Microbiological oxidation of the pentyl side chain of cannabinoids

The role of microorganisms in the biotransformation of psychoactive substances and its forensic relevance: a critical interdisciplinary review

Microorganisms are widespread on the planet being able to adapt, persist, and grow in diverse environments, either rich in nutrient sources or under harsh conditions. The comprehension of the interaction between microorganisms and drugs is relevant for forensic toxicology and forensic chemistry, elucidating potential pathways of microbial metabolism and their implications. Considering the described scenario, this paper aims to provide a comprehensive and critical review of the state of the art of interactions amongst microorganisms and common drugs of abuse. Additionally, other drugs of forensic interest are briefly discussed. This paper outlines the importance of this area of investigation, covering the intersections between forensic microbiology, forensic chemistry, and forensic toxicology applied to drugs of abuse, and it also highlights research potentialities.

Key points

Microorganisms are widespread on the planet and grow in a myriad of environments.Microorganisms can often be found in matrices of forensic interest.Drugs can be metabolized or produced (e.g. ethanol) by microorganisms.

Microbial Biotransformation of Cannabidiol (CBD) from Cannabis sativa

Microbial biotransformation of cannabidiol was assessed using 31 different microorganisms. Only Mucor ramannianus (ATCC 9628), Beauveria bassiana (ATCC 7195), and Absidia glauca (ATCC 22 752) were able to metabolize cannabidiol. M. ramannianus (ATCC 9628) yielded five metabolites, namely, 7,4″β-dihydroxycannabidiol (1: ), 6β,4″β-dihydroxycannabidiol (2: ), 6β,2″β-dihydroxycannabidiol (3: ), 6β,3″α-dihydroxycannabidiol (4: ), and 6β,7,4″β-trihydroxycannabidiol (5: ). B. bassiana (ATCC 7195) metabolized cannabidiol to afford six metabolites identified as 7,3″-dihydroxycannabidivarin (6: ), 7-hydroxycannabidivarin-3″-carboxylic acid (7: ), 3″-hydroxycannabidivarin (8: ), 4″β-hydroxycannabidiol (9: ), and cannabidivarin-3″-carboxylic acid (10: ) along with compound 1: . Incubation of cannabidiol with A. glauca (ATCC 22 752) yielded three metabolites, 6α,3″-dihyroxycannabidivarin (11: ), 6β,3″-dihyroxycannabidivarin (12: ), and compound 6: . All compounds were evaluated for their antimicrobial and antiprotozoal activity.

Human Metabolites of Cannabidiol: A Review on Their Formation, Biological Activity, and Relevance in Therapy

Cannabidiol (CBD), the main nonpsychoactive constituent of Cannabis sativa, has shown a wide range of therapeutically promising pharmacological effects either as a sole drug or in combination with other drugs in adjunctive therapy. However, the targets involved in the therapeutic effects of CBD appear to be elusive. Furthermore, scarce information is available on the biological activity of its human metabolites which, when formed in pharmacologically relevant concentration, might contribute to or even account for the observed therapeutic effects. The present overview summarizes our current knowledge on the pharmacokinetics and metabolic fate of CBD in humans, reviews studies on the biological activity of CBD metabolites either in vitro or in vivo, and discusses relevant drug–drug interactions. To facilitate further research in the area, the reported syntheses of CBD metabolites are also catalogued.

In vitro stability of free and glucuronidated cannabinoids in urine following controlled smoked cannabis

Analyte stability is an important factor in urine test interpretation, yet cannabinoid stability data are limited. A comprehensive study of Δ(9)-tetrahydrocannabinol (THC), 11-hydroxy-THC (11-OH-THC), 11-nor-9-carboxy-THC (THCCOOH), cannabidiol, cannabinol, THC-glucuronide, and THCCOOH-glucuronide stabilities in authentic urine was completed. Urine samples after ad libitum cannabis smoking were pooled to prepare low and high pools for each study participant; baseline concentrations were measured within 24 h at room temperature (RT), 4 °C and -20 °C. Stability at RT, 4 °C and -20 °C was evaluated by Friedman tests for up to 1 year. THCCOOH, THC-glucuronide, and THCCOOH-glucuronide were quantified in baseline pools. RT THCCOOH baseline concentrations were significantly higher than -20 °C, but not 4 °C baseline concentrations. After 1 week at RT, THCCOOH increased, THCCOOH-glucuronide decreased, but THC-glucuronide was unchanged. In RT low pool, total THCCOOH (THCCOOH + THCCOOH-glucuronide) was significantly lower after 1 week. At 4 °C, THCCOOH was stable 2 weeks, THCCOOH-glucuronide 1 month and THC-glucuronide for at least 6 months. THCCOOH was stable frozen for 1 year, but 6 months high pool results were significantly higher than baseline; THC-glucuronide and THCCOOH-glucuronide were stable for 6 months. Total THCCOOH was stable 6 months at 4 °C, and frozen 6 months (low) and 1 year (high). THC, cannabidiol and cannabinol were never detected in urine; although not detected initially, 11-OH-THC was detected in 2 low and 3 high pools after 1 week at RT. Substantial THCCOOH-glucuronide deconjugation was observed at RT and 4 °C. Analysis should be conducted within 3 months if non-hydrolyzed THCCOOH or THCCOOH-glucuronide quantification is required.

Hydroxylation and further oxidation of delta9-tetrahydrocannabinol by alkane-degrading bacteria

The microbial biotransformation of Delta(9)-tetrahydrocannabinol was investigated using a collection of 206 alkane-degrading strains. Fifteen percent of these strains, mainly gram-positive strains from the genera Rhodococcus, Mycobacterium, Gordonia, and Dietzia, yielded more-polar derivatives. Eight derivatives were produced on a mg scale, isolated, and purified, and their chemical structures were elucidated with the use of liquid chromatography-mass spectrometry, (1)H-nuclear magnetic resonance (1H-NMR), and two-dimensional NMR (1H-1H correlation spectroscopy and heteronuclear multiple bond coherence). All eight biotransformation products possessed modified alkyl chains, with hydroxy, carboxy, and ester functionalities. In a number of strains, beta-oxidation of the initially formed C5 carboxylic acid led to the formation of a carboxylic acid lacking two methylene groups.

Metabolism of cannabidiol by the rat

Metabolites of CBD excreted into the bile and perfusion fluid were examined in a rat liver perfusion preparation. Metabolites were extracted with ethyl acetate and identified by GC/MS as TMS derivatives. Four mono- and five di-hydroxy metabolites were identified with major sites of metabolic attack being at C-7 and C-4". A hydroxy-ketone was detected but not fully identified. All biliary metabolites were conjugated with glucuronic acid. Urinary metabolites were studied in rats with samples taken at times to 25 h after drug administration. Unmetabolized CBD and 13 metabolites were identified by GC/MS. Major metabolites were acids with beta-oxidation being a prominent pathway. The 6- and 7-hydroxy derivatives of 4",5"-bis,nor-CBD-3"-oic acid were the most abundant compounds but substantial concentrations of the di-acids, CBD-5",7-dioic acid and 4",5"-bis,nor-CBD-3",7-dioic acid were present. Concentrations of the more highly oxidized metabolites increased with time.

In vitro metabolism of cannabidiol in the rabbit: identification of seventeen new metabolites including thirteen dihydroxylated in the isopropenyl chain

The metabolism of cannabidiol (CBD) was studied in liver microsomes from the female New Zealand white rabbit. Metabolites were extracted with ethyl acetate, concentrated by chromatography on Sephadex LH-20 and examined as trimethylsilyl (TMS), methyl ester/TMS and (2H9)TMS derivatives by gas chromatography/mass spectrometry. Thirty-nine metabolites, mainly mono-, di- and tri-hydroxy compounds, were identified; 17 of these have not been reported before. New metabolites included 8,9-dihydroxy-8,9-dihydro-CBD (two isomers) and seven monohydroxy derivatives of each of these two compounds. The mass spectra of the TMS derivatives of metabolites not hydroxylated in the isopropenyl group were generally dominated by the ion produced by retro-Diels-Alder cleavage of the terpene ring. Other structurally informative ions included the tropylium ion and fragments diagnostic of hydroxylation at C-1", C-2", C-3", C-4" and C-7. The spectra of the TMS derivatives of metabolites hydroxylated in the isopropenyl group were generally dominated by the ion at m/z 143. This involved loss of CH2OTMS and a retro-Diels-Alder fragmentation analogous to that seen in the other metabolites, but with charge retention by the other (smaller) fragment. Other, related fragment ions also characterized these metabolites.

Further studies on the oxidative cleavage of the pentyl side-chain of cannabinoids: identification of new biotransformation pathways in the metabolism of 3'-hydroxy-delta-9-tetrahydrocannabinol by the mouse

1. Oxidative degradation of the pentyl side-chain of cannabinoids leading to compounds containing even numbers of carbon atoms was studied by investigating the in vivo metabolism of 2'- and 3'-hydroxy-delta-9-tetrahydrocannabinol (THC). 2. The hydroxy cannabinoids were administered i.p. to mice, the livers were removed after 1 h and extracted metabolites were identified by g.l.c.-mass spectrometry. 3. The major metabolic route for both compounds was hydroxylation at the allylic 11-position followed by oxidation to a carboxylic acid. Additional hydroxylation occurred at C-8. 4. Little oxidative degradation of the side-chain was found for 2'-hydroxy-delta-9-THC but abundant metabolites were formed by this route from the 3'-hydroxy compound. 5. The major metabolites of this type were acids containing three carbon atoms in the chain. These are the normal products of beta-oxidation but their formation from an (omega-2)-hydroxy intermediate appears novel. 6. Other metabolites contained two carbon atoms in the side-chain but were alcohols rather than acids and were again apparently formed by novel mechanisms. 7. The results indicate that the major route leading to cannabinoid metabolites with two-carbon side-chains (loss of three carbon atoms) is initiated by omega-2 hydroxylation.