Radical scavenging activity of bisbenzylisoquinoline alkaloids and traditional prophylactics against chemotherapy-induced oral mucositis.

BACKGROUND AND OBJECTIVE

Oral mucositis is a major severe toxic side-effect of systemic chemotherapy and irradiation in patients with cancer. Various free radical scavengers have been shown to prevent chemotherapy-induced skin necrosis. The objective of this study was to determine the antioxidant activity of a bisbenzylisoquinoline alkaloidal compound (BIQAC) and a series of chemicals, including allopurinol, used clinically for the treatment of chemotherapy-induced mucositis.

METHODS

Allopurinol, melatonin, camostat mesilate, gabexate mesilate, hydroquinone and BIQAC were tested for their radical scavenging activities on four different radical species: 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) cation radical (ABTS(+)) using standard methods, and superoxide anion radical (O(2) (-)) and hydroxyl radical (OH()) using electron spin resonance.

RESULTS

Allopurinol had radical scavenging activity against O(2) (-) only. Melatonin had strong radical scavenging activity against ABTS(+), and weak activity against DPPH radical and OH(). Camostat mesilate had weak radical scavenging activity against OH(). Gabexate mesilate had no radical scavenging activity against any of these radicals. Hydroquinone had strong radical scavenging activity against DPPH radical and ABTS(+), and moderate activity against both O(2) (-) and OH(). BIQAC had moderate radical scavenging activity against DPPH radical, strong radical scavenging activity against ABTS(+) and O(2) (-), and weak activity against OH(*).

CONCLUSION

The BIQAC had the most braod-spectrum radical scavenging activity, suggesting that it may be effective against chemotherapy-induced mucositis. These findings also suggest that this radical-scavenging activity screening method, against four kinds of radicals, may be useful for the screening of radical scavenging activity of new natural and synthetic chemicals.