St. John's Wort (Hypericum spp.) - Relation between the Biological Source and Medical Properties

Abstract

The genus Hypericum L. (Hypericaceae) comprises around 500 species divided in 36 sections. From ancient times, the common St. John‘s wort (Hypericum perforatum L.) was often used in traditional pharmacy and medicine, and as important source of traditional drugs was, subjected to wide spectra of researches. Summarised data assured several clinical indications, which confirm the effectiveness of traditional uses. Thus, constant worldwide rise of demand for Hyperici herba is present. World Health Organization (WHO) has marked H. perforatum as the only botanical source of Hyperici herba, but some pharmacopoeias list Hypericum maculatum side by side with H. perforatum. So, the question is whether some other species of the genus also could be used for that purpose. Depending on indications, two main types of preparations obtained from Hyperici herba are available on the market. Water alcoholic extracts are mainly indicated in the cases of mild to moderate depression and oil macerates are being used in treatment of burns, eczema, dyspepsia, gastric ulcer and inflammation. Recently, more and more attention is being given to the other representatives of the genus Hypericum, such are H. maculatum, H. barbatum, H. rocheli, H. umbellatum, H. rumeliacum, etc. Different analytical methods such are liquid and gas chromatography revealed the chemical profiles of these species. Also, numerous in vitro test-systems gave the opportunity for evaluation of their biological potential. Considering that the main bioactive compounds present in H. perforatum are flavonoids (rutin, quercitrin, quercetin, hyperoside, amentoflavone), naphtodianthrones (hypericin, pseudohypercin), phloro- glucinol derivatives (hyperforin, adhyperforin), tannins and essential oil, a certain level of resemblance between chemical profiles of different representatives of the genus can be observed. Furthermore, the existence of similarity in main compounds of analysed essential oils cannot be denied. It is important to highlight that in some species of the genus certain compounds occur even in higher levels than in H. perforatum (e.g. H. rumeliacum and H. barbatum are especially rich in hypericins). But, it is confirmed that the amounts of secondary metabolites vary not only related to the species, but also in relation to ecological factors of the habitats and stage of plant development. Additionally, novel possible botanical sources of Hyperici herba show comparable and, in some cases, stronger antioxidant, cytotoxic, antimicrobial, antifungal and antiviral potential than the H. perforatum.