Medknow Publications on behalf of the Association of Radiation Oncologists of India (AROI)
Abstract
Potential of herbs and other plant-based formulations have been
increasingly recognized in prevention and treatment of human diseases
including cancer. There exist enormous prospect for screening and
evaluation of herbal/plant products for developing effective
radiosensitization and radioprotection relevant to nuclear research
program. Investigations in our laboratory have focused on the mechanism
of activity of variety of anticancer and antioxidant agents, namely,
Eugenol, (EU), Ellagic acid (EA), Triphala (TPL), Tocopherol Succinate
(TOS) and Arachidonic acid on normal and cancer cells with view to
design effective protocols in practical radioprotection and cancer
radiotherapy. This paper is mainly focused on studies on cytotoxic
effects on cancer cell lines. Results have shown that these agents
produced radiosensitizing action involving oxidative damage, membrane
alteration and damage to nucleic acid in various human cell lines.
Studies were performed employing fluorescence probes and electron spin
resonance methods and gel electrophoresis protocols. It has been found
that cytotoxic effect was induced by initiating membrane oxidative
damage and by triggering intracellular generation of reactive oxygen
species (ROS) by gamma radiation in combination with phytochemicals
like TPL, EA and TOS in tumor cell line Ehrlich Ascites (EAC), Human
cervical (HeLa) and breast (MCF-7) cells. Membrane damage and ROS
generation was measured by DPH and DCF-FDA fluorescent probes
respectively after exposure to low to moderate doses of gamma
radiation. This talk will present the cytotoxic effects of
phytochemicals in combination with ionizing radiation. It is emphasized
that modulation of membrane peroxidative damage and intra cellular ROS
may help achieve efficient killing of cancer cells which may provide a
new approach to developing effective treatment of cancer