An Examination of Anthocyanins' and Anthocyanidins' Affinity for Cannabinoid Receptors

A growing body of evidence suggests that anthocyanins and anthocyanidins may possess analgesic properties in addition to neuroprotective and anti-inflammatory activities. These functionalities suggest a role for the cannabinoid receptor (CB) in mediating biological effects. Competitive radioligand binding assays identified cyanidin (K-i = 16.2 mu M) and delphinidin (K-i = 21.3 mu M) as ligands with moderate affinity to human CB1. For CB2, similar affinities were achieved by cyanidin (K-i = 33.5 mu M), delphinidin (K-i = 34.3 mu M), and peonidin (K-i = 46.4 mu M). Inhibition constants > 50 mu M were obtained for pelargonidin, malvidin, cyanidin-3,5-di-O-glucoside, cyanidin-3-O-glucoside, cyanidin-3-O-galactoside, and cyanidin-3-O-rutinoside for both CB subtypes.