Germacrene Analogs are Anti-androgenic on Androgen-dependent Cells

Anti-androgenic drugs are treatments for androgen-related disorders such as benign prostatic hyperplasia, acne, hirsutism, and androgenic alopecia. Germacrone (1), a sesquiterpene isolated from hexane extracts of Curcuma aeruginosa Roxb. rhizome, is an androgen inhibitor of steroid 5-alpha reductase in-vitro. Here, we used the similarity of germacrone's α,ß-unsaturated carbonyl to testosterone's α,ß-unsaturated carbonyl to find germacrene analogs obtained from this plant and by semi-synthesis that might be more potent steroid 5-alpha reductase inhibitors. 8-Hydroxy germacrene B (4) was ~13-fold more potent than its parent, 1 and the most potent (IC50, 0.15±0.022 mM) among 9 compounds tested. The conformation of its cyclodecadiene ring and the α,ß-unsaturated ketone/hydroxy in the germacrene molecule might be crucial role for its anti-androgen activity. Moreover, 1 and 4 showed mild cytotoxic effect on prostate cancer cells. Neither compound was cytotoxic towards human dermal papilla cells at 100 μg/mL. We show that this SAR strategy created promising anti-androgenics for androgen dependent disorders and may create further analogues with further improvements in selectivity and clinical efficacy.

Germacrene Analogs are Anti-androgenic on Androgen-dependent Cells

Anti-androgenic drugs are treatments for androgen-related disorders such as benign prostatic hyperplasia, acne, hirsutism, and androgenic alopecia. Germacrone (1), a sesquiterpene isolated from hexane extracts of Curcuma aeruginosa Roxb. rhizome, is an androgen inhibitor of steroid 5-alpha reductase in- vitro. Here, we used the similarity of germacrone's ,t,B-unsaturated carbonyl to testosterone's α,β-unsaturated carbonyl to find germacrene analogs obtained from this plant and by semi-synthesis that might be more potent steroid 5-alpha reductase inhibitors. 8-Hydroxy germacrene B (4) was -13-fold more potent than its parent, I and the most potent (ICso, 0.15 ± 0.022 mM) among 9 compounds tested. The conformation of its cyclodecadiene ring and the α,β-unsaturated ketone/hydroxy in the germacrene molecule might be crucial role for its anti-androgen activity. Moreover, I and 4 showed mild cytotoxic effect on prostate cancer cells. Neither compound was cytotoxic towards human dermal papilla cells at 100 μg/mL. We show that this SAR strategy created promising anti-androgenics for androgen dependent disorders and may create further analogues with further improvements in selectivity and clinical efficacy.

Synergistic effect of atorvastatin and Cyanidin-3-glucoside on angiotensin II-induced inflammation in vascular smooth muscle cells

Statins have often been used in atherosclerosis treatment because of its pleiotropic effects on inflammation. However, some adverse effects of high doses of statin show reverse effects after withdrawal. Cyanidin-3-glucoside (C3G) is a powerful anti-inflammation and antioxidant that has been of interest for use in combination with low doses of statin, which may be alternative treatment for atherosclerosis. The objective is to investigate the synergistic effect of atorvastatin and C3G in angiotensin II (Ang II)-induced inflammation in vascular smooth muscle cells. Human aortic smooth muscle cells (HASMCs) were exposed to Ang II with or without atorvastatin and C3G alone, or in combination. The results revealed that the combination of atorvastatin and C3G produces synergism against inflammation and oxidative stress. The mechanism of the combination of atorvastatin and C3G suppressed the translocation of the p65 subunit of NF-κB from cytosol to nucleus, and attenuated the expression of proteins including inducible nitric oxide synthase, intracellular adhesion molecule 1(ICAM-1), and vascular cell adhesion molecule 1(VCAM-1), in addition to nitric oxide (NO) production. Moreover, C3G exerts the antioxidative properties of atorvastatin through down-regulating NOX1 and promoting the activity of the Nrf2(-)ARE signaling pathway and downstream proteins including heme oxygenase (HO-1), NAD(P)H:quinoneoxidoreductase 1 (NQO-1), and glutamate-cysteine ligase catalytic subunit (γ-GCLC), besides increasing the activity of superoxide dismutase (SOD) enzymes. Taken together, these results suggest that a combination of low dose statins and C3G might serve as a potential regulator of the atherosclerosis process which is mediated by attenuating oxidative stress, thereby inhibiting NF-κB and activating Nrf2 signaling pathways induced by Ang II.

Ethyl rosmarinate relaxes rat aorta by an endothelium-independent pathway

Ethyl rosmarinate is an ester derivative of rosmarinic acid, a major constituent of Hyptis suaveolens. The present study investigated the vasorelaxant mechanism of ethyl rosmarinate in isolated rat aortic rings using an organ bath system. Ethyl rosmarinate (0.1 µM-3mM) produced concentration-dependent relaxation in aortic rings pre-contracted with phenylephrine (10 µM), exhibiting a pD2 value of 4.56 ± 0.08 and an Emax value of 93.82 ± 5.00% (in endothelium-intact rings), as well as a pD2 value of 4.42 ± 0.05 and an Emax value of 92.10 ± 3.78% (in endothelium-denuded rings). In the endothelium-denuded rings, the vasorelaxant effect of ethyl rosmarinate was reduced by only 4-aminopyridine (1mM); however, this was not the case with tetraethylammonium (5mM), glibenclamide (10 µM), barium chloride (1mM), and 1H-[1,2,4] oxadiazolo [4,3-a]quinoxalin-1-one (ODQ, 1 µM). Ethyl rosmarinate also reduced the contraction induced by phenylephrine (10 µM) and caffeine (20mM) in a Ca(2+)-free solution, and inhibited the contraction induced by increasing extracellular Ca(2+) influx, which was induced by KCl (80 mM). Ethyl rosmarinate (10 µM) inhibits concentration-response curves for phenylephrine, while in the same concentration of ethyl rosmarinate has no effect on contractions induced by increasing concentrations of calcium in the presence of high extracellular potassium. Our results suggests that ethyl rosmarinate induces relaxation in aortic rings via an endothelium-independent pathway, which involves the opening of voltage-gated potassium (Kv) channels and the blockade of both Ca(2+)release from intracellular stores and extracellular Ca(2+) influx. Moreover, ethyl-rosmarinate acts on the extracellular Ca(2+) influx inhibition by interacting with voltage-operated calcium channels (VOCCs) and receptor-operated calcium channels (ROCCs).

Coumarins and flavonoid from Murraya paniculata (L.) Jack: Antibacterial and anti-inflammation activity

The ethyl acetate extract of leaves of Murraya paniculata (L.) Jack was described in the previous in vitro study on the inhibition effect on the growth of periodontopathic bacteria and the reduction of cytokines from LPS-stimulated macrophages. In this study, four coumarins including murrangatin (1), murrangatin acetate (2), murranganonesenecionate (3), micropubescin (4) and one flavonoid, 3', 4', 5', 7-tetramethoxyflavone (5) were isolated from the leaves of ethyl acetate extract of M. paniculata. MTT assay was used to test cytotoxicity on human gingival fibroblast and monocytes. The isolated compounds were evaluated for their antibacterial effect against Porphyromonas gingivalis (ATCC33277) and anti-inflammation on lipopolysaccharide-stimulated inflammation using monocyte cells. All isolated compounds exhibited antibacterial activity against P. gingivalis (ATCC 33277). Murranganonesenecionate (3) was highly potent anti-inflammation properties. The coumarin constituents from M. paniculata leaves might be potential lead molecules for the development of antimicrobial drugs for treating periodontal disease.

Protective effect of diarylheptanoids from Curcuma comosa on primary rat hepatocytes against t-butyl hydroperoxide-induced toxicity

CONTEXT

Curcuma comosa Roxb. (Zingiberaceae) has traditionally been used as an anti-inflammatory agent in liver, and recent study has shown its hepatoprotective effect against CCl4-induced liver injury in vivo.

OBJECTIVE

This study further assesses the protective effect of C. comosa extracts and its isolated compounds against tert-butyl hydroperoxide (t-BHP)-induced hepatotoxicity in isolated primary rat hepatocytes.

MATERIALS AND METHODS

Isolated primary hepatocytes were pretreated with either ethanol (5-50 μg/ml) or hexane extract (1-50 μg/ml), or two diarylheptanoids (4-35 μM): compound D-91 [1-(4-hydroxyphenyl)-7-phenyl-(6E)-6-hepten-3-ol] and compound D-92 [(3S)-1-(3,4-dihydroxyphenyl)-7-phenyl-(6E)-6-hepten-3-ol], from C. comosa for 2 h prior to exposure to 1.5 mM t-BHP for 15 and 30 min. Their hepatoprotective activities were then determined.

RESULTS

t-BHP markedly caused the formation of MDA and ALT leakage from the hepatocytes. Pretreatment with the C. comosa ethanol extract showed greater protective effect than the hexane extract, and the effect was concentration related. Treating the hepatocytes with compound D-92 provided greater protective effect than compound D-91. IC50 values of compounds D-91, D-92, and silymarin for the protection of ALT leakage at 30 min were 32.7 ± 1.1, 9.8 ± 0.7, and 160 ± 8 μM, respectively. Further investigation showed that compound D-92 was more effective in maintaining the intracellular glutathione content in the t-BHP treated group, whereas the reduction in antioxidant enzymes, glutathione peroxidase and glutathione-S-transferase activities, were not improved.

DISCUSSION AND CONCLUSION

Results suggest that diarylheptanoids are the active principles that provide protection against t-BHP-induced injury. Their ability to maintain intracellular glutathione content is the main mechanisms underlying the protective action.

Suppression effects of O-demethyldemethoxycurcumin on thapsigargin triggered on endoplasmic reticulum stress in SK-N-SH cells

Endoplasmic reticulum (ER) stress is involved in neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease. Therefore, interventions that attenuate ER stress may contribute to induction in apoptotic cell death. This study aimed to evaluate the potential involvement of O-demethyldemethoxycurcumin, an analog of curcuminoids, on thapsigargin-induced apoptosis in cultured neuroblastoma (SK-N-SH) cells through the ER stress signaling pathway. The results showed that O-demethyldemethoxycurcumin reduced thapsigargin induced cell death in SK-N-SH cells and the release of lactate dehydrogenase (LDH) by decreasing the apoptotic cell death induced by thapsigargin. Consistent with these findings, O-demethyldemethoxycurcumin inhibited the thapsigargin-induced activation of cleavagecaspase-12. Moreover, O-demethyldemethoxycurcumin attenuated the intracellular Ca(2+) level and the expression of the calpain protein. O-demethyldemethoxycurcumin also downregulated the expression of ER stress signaling proteins, including the phosphorylation of PKR-like endoplasmic reticulum kinase (p-PERK), the phosphorylation of inositol-requiring enzyme 1 (p-IRE1), activating transcription factor 6 (ATF6), binding immunoglobulin protein (BiP) and C/EBP homologous protein (CHOP). Our findings suggest that O-demethyldemethoxycurcumin could protect against thapsigargin-induced ER stress in SK-N-SH cells.

Development of phenotypic and transcriptional biomarkers to evaluate relative activity of potentially estrogenic chemicals in ovariectomized mice

BACKGROUND

Concerns regarding potential endocrine-disrupting chemicals (EDCs) have led to a need for methods to evaluate candidate estrogenic chemicals. Our previous evaluations of two such EDCs revealed a response similar to that of estradiol (E2) at 2 hr, but a less robust response at 24 hr, similar to the short-acting estrogen estriol (E3).

OBJECTIVES

Microarray analysis using tools to recognize patterns of response have been utilized in the cancer field to develop biomarker panels of transcripts for diagnosis and selection of treatments most likely to be effective. Biological effects elicited by long- versus short-acting estrogens greatly affect the risks associated with exposures; therefore, we sought to develop tools to predict the ability of chemicals to maintain estrogenic responses.

METHODS

We used biological end points in uterine tissue and a signature pattern-recognizing tool that identified coexpressed transcripts to develop and test a panel of transcripts in order to classify potentially estrogenic compounds using an in vivo system. The end points used are relevant to uterine tissue, but the resulting classification of the compounds is important for other sensitive tissues and species.

RESULTS

We evaluated biological and transcriptional end points with proven short- and long-acting estrogens and verified the use of our approach using a phytoestrogen. With our model, we were able to classify the diarylheptanoid D3 as a short-acting estrogen.

CONCLUSIONS

We have developed a panel of transcripts as biomarkers which, together with biological end points, might be used to screen and evaluate potentially estrogenic chemicals and infer mode of activity.

Diarylheptanoids of Curcuma comosa with inhibitory effects on nitric oxide production in macrophage RAW 264.7 cells

Eight new diarylheptanoids, a 1.2:1 mixture of (3S)- and (3R)-1-(4-hydroxyphenyl)-7-phenyl-(4E,6E)-4,6-heptadien-3-ol (1a and 1b), a racemic mixture of (3S)- and (3R)-1-(4-hydroxyphenyl)-3-methoxy-7-phenyl-(4E,6E)-4,6-heptadiene (2a and 2b), a ca. 1:1 mixture of (3S)- and (3R)-1-(4-hydroxy-3- methoxyphenyl)-3-methoxy-7-phenyl)-(4E,6E)-4,6-heptadiene (3a and 3b), 3-acetoxy-1-(3,4-dihydroxyphenyl)-7-phenylheptan-5-ol (4), (3R)-1-(4,5- dihydroxyphenyl)-7-phenyl-(6E)-6-hepten-3,2'-epoxide (5), and thirteen known diarylheptanoids, 6-12, a 3:1 mixture of 13a and 13b, and 14-17, were isolated from the rhizomes of Curcuma comosa from Sakon Nakhon, northeastern part of Thailand. The isolated compounds were evaluated for their anti- inflammatory activities on the inhibition of lipopolysaccharide-induced nitric oxide production in macrophage RAW 264.7 cells and the diarylheptanoids 1a and 1b mixture and 14 exhibited potent inhibitory activity.

Diarylheptanoids of Curcuma comosa with Inhibitory Effects on Nitric Oxide Production in Macrophage RAW 264.7 Cells

Eight new diarylheptanoids, a 1.2:1 mixture of (3S)- and (3 R)-1-(4-hydroxyphenyl)-7-phenyl-(4 E,6 E)-4,6-heptadien-3-ol (1a and 1b), a racemic mixture of (3S)- and (3 R)-1-(4-hydroxyphenyl)-3-methoxy-7-phenyl-(4 E,6 E)-4,6-heptadiene (2a and 2b), a ca. 1:1 mixture of (3S)- and (3 R)-1-(4-hydroxy-3-methoxyphenyl)-3-methoxy-7-phenyl)-(4 E,6 E)-4,6-heptadiene (3a and 3b), 3-acetoxy-1-(3,4-dihydroxyphenyl)-7-phenylheptan-5-ol (4), (3 R)-1-(4,5-dihydroxyphenyl)-7-phenyl-(6 E)-6-hepten-3,2′-epoxide (5), and thirteen known diarylheptanoids, 6-12, a 3:1 mixture of 13a and 13b, and 14-17, were isolated from the rhizomes of Curcuma comosa from Sakon Nakhon, northeastern part of Thailand. The isolated compounds were evaluated for their antiinflammatory activities on the inhibition of lipopolysaccharide-induced nitric oxide production in macrophage RAW 264.7 cells and the diarylheptanoids 1a and 1b mixture and 14 exhibited potent inhibitory activity.

Potent trypanocidal curcumin analogs bearing a monoenone linker motif act on trypanosoma brucei by forming an adduct with trypanothione

We have previously reported that curcumin analogs with a C7 linker bearing a C4-C5 olefinic linker with a single keto group at C3 (enone linker) display midnanomolar activity against the bloodstream form of Trypanosoma brucei. However, no clear indication of their mechanism of action or superior antiparasitic activity relative to analogs with the original di-ketone curcumin linker was apparent. To further investigate their utility as antiparasitic agents, we compare the cellular effects of curcumin and the enone linker lead compound 1,7-bis(4-hydroxy-3-methoxyphenyl)hept-4-en-3-one (AS-HK014) here. An AS-HK014-resitant line, trypanosomes adapted to AS-HK014 (TA014), was developed by in vitro exposure to the drug. Metabolomic analysis revealed that exposure to AS-HK014, but not curcumin, rapidly depleted glutathione and trypanothione in the wild-type line, although almost all other metabolites were unchanged relative to control. In TA014 cells, thiol levels were similar to untreated wild-type cells and not significantly depleted by AS-HK014. Adducts of AS-HK014 with both glutathione and trypanothione were identified in AS-HK014-exposed wild-type cells and reproduced by chemical reaction. However, adduct accumulation in sensitive cells was much lower than in resistant cells. TA014 cells did not exhibit any changes in sequence or protein levels of glutathione synthetase and γ-glutamylcysteine synthetase relative to wild-type cells. We conclude that monoenone curcuminoids have a different mode of action than curcumin, rapidly and specifically depleting thiol levels in trypanosomes by forming an adduct. This adduct may ultimately be responsible for the highly potent trypanocidal and antiparasitic activity of the monoenone curcuminoids.

Turmeric toxicity in A431 epidermoid cancer cells associates with autophagy degradation of anti-apoptotic and anti-autophagic p53 mutant

The keratinocyte-derived A431 Squamous Cell Carcinoma cells express the p53R273H mutant, which has been reported to inhibit apoptosis and autophagy. Here, we show that the crude extract of turmeric (Curcuma longa), similarly to its bioactive component Curcumin, could induce both apoptosis and autophagy in A431 cells, and these effects were concomitant with degradation of p53. Turmeric and curcumin also stimulated the activity of mTOR, which notoriously promotes cell growth and acts negatively on basal autophagy. Rapamycin-mediated inhibition of mTOR synergized with turmeric and curcumin in causing p53 degradation, increased the production of autophagosomes and exacerbated cell toxicity leading to cell necrosis. Small-interference mediated silencing of the autophagy proteins BECLIN 1 or ATG7 abrogated the induction of autophagy and largely rescued p53 stability in Turmeric-treated or Curcumin-treated cells, indicating that macroautophagy was mainly responsible for mutant p53 degradation. These data uncover a novel mechanism of turmeric and curcumin toxicity in chemoresistant cancer cells bearing mutant p53.

Demethoxycurcumin from Curcuma longa rhizome suppresses iNOS induction in an in vitro inflamed human intestinal mucosa model

BACKGROUND

It is known that inducible nitric oxide synthase (iNOS)/nitric oxide (NO) plays an integral role during intestinal inflammation, an important factor for colon cancer development. Natural compounds from Curcuma longa L. (Zingiberaceae) have long been a potential source of bioactive materials with various beneficial biological functions. Among them, a major active curcuminoid, demethoxycurcumin (DMC) has been shown to possess anti-inflammatory properties in lipopolysaccharide (LPS)-activated macrophages or microglia cells. However, the role of DMC on iNOS expression and NO production in an in vitro inflamed human intestinal mucosa model has not yet been elucidated. This study concerned inhibitory effects on iNOS expression and NO production of DMC in inflamed human intestinal Caco-2 cells. An in vitro model was generated and inhibitory effects on NO production of DMC at 65 μM for 24-96 h were assessed by monitoring nitrite levels. Expression of iNOS mRNA and protein was also investigated. DMC significantly decreased NO secretion by 35-41% in our inflamed cell model. Decrease in NO production by DMC was concomitant with down-regulation of iNOS at mRNA and protein levels compared to proinflammatory cytokine cocktail and LPS-treated controls. Mechanism of action of DMC may be partly due to its potent inhibition of the iNOS pathway. Our findings suggest that DMC may have potential as a therapeutic agent against inflammation-related diseases, especially in the gut.

Di-O-demethylcurcumin protects SK-N-SH cells against mitochondrial and endoplasmic reticulum-mediated apoptotic cell death induced by Aβ25-35

Alzheimer's disease (AD) is a neurodegenerative and progressive disorder. The hallmark of pathological AD is amyloid plaque which is the accumulation of amyloid β (Aβ) in extracellular neuronal cells and neurofibrillary tangles (NFT) in neuronal cells, which lead to neurotoxicity via reactive oxygen species (ROS) generation related apoptosis. Loss of synapses and synaptic damage are the best correlates of cognitive decline in AD. Neuronal cell death is the main cause of brain dysfunction and cognitive impairment. Aβ activates neuronal death via endoplasmic reticulum (ER) stress and mitochondria apoptosis pathway. This study investigated the underlying mechanisms and effects of di-O-demethylcurcumin in preventing Aβ-induced apoptosis. Pretreatment with di-O-demethylcurcumin for 2 h, which was followed by Aβ25-35 (10 µM) in human neuroblastoma SK-N-SH cells improved cell viability by using MTS assay and decreased neuronal cell apoptosis. Pretreatment with di-O-demethylcurcumin attenuated the number of nuclear condensations and number of apoptotic cells in Aβ25-35-induced group in a concentration-dependent manner by using transmission electron microscope (TEM) and flow cytometry, respectively. Di-O-demethylcurcumin also increased the ratio of Bcl-XL/Bax protein, and reduced intracellular ROS level, cytochrome c protein expression, cleaved caspase-9 protein expression, and cleaved caspase-3 protein expression. Additionally, di-O-demethylcurcumin treatment also reduced the expression of ER stress protein markers, including protein kinase RNA like endoplasmic reticulum kinase (PERK) phosphorylation, eukaryotic translation initiation factor 2 alpha (eIF2α) phosphorylation, inositol-requiring enzyme 1 (IRE1) phosphorylation, X-box-binding protein-1 (XBP-1), activating transcription factor (ATF6), C/EBP homologous protein (CHOP), and cleaved caspase-12 protein. CHOP and cleaved caspase-12 protein are the key mediators of apoptosis. Our data suggest that di-O-demethylcurcumin is a candidate protectant against neuronal death through its suppression of the apoptosis mediated by mitochondrial death and ER stress pathway.

Curcuminoid derivatives enhance telomerase activity in an in vitro TRAP assay

The length of telomeres controls the life span of eukaryotic cells. Telomerase maintains the length of telomeres in certain eukaryotic cells, such as germline cells and stem cells, and allows these cells to evade replicative senescence. Here, we report for the first time a number of curcuminoid derivatives that enhance telomerase activity in an in vitro TRAP assay. A preliminary analysis of structure-activity relationships found that the minimal requirement for this enhanced telomerase activity is a curcuminoid core with at least one n-pentylpyridine side chain, while curcuminoids with two such side chains exhibit even greater activity. The finding here might lead to a new class of telomerase activators that act directly or indirectly on telomerase, rather than through the reactivation of the telomerase reverse transcriptase (TERT) gene associated with other telomerase activators found in the literature.

Curcumin analogues inhibit phosphodiesterase-5 and dilate rat pulmonary arteries

Objectives

Phosphodiesterase (PDE)-5 inhibitors are useful as vasodilators for the treatment of pulmonary arterial hypertension. We aimed to study curcumin analogues for PDE5 inhibitory activity and vasorelaxation of rat pulmonary arteries.

Methods

Three natural curcuminoids (1–3) and six synthetic analogues (4–9) were tested for PDE5 and PDE6 inhibitory activities using enzymatic radioassay. Their vasorelaxation was measured using freshly isolated segments of rat pulmonary artery and aorta.

Key findings

Curcuminoids (1–3) mildly inhibited PDE5 (half maximal inhibitory concentration (IC50) = 18 µm): the metamethoxyl of curcumin was important for PDE5 inhibition. But hydroxyl rearrangements, removing both methoxyls and one ketomethylene, yielded the potent 7 and 9 (IC50 = 4 µm) (compared with sildenafil, IC50 = 0.03 µm). Only 1, 3 and 4 were PDE5 selective over PDE6. Triazole-carboxylic addition provided water-solubility while preserving potency. All analogues possessed concentration-dependent vasorelaxant activity on pulmonary arteries (40% of maximal effective concentration (EC40) = 29–90 µm, maximum response = 60–90% at 300 µm), while compounds (1–8) were weakly acting in aorta (maximum response <40%). Only demethoxycurcumin (2) and analogues 5, 8, 9 had endothelium-dependent actions. Sildenafil was highly potent (EC40 = 0.04 µm) and highly endothelium dependent in pulmonary artery but weak on intact aorta (EC40 = 1.8 µm). Activity profiles suggest actions through additional cell pathways for promoting vasorelaxation.

Conclusions

Curcumin analogues are potential leads for developing efficacious and selective PDE5 inhibitors and other pathologies of pulmonary hypertension.

Computational analyses of curcuminoid analogs against kinase domain of HER2

BACKGROUND

Human epidermal growth factor receptor 2 (HER2) has an important role in cancer aggressiveness and poor prognosis. HER2 has been used as a drug target for cancers. In particular, to effectively treat HER2-positive cancer, small molecule inhibitors were developed to target HER2 kinase. Knowing that curcumin has been used as food to inhibit cancer activity, this study evaluated the efficacy of natural curcumins and curcumin analogs as HER2 inhibitors using in vitro and in silico studies. The curcumin analogs considered in this study composed of 4 groups classified by their core structure, β-diketone, monoketone, pyrazole, and isoxazole.

RESULTS

In the present study, both computational and experimental studies were performed. The specificity of curcumin analogs selected from the docked results was examined against human breast cancer cell lines. The screened curcumin compounds were then subjected to molecular dynamics simulation study. By modifying curcumin analogs, we found that protein-ligand affinity increases. The benzene ring with a hydroxyl group could enhance affinity by forming hydrophobic interactions and the hydrogen bond with the hydrophobic pocket. Hydroxyl, carbonyl or methoxy group also formed hydrogen bonds with residues in the adenine pocket and sugar pocket of HER2-TK. These modifications could suggest the new drug design for potentially effective HER2-TK inhibitors. Two outstanding compounds, bisdemethylcurcumin (AS-KTC006) and 3,5-bis((E)-3,4-dimethoxystyryl)isoxazole (AS-KTC021 ),were well oriented in the binding pocket almost in the simulation time, 30 ns. This evidence confirmed the results of cell-based assays and the docking studies. They possessed more distinguished interactions than known HER2-TK inhibitors, considering them as a promising drug in the near future.

CONCLUSIONS

The series of curcumin compounds were screened using a computational molecular docking and followed by human breast cancer cell lines assay. Both AS-KTC006 and AS-KTC021 could inhibit breast cancer cell lines though inhibiting of HER2-TK. The intermolecular interactions were confirmed by molecular dynamics simulation studies. This information would explore more understanding of curcuminoid structures and HER2-TK.

Bone sparing effect of a novel phytoestrogen diarylheptanoid from Curcuma comosa Roxb. in ovariectomized rats

Phytoestrogens have been implicated in the prevention of bone loss in postmenopausal osteoporosis. Recently, an active phytoestrogen from Curcuma comosa Roxb, diarylheptanoid (DPHD), (3R)-1,7-diphenyl-(4E,6E)-4,6-heptadien-3-ol, was found to strongly promote human osteoblast function in vitro. In the present study, we demonstrated the protective effect of DPHD on ovariectomy-induced bone loss (OVX) in adult female Sprague-Dawley rats with 17β-estradiol (E₂, 10 µg/kg Bw) as a positive control. Treatment of OVX animals with DPHD at 25, 50, and 100 mg/kg Bw for 12 weeks markedly increased bone mineral density (BMD) of tibial metaphysis as measured by peripheral Quantitative Computed Tomography (pQCT). Histomorphometric analysis of bone structure indicated that DPHD treatment retarded the ovariectomy-induced deterioration of bone microstructure. Ovariectomy resulted in a marked decrease in trabecular bone volume, number and thickness and these changes were inhibited by DPHD treatment, similar to that seen with E₂. Moreover, DPHD decreased markers of bone turnover, including osteocalcin and tartrate resistant acid phosphatase (TRAP) activity. These results suggest that DPHD has a bone sparing effect in ovariectomy-induced trabecular bone loss and prevents deterioration of bone microarchitecture by suppressing the rate of bone turnover. Therefore, DPHD appears to be a promising candidate for preserving bone mass and structure in the estrogen deficient women with a potential role in reducing postmenopausal osteoporosis.