Pharmacological Effects of a Decolorised St. Johns Wort Extract Designed for Topical Application

St. John's Wort extract (=Hypericum perforatum L. extract) is a very well-established phytotherapeutic drug for the treatment of nervous disorders. Its beneficial effects against mild to moderate depression have been proven in several clinical studies. On the other hand, in the form of its oil, St.John's Wort was also externally used for the treatment of sores, ulcers, burns, myalgia, and bruises [1]. More recently, beneficial dermatological effects were demonstrated for a lipophilic preparation of St. Johns Wort [2]. As for several ingredients of St. John's Wort, anti-viral, anti-bacterial, anti-proliferative and anti-inflammatory properties have been reported, its extracts may be effective against respective diseases as well, when applied topically. Normally, St. Johns Wort extract are deeply coloured due to presence of chlorophyll and proanthocyanidin pigments. In order to provide for an extract, acceptable for use in a topical preparation, we have developed a procedure to remove pigments from a crude extract. The method employed a selective solid phase extraction with Diaion HP-20 (polystyrene resin) to obtain an extract largely free from green (chlorophylls) and brownish (proanthocyanidins) pigments. This extract and its individual components were tested for activity against Herpes simplex Virus (HSV-1) and gram-positive bacteria including methicillin-resistent Staphylococcus aureus (MRSA). Antiphlogistic properties were examined using the croton oil ear-oedema model. Furthermore, the extract was tested for inhibition of human keratinocyte proliferation (psoriasis), and for inhibition of 5a-reductase (acne). The extract displayed significant activity in these test models, with a variable contribution of the individual ingredients.

References: 1. Maisenbacher, P. (1991), Ph.D. Thesis, Tübingen. 2. Schempp, Ch. et al. (2003), Phytomedicine 10: 31–37.