concentrations were observed within a normal dosage range and no accumulation occurred. In healthy male volunteers, 612 mg dry extract of St. John's wort produced hyperforin pharmacokinetics characterised by a half life of 19.64 hours. Pharmacodynamics Hyperforin may be a constituent responsible for the antidepressant and anxiolytic properties of the extracts of St. John's wort. In vitro, it acted as a reuptake inhibitor of monoamines (MRI), including serotonin, norepinephrine, dopamine, and of GABA and glutamate, with IC50 values of 0.05-0.10 μg/mL for all compounds, with the exception of glutamate, which is in the 0.5 μg/mL range. In other laboratory studies, hyperforin induced cytochrome P450 enzymes CYP3A4 and CYP2C9 by binding to and activating the pregnane X receptor. Hyperforin Biosynthesis Hyperforin is a polyprenylated acylphloroglucinol (PPAP) derivative with a pholoroisobutyrophenone bicyclic core. Isobutryl-CoA (17) has been determined to be one of the initial primary metabolite starter molecules in the biosynthesis of the hyperforin core structure. Isobutryl-CoA is derived from an a-ketoisovalerate intermediate (15). The bicyclic structure suggests that it has elements of meroterpenoid origin. The nucleus of hyperforin is formed in a sequence condensation of one molecule of isobutyryl-CoA and three molecules of malonyl-CoA, both catalyzed by Isobutyrophenone synthase. Type III PKS enzymes will catalyze the decarboxylative condensation of enzyme active sites to generate scaffolding. These enzymes preferred a different substrate and did not produce identical products. The cell-free extracts from the cell cultures were incubated with isobutyryl-CoA and malonyl-CoA, phlorisobutyrophenone was formed (18). THe enzymatic reaction was identified as BUS. PIVP is a similar function of enzyme in glandular hairs of hop cones. Two acylphloroglucinoal cores PICP and PIBP formed are formed by claisen condensation but will differ in substrate and enzyme specificities. PIVP will use isovaleryl-CoA in the presence of an enzyme VSP, and PIBP will use isobutyryl-CoA in the presence of bus resulting in the production of adhyperforin and hyperforin. However, hyperforin is an easily degradable compound highly sensitive to heat and light in its powder form or within a solution, making it difficult to determine a true synthesis route for hyperforin making this synthesis route a possible route. Antidepressant research Two meta-analyses of preliminary clinical trials evaluating the efficacy of St. John's wort for treating mild-to-moderate depression indicated a response similar to selective serotonin reuptake inhibitors and with better tolerance, although the long-term generalization of study results was limited by the short duration (4–12 weeks) of reviewed