Hyperforin is one of the principal constituents identified in St John's wort. Hyperforin is a prenylated phloroglucinol believed to be the main active constituent responsible for its antidepressant effects. (Barnes et al., 2002) Hyperforin has been shown to inhibit the uptake of 5-HT, dopamine, noradrenaline, GABA and glutamate. (Chatterjee et al., 1998)

References

• Barnes J, Anderson LA, Phillipson JD (2002). Herbal Medicines: A guide for healthcare professionals (2 ed.) London: Pharmaceutical Press. ISBN 0-8536947-4-5
• Chatterjee SS, Bhattacharya SK, Wonnemann M, Singer A, Muller WE (1998a). Hyperforin as a possible antidepressant component of hypericum extracts. Life Sci 63 (6), 499-510.

Antidepressants