Chemical Profiling of Medical Cannabis Extracts

Abstract

Medical cannabis has been legally available for patients in a number of countries. Licensed producers produce a variety of cannabis strains with different concentrations of phytocannabinoids. Phytocannabinoids in medical cannabis are decarboxylated when subjected to heating for consumption by the patients or when extracted for preparing cannabis derivative products. There is little understanding of the true chemical composition of cannabis extracts, changes occurring during heating of the extracts, and their relevance to pharmacological effects. We investigated the extract from a popular commercial strain of medical cannabis, prior to and after decarboxylation, to understand the chemical profiles. A total of up to 62 compounds could be identified simultaneously in the extract derived from commercial cannabis, including up to 23 phytocannabinoids. Upon heating, several chemical changes take place, including the loss of carboxylic group from the acidic phytocannabinoids. This investigation attempts to reveal the chemical complexity of commercial medical cannabis extracts and the differences in the chemical composition of the native extract and the one subjected to heat. Comprehensive chemical analyses of medical cannabis extracts are needed for standardization, consistency, and, more importantly, an informed employment of this substance for therapeutic purposes.

Figure 1

Biosynthesis of major phytocannabinoids.^,,,

Figure 2

Simplified schematic of the mass spectral signals from native cannabis resin and the corresponding compounds. Numbers in bold are the mass for compounds identified in the cannabinoid biosynthetic pathway (Figure 1).

Figure 3

Fragmentation patterns for (A) orientin (17), (B) cannabisin A (18), (C) Δ⁹-tetrahydrocannabinolic acid (19), and (D) cannabigerolic acid (20, CBGA).

Figure 4

Decarboxylation of chlorophyll (C₅₅H₇₂MgN₄O₅ → C₃₂H₃₀MgN₄O₂^•).

Figure 5

Chemical structures of the phytocannabinoids, (A) 11-hydroxy-Δ⁹-tetrahydrocannabinolic acid A (23), (B) (±)-6,7-cis/trans-epoxycannabigerolic acid (24), (C) 8-keto-Δ⁹-tetrahydrocannabinolic acid A (25), (D) 8β,11-bis-hydroxy-Δ⁹-tetrahydrocannabinolic acid (26), (E) (−)-7R-cannabicourmaronic acid (27), and (F) cannabifuran.

Figure 6

Simplified schematic of the mass spectral signals from activated (decarboxylated) cannabis resin and the corresponding compounds. Numbers in bold are the mass for compounds identified in the cannabinoid biosynthetic pathway (Figure 1).