Curcumol

Eur J Pharm Sci. 2014 Dec 18;65:21-8.

Curcumol induces HSC-T6 cell death through suppression of Bcl-2: involvement of PI3K and NF-κB pathways.[Pubmed: 25220584]

The major feature in the molecular pathogenesis of hepatic fibrosis requires maintenance of the activated hepatic stellate cells (HSCs) phenotype by both proliferation and inhibition of apoptosis. Thus, the induction of activated HSCs apoptosis has been proposed as an antifibrotic treatment strategy. Curcumol has pro-apoptotic activity in a number of cancer cell types.
METHODS AND RESULTS:
The aim of this study is to test the hypothesis that the interruption of the phosphatidylinositol 3 kinase (PI3K)/nuclear factor-κB (NF-κB) signaling pathway by Curcumol might induce apoptosis of activated HSCs. Our results indicated that Curcumol-induced growth inhibition correlated with apoptosis induction as evidenced by Annexin V staining, and cleavage of caspase-3 and poly (ADP-ribose) polymerase (PARP) in HSC-T6. Importantly, we show that the apoptotic effect of Curcumol was specific to the activated HSCs (HSC-T6). Suppression of the NF-κB translocation via inhibition of IκB-α phosphorylation by the Curcumol led to the inhibition of expression of NF-κB-regulated gene, e.g. Bcl-xL and Bcl-2, in a PI3K-dependent manner, which is upstream of NF-κB activation. Also, Curcumol-mediated apoptosis of HSC-T6 were reversed by LY294002 and Bay 11-7082. Taken together, our findings perfectly support the hypothesis and demonstrate that the inhibition of PI3K/NF-κB pathway by Curcumol lead to HSC-T6 apoptosis.
CONCLUSIONS:
Thus, our study indicates that Curcumol is a potential candidate for further preclinical study aimed at the treatment of liver fibrosis.

Eur J Pharmacol. 2014 Jan 15;723:339-45.

Curcumol exhibits anti-inflammatory properties by interfering with the JNK-mediated AP-1 pathway in lipopolysaccharide-activated RAW264.7 cells.[Pubmed: 24269960]

Curcumol is one of the major components of the essential oil of Rhizoma Curcumae, a common traditional Chinese medicine with anti-inflammatory properties. However, the anti-inflammatory activity and the underlying molecular mechanisms of this compound remain unclear.
METHODS AND RESULTS:
In the present study, the anti-inflammation effect of Curcumol on lipopolysaccharide (LPS)-induced RAW264.7 cells is demonstrated along with its underlying mechanisms. We show that Curcumol inhibits LPS-induced NO production by suppressing iNOS mRNA expression and protein level but not iNOS activity. Moreover, Curcumol inhibits LPS-induced production of TNF-α, IL-1β and IL-6 at both the transcriptional and translational levels. Further investigations reveal that these effects mainly act via suppressing JNK-mediated AP-1 rather than the NF-κB pathway; these effects include a decrease in the phosphorylation level of JNK and a direct inhibition of the activity of p-JNK.
CONCLUSIONS:
These data provide scientific molecular evidence that Curcumol may be a potential lead compound for a novel anti-inflammatory drug because of its inhibitory activity on the production of various inflammatory mediators.

Neuropharmacology. 2014 Jun;81:244-55.

Curcumol from Rhizoma Curcumae suppresses epileptic seizure by facilitation of GABA(A) receptors.[Pubmed: 24565642 ]

Rhizoma Curcumae is a common Chinese dietary spice used in South Asia and China for thousands of years. As the main extract, Rhizoma Curcumae oil has attracted a great interest due to its newly raised therapeutic activities including its pharmacological effects upon central nervous system such as neuroprotection, cognitive enhancement, and anti-seizure efficacy; however the molecular mechanisms and the target identification remain to be established.
METHODS AND RESULTS:
Here we characterize an inhibitory effect of Curcumol, a major bioactive component of Rhizoma Curcumae oil, on the excitability of hippocampal neurons in culture, the basal locomotor activity of freely moving animals, and the chemically induced seizure activity in vivo. Electrophysiological recording showed that acute application of Curcumol significantly facilitated the γ-aminobutyric acid (GABA)-activated current in cultured mouse hippocampal neurons and in human embryonic kidney cells expressing α1- or α5-containing A type GABA (GABAA) receptors in a concentration-dependent manner. Measurement of tonic and miniature inhibitory postsynaptic GABAergic currents in hippocampal slices indicated that Curcumol enhanced both forms of inhibition. In both pentylenetetrazole and kainate seizure models, Curcumol suppressed epileptic activity in mice by prolonging the latency to clonic and tonic seizures and reducing the mortality as well as the susceptibility to seizure, presumably by facilitating the activation of GABAA receptors.
METHODS AND RESULTS:
Taken together, our results identified Curcumol as a novel anti-seizure agent which inhibited neuronal excitability through enhancing GABAergic inhibition.

Front Physiol . 2018 Mar 20;9:234.

Curcumol Exerts Anticancer Effect in Cholangiocarcinoma Cells via Down-Regulating CDKL3[Pubmed: 29615928]

Abstract Curcumol is the major component extracted from root of Rhizoma Curcumae. Recent studies have shown that Curcumol exerts therapeutic effects against multiple conditions, particularly cancers. However, the therapeutic role and mechanism of Curcumol against cholangiocarcinoma cells are still unclear. In our current research, we tested the effect of Curcumol in cholangiocarcinoma cells, and using two-dimensional electrophoresis, proteomics and bioinformatics, we identified cyclin-dependent kinase like 3 (CDKL3) as a potential target for Curcumol. We have demonstrated that Curcumol can evidently suppress growth and migration of cholangiocarcinoma cells. Furthermore, Curcumol could significantly block the cell cycle progression of the cholangiocarcinoma cells. These effects could be largely attributed to the inhibition of CDKL3 by Curcumol. Further studies have recapitulated the oncogenic role of CDKL3 in that knockdown of CDKL3 by lentiviral mediated transfection of shRNA against CDKL3 also led to a significant inhibition on cell proliferation, migration, invasion, and cell cycle progression. Given the high level of CDKL3 expression in human cholangiocarcinoma tissues and cell lines, we speculated that CDKL3 may constitute a potential biological target for Curcumol in cholangiocarcinoma. Keywords: CDKL3; cell cycle; cholangiocarcinoma; Curcumol; proteomics.

J Ethnopharmacol . 2018 Jan 10;210:1-9.

Curcumol induces cell cycle arrest in colon cancer cells via reactive oxygen species and Akt/ GSK3β/cyclin D1 pathway[Pubmed: 28684297]

Abstract Ethnopharmacological relevance: Curcuma kwangsiensis S. G. Lee & C. F. Liang (Guangxi ezhu, in Chinese) belongs to the Zingiberaceae family, has been used as a traditionally Chinese medicine nearly 2000 year. Curcumol is one of the guaiane-type sesquiterpenoid hemiketal isolated from medicine plant Curcuma kwangsiensis S. G. Lee & C. F. Liang, which has been reported possesses anti-cancer effects. Our previous study found that the most contribution to inhibit nasopharyngeal carcinoma cell growth was Curcumol. Aim of the study: To assess the effect of Curcumol on cell cycle arrest against human colon cancer cells (CRC) cells (LoVo and SW480) and explore its mechanism in vitro and in vivo. Materials and methods: Curcumol was dissolved in absolute ethyl alcohol. The concentration of absolute ethyl alcohol in the control group or in experimental samples was always 1/500 (v/v) of the final medium volume. LoVo and SW480 cells were treated with different concentrations of Curcumol (0, 53, 106, 212 and 424μM). And then the cell cycle of each group was examined by flow cytometry. The protein levels of PI3K, p-Akt, cyclin D1, cyclin E, CDK2, CDK4 and GSK3β were determined by Western blot. The mRNA expression of PI3K, Akt, cyclin D1, CDK4, P27, p21, and P16 in the treated cells were analyzed by real-time RT-PCR. In addition, the antitumor activity of Curcumol was evaluated in nude mice bearing orthotopic tumor implants. Results: Curcumol induced cell cycle arrest in G1/S phase. RT-qPCR and Western blot data showed that Curcumol enhanced the expression of GSK3β, P27, p21 and P16, and decreased the levels of PI3K, phosphorylated Akt (p-Akt), cyclin D1, CDK4, cyclin E and CDK2. Furthermore, Curcumol induced reactive oxygen species (ROS) generation in LoVo cells, and ROS scavenger N-acetylcysteine (NAC) significantly reversed Curcumol-induced cell growth inhibition. Besides, Curcumol also prevented the growth of human colon cancer cells xenografts in nude mouse, accompanied by the reduction of PI3K, Akt, cyclin D1, CDK4, cycln E and significant increase of GSK3β. Conclusions: Curcumol caused cell cycle arrest at the G0/G1 phase by ROS production and Akt/ GSK3β/cyclin D1 pathways inactivation, indicating the potential of Curcumol in the prevention of colon cancer carcinogenesis. Keywords: Akt; Cell cycle; Colon cancer; Curcumol; Cyclin D1; ROS.

Int J Mol Sci. 2015 Aug; 16(8): 19851–67.

Curcumol Inhibits Growth and Induces Apoptosis of Colorectal Cancer LoVo Cell Line via IGF-1R and p38 MAPK Pathway[Pubmed: 26307972]

Curcumol, isolated from the traditional medical plant Rhizoma Curcumae, is the bioactive component of Zedoary oil, whose potential anti-tumor effect has attracted considerable attention in recent years. Though many researchers have reported Curcumol and its bioactivity, the potential molecular mechanism for its anti-cancer effect in colorectal cancer LoVo cells still remains unclear.
METHODS AND RESULTS:
In the present study, we found that Curcumol showed growth inhibition and induced apoptosis of LoVo cells in a dose- and time-dependent manner. The occurrence of its proliferation inhibition and apoptosis came with suppression of IGF-1R expression, and then increased the phosphorylation of p38 mitogen activated protein kinase (MAPK), which might result in a cascade response by inhibiting the CREB survival pathway and finally triggered Bax/Bcl-2 and poly(ADP-ribose) polymerase 1 (PARP-1) apoptosis signals. Moreover, Curcumol inhibited colorectal cancer in xenograft models of nude mice. Immunohistochemical and Western blot analysis revealed that Curcumol could decrease the expression of ki-67, Bcl-2 as well as CREB1, and increase the expression of Bax and the phosphorylation of p38, which were consistent with our in vitro study.
CONCLUSIONS:
Overall, our in vitro and in vivo data confirmed the anti-cancer activity of Curcumol, which was related to a significant inhibition of IGF-1R and activation of p38 MAPKs, indicating that Curcumol may be a potential anti-tumor agent for colorectal carcinoma therapy.

Biochem Biophys Res Commun. 2014 May 2;447(2):364-70.

Curcumol suppresses RANKL-induced osteoclast formation by attenuating the JNK signaling pathway.[Pubmed: 24732351]

Osteoclasts, derived from hemopoietic progenitors of the monocyte/macrophage lineage, have a unique role in bone resorption, and are considered a potential therapeutic target in the treatment of such pathologic bone diseases as osteoporosis, rheumatoid arthritis, and periodontitis.
METHODS AND RESULTS:
In the present study, we demonstrate that Curcumol, one of the major components of the essential oil of Rhizoma Curcumae, exhibits an inhibitory effect on receptor activator of nuclear factor kappaB ligand (RANKL)-induced osteoclast differentiation with both bone marrow-derived macrophages and RAW264.7 cells in a dose-dependent manner. In addition, RANKL-induced mRNA expression of osteoclast-specific genes, such as tartrate-resistant acid phosphatase, calcitonin receptor, and cathepsin K, is prominently reduced in the presence of Curcumol. Furthermore, the molecular mechanism of action was investigated, and Curcumol inhibited osteoclastogenesis by specifically impairing RANKL-induced c-Jun N-terminal kinase (JNK)/activator protein-1 (AP-1) signaling, which was further identified in rescue studies by means of anisomycin, a JNK signaling-specific activator.
CONCLUSIONS:
Taken together, these findings suggest that Curcumol suppresses RANKL-induced osteoclast differentiation through the JNK/AP-1 signaling pathway, and may be useful as a therapeutic treatment for bone resorption-associated diseases.

Evid Based Complement Alternat Med. 2012;2012:746426.

Inhibitory Effect of Curcumol on Jak2-STAT Signal Pathway Molecules of Fibroblast-Like Synoviocytes in Patients with Rheumatoid Arthritis.[Pubmed: 22474524]

Hyperplasia of synovial membrane in rheumatoid arthritis (RA) is a critical pathological foundation for inducing articular injury. The janus kinase and signal transducer and activator of transcription (Jak-STAT) pathway plays a critical role in synovial membrane proliferation induced by platelet-derived growth factor (PDGF). To explore the anti-cell proliferation mechanism of Curcumol, a pure monomer extracted from Chinese medical plant zedoary rhizome, the changes of Jak2-STAT1/3 signal pathway-related molecules in synoviocytes were observed in vitro.
METHODS AND RESULTS:
In this study, the fibroblast-like synoviocytes (FLS) in patients with RA were collected and cultured. The following parameters were measured: cell proliferation (WST-1 assay), cell cycles (fluorescence-activated cell sorting, FACS), STAT1 and STAT3 activities (electrophoretic mobility shift assay, EMSA), and the protein expressions of phosphorylated Jak2, STAT1, and STAT3 (Western blot). It was shown that Curcumol could inhibit the RA-FLS proliferation and DNA synthesis induced by PDGF-BB in a dose-dependent manner in vitro. The transcription factors activities of STAT1 and STAT3 were obviously elevated after PDGF-BB stimulation (P < 0.05). Super-shift experiments identified the STAT1 or STAT3 proteins in the complex. Furthermore, the different concentration Curcumol could downregulate the DNA binding activities of STAT1 and STAT3 (P < 0.05) and inhibit the phosphorylation of Jak2 while it had no effect on the protein expressions of STAT1 and STAT3. Positive correlations were found between changes of cell proliferation and DNA-binding activities of STAT1 and STAT3, respectively (P < 0.01).
CONCLUSIONS:
In conclusion, Curcumol might suppress the FLS proliferation and DNA synthesis induced by PDGF-BB through attenuating Jak2 phosphorylation, downregulating STAT1 and STAT3 DNA-binding activities, which could provide theoretical foundation for clinical treatment of RA.activities, which could provide theoretical foundation for clinical treatment of RA.