Radioprotective effect of Haritaki

Radiation protection by Terminalia chebula: some mechanistic aspects

Radioprotective ability of the aqueous extract of the fruit of Terminalia chebula (TCE) was evaluated for its antioxidant and radioprotective abilities. TCE (50 microg) was able to neutralise 1,1-diphenyl-2-picrylhydrazyl, a stable free radical by 92.9%. The free radical neutralizing ability of TCE was comparable to that of ascorbate (100 microM) 93.5% and gallic acid (100 microM) 91.5% and was higher than that of the diethyldithiocarbamate (200 microM) 55.4%, suggesting the free radical activity of TCE. TCE protected the plasmid DNA pBR322 from undergoing the radiation-induced strand breaks. Radiation damage converts the supercoiled form (ccc) of plasmid to open circular form (oc); the presence of TCE during radiation exposure protected the plasmid from undergoing these damages. The administration of TCE (80 mg/kg body weight, i.p.) prior to whole body irradiation of mice (4 Gy) resulted in a reduction of peroxidation of membrane lipids in the mice liver as well as a decrease in radiation-induced damage to DNA, as assayed by single-cell gel electrophoresis (comet assay). TCE also protected the human lymphocytes from undergoing the gamma radiation-induced damage to DNA exposed in vitro to 2 Gy gamma-radiation. These results suggest the radioprotective ability of TCE.

Studies on the aqueous extract of Terminalia chebula as a potent antioxidant and a probable radioprotector

Aqueous extract of a natural herb, Terminalia chebula was tested for potential antioxidant activity by examining its ability to inhibit ?-radiation-induced lipid peroxidation in rat liver microsomes and damage to superoxide dismutase enzyme in rat liver mitochondria. The antimutagenic activity of the extract has been examined by following the inhibition of ?-radiation-induced strand breaks formation in plasmid pBR322 DNA. In order to understand the phytochemicals responsible for this, HPLC analysis of the extract was carried out, which showed the presence of compounds such as ascorbate, gallic acid and ellagic acid. This was also confirmed by cyclic voltammetry. The extract inhibits xanthine/xanthine oxidase activity and is also an excellent scavenger of DPPH radicals. The rate at which the extract and its constituents scavenge the DPPH radical was studied by using stopped-flow kinetic spectrometer. Based on all these results it is concluded that the aqueous extract of Terminalia chebula acts as a potent antioxidant and since it is able to protect cellular organelles from the radiation-induced damage, it may be considered as a probable radioprotector.

The fruits of Indian medicinal plant Terminalia chebula are known for their pharmacological activity and in this paper it has been shown that the extract can be used as an effective antioxidant. The aqueous extract was found to be a very efficient inhibitor of radiation-induced lipid peroxidation and damage to the SOD enzyme. It can prevent strand break formation in supercoiled DNA. It is an excellent free radical scavenger, a property arising mainly from the presence of well-known antioxidants like

Radioprotective effect of Terminalia Chebula Retzius extract against γ-irradiation-induced oxidative stress

The present study was undertaken to evaluate the radioprotective effect of Terminalia chebula Retzius extract against γ-irradiation-induced oxidative stress in rats. Major phenolic compounds such as total phenolics, flavonoids and triterpenoids contents of Terminalia chebula extract (TCE) were measured. Potential antioxidant activity of TCE was tested by free radical scavenging activity (FRSA) using 1,1,2,2-diphenyl-p-picryl hydrazyl (DPPH), total antioxidant power (TAP) using ferric reducing antioxidant power (FRAP), metal chelating activity (MCA) and inhibition of DNA damage of plasmid (pBR322). In vitro studies showed that TCE possesses potential antioxidant activity and protected plasmid DNA against breakage induced by Fenton reactants. Endogenous spleen colony forming unit (CFU) assay, DNA damage using rat peripheral blood by single cell gel electrophoresis (comet assay) and intestinal histopathological studies in rats were performed in order to find the radioprotective effect of TCE. Animals were divided into various groups and pretreated with TCE (80 mg/kg body weight, i.p.) for 5 days prior to whole body γ-irradiation. The results showed that TCE administration prior to γ-irradiation significantly enhanced the CFU counts, reduced radiation-induced cellular DNA damage and gastrointestinal cell death. The results suggested that TCE is able to protect from γ-irradiation-induced oxidative stress and may considered as probable radioprotector.

The results of the present study strongly suggest that TCE has significant antioxidant properties as well as it minimizes the radiation-induced damages. The pretreatment with TCE prior to γ-irradiation exposure reduced the extent of intestinal cellular radiation damage and accelerated the recovery process of endogenous antioxidant system of the animal to sustain oxidative assault. Therefore, Terminalia chebula may act as a radioprotector.