Harmalol (HM)

Harmalol is a bio-active beta-carboline and a member of the harmala alkaloids. Harmala alkaloids are considered Schedule 9 prohibited substances under the Poisons Standard (October 2015). A Schedule 9 substance is a substance which may be abused or misused, the manufacture, possession, sale or use of which should be prohibited by law except when required for medical or scientific research, or for analytical, teaching or training purposes with approval of Commonwealth and/or State or Territory Health Authorities. Harmalol exhibits pH dependent structural equilibrium between protonated and deprotonated forms with a pKa of 7.8 as revealed from spectroscopic titration. The compound exists as protonated (structure I) and deprotonated (structure II) form in the pH range 1-7 and 9-12, respectively. This transition has been presumably induced by the polyanionic phosphate backbone of DNA at high concentration.