Curcuminoid Analogues Research Articles

Study of the Effects of Novel Analogs of Calebin-A on Melanogenesis

In our previous study, we documented the anti-melanogenic efficacy of calebin-A (CBA), which is a curcuminoid analog. The effects of its newly synthesized analogs, i.e., bisdemethoxy calebin (BD), demethoxycalebin-1 (DA1), demethoxycalebin-2 (DA2), and tetrahydrocalebin-A (THCBA), on melanogenesis have not been examined yet. Herein, we evaluated these four CBA analogs to determine their impacts on the enzymatic activity of mushroom tyrosinase. Additionally, we examined their effects on melanogenesis and the tyrosinase activity in B16F10 mouse and MNT-1 human melanoma cells. The antioxidant activity of the analogs was also assessed. Our results revealed that BD was ineffective, while DA1 and DA2 showed similar antioxidant activities, with THCBA exhibiting the greatest antioxidant activity. Next, the diphenolase activity assay results revealed that DA1 showed the most excellent inhibitory efficacy, DA2 and BD showed similar inhibition profiles, and THCBA was ineffective. In addition, the results of the monophenolase activity showed a similar pattern, except that THCBA suppressed the activity. The four analogs were evaluated for any cytotoxicity over a 48 h duration in B16F10 and HaCaT keratinocytes, where DA1 exerted cytotoxicity at the concentration of 50 µM. Based on this, the analogs were evaluated over a 10–50 µM concentration range, while DA1 was evaluated over 10–35 µM. BD showed the greatest efficacy at multiple concentrations in significantly diminishing melanogenesis in hormone-stimulated B16F10 cells, while DA1 and DA2 suppressed melanin at 35 and 50 µM, respectively, and THCBA stimulated melanogenesis at 50 µM. In addition, BD and DA1 suppressed tyrosinase activity in B16F10 cells, with no effect in the case of DA2 and THCBA analogs. However, in MNT-1 cells, only DA1 showed efficacy in suppressing melanin production while the other three analogs were ineffective. Interestingly, BD and DA1 suppressed MNT-1 cell tyrosinase activity. Collectively, our results indicate that of the four analogs, DA1 merits further investigation as a potential compound for hyperpigmentation skin disorders. Additional research is necessary to delineate the molecular mechanisms underlying the melanogenesis-inhibitory effect of CBA analogs and examine their efficacy in diminishing melanogenesis in normal human melanocytes.

Curcumin piperidone derivatives induce caspase-dependent apoptosis and suppress miRNA-21 expression in LN-18 human glioblastoma cells

BackgroundPreviously, we have reported on the two curcuminoid analogues with piperidone derivatives, namely FLDP-5 and FLDP-8 have more potent anti-proliferative and anti-migration effects than curcumin. In this study, we further investigated the mode of cell death and the mechanism involved in the cell death process induced by these analogues on human glioblastoma LN-18 cells.ResultsThe FLDP-5 and FLDP-8 curcuminoid analogues induced LN-18 cell death through apoptosis in a concentration-dependent manner following 24 h of treatment. These analogues induced apoptosis in LN-18 cells through significant loss of mitochondrial mass and mitochondrial membrane potential (MMP) as early as 1-hour of treatment. Interestingly, N-acetyl-l-cysteine (NAC) pretreatment did not abolish the apoptosis induced by these analogues, further confirming the cell death process is independent of ROS. However, the apoptosis induced by the analogues is caspases-dependent, whereby pan-caspase pretreatment inhibited the curcuminoid analogues-induced apoptosis. The apoptotic cell death progressed with the activation of both caspase-8 and caspase-9, which eventually led to the activation of caspase-3, as confirmed by immunoblotting. Moreover, the existing over-expression of miRNA-21 in LN-18 cells was suppressed following treatment with both analogues, which suggested the down-regulation of the miRNA-21 facilitates the cell death process.ConclusionThe FLDP-5 and FLDP-8 curcuminoid analogues downregulate the miRNA-21 expression and induce extrinsic and intrinsic apoptotic pathways in LN-18 cells.

Optical signatures of cisplatin assembled with curcuminoids: Theoretical simulations to develop novel anticancer prodrugs

Curcuma derivatives are widely used as natural pigments in the food industry. Recent biological studies demonstrated that one of its major components, curcuminoids, might also positively impact human health. Herein, we use theoretical tools to combine cisplatin, the golden standard of chemotherapy, to curcuminoid analogues that have previously shown anticancer properties. Our goal is to rationalize the design of a series of prodrugs prone to be photo-activated by visible light. The simulations performed in this contribution disclose two novel complexes absorbing in the first phototherapeutic window, i.e., in the 600–800 nm domain. The optimizations of these structures within the framework of photoactivated chemotherapy are discussed.

Curcuminoid analogues with substituted naphthyl ring and their transition metal chelates- Antibacterial and Antitumor studies

Curcuminoid analogues with substituted naphthyl ring and their transition metal chelates- Antibacterial and Antitumor studies

Rational design, synthesis, and pharmacological characterisation of dicarbonyl curcuminoid analogues with improved stability against lung cancer via ROS and ER stress mediated cell apoptosis and pyroptosis

Curcumin is a natural medicine with a wide range of anti-tumour activities. However, due to β-diketone moiety, curcumin exhibits poor stability and pharmacokinetics which significantly limits its clinical applications. In this article, two types of dicarbonyl curcumin analogues with improved stability were designed through the calculation of molecular stability by density functional theory. Twenty compounds were synthesised, and their anti-tumour activity was screened. A plurality of analogues had significantly stronger activity than curcumin. In particular, compound B2 ((2E,2′E)-3,3′-(1,4-phenylene)bis(1-(2-chlorophenyl)prop-2-en-1-one)) exhibited excellent anti-lung cancer activity in vivo and in vitro. In addition, B2 could upregulate the level of reactive oxygen species in lung cancer cells, which in turn activated the endoplasmic reticulum stress and led to cell apoptosis and pyroptosis. Taken together, curcumin analogue B2 is expected to be a novel candidate for lung cancer treatment with improved chemical and biological characteristics.

Curcumin piperidone derivatives induce anti-proliferative and anti-migratory effects in LN-18 human glioblastoma cells

Curcumin has demonstrated potential cytotoxicity across various cell lines despite its poor bioavailability and rapid metabolism. Therefore, our group have synthesized curcuminoid analogues with piperidone derivatives, FLDP-5 and FLDP-8 to overcome these limitations. In this study, the analogues were assessed on LN-18 human glioblastoma cells in comparison to curcumin. Results from cytotoxicity assessment showed that FLDP-5 and FLDP-8 curcuminoid analogues caused death in LN-18 cells in a concentration-dependent manner after 24-h treatment with much lower IC50 values of 2.5 µM and 4 µM respectively, which were more potent compared to curcumin with IC50 of 31 µM. Moreover, a significant increase (p < 0.05) in the level of superoxide anion and hydrogen peroxide upon 2-h and 6-h treatment confirmed the oxidative stress involvement in the cell death process induced by these analogues. These analogues also showed potent anti-migratory effects through inhibition of LN-18 cells’ migration and invasion. In addition, cell cycle analysis showed that these analogues are capable of inducing significant (p < 0.05) S-phase cell cycle arrest during the 24-h treatment as compared to untreated, which explained the reduced proliferation indicated by MTT assay. In conclusion, these curcuminoid analogues exhibit potent anti-cancer effects with anti-proliferative and anti-migratory properties towards LN-18 cells as compared to curcumin.

Rational Design, Synthesis, and Pharmacological Characterization of Dicarbonyl Curcuminoid Analogs with Improved Stability Against Lung Cancer Via ROS and ER Stress Mediated Cell Apoptosis and Pyroptosis

Rational Design, Synthesis, and Pharmacological Characterization of Dicarbonyl Curcuminoid Analogs with Improved Stability Against Lung Cancer Via ROS and ER Stress Mediated Cell Apoptosis and Pyroptosis

Anti-Metastatic and Anti-Angiogenic Effects of Curcumin Analog DK1 on Human Osteosarcoma Cells In Vitro.

Osteosarcoma (OS) is a life-threatening malignant bone tumor associated with poor prognosis among children. The survival rate of the patient is still arguably low even with intensive treatment provided, plus with the inherent side effects from the chemotherapy, which gives more unfavorable outcomes. Hence, the search for potent anti-osteosarcoma agent with promising safety profile is still on going. Natural occurring substance like curcumin has gained a lot of attention due to its splendid safety profile as well as it pharmacological advantages such as anti-metastasis and anti-angiogenesis. However, natural curcumin was widely known for its poor cellular uptake, which undermines all potential that it possesses. This prompted the development of synthetically synthesized curcuminoid analog, known as (Z)-3-hydroxy-1-(2-hydroxyphenyl)-3-phenylprop-2- en-1-one (DK1). In this present study, in vitro scratch assay, transwell migration/invasion assay, HUVEC tube formation assay, and ex vivo rat aortic ring assays were performed in order to investigate the anti-metastatic and anti-angiogenic potential of DK1. For further comprehension of DK1 mechanism on human osteosarcoma cell lines, microarray gene expression analysis, quantitative polymerase chain reaction (qPCR), and proteome profiler were adopted, providing valuable forecast from the expression of important genes and proteins related to metastasis and angiogenesis. Based on the data gathered from the bioassays, DK1 was able to inhibit the metastasis and angiogenesis of human osteosarcoma cell lines by significantly reducing the cell motility, number of migrated and invaded cells as well as the tube formation and micro-vessels sprouting. Additionally, DK1 also has significantly regulated several cancer pathways involved in OS proliferation, metastasis, and angiogenesis such as PI3K/Akt and NF-κB in both U-2 OS and MG-63. Regulation of PI3K/Akt caused up-regulation of genes related to metastasis inhibition, namely, PTEN, FOXO, PLK3, and GADD45A. Meanwhile, NF-κB pathway was regulated by mitigating the expression of NF-κB activator such as IKBKB and IKBKE in MG-63, whilst up-regulating the expression of NF-κB inhibitors such as NFKBIA and NFKBIE in U-2 OS. Finally, DK1 also has successfully hindered the metastatic and angiogenic capability of OS cell lines by down-regulating the expression of pro-metastatic genes and proteins like MMP3, COL11A1, FGF1, Endoglin, uPA, and IGFBP2 in U-2 OS. Whilst for MG-63, the significantly down-regulated oncogenes were Serpin E1, AKT2, VEGF, uPA, PD-ECGF, and Endoglin. These results suggest that curcumin analog DK1 may serve as a potential new anti-osteosarcoma agent due to its anti-metastatic and anti-angiogenic attributes.

A Synthetic Curcuminoid Analogue, 2,6-Bis-4-(Hydroxyl-3-Methoxybenzylidine)-Cyclohexanone (BHMC) Ameliorates Acute Airway Inflammation of Allergic Asthma in Ovalbumin-Sensitized Mice.

2,6-Bis-(4-hydroxyl-3-methoxybenzylidine) cyclohexanone (BHMC), a synthetic curcuminoid analogue, has been shown to exhibit anti-inflammatory properties in cellular models of inflammation and improve the survival of mice from lethal sepsis. We further evaluated the therapeutic effect of BHMC on acute airway inflammation in a mouse model of allergic asthma. Mice were sensitized and challenged with ovalbumin (OVA), followed by intraperitoneal administration of 0.1, 1, and 10 mg/kg of BHMC. Bronchoalveolar lavage fluid, blood, and lung samples were collected, and the respiratory function was measured. OVA sensitization and challenge increased airway hyperresponsiveness (AHR) and pulmonary inflammation. All three doses of BHMC (0.1-10 mg/kg) significantly reduced the number of eosinophils, lymphocytes, macrophages, and neutrophils, as well as the levels of Th2 cytokines (IL-4, IL-5 and IL-13) in bronchoalveolar lavage fluid (BALF) as compared to OVA­challenged mice. However, serum level of IgE was not affected. All three doses of BHMC (0.1-10 mg/kg) were effective in suppressing the infiltration of inflammatory cells at the peribronchial and perivascular regions, with the greatest effect observed at 1 mg/kg which was comparable to dexamethasone. Goblet cell hyperplasia was inhibited by 1 and 10 mg/kg of BHMC, while the lowest dose (0.1 mg/kg) had no significant inhibitory effect. These findings demonstrate that BHMC, a synthetic nonsteroidal small molecule, ameliorates acute airway inflammation associated with allergic asthma, primarily by suppressing the release of inflammatory mediators and goblet cell hyperplasia to a lesser extent in acute airway inflammation of allergic asthma.

Cytotoxicity and Apoptosis Effects of Curcumin Analogue (2E,6E)-2,6-Bis(2,3-Dimethoxybenzylidine) Cyclohexanone (DMCH) on Human Colon Cancer Cells HT29 and SW620 In Vitro.

Colorectal cancer (CRC) is the third most common type of cancer worldwide and a leading cause of cancer death. According to the Malaysian National Cancer Registry Report 2012–2016, colorectal cancer was the second most common cancer in Malaysia after breast cancer. Recent treatments for colon cancer cases have caused side effects and recurrence in patients. One of the alternative ways to fight cancer is by using natural products. Curcumin is a compound of the rhizomes of Curcuma longa that possesses a broad range of pharmacological activities. Curcumin has been studied for decades but due to its low bioavailability, its usage as a therapeutic agent has been compromised. This has led to the development of a chemically synthesized curcuminoid analogue, (2E,6E)-2,6-bis(2,3-dimethoxybenzylidine) cyclohexanone (DMCH), to overcome the drawbacks. This study aims to examine the potential of DMCH for cytotoxicity, apoptosis induction, and activation of apoptosis-related proteins on the colon cancer cell lines HT29 and SW620. The cytotoxic activity of DMCH was evaluated using the [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) cell viability assay on both of the cell lines, HT29 and SW620. To determine the mode of cell death, an acridine orange/propidium iodide (AO/PI) assay was conducted, followed by Annexin V/FITC, cell cycle analysis, and JC-1 assay using a flow cytometer. A proteome profiler angiogenesis assay was conducted to determine the protein expression. The inhibitory concentration (IC50) of DMCH in SW620 and HT29 was 7.50 ± 1.19 and 9.80 ± 0.55 µg/mL, respectively. The treated cells displayed morphological features characteristic of apoptosis. The flow cytometry analysis confirmed that DMCH induced apoptosis as shown by an increase in the sub-G0/G1 population and an increase in the early apoptosis and late apoptosis populations compared with untreated cells. A higher number of apoptotic cells were observed on treated SW620 cells as compared to HT29 cells. Human apoptosis proteome profiler analysis revealed upregulation of Bax and Bad proteins and downregulation of Livin proteins in both the HT29 and SW620 cell lines. Collectively, DMCH induced cell death via apoptosis, and the effect was more pronounced on SW620 metastatic colon cancer cells, suggesting its potential effects as an antimetastatic agent targeting colon cancer cells.

1,7‑Bis(4‑hydroxy‑3‑methoxyphenyl)‑1,4,6‑heptatrien‑3‑one alleviates lipopolysaccharide‑induced inflammation bytargeting NF‑κB translocation in murinemacrophages and it interacts with MD2 in silico.

Trienones are curcuminoid analogues and are minor constituents in the rhizomes of numerous Curcuma plant species. Studies investigating the biological activities of trienones, particularly their anti‑inflammatory activities, are limited. In the present study, the trienone 1,7‑bis(4‑hydroxy‑3‑methoxyphenyl)‑1,4,6‑heptatrien‑3‑one(HMPH) was structurally modified from curcumin using a novel and concise method. HMPH was shown to exhibit potential anti‑inflammatory effects on lipopolysaccharide(LPS)‑activated RAW264.7 macrophages. Furthermore, LPS‑induced nitric oxide secretion in RAW264.7 cells was markedly and dose‑dependently inhibited by HMPH; in addition, HMPH had a greater efficacy compared with curcumin. This inhibition was accompanied by the suppression of inducible nitric oxide synthase and cyclooxygenase‑2 expression, as well as pro‑inflammatory cytokine secretion. To elucidate the molecular mechanism underlying the anti‑inflammatory effects of HMPH, the effects of this compound on nuclear factor‑κB(NF‑κB) translocation were assessed. HMPH significantly inhibited the translocation of p65 NF‑κB into the nucleus to a greater extent than curcumin, thus indicating that HMPH has more potent anti‑inflammatory activity than curcumin. In addition, an insilico modelling study revealed that HMPH possessed stronger binding energy to myeloid differentiation factor2(MD2) compared with that of curcumin, and indicated that the anti‑inflammatory effects of HMPH may be through upstream inhibition of the inflammatory pathway. In conclusion, HMPH may be considered a promising compound for reducing inflammation via targeting p65 NF‑κB translocation and interfering with MD2 binding.

Curcuminoid analogs, a novel class of drugs for the treatment of Glioblastoma multiforme

Glioblastoma multiforme is one of the glial‐derived malignant primary brain tumors in adults with a poor prognosis. The average survival period still remains between 14–16 months despite various treatment modalities involving combination of surgery, radiotherapy and chemotherapy with temozolomide, an imidazotetrazine derivative. Curcumin (#1) is a plant derived dietary constituent, and has been shown to play a role in preventing many cancers. We investigated for the first time the potencies and the molecular mechanisms of action of #1 and its three synthetic analogs (#7, #20, and #32) that were prepared through an acid catalyzed condensation with various hydrazine derivatives. Cultures of grade IV glioblastoma multiforme (GBM) MG118 cells (5,000/cm2) were treated with various concentrations (0.01–100μmole) of #1, #7, #20 or #32 for 24 hr. along with temozolomide (0.1–300μmole) as positive control. Cell viability/toxicity was assessed by Cell Titer Glo 2.0 Assay, and by the fluorescent dyes Hoechst 33342/Propidium iodide‐based live‐dead cell assay. Apoptosis was directly assessed by TACS Annexin V‐FITC Apoptosis detection kit. Concurrently, we measured the effects of these analogs on the expression of pro‐angiogenic HIF1α, VEGF, and chemokine receptor 4 (CXCR4) by western blotting analyses and quantitated using GAPDH loading controls. Additionally, we formulated curcuminoid‐loaded nanoparticles &amp; optimized it using Design Expert (DoE) software and then evaluated the prepared formulation for determining the cytotoxic effects in GBM. Our results show that the tested analogs dose‐dependently caused apoptosis, decreased cell viability and inhibited cell proliferation in the order #32&gt; #20&gt; #7&gt; #1&gt;&gt;temozolamide, suggesting that synthetic cucuminoids 32 and 20 are more potent than their parent compound and the current drug temozolomide. Additionally, we noted that these two analogs down‐regulated the expression of VEGF, and anti‐hypoxic HIF1α, and the chemokine receptor CXCR4 a known mediator of cancer cell proliferation and invasion. Thus our preclinical results demonstrate that compounds 32 and 20 may be two novel class of drugs for the treatment of GBM by down‐regulation of key targets that are critical for GBM survival and metastasis.Support or Funding InformationPartial support from an Institutional grant (ACS), and a grant from NIMHD/NIH #2G12MD007605 (KR).

A Synthetic Curcuminoid Analog, (2E,6E)-2,6-bis(2-(trifluoromethyl)benzylidene)cyclohexanone, Ameliorates Impaired Wound Healing in Streptozotocin-Induced Diabetic Mice by Increasing miR-146a.

The impairment in diabetic wound healing represents a significant clinical problem, with no efficient targeted treatments for these wound disorders. Curcumin is well confirmed to improve diabetic wound healing, however, its low bioavailability and poor solubility severely limit its clinical application. This study aims to provide the pharmacological basis for the use of (2E,6E)-2,6-bis(2-(trifluoromethyl)benzylidene)cyclohexanone (C66). The results showed that topically applied C66 improved cutaneous wound healing in vivo. Further studies showed that C66 treatment increased the level of microRNA-146a (miR-146a) in the wounds in streptozotocin (STZ)-induced diabetic mice, downregulated the expression of interleukin-1 receptor-associated kinase 1 (IRAK1) and phosphorylated nuclear factor-κB (NF-κB) p65 subunit (p-p65) (both p < 0.05), and suppressed the mRNA expression of inflammation-related cytokines, tumor necrosis factor-α (TNF-α), interleukin-8 (IL-8), and interleukin-6 (IL-6). The in vitro data obtained in human umbilical vein endothelial cells (HUVECs) showed that C66 could reverse high glucose (HG)-induced NF-κB activation due to upregulation of miR-146a expression, which matched the in vivo findings. In conclusion, the present study indicates that C66 exerts anti-inflammation activity and accelerates skin wound healing of diabetic mice, probably via increasing miR-146a and inhibiting the NF-κB-mediated inflammation pathway. Therefore, C66 may be a promising alternative for the treatment of diabetic wounds.

Novel drug isolated from mistletoe (1E,4E)-1,7-bis(4-hydroxyphenyl)hepta-1,4-dien-3-one for potential treatment of various cancers: synthesis, pharmacokinetics and pharmacodynamics.

(1E,4E)-1,7-Bis(4-hydroxyphenyl)hepta-1,4-dien-3-one (DHDK) is a novel curcuminoid analogue isolated from mistletoe. DHDK exhibits better anti-tumour activity, higher bioavailability and superior stability than curcumin. DHDK is difficult to isolate from Viscum coloratum, but it can be synthesised. MTT (methylthiazolyldiphenyl tetrazolium bromide) assay was used to evaluate the in vitro cytotoxic activity of synthesised DHDK on 12 cancer cell lines. Results showed that DHDK exhibited excellent potential as an anticancer agent, especially for breast and lung cancer. Efficacy was further evaluated in vivo by using MCF-7 breast cancer models. DHDK showed a dose-dependent relationship without weight reduction, mortality growth inhibition or tissue toxicity. Pharmacokinetics and tissue distribution statistics were determined by LC-ESI-MS/MS. This work provided preliminary data on this natural compound and could open up new prospects for changing related parameters to improve drug efficacy.

Calebin-A, a Curcuminoid Analog Inhibits α-MSH-Induced Melanogenesis in B16F10 Mouse Melanoma Cells

Hyperpigmentation skin disorders comprise melasma, age spots, and post-inflammatory hyperpigmentation. They are characterized by an aberrant upregulation of melanin pigment and pose a significant burden aesthetically. Calebin-A (CBA) is a natural curcuminoid analog derived from turmeric root (Curcuma longa) but, unlike curcumin, it has not been explored yet for anti-melanogenic activity. Hence, in the current study, we studied CBA for its effects on α-melanocyte stimulating hormone (αMSH)-stimulated melanogenesis in B16F10 mouse melanoma cells. Our results showed that CBA (20 μM) significantly suppressed αMSH-stimulated melanogenesis after 48 h treatment. The underlying mechanisms of CBA’s anti-melanogenic activity were studied, and it was shown that CBA did not affect either intracellular tyrosinase activity or the direct activity of tyrosinase enzyme. Additionally, CBA did not affect intracellular α-glucosidase activity but significantly inhibited direct α-glucosidase activity. CBA also directly scavenged 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radicals, consistent with potent antioxidant activity but did not inhibit intracellular reactive oxygen species (ROS). CBA increased acidification of cellular organelles and inhibited maturation of melanosomes by significantly reducing the number of mature melanosomes. Our results indicate that CBA may hold promise as a pigmentation inhibitor for hyperpigmentation disorders for cosmetic use by targeting pathways other than tyrosinase inhibition. Further studies to delineate the molecular signaling mechanism of melanogenesis inhibition and test anti-melanogenesis efficacy of CBA in human skin melanocytes and skin equivalents are warranted.

Curcuminoid Analogs Differentially Modulate Nuclear Factor Kappa-Light-Chain-Enhancer, P65 Serine276, Mitogen- and Stress-activated Protein Kinase 1 And MicroRNA 148a Status

Background: Curcumin has been used successfully to treat inflammatory conditions; however, reliability and repeatability of clinical and bench research results have been a challenge. Curcumin is comprised of 3 curcuminoid analogs that can vary in proportion from one extract to another, even from batch to batch from the same commercial supplier. A better understanding of how each curcuminoid analog comprising the curcumin extract can partake in the overall curcumin pharmacology might give us better insight on the polypharmacology involved. Methods/Results: Applied as pretreatment drugs, all 3 curcuminoids, curcumin I (diferuloylmethane), curcumin II (demethoxycurcumin), and curcumin III (bisdemthoxycurcumin), are shown here to modulate 3 key subcellular drug targets differentially. Nucleotranslocation by the curcuminoids is not apparent in the lipopolysaccharide-induced BV2 (immortalised murine microglial cell line) cells. At a nuclear level, multiple compounding findings related to curcumin pharmacology, regulate transactivation of the Nuclear Factor kappa-light-chain-enhancer (NF-kB) heterodimer once it has translocated. Each of the 3 curcuminoid analogs seems to inhibit phosphorylation of p65 (REL-associated protein involved in NF-κB protein formation) at residue serine276 of the transcription factor’s transactivation domain with curcumin I showing a significant hindrance. On the other hand, curcumin III and not curcumins I or II is found to significantly downregulate mitogen- and stress-activated protein kinase 1 status in both the cytosol and the nucleus of these cells. The upstream mechanism repressing mitogen- and stress-activated protein kinase 1 status is also shown to be the upregulation of MIR 148a by curcumin III. Curcumin II shows downregulatory activity of microRNA (MIR) 148a in opposition to curcumin III’s upregulatory activity; whereas curcumin I remains neutral with regards to this target. Conclusions: These results demonstrate that although there are some common targets and biochemical activity by the curcuminoid analogs, a differential activity by each can also be observed on other targets. These new findings show us that the common curcumin extract can be utilized with greater selectivity against specific drug targets and the associated disease pathologies. It also demonstrates the importance of establishing a standardization process that takes into account these curcuminoid proportions with the objective of improving reliability of pharmacology and repeatability of research outcomes.

Anti-Edematogenic and Anti-Granuloma Activity of a Synthetic Curcuminoid Analog, 5-(3,4-Dihydroxyphenyl)-3-hydroxy-1-(2-hydroxyphenyl)penta-2,4-dien-1-one, in Mouse Models of Inflammation.

Curcumin, derived from the rhizome Curcuma longa, has been scientifically proven to possess anti-inflammatory activity but is of limited clinical and veterinary use owing to its low bioavailability and poor solubility. Hence, analogs of curcuminoids with improved biological properties have been synthesized to overcome these limitations. This study aims to provide the pharmacological basis for the use of 5-(3,4-dihydroxyphenyl)-3-hydroxy-1-(2-hydroxyphenyl)penta-2,4-dien-1-one (DHHPD), a synthetic curcuminoid analog, as an anti-edematogenic and anti-granuloma agent. The carrageenan-induced paw edema and the cotton pellet-induced granuloma assays were used to assess the anti-inflammatory activity of DHHPD in mice. The effects of DHHPD on the histaminergic, serotonergic, and bradykininergic systems were determined by the histamine-, serotonin-, and bradykinin-induced paw edema tests, respectively. DHHPD (0.1, 0.3, 1, and 3 mg/kg, intraperitoneal) evoked significant reductions (p < 0.05) in carrageenan-induced paw edema at different time intervals and granuloma formation (p < 0.0001) by 22.08, 32.57, 37.20, and 49.25%, respectively. Furthermore, DHHPD significantly reduced paw edema (p < 0.05) induced by histamine, serotonin, and bradykinin. The present study suggests that DHHPD exerts anti-edematogenic activity, possibly by inhibiting the synthesis or release of autacoid mediators of inflammation through the histaminergic, serotonergic, and bradykininergic systems. The anti-granuloma effect may be attributed to the suppression of transudative, exudative, and proliferative activities associated with inflammation.

Synthetic curcuminoid analogues abrogate oxidationinduced cell death and promote myogenic differentiation of C2C12 mouse myoblasts

Purpose: To investigate the ability of two synthetic curcuminoid analogues, 6-(4-hydroxy-3-methoxyphenethyl)-5-(3-(4-hydroxy-3-methoxyphenyl)propanoyl)-4-phenyl-3,4-dihydropyrimidin-2(1H)-one (compound A) and 6-(4-hydroxy-3-methoxyphenethyl)-4-(4-hydroxy-3-methoxyphenyl)-5-(3-(4- hydroxy-3-methoxyphenyl)propanoyl)-3,4-dihydropyrimidin-2(1H)-one (compound B), to protect against oxidation-induced cell death and the potential to enhance proliferation and differentiation of C2C12 myoblast cells.Methods: Antioxidant activity of curcuminoid analogues was evaluated by DPPH assay. The cytotoxic activity of the compounds (0 - 25 mM) on C2C12 myoblasts was determined by MTT assay while the effect on cell proliferation was assessed by BrdU uptake. Myoblast cell differentiation was measured by the formation of myotubes and myosin heavy chain (MHC) protein expression using immunofluorescence staining and Western blotting, respectively.Results: Both curcuminoid analogues exhibited strong anti-oxidant activity of up to 3-fold greater than that of ascorbic acid, and were non-toxic to C2C12 myoblasts at concentrations up to 25 mM. Furthermore, these curcuminoid analogues mitigated myoblast cell death induced by oxidative stress. Notably, both analogues (10 nM) had no effect on cell proliferation. However, only compound A significantly enhanced myoblast differentiation comparable to the effects of dihydrotestosterone (1 μM) and estradiol (10 nM).Conclusion: The results suggest that compound A may serve as a lead compound for the development of suitable therapeutic agents for muscle injuries and diseases.Keywords: Curcuminoid analogues, Antioxidant, Cell proliferation, Cell differentiation, Myoblasts

Analgesic Effect of 5-(3,4-Dihydroxyphenyl)-3-hydroxy-1-(2-hydroxyphenyl)penta-2,4-dien-1-one in Experimental Animal Models of Nociception

Curcuminoids derived from turmeric rhizome have been reported to exhibit antinociceptive, antioxidant and anti-inflammatory activities. We evaluated the peripheral and central antinociceptive activities of 5-(3,4-dihydroxyphenyl)-3-hydroxy-1-(2-hydroxyphenyl)penta-2,4-dien-1-one (DHHPD), a novel synthetic curcuminoid analogue at 0.1, 0.3, 1 and 3 mg/kg (intraperitoneal), through chemical and thermal models of nociception. The effects of DHHPD on the vanilloid and glutamatergic systems were evaluated through the capsaicin- and glutamate-induced paw licking tests. Results showed that DHHPD significantly (p < 0.05) attenuated the writhing response produced by the 0.8% acetic acid injection. In addition, 1 and 3 mg/kg of DHHPD significantly (p < 0.05) reduced the licking time spent by each mouse in both phases of the 2.5% formalin test and increased the response latency of mice on the hot-plate. However, the effect produced in the latter was not reversed by naloxone, a non-selective opioid receptor antagonist. Despite this, DHHPD decreased the licking latency of mice in the capsaicin- and glutamate-induced paw licking tests in a dose response manner. In conclusion, DHHPD showed excellent peripheral and central antinociceptive activities possibly by attenuation of the synthesis and/or release of pro-inflammatory mediators in addition to modulation of the vanilloid and glutamatergic systems without an apparent effect on the opioidergic system.

The Molecular Targets and Anti-Invasive Effects of 2,6-bis-(4-hydroxyl-3methoxybenzylidine) cyclohexanone or BHMC in MDA-MB-231 Human Breast Cancer Cells.

In order to metastasize, tumor cells need to migrate and invade the surrounding tissues. It is important to identify compound(s) capable of disrupting the metastasis of invasive cancer cells, especially for hindering invadopodia formation, so as to provide anti-metastasis targeted therapy. Invadopodia are thought to be specialized actin-rich protrusions formed by highly invasive cancer cells to degrade the extracellular matrix (ECM). A curcuminoid analogue known as 2,6-bis-(4-hydroxy-3-methoxybenzylidine)cyclohexanone or BHMC has shown good potential in inhibiting inflammation and hyperalgesia. It also possesses an anti-tumor effects on 4T1 murine breast cancer cells in vivo. However, there is still a lack of empirical evidence on how BHMC works in preventing human breast cancer invasion. In this study, we investigated the effect of BHMC on MDA-MB-231 breast cancer cells and its underlying mechanism of action to prevent breast cancer invasion, especially during the formation of invadopodia. All MDA-MB-231 cells, which were exposed to the non-cytotoxic concentrations of BHMC, expressed the proliferating cell nuclear antigen (PCNA), which indicate that the anti-proliferative effects of BHMC did not interfere in the subsequent experiments. By using a scratch migration assay, transwell migration and invasion assays, we determined that BHMC reduces the percentage of migration and invasion of MDA-MB-231 cells. The gelatin degradation assay showed that BHMC reduced the number of cells with invadopodia. Analysis of the proteins involved in the invasion showed that there is a significant reduction in the expressions of Rho guanine nucleotide exchange factor 7 (β-PIX), matrix metalloproteinase-9 (MMP-9), and membrane type 1 matrix metalloproteinase (MT1-MMP) in the presence of BHMC treatment at 12.5 µM. Therefore, it can be postulated that BHMC at 12.5 µM is the optimal concentration for preventing breast cancer invasion.