In vitro activity: Hordenine (N,N-dimethyl-4-hydroxyphenylethylamine) is a phenylethylamine alkaloid with antibacterial and antibiotic properties. It inhibits the uptake of norepinephrine in mammals, working as a stimulant. It is produced in nature by several varieties of plants in the family Cactaceae and by some in Acacia. Recent study shows that hordenine may be an effective inhibitor of hyperpigmentation. it inhibits melanogenesis by suppressing cAMP production, which is involved in the expression of melanogenesis-related proteins.

J Pharm Pharmacol. 1989 Jun;41(6):421-3; Food Chem. 2013 Nov 1;141(1):174-81.