Quantification of mesembrine and mesembrenone in mouse plasma using UHPLC-QToF-MS: Application to a pharmacokinetic study

Authors: MANDA, VAMSHI - University Of Mississippi; AVULA, BHARATHI - University Of Mississippi; ASHFAQ, KHALID - University Of Mississippi; ABE, NAOHITO - University Of Mississippi; KHAN, IKHLAS - University Of Mississippi; KHAN, SHABANA - University Of Mississippi

Submitted to: Biomedical Chromatography
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/11/2016
Publication Date: 9/15/2016
Citation: Manda, V.K., Avula, B., Ashfaq, K., Abe, N., Khan, I.A., Khan, S.I. 2016. Quantification of mesembrine and mesembrenone in mouse plasma using UHPLC-QToF-MS: Application to a pharmacokinetic study. Biomedical Chromatography. doi:10.1002/bmc.3815.

Interpretive Summary: Sceletium tortuosum, commonly named as Kanna, or Channa, is an indigenous herb of South Africa. Sceletium extract is widely used throughout the world as an herbal supplement in the treatment of anxiety and stress. The two main medicinally active components of Sceletium are mesembrine and mesembrenone. In this study, we developed a sensitive and very easy to use analytical method to analyze these two compounds in plasma. In addition, we evaluated the concentrations of mesembrine and mesembrenone in plasma after injecting into the mice, using our analytical method. Our method can be used for the analysis in future human clinical trials of these two compounds.

Technical Abstract: Sceletium tortuosum, commonly named as Kanna, or Channa, is an indigenous herb of South Africa. Traditionally, the plant is consumed in the form of a tincture, chewing dried leaves or smoking and is widely used in the treatment of central nervous system (CNS) related disorders such as anxiety, depression, and stress. Sceletium extract is widely used throughout the world as an herbal supplement in the treatment of anxiety and stress. The two main pharmacologically active alkaloids are reported to be mesembrenone and mesembrine. Despite the wide use and reports in literature confirming the pharmacological activities of Sceletium extract, there are no in vivo pharmacokinetic studies of its active ingredients. In addition to this, there are no reported analytical methods in literature which quantify these two important alkaloids of Sceletium extract in plasma. Therefore, the objectives of the current study include: 1. To develop and validate a simple, rapid, and sensitive analytical method for simultaneous quantification of mesembrenone and mesembrine. 2. To apply this validated method to determine the intravenous (IV) and per oral (PO) plasma pharmacokinetics of mesembrenone and mesembrine in mouse. Ultra-High Performance Liquid Chromatography-Mass Spectrometry (UHPLC/QToF-MS) with a mobile phase of water and acetonitrile with 0.1 % formic acid at a flow rate of 0.23 mL/min was employed to achieve our objectives. The compounds were extracted using protein precipitation method by methanol (100%). Quinine was used as an internal standard. The lower limit of quantification for both the compounds was 10 ng/mL and the calibration curve was linear over the range of 10-1000 ng/mL (r2=0.99). The extraction recovery was between 87 to 93% for both compounds with no matrix effects on the analysis. The accuracy and precision were within ±15% (89-106%) for all QC samples (10, 100, and 1000 ng/mL). This validated method was successfully used to evaluate the IV plasma pharmacokinetics of mesembrine and mesembrenone (15 mg/kg) in mouse.