Extraction of cannabinoids using vegetable oils and its uva-photoprotective effect on human skin keratinocytes

Abstract

Nowadays, vegetable oil has attracted attention in its role as an alternative solvent. Its ability to dissolve various active compounds from plants has been proven by several previous studies. Moreover, other benefits of the use of vegetable oil as a solvent are affordable, non-toxic, and eco-friendly. The extraction process is one of the crucial factors that affect the quality of cannabis. Ethanol is still consistently the best solvent for cannabis extraction in terms of yield production compared to other organic solvents used in this study including oil whose yield cannot be calculated since vegetable oil cannot be evaporated. HPTLC fingerprint revealed that the cannabis oil extracts using various vegetable oils including virgin coconut oil (VCO), olive oil (OO), perilla seed oil (PSO), sacha inchi oil (SIO), rice bran oil (RBO), and sesame seed oil (SSO) showed a similar cannabinoid profile with the organic solvent extracts which were indicated by the presence of CBG, CBN, THC, and CBD. The influence of the heating process before extraction was tested. It was found that both acid and neutral forms of cannabinoids were detected even the cannabis flowers were heated before extraction. This indicated that the heating process before extraction was not sufficiently efficient to complete the decarboxylation reaction. Extraction of the cannabis obtained from ONCB Thailand by a group of evaporable solvents tends to yield higher CBD content than THC. On contrary, the supercritical CO2 solvent yielded a higher content of THC than CBD and the highest content of both THC and CBD among other solvents tested. The vegetable oils provided the lowest amount of both CBD (0.01-0.02%w/w) and THC (0.02-0.03%w/w). For antioxidation assay, CBG, CBN, THC, CBD, and other unidentified compounds showed the activity. Within a group of organic solvents and a group of vegetable oils, the winterized supercritical CO2 (W-ScCO2) extract and the RBO extract showed the strongest activity with an IC50 value of 0.03 ± 0.006 mg/mL and 3.35 ± 0.120 mg/mL, respectively. Furthermore, the ethanol extract, the W-ScCO2 extract, and the VCO extract were tested for their UVA photoprotective effect on HaCat cells. It was found the W-ScCO2 extract significantly protected the UVA-irradiated cell whilst the VCO extract as well as pure CBD and THC showed an insignificant effect.