Supercritical extraction of phloroglucinols from St. John's wort (Hypericum Perforatum L.) - Process optimization, mathematical modeling and antimicrobial activity

Abstract

St. John's Wort (Hypericum perforatum L.) has been widely used as an anti-inflammatory and healing agent in traditional medicine. Some para-pharmaceutical products, prepared from the extract of St. John's Wort, are frequently used because of their anti-depressive and antiviral properties. Moreover, the extract prepared from St. John's Wort (H. perforatum L.) has been also reported to have an antimicrobial, anti-inflammatory, and healing effect. Thus, extraction of a specific component from St. John's Wort which gives a high yield of total extract and high content of desired pharmacological active compounds is obviously in focus of many research activities today. Despite the evident clinical effects, there is still a controversy regarding the active principle of the extracts. Some authors attribute the antidepressant activity to hypericin and its derivatives, whereas, other studies are in the favor of hyperforin. Hyperforin, as a phloroglucinol derivative is a relatively lipophilic compound which is susceptible to rapid thermal, light-induced and oxidative decomposition. Adhyperforin presents its methyl derivative. The supercritical fluid extraction (SFE) is an outstanding method for the extraction of natural agents and valuable components from plant materials, because heat-sensitive compounds can be extracted without any degradation, and in addition, it is an environmentally acceptable technology. Supercritical carbon dioxide (SCCO2) is the most useful supercritical fluid in the food industry, because it is non-toxic, non-explosive, and available in high (food grade) purity and can be removed from the extracted products without leaving any residue. The main goal of this study was oriented to the investigation of process optimization of the best extraction method applicable to intergradient in food and pharmaceutical industry - supercritical fluid extraction as well as the antimicrobial activity of obtained extracts. The first part of study will represent the literature review of St. John's Wort occurrence in nature, their health effects and medical and pharmaceutical use.