate among C. roseus samples on the basis of content of targeted TIAs.