Curcumin, demethoxycurcumin, bisdemethoxycurcumin, tetrahydrocurcumin and turmerones differentially regulate anti-inflammatory and anti-proliferative responses through a ROS-independent mechanism.
Curcumin, a component of turmeric (Curcuma longa), has been shown to exhibit chemopreventive activity. Whether analogs of curcumin (Cur), such as demethoxycurcumin (DMC), bisdemethoxycurcumin (BDMC), tetrahydrocurcumin (THC) and turmerones, modulate inflammatory signaling and cell proliferation signaling to same extent as curcumin was investigated. The results indicate that the relative potency for suppression of tumor necrosis factor (TNF)-induced nuclear factor-kappaB (NF-kappaB) activation was Cur > DMC > BDMC; thus suggesting the critical role of methoxy groups on the phenyl ring. THC, which lacks the conjugated bonds in the central seven-carbon chain, was completely inactive for suppression of the transcription factor. Turmerones also failed to inhibit TNF-induced NF-kappaB activation. The suppression of NF-kappaB activity correlated with inhibition of NF-kappaB reporter activity and with down-regulation of cyclooxygenase-2, cyclin D1 and vascular endothelial growth factor, all regulated by NF-kappaB. In contrast to NF-kappaB activity, the suppression of proliferation of various tumor cell lines by Cur, DMC and BDMC was found to be comparable; indicating the methoxy groups play minimum role in the growth-modulatory effects of curcumin. THC and turmerones were also found to be active in suppression of cell growth but to a much lesser extent than curcumin, DMC and BDMC. Whether suppression of NF-kappaB or cell proliferation, no relationship of any of the curcuminoid was found with reactive oxygen species (ROS) production. Overall, our results demonstrated that different analogs of curcumin present in turmeric exhibit variable anti-inflammatory and anti-proliferative activities, which do not correlate with their ability to modulate the ROS status.
Sandur
Santosh K
SK
Cytokine Research Section, Department of Experimental Therapeutics, Box 143, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
Pandey
Manoj K
MK
Sung
Bokyung
B
Ahn
Kwang Seok
KS
Murakami
Akira
A
Sethi
Gautam
G
Limtrakul
Pornngarm
P
Badmaev
Vladimir
V
Aggarwal
Bharat B
BB
D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry / Q000494:pharmacology*; D045744:Cell Line, Tumor; D003474:Curcumin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology*; D036381:Diarylheptanoids; D005978:Glutathione / Q000378:metabolism; D006131:Growth Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D019169:Jurkat Cells; D016328:NF-kappa B / Q000378:metabolism / Q000502:physiology; D010084:Oxidation-Reduction; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology; D020298:U937 Cells
D000894:Anti-Inflammatory Agents, Non-Steroidal; D036381:Diarylheptanoids; D006131:Growth Inhibitors; D016328:NF-kappa B; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; C096277:tetrahydrocurcumin; C034786:bisdemethoxycurcumin; D005978:Glutathione; D003474:Curcumin; C050229:demethoxycurcumin