E. Sikora et al., INHIBITION OF PROLIFERATION AND APOPTOSIS OF HUMAN AND RAT T-LYMPHOCYTES BY CURCUMIN, A CURRY PIGMENT, Biochemical pharmacology, 54(8), 1997, pp. 899-907
Curcumin (diferuoylmethane), the yellow pigment: in the rhizome of tum
eric (Curcuma longa), an ingredient of curry spice, is known to exhibi
t a variety of pharmacological effects including antitumor, antiinflam
matory, and antiinfectious activities. Although its precise mode of ac
tion remains elusive, curcumin has been shown to suppress the activity
of the AP-1 transcription factor in cells stimulated to proliferate.
In this study, we observed that curcumin (50 mu M) inhibited prolifera
tion of rat thymocytes stimulated with concanavalin A (Con A) as well
as that of human Jurkat lymphoblastoid cells in the logarithmic growth
phase. The pigment also inhibited apoptosis in dexamethasone-treated
rat thymocytes and in UV-irradiated Jurkat cells as judged by DNA ladd
er formation, cellular morphological changes, and flow cytometry analy
sis. The inhibition of apoptosis by curcumin in rat thymocytes was acc
ompanied by partial suppression of AP-1 activity. Complete suppression
of AP-1 activity was observed in Con A-treated, proliferating thymocy
tes. The capacity of curcumin to inhibit both cell growth and death st
rongly implies that these two biological processes share a common path
way at some point and that curcumin affects a common step, presumably
involving a modulation of the AP-1 transcription factor. (C) 1997 Else
vier Science Inc.