Phytochemical analysis of the ethanolic extract of Maclura pomifera fruits yielded four new compounds (I-IV) along with eleven known compounds (V-XV). The crude extract exhibited significant activity towards cannabinoid receptors (CB1: 103.4% displacement; CB2: 68.8% displacement) and possibly allosteric interaction with and opioid receptors (−49.7 and −53.8% displacement, resp.). Compound I was found to be possibly allosteric for and opioid receptors (−88.4 and −27.2% displacement, resp.) and showed moderate activity (60.5% displacement) towards CB1 receptor. Compound II exhibited moderate activity towards cannabinoid receptors CB1 and CB2 (47.9 and 42.3% displacement, resp.). The known compounds (V-VIII) exhibited prominent activity towards cannabinoid receptors: pomiferin (V) (IC 50 of 2.110 and 1.318 M for CB1 and CB2, resp.), auriculasin (VI) (IC 50 of 8.923 M for CB1), warangalone (VII) (IC 50 of 1.670 and 4.438 M for CB1 and CB2, resp.), and osajin (VIII) (IC 50 of 3.859 and 7.646 M for CB1 and CB2, resp.). The isolated compounds were also tested for inhibition of human monoamine oxidase-A and monoamine oxidase-B enzymes activities, where all the tested compounds showed fewer inhibitory effects on MAO-A compared to MAO-B activities: auriculasin (VI) (IC 50 of 1.91 and 45.98 M for MAO-B and MAO-A, resp.).