Takayuki Nagano (1,#), Yasuo Oyama (1,#), Noriko Kajita (1), Lumi Chikahisa
(1,2), Mami Nakata (1), Eisuke Okazaki (1) and Toshiya Masuda (1)
(1) Laboratories of Cellular Signaling and Bioorganic Chemistry, Faculty of Integrated Arts and Sciences, The University of Tokushima, Tokushima 770, Japan
(2) Cancer Research Laboratory, Taiho Pharmaceutical Co., Ltd., Hanno 357, Japan
(#) Present address: Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Oaska 565, Japan
(*) To whom correspondence should be addressed.
Abstract: Effects of new complex curcuminoids (cassumunin A and cassumunin B) isolated from tropical ginger, Zingiber cassumunar, were examined in dissociated rat thymocytes suffering from oxidative stress induced by 3 mM hydrogen peroxide by using a flow cytometer and ethidium bromide. The effects were compared with those of curcumin, a natural antioxidant, whose chemical structure is included in those of cassumunins A and B. Pretreatment of rat thymocytes with the respective cassumunins at concentrations ranging from 100 nM to 3 microM dose-dependently prevented the hydrogen peroxide (H2O2)-induced decrease in cell viability. It had the same action, although less effective, against the treatment with cassumunin A or B (3 microM) immediately after or 60 min after start of the oxidative stress. Respective potencies of cassumunins A and B in protecting the cells suffering from H202-induced oxidative stress were greater than that of curcumin. It is suggested that cassumunins A and B may possess a potent protective action on living cells suffering from oxidative stress.
Keywords: Curcumin, Curcuminoid, Zingiber cassumunar, Flow cytometry, Oxidative stress