Hypericins as potential leads for new therapeutics.

Area of Science:

• Natural Product Chemistry
• Photochemistry
• Pharmacology

Background:

• Naphthodianthrones, hypericin and pseudohypericin, isolated from Hypericum perforatum L., are polyphenols with unique structures and properties.
• These compounds exhibit notable antitumor, antiviral, and antidepressant activities.
• Hypericin is a potent photosensitizer, generating reactive oxygen species (ROS) and singlet oxygen, crucial for its biological effects.

Purpose of the Study:

• To review recent advances (post-2005) in the chemistry and biological activities of pure hypericin and pseudohypericin.
• To focus on in vitro and in vivo studies of these naphthodianthrones.
• To exclude studies on Hypericum perforatum extracts, pharmacokinetics, and clinical data.

Main Methods:

• Comprehensive literature search using Medline (PubMed), ChemSciFinder, and Scirus Library databases.
• Inclusion of studies from 2005 onwards, with no language restrictions.
• Focus on pure compounds, excluding plant extracts and clinical trials.

Main Results:

• Hypericin's photodynamic properties are central to its efficacy in cancer photodynamic therapy (PDT).
• It induces cancer cell apoptosis and/or necrosis through ROS and singlet oxygen generation.
• Multiple mechanisms, including antiangiogenesis and immune responses, alongside pathways like intrinsic/extrinsic apoptosis and ERK inhibition, are implicated.

Conclusions:

• Hypericin and pseudohypericin possess significant therapeutic potential, particularly in oncology via PDT.
• Understanding their complex mechanisms of action is crucial for further development.
• Continued research into these naphthodianthrones promises novel therapeutic strategies.