Establishing GPCR Targets of hMAO Active Anthraquinones from Linn Seeds Using and Methods.

The present study examines the effect of human monoamine oxidase active anthraquinones emodin, alaternin (=7-hydroxyemodin), aloe-emodin, and questin from Linn seeds in modulating human dopamine (hDR, hDR, and hDR), serotonin (h5-HTR), and vasopressin (hVR) receptors that were predicted as prime targets from proteocheminformatics modeling cell-based functional assays, and explores the possible mechanisms of action modeling. Emodin and alaternin showed a concentration-dependent agonist effect on hDR with EC values of 21.85 ± 2.66 and 56.85 ± 4.59 μM, respectively. On hVR, emodin and alaternin showed an antagonist effect with IC values of 10.25 ± 1.97 and 11.51 ± 1.08 μM, respectively. Interestingly, questin and aloe-emodin did not have any observable effect on hVR. Only alaternin was effective in antagonizing h5-HTR (IC: 84.23 ± 4.12 μM). studies revealed that a hydroxyl group at C1, C3, and C8 and a methyl group at C6 of anthraquinone structure are essential for hDR agonist and hVR antagonist effects, as well as for the H-bond interaction of 1-OH group with Ser192 at a proximity of 2.0 Å. Thus, based on and results, hVR, hDR, and h5-HTR appear to be prime targets of the tested anthraquinones.