The study was planned to evaluate modulatory effect of aqueous extract of Piper betle leaf (PBL) on ionizing radiation mediated oxidative stress leading to normal tissues damage during
radiotherapy and other radiation exposures. The total
polyphenols and
flavonoids known as
free radical scavenger (
chelators) were measured in the extract. To ascertain
antioxidant potential of PBL extract we studied
free radical scavenging,
metal chelation, reducing power, lipid peroxidation inhibition and ferric reducing
antioxidant properties (FRAP) using in vitro assays. Mice were exposed to varied radiation doses administered with the same extract prior to irradiation to confirm its oxidative stress minimizing efficacy by evaluating ferric reducing ability of plasma,
reduced glutathione, lipid peroxidation and micro-nuclei frequency. PBL extract was effective in scavenging DPPH (up to 92% at 100 microg/ml) and
superoxide radicals (up to 95% at 80 microg/ml), chelated
metal ions (up to 83% at 50 microg/ml) and inhibited lipid peroxidation (up to 55.65% at 500 microg/ml) in a dose dependant manner using in vitro model.
Oral administration of PBL extract (225 mg/kg
body weight) 1 hr before irradiation in mice significantly enhanced (p < 0.01) radiation abated
antioxidant potential of plasma and GSH level in all the observed organs. The treatment with extract effectively lowered the radiation induced lipid peroxidation at 24 hrs in all the selected organs with maximum inhibition in thymus (p < 0.01). After 48 hrs, lipid peroxidation was maximally inhibited in the group treated with the extract. Frequency of radiation induced micronucleated cells declined significantly (34.78%, p < 0.01) at 24 hrs post-irradiation interval by PBL extract administration. The results suggest that PBL extract has high
antioxidant potential and relatively non-toxic and thus could be assertively used to mitigate
radiotherapy inflicted normal tissues damage and also
injuries caused by moderate doses of radiation during unplanned exposures.