Submitted to: Book Chapter
Publication Type: Book / chapter
Publication Acceptance Date: 2/17/2008
Publication Date: 4/8/2008
Citation: Kirakosyan,, A., Gibson, D.M., Kaufmann,, P.B. 2008. The production of dianthrones and phloroglucinol derivatives in St. John’s wort. In: Ramawat, K.G., Merillon, J. editors. Bioactive Molecules and Medicinal Plants. XXIV Edition. Springer. p. 149-162. Interpretive Summary: Hypericum perforatum L. (family Hypericaceae), commonly called St. John’s wort, has been used as an herbal remedy for many centuries, and it is a known producer of several biologically active compounds. We were invited to summarize the status of the use of this herb and potential avenues of production of the active compounds. This book chapter summarizes our work, as well as a number of other laboratories, that investigated the biochemical pathways involved and the various methods that can be used to optimize the production of the biologically active compounds in St. John's wort.
Technical Abstract: In recent decades, natural product research has developed in a particular and precise manner in order to identify compounds for treatment of several diseases such as cancer, depression, heart failure, inflammation, and even discovering natural products with strong antiviral actions. There are many medicinal plants that produce chemically more complicated secondary metabolites in nature than is possible to synthesize chemically, or is less feasible. St. John’s wort, Hypericum perforatum has been used as an herbal remedy for many disorders from the ancient times (as early as B.C.). It has particular interest for phytochemistry because of the large range of compounds that are active phytopharmaceuticals. This plant produces several types of biologically active compounds, including the hypericins, a family of dianthrones localized within specialized glands found predominantly on flowers and leaves, and the hyperforins, a family of prenylated acylphloroglucinols localized in the reproductive structures of the plant. St. John’s wort also produces other secondary metabolites that include flavonoids, procyanidins, tannins, essential oils, amino acids, phenylpropanoids, xanthones, and other water-soluble components. Hypericin and pseudohypericin have been demonstrated to have anti-viral and anti-cancer activity. Moreover, photodynamic hypericin activities displayed under the influence of light are used for therapy in various diseases. Hyperforin and adhyperforin, the major ploroglucinol derivatives in this plant, display potent anti-microbial and anti-depressive activity. Hyperforin exhibits antidepressant activity by a novel mechanism of action, antibiotic activity against gram-positive bacteria, and antitumoral activity in vivo. While the physiological functions of these compounds in mature plants have still not been revealed, the pharmaceutical benefits of them are obvious and have progressively been introduced for treatment of mild or moderate depression, or for some kinds of viral infections. The seasonal harvesting of this plant, loss of biodiversity, variability in quality, and contamination issues currently triggers the search for alternative methods for hypericins and hyperforins (hypericin and hyperforin) production. Thus, we will discuss in this chapter the production of these important compounds by means of plant biotechnology.