Quality Control & Assurance Issues

Even though both of the constituents are considered equally important, the active ingredient of Hypericum perforatum is not yet known. Hypericin has shown weak antidepressant activity. It is being used as a marker compound and has a significant role to play in quality control. Initially Hypericin was shown as an antidepressant constituent of Hypericum perforatum. It weakly inhibits the enzyme Monoamine oxidase (MAO). In addition, Hypericin has been shown to have antiviral activity and will inhibit succinoxidase, NADPH-oxidase, tyrosinkinase and protein kinase C. Hypericin belongs to a group of compounds known as napthodianthrones, which constituent 0.1-0.15% of the dried herb. Hypericin content varies from 0.02-2.5%. Standardization to the marker compound is important for quality control and consistency. The companies usually take 0.3% Hypericin as standard.
Hyperforin in animal studies has shown the ability to inhibit the uptake of neurotransmitters, and accumulated data strongly favors hyperforin as the possible antidepressant constituent of Hypericum perforatum. Hyperforin belong to acylphloroglucinol group of compounds and it is highly unstable compound. Hyperforin not only inhibits the neuronal uptake of serotonin, norepinephrine and dopamine like many other antidepressants, but it also inhibits GABA and L-glutamate uptake.
The present scenario is such that companies have shifted to standardized extracts containing 2.8% of hyperforin. Some companies are marketing Hypericum perforatum extract standardized to contain 2.8 % of hyperforin and 0.3 % of hypericin.Another factor to consider is the part of the herb used in medicine. Hypericin and hyperforin exists in the flowering tops of Hypericum perforatum with very little or negligible amounts in other parts. Hypericin content varies from 0.02% – 2.5% and the extract present in the market contains 0.3% of hypericin. The Hyperforin content of the fresh plant is not known but the dried herb contains Hyperforin up to 2.8%. The percentage of hyperforin varies substantially with stages of development of Hypericum Perforatum.