Cannabichromene and Delta(9)-Tetrahydrocannabinolic Acid Identified as Lactate Dehydrogenase-A Inhibitors by in Silico and in Vitro Screening

Cannabis sativa contains >120 phytocannabinoids, but our understanding of these compounds is limited. Determining the molecular modes of action of the phytocannabinoids may assist in their therapeutic development. Ligand-based virtual screening was used to suggest novel protein targets for phytocannabinoids. The similarity ensemble approach, a virtual screening tool, was applied to target identification for the phytocannabinoids as a class and predicted a possible interaction with the lactate dehydrogenase (LDH) family of enzymes. In order to evaluate this in silico prediction, a panel of 18 phytocannabinoids was screened against two LDH isozymes (LDHA and LDHB) in vitro. Cannabichromene (CBC) and Delta(9)-tetrahydrocannabinolic acid (Delta(9)-THCA) inhibited LDHA via a noncompetitive mode of inhibition with respect to pyruvate, with K-i values of 8.5 and 6.5 mu M, respectively. In silico modeling was then used to predict the binding site for CBC and Delta(9)-THCA. Both were proposed to bind within the nicotinamide pocket, overlapping the binding site of the cofactor NADH, which is consistent with the noncompetitive modes of inhibition. Stemming from our in silico screen, CBC and Delta(9)-THCA were identified as inhibitors of LDHA, a novel molecular target that may contribute to their therapeutic effects.

Automated summary

Based on ligand-based virtual screening, novel protein targets for phytocannabinoids were suggested, with Cannabichromene (CBC) and Delta(9)-tetrahydrocannabinolic acid (Delta(9)-THCA) identified as inhibitors of LDHA through noncompetitive mode of inhibition, binding within the nicotinamide pocket. This study highlights the potential therapeutic effects and molecular interactions of phytocannabinoids with LDHA enzymes.