Antioxidative and radioprotective activities of semiquinone glucoside derivative (SQGD) isolated from Bacillus sp. INM-1

Abstract

A semiquinone glucoside derivative (SQGD) was isolated from a radioresistant bacterium Bacillus sp. INM-1 and its antioxidant and radioprotective activities were evaluated using in vitro assays. Natural stable free radical properties of SQGD in solid as well as in solution form were estimated using Electron Paramagnetic Resonance (EPR) spectrometry. Results of the study were demonstrated high reducing power (1.267 ± 0.03356 U(abs)) and nitric oxide radicals scavenging activity (34.684 ± 2.132%) of SQGD. Maximum lipid peroxidation inhibitory activity of SQGD was found to be 74.09 ± 0.08% at 500 μg/ml concentration. Similarly, significant (39.54%; P < 0.05) protection to the liposomal artificial membrane against gamma radiation was observed by SQGD in terms of neutralization of gamma radiation-induced TBARS radicals in vitro. OH(-) radicals scavenging efficacy of SQGD was estimated in terms of % inhibition in deoxy D: -ribose degradation by non-site-specific and site-specific assay. The maximum (54.01 ± 1.01%) inhibition of deoxy D: -ribose degradation was observed in non-site-specific manner, whereas, site-specific inhibition was observed to be 46.36 ± 0.5% at the same concentration (250 μg/ml) of SQGD. EPR spectroscopic analysis of the SQGD indicated ~80% reduction of DPPH radicals at 6.4% concentration. EPR spectral analysis of SQGD was revealed an appearance of very strong EPR signal of 2.00485 (crystalline form) and 2.00520 (solution form) g(y) tensor value, which were an established characteristic of o-semiquinone radicals. Therefore, it can be concluded that SQGD is a natural stable o-semiquinone-type radical, possessing strong antioxidant activities and can effectively neutralize radiation induced free radicals in biological system.

Comparative Investigation on Radical Scavenging Activity and Protective Properties of Natural Isolated and Synthetic Antioxidants

“…Radical-mediated oxidative stress have been implicated different disease, including tumors and cancer like lung cancer, leukemia, breast cancer, ovary, rectum cancers, etc. (6,7,8,9,10,11,12,13,14,15,16). The effects of ROS/RNS can be connected and overcome by using external supplementation of antioxidants with natural or synthetic origin.…”

“…(crystalline form) was provided for the present study by INMAS, India (8). Nitroxyl labeled agent SLENU analogue of the anticancer drug Lomustine (CCNU), was synthesized as previously described (3).…”

“…2B). After inhibition lipid peroxide radicals, can be presumed that both agents exhibit an anti-inflammatory effect indirectly, which is demonstrated their protective properties (8). EPR spectroscopy is a highly sensitive technique utilized for investigation of free radical scavenging capacity and radical structures in synthetic and naturally isolated antioxidants (9,10,11,12,13).…”

“…The experience in the free radical biology and cancer therapy shows that the normal cells are characterized with low levels of ROS/RNS and constant levels of some scavenging activities. In human body and cells the total ROS/RNS levels are determinated by the levels of: superoxide radicals, nitric oxide radicals, endproducts of lipid peroxidation, liposomal preparation, electron donation potential, enzymes, extracting an electron from natural antioxidants and from synthetic agents (7,8,9,10,11,12,13,14,15,16,17,18). Antioxidant prophylaxis and therapy is an effective modern method for preventing abnormal production of ROS and limit their harmful effects on the body.…”

“…In recent years, increasing studies are performed on the effects of the treatment of many diseases with combinations of synthetic medicines and other radical scavengers. Use of appropriate natural and synthetic antioxidant substances reduces the level of lipid peroxidation and increases the activity of antioxidant enzyme defense system and ultimately reduces radiotherapy-and chemotherapy-induced oxidative stress and negative consequences (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15). The purpose of this study was to evaluate and compare the free radical scavenging activity and protective properties of the natural product SQGD isolated from a radioresistant bacterium Bacillus sp.…”