title: Identification, characterization and distribution of monoterpene indole alkaloids in Rauwolfia species by Orbitrap Velos Pro mass spectrometer.
abstract: Monoterpene indole alkaloids (MIAs) are medicinally important class of compounds abundant in the roots of Rauwolfia species (Apocynaceae). MIAs such as yohimbine (aphrodisiac agent) and reserpine (antihypertensive, tranquilizer) are the official drugs included in Model List of Essential Drugs of World Health Organization (WHO). Therefore, we have attempt to identify and characterize the MIAs in the crude extracts of six Rauwolfia species using ultrahigh-performance liquid chromatography coupled with Orbitrap Velos Pro hybrid mass spectrometer. The identity of the MIAs were construed using the high resolution tandem mass spectrometry (HRMS/MS) spectra of standard compounds 'yohimbine' and 'reserpine' in higher energy collisional dissociation (HCD) and collision-induced dissociation (CID) modes. The diagnostic fragment ions found in HCD mode was highly affected by variation of normalized collision energy (NCE) and gave few product ions ('C-F') while CID produced intense and more diagnostic product ions ('A-F'). Consequently, CID-MS/MS mode provided significantly more structural information about basic skeleton and therefore the recommended mode for analysis of MIAs. Furthermore, six diagnostic fragmentation pathways were established by multi-stage mass analysis (MS(n) (n=5)) analysis which gave information regarding the substitution. Fragment ions 'A-F' revealed the number and position of substituents on indole and terpene moieties. The proposed diagnostic fragmentation pathways have been successfully applied for identification and characterization of MIAs in crude root extracts of six Rauwolfia species. Ten bioactive reserpine class of MIAs were tentatively identified and characterized on the basis of chromatographic and mass spectrometric features as well as HRMS/MS an MS(n) (n=4) analysis.
authors.affiliation: Sophisticated Analytical Instrument Facility, CSIR-Central Drug Research Institute, Lucknow, 226031 Uttar Pradesh, India.
authors.forename: Sunil
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Sophisticated Analytical Instrument Facility, CSIR-Central Drug Research Institute, Lucknow, 226031 Uttar Pradesh, India; Academy of Scientific and Innovative Research (AcSIR), New Delhi 110025, India.
authors.forename: Awantika
authors.initials: A
authors.lastname: Singh
authors.affiliation: Sophisticated Analytical Instrument Facility, CSIR-Central Drug Research Institute, Lucknow, 226031 Uttar Pradesh, India; Academy of Scientific and Innovative Research (AcSIR), New Delhi 110025, India.
authors.forename: Vikas
authors.initials: V
authors.lastname: Bajpai
authors.affiliation: Sophisticated Analytical Instrument Facility, CSIR-Central Drug Research Institute, Lucknow, 226031 Uttar Pradesh, India; Academy of Scientific and Innovative Research (AcSIR), New Delhi 110025, India. Electronic address: brijesh_kumar@cdri.res.in.
authors.forename: Brijesh
authors.initials: B
authors.lastname: Kumar
mesh_terms: D010936:Plant Extracts / Q000032:analysis* / Q000737:chemistry*; D018517:Plant Roots; D011926:Rauwolfia; D046948:Secologanin Tryptamine Alkaloids / Q000032:analysis* / Q000737:chemistry*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D010936:Plant Extracts; D046948:Secologanin Tryptamine Alkaloids
keywords: Collision-induced dissociation; Higher energy collisional dissociation; Monoterpene indole alkaloids; Orbitrap Velos Pro; Rauwolfia species