GC-MS, LC-MSn, LC-high resolution-MSn, and NMR studies on the metabolism and toxicological detection of mesembrine and mesembrenone, the main alkaloids of the legal high “Kanna” isolated from Sceletium tortuosum

Abstract

Mesembrine and mesembrenone are the main alkaloids of Sceletium tortuosum, a plant species that was used for sedation and analgesia by the KhoiSan, previously known as Hottentots, a tribe in South Africa. After fermentation, the obtained preparation called "Kanna" or "Kougoed" was used by chewing, smoking, or sniffing. Today, Kanna gains popularity by drug users as legal high. For monitoring such consumption, metabolism studies are mandatory because the metabolites are mostly the analytical targets, especially in urine. Therefore, the metabolism of both alkaloids was investigated in rat urine and pooled human liver preparations after several sample work-up procedures. As both alkaloids were not commercially available, they were isolated from plant material by Soxhlet extraction, and their identity confirmed by NMR. The metabolites were identified using gas chromatography-mass spectrometry (GC-MS) and liquid chromatography coupled to linear ion trap high resolution mass spectrometry (LC-HR-MS(n)). Both alkaloids were O- and N-demethylated, dihydrated, and/or hydroxylated at different positions. The phenolic metabolites were partly excreted as glucuronides and/or sulfates. Most of the phase I metabolites identified in rat urine could be detected also in the human liver preparations. After a common user's low dose application of mesembrine, mainly the O- and N demethyl-dihydro, hydroxy, and bis-demethyl-dihydro metabolites, and in case of mesembrenone only the N-demethyl and the N-demethyl-dihydro metabolite could be detected in rat urine using the authors' standard urine screening approaches (SUSA) by GC-MS or LC-MS(n). Thus, it should be possible to monitor a consumption of mesembrine and/or mesembrenone assuming similar pharmacokinetics in humans.

Risk Associated with the Use of Selected Ingredients in Food Supplements

“…Kanna, however, is detected in forensics to be a component of ‘designer drugs’ or as adulterated (fake) marijuana, which confirms the psychotropic potential of S. tortuosum [92,93] …”

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

“…This data suggests that these alkaloids have very low oral bioavailability. A recent study has shown that mesembrine and mesembrenone are metabolically unstable in human liver microsomes (Meyer et al ., ). Additional factors such as instability in gastric and intestinal fluids may further contribute to observed low bioavailability of mesembrine and mesembrenone observed in this study.…”

Microbial biotransformation of five pyrrolidinophenone‐type psychoactive substances in wastewater and a wastewater isolated Pseudomonas putida strain

“…In contrast, the main alpha‐cleaved fragment ion in the TPs with a carbon‐bonded hydroxylation in the pyrrolidine ring ( Ib , IIIb , Vb ), carried the oxygen, which indicated a bond with a higher stability in the collision cell. All detected N‐ oxides eluted after the unchanged compound (Table ), whereas carbon‐bonded hydroxylation usually elutes before the unchanged compound using reversed phase chromatography . So far, metabolism studies of MPHP, MPBP, and MOPPP have only been analyzed using GC–MS, where N‐ oxides are not observed.…”

“…All detected N-oxides eluted after the unchanged compound (Table 2), whereas carbon-bonded hydroxylation usually elutes before the unchanged compound using reversed phase chromatography. [11,[32][33][34] So far, metabolism studies of MPHP, MPBP, and MOPPP have only been analyzed using GC-MS, where N-oxides are not observed. Evaluation on microbial biotransformation of environmentally relevant compounds, including pharmaceuticals, using activated sludge models have reported N-oxide formation of tertiary nitrogens.…”