Depression commonly causes chronic stimulation of the Hypophyseal-Pituitary-Adrenal (HPA) axis with over-secretion of ACTH (Growth Hormone) and cortisol. The author’s previously showed that both an alcohol extract of St. John’s Wort (Hypericum perforatum) and hypericin, a constituent of St. John’s Wort, reduced the activity of the HPA axis. (Hyperforin was inactive in reducing HPA stimulation.)

The present study was done to study the action of hypericin and flavonoids from St. John’s Wort. The following chemicals were studied:

Hypericin.

Hyperosin

Isoquercitrin.

Miqueliain.

These extracts of St. John’s Wort all significantly reduced the production of ACTH and corticosterone by 40-70% for two weeks. But none of them had any effect after eight weeks. The failure of these chemicals to modulate HPA activity after eight weeks cannot be explained at the present time.

CONCLUSION: Hypericin and other flavonoids play a role in moderating HPA activity. Flavoinoids may play a role in the anti-depressant action of St. John’s Wort. Hyperforin was inactive in reducing plasma levels of ACTH and corticosterone.

The results of the study confirm that oral flavonoids can reach the central nervous system.

NOTE: ACTH increases corticosterone. Over-secretion of corticosterone has side effects in chronic depression, such as sodium retention with blood pressure increases and reduced glucose tolerance. St. John’s Wort would be expected to reduce these complications of chronic depression, at least for the short term.

Read about the production of hypericin by a fungus of St. John’s Wort.

PMID: 15490333.

Summary #197.