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ANTI‐cancer Activities of Hypericin in the Dark ¶
Author(s) -
Blank Michael,
Mandel Mathilda,
Hazan Sadick,
Keisari Yona,
Lavie Gad
Publication year - 2001
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1562/0031-8655(2001)0740120acaohi2.0.co2
Subject(s) - hypericin , oxidizing agent , apoptosis , cancer research , chemistry , photodynamic therapy , cancer cell , electron acceptor , growth inhibition , reducing agent , phototoxicity , photochemistry , cell culture , cancer , in vitro , biochemistry , biology , pharmacology , medicine , organic chemistry , genetics
The potent photodynamic properties of hypericin (HY) elicit a range of light‐dependent virucidal and tumoricidal activities. Yet, a relatively low reduction/oxidation potential endows HY with electron accepting and donating properties enabling it to act as both an oxidizing and a reducing agent. HY can thus compete as an electron acceptor from bioenergized reduction/oxidation reactions generating its excitation energy for biological activities from physiological reduction/oxidation reactions in the absence of light. Our studies show that HY can inhibit the growth of highly metastatic murine breast adenocarcinoma and squamous cell carcinoma tumors in culture. Furthermore, we show that HY can interfere with the growth of these tumors in mice reducing tumor size and prolonging animal survival in complete absence of light. While there is no evidence that HY induces apoptosis in these cells in the dark, 3 H‐thymidine incorporation into DNA was significantly reduced indicating effects that are apparently cytostatic in nature compared to the cytocidal effects of HY with light.