Strictosidinic acid, an orally active glycoside indole monoterpene alkaloid isolated from Psychotria myriantha leaves, inhibits precursor enzymes of 5-HT biosynthesis and reduces the 5-HT levels. Strictosidinic acid has peripheral analgesic and antipyretic activities in mice[2].In Vivo: Strictosidinic acid (20 μg/μl; intra-hippocampal injection) causes a significance of 83.5% reduction in 5-HT levels. Strictosidinic acid (10 mg/kg; i.p.) causes a 63.4% reduction in 5-HT levels and a 67.4% reduction in DOPAC values in male Wistar rats, weighing 200-250 g.