New Insights on Hemp Oil Enriched in Cannabidiol: Decarboxylation, Antioxidant Properties and In Vitro Anticancer Effect

Anca Roxana Petrovici, Natalia Simionescu, Andreea Isabela Sandu, Vasile Paraschiv, Mihaela Silion and Mariana Pinteala


Antioxidants, 2021, 10, 738.

doi : 10.3390/antiox10050738

 

Abstract :

This study aimed to obtain and characterize extracted hemp oil enriched in cannabidiol (CBD) by decarboxylation of cannabidiolic acid (CBDA) and to give new insights into its antioxidant and anticancer effects. Optimization of CBDA decarboxylation in hemp oil was performed, and CBD and CBDA contents and purities were determined by flash chromatography, 1H- and 13C-NMR. The antioxidant properties of CBD-enriched oil were investigated by Fe2+ chelating activity, Fe3+ reducing antioxidant power assay, O2 scavenging activity, HO scavenging ability and lipid peroxidation inhibitory assay, and its cytotoxicity, apoptosis- and oxidative stress inducing effects on NHDF, MeWo, HeLa, HepG2 and HOS cells were determined. The CBD concentration in hemp oil was increased by CBDA soft decarboxylation optimized at 90 C, for 1 h and the resulting oil was capable of reducing iron, scavenging free radicals and inhibiting lipid peroxidation in cell-free oxidative conditions. CBD-enriched oil promoted NHDF proliferation at up to 15 g CBD/mL, while inducing apoptosis and ROS production and modulating antioxidant enzymes’ gene expression in cancer cells, being selective for osteosarcoma cells, and induced apoptosis by p53- and ROS-independent mechanisms. CBD-enriched hemp oil demonstrated antioxidant properties in oxidative conditions and promoted normal fibroblasts’ proliferation, while inducing apoptosis and ROS production in cancer cells.

Keywords : cannabidiol; hemp oil; soft decarboxylation; antioxidant properties; reactive oxygen species; apoptosis; osteosarcoma

 

1. Introduction

Cannabis sativa L. or hemp was one of the first plants used to obtain fibers, oil and
biomass and is cultivated specifically for its industrial uses. In addition, hemp-derived
products are used as medicine, cosmetics, biofuel and animal feed, as well as for paper,
varnishes, inks and phytoremediation [1]. The production of C. sativa L. and its derived
products is regulated by European legislation, which states that hemp cultivation is permitted only if it contains less than 0.2% (w/w) D9-tetrahydrocannabinol (THC) due to its psychoactive effects (Regulation 1307/2013). Like in most European countries, hemp products are legal in Romania as long as their THC concentration is below 0.2%. In addition to THC, there are more than 100 other active compounds in hemp [2–4], and it was observed from in vitro and in vivo studies that hemp extracts exhibit significant synergistic biological effects, as compared to their individual compounds, inhibiting cancer cells’ proliferation, angiogenesis and metastasis, as well as promoting apoptosis [5]. However, non-cancerous cells respond differently to cannabinoids, their viability remaining unchanged or even being increased [6].

On the other hand, the main targets of cancer treatments are the reduction in tumor sizes, the inhibition of angiogenesis and metastasis and, primarily, the induction of controlled cancer cell death, i.e., apoptosis. The principal issue of chemotherapeutic agents, however, is that they commonly have severe side effects, attacking normal, healthy cells as well as cancer cells. This issue could be mitigated by the use of natural compounds or mixtures, which have very few and mild side effects while exhibiting anticancer properties and/or alleviating chemotherapy fallouts.

The main proposed mechanism of action for cannabinoids in cancer cells is the induction of apoptosis by stimulating the production of reactive oxygen species (ROS) [6]. It is well known that ROS, such as superoxide anion radical (O2), hydroxyl radical (HO) or hydrogen peroxide (H2O2), are produced in living cells as secondary metabolic products and are required for normal cell function at physiological concentrations [7]. H2O2 activates various redox signaling pathways and exhibits either pro- or anti-apoptotic activities, depending on its concentration and cellular localization [8].

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