Abstract
Hypericin (4,5,7,4′,5′,7′-hexahydroxy-2,2′-dimethylnaphtodianthrone) is a naturally occurring chromophore found in some species of the genus Hypericum, especially Hypericum perforatum L. (St. John's wort), and in some basidiomycetes (Dermocybe spp.) or endophytic fungi (Thielavia subthermophila). In recent decades, hypericin has been intensively studied for its broad pharmacological spectrum. Among its antidepressant and light-dependent antiviral actions, hypericin is a powerful natural photosensitizer that is applicable in the photodynamic therapy (PDT) of various oncological diseases. As the accumulation of hypericin is significantly higher in neoplastic tissue than in normal tissue, it can be used in photodynamic diagnosis (PDD) as an effective fluorescence marker for tumor detection and visualization. In addition, light-activated hypericin acts as a strong pro-oxidant agent with antineoplastic and antiangiogenic properties, since it effectively induces the apoptosis, necrosis or autophagy of cancer cells. Moreover, a strong affinity of hypericin for necrotic tissue was discovered. Thus, hypericin and its radiolabeled derivatives have been recently investigated as potential biomarkers for the non-invasive targeting of tissue necrosis in numerous disorders, including solid tumors. On the other hand, several light-independent actions of hypericin have also been described, even though its effects in the dark have not been studied as intensively as those of photoactivated hypericin. Various experimental studies have revealed no cytotoxicity of hypericin in the dark; however, it can serve as a potential antimetastatic and antiangiogenic agent. On the contrary, hypericin can induce the expression of some ABC transporters, which are often associated with the multidrug resistance (MDR) of cancer cells. Moreover, the hypericin-mediated attenuation of the cytotoxicity of some chemotherapeutics was revealed. Therefore, hypericin might represent another St. John's wort metabolite that is potentially responsible for negative herb–drug interactions. The main aim of this review is to summarize the benefits of photoactivated and non-activated hypericin, mainly in preclinical and clinical applications, and to uncover the “dark side” of this secondary metabolite, focusing on MDR mechanisms.
Highlights
Hypericin (4,5,7,4′,5′,7′-hexahydroxy-2,2′-dimethylnaphtodiant hrone) is a naturally occurring compound synthesized by some species of the genus Hypericum
As hypericin is a bioactive compound that is applicable in several medicinal approaches, its content has been evaluated in in vitro grown Hypericum perforatum and in its transgenic clones (Cellárová et al, 1997; Košuth et al, 2003; Koperdáková et al, 2009), or in Hypericum cultures exposed to various biotechnological applications that focused on their preservation or stimulation of secondary metabolite production (Urbanová et al, 2006; Brunáková et al, 2015; reviewed in: Cellárová, 2011)
We have summarized the medicinal applications of light-activated and non-activated hypericin in the field of oncology
Summary
Hypericin (4,5,7,4′,5′,7′-hexahydroxy-2,2′-dimethylnaphtodiant hrone) is a naturally occurring compound synthesized by some species of the genus Hypericum. In addition to St. John’s wort, this secondary metabolite was found in several other Hypericum species (Kitanov, 2001; Ayan et al, 2004) and in some basidiomycetes (Dermocybe spp.) (Dewick, 2002; Garnica et al, 2003) or endophytic fungi growing in Hypericum perforatum (Thielavia subthermophila) (Kusari et al, 2008, 2009). As hypericin is a bioactive compound that is applicable in several medicinal approaches, its content has been evaluated in in vitro grown Hypericum perforatum and in its transgenic clones (Cellárová et al, 1997; Košuth et al, 2003; Koperdáková et al, 2009), or in Hypericum cultures exposed to various biotechnological applications that focused on their preservation or stimulation of secondary metabolite production (Urbanová et al, 2006; Brunáková et al, 2015; reviewed in: Cellárová, 2011)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
