Simultaneous Determination of Bioactive Monoterpene Indole Alkaloids in Ethanolic Extract of Seven Rauvolfia Species using UHPLC with Hybrid Triple Quadrupole Linear Ion Trap Mass Spectrometry

Introduction Rauvolfia serpentina is an endangered plant species due to its over-exploitation. It has highly commercial and economic importance due to the presence of bioactive monoterpene indole alkaloids (MIAs) such as ajmaline, yohimbine, ajmalicine, serpentine and reserpine. Objective To develop a validated, rapid, sensitive and selective ultra-high-performance liquid chromatography coupled with hybrid triple quadrupole-linear ion trap mass spectrometry (UHPLC-QqQLIT-MS/MS) method in the multiple reaction monitoring (MRM) mode for simultaneous determination of bioactive MIAs in ethanolic extract of seven Rauvolfia species and herbal formulations. Methods The separation of MIAs was achieved on an ACQUITY UPLC BEH™ C18 column (1.7 μm, 2.1 mm × 50 mm) using a gradient mobile phase (0.1% aqueous formic acid and acetonitrile) at flow rate 0.3 μL/min in 7 min. The validated method showed good linearity (r2 ≥ 0.9999), limit of detection (LOD) (0.06–0.15 ng/mL), limit of quantitation (LOQ) (0.18–0.44 ng/mL), precisions [intraday: relative standard deviation (RSD) ≤ 2.24%, interday: RSD ≤ 2.74%], stability (RSD ≤ 1.53%) and overall recovery (RSD ≤ 2.23%). Results The validated method was applied to quantitate MIAs. Root of Rauvolfia vomitoria showed a high content of ajmaline (48.43 mg/g), serpentine (87.77 mg/g) whereas high quantities of yohimbine (100.21 mg/g) and ajmalicine (120.51 mg/g) were detected in R. tetraphylla. High content of reserpine was detected in R. micrantha (35.18 mg/g) and R. serpentina (32.38 mg/g). Conclusion The encouraging results of this study may lead to easy selection of suitable Rauvolfia species according to the abundance of MIAs. Copyright © 2016 John Wiley & Sons, Ltd.