Opuntia ficus indica cladode extract inhibit DNA double-strand breaks and locally multiply damaged sites induced by gamma radiation

It is beyond doubt that radiotherapy is extremely effective in treating a wide variety of cancers. The sensitivity of the surrounding normal tissues limits the amount of radiation administered to the tumor. There is an urgent need to develop a treatment that combines pharmacological treatment with ionizing radiation (IR) specifically designed to specifically target cancer cells while protecting the surrounding normal tissue, resulting in an increase in the efficacy of the cancer treatment. IR could cause many types of DNA lesions. Double-strand breaks (DSBs) and locally multiple damaged sites (LMDS) are the main radiotoxic damages. Recently, the identification of new antioxidants from natural sources has attracted the attention of scientists. In this context, the present study aims to determine if the Opuntia ficus indica cladode extract (CE) can be used as a radioprotector.

Materials and methods

The DNA treated by ¹³⁷Cs γ-radiation (25–700 Gy) in the absence or presence of cactus cladode extract (CCE) was added to the E. coli base excision repair. The amounts of both DNA damages were calculated using the electrophoretic method.

Results

The irradiation of DNA in the presence of CCE induced a dramatic decrease of the yields of purine and pyrimidine-DSB. A decrease of 65 % and 84 % of the purine and pyrimidine-DSB sensitive sites have been calculated, respectively, when the sample added CCE3 during the radiotreatment. Moreover, a reduction of 80 % in the amount of Nth + Fpg-DSB SSs (non-DSB cluster damage) after γ-irradiation in the presence of CCE3 was observed.

Conclusion

Through the present it was found that the CCE can play an important role as a radio protector, maybe by scavenging the ROS formed during radio treatment or by other unknown pathways. The most toxic DNA lesions (DSBs, and LMDS) decreased dramatically. Studies aimed at obtaining more documentation about CCE components with potential radio-preventive activity are desirable because of their protective properties.