Hydroxychavicol, a novel betel leaf component, inhibits platelet aggregation by suppression of cyclooxygenase, thromboxane production and calcium mobilization

Inducing phospholipase A2 and cyclooxygenase-2 expression and prostaglandins' production of human dental pulp cells by activation of NOD receptor and its downstream signaling

Dental caries with invasion and infection by microorganisms may induce pulpitis and intolerable pain. L-Ala-γ-D-Glu-mDAP (TriDAP) is a DAP-comprising muramyl tripeptide and a peptidoglycan degradation product found in gram-negative pulpal pathogens. TriDAP activates nucleotide-binding oligomerization domain1/2 (NOD1/NOD2) and induces tissue inflammatory responses. This study aimed to test whether TriDAP stimulates cytosolic phospholipase A2 (cPLA2), cyclooxygenase-2 (COX-2), and prostanoid production in human dental pulp cells (HDPCs) and their inhibition by signal transduction inhibitors, melatonin, and eugenol. We found that TriDAP stimulated cPLA2 and COX-2 expression as well as prostaglandin E2 (PGE2) and PGF2α secretion in HDPCs. TriDAP activated TAK1, MEK/ERK, and p38 signaling. COX-2 expression, PGE2, and PGF2α production induced by TriDAP were prevented by 5Z-7oxozeaenol, SB203580, and U0126. Moreover ASB14780 (a cPLA2 inhibitor) and the clinical drugs melatonin and eugenol suppressed TriDAP- and Poly(I:C)-stimulated PGE2 and PGF2α production. These results indicate that NOD activation in HDPCs may stimulate COX-2 expression and prostaglandin production, which are crucial in pulpal inflammatory and repair responses. The effects of TriDAP and Poly(I:C) were associated with TAK1, p38, MEK/ERK, and cPLA2 in pulpal inflammation. PLA2 inhibitors, melatonin, and eugenol can be used to control pulpal inflammation associated with NOD1/2 and TLR3 activation.

Hydroxychavicol Inhibits In Vitro Osteoclastogenesis via the Suppression of NF-κB Signaling Pathway

Hydroxychavicol, a primary active phenolic compound of betel leaves, previously inhibited bone loss in vivo by stimulating osteogenesis. However, the effect of hydroxychavicol on bone remodeling induced by osteoclasts is unknown. In this study, the anti-osteoclastogenic effects of hydroxychavicol and its mechanism were investigated in receptor activator of nuclear factor kappa-B ligand (RANKL)-induced osteoclasts. Hydroxychavicol reduced the number of tartrate resistance acid phosphatase (TRAP)-positive multinucleated, F-actin ring formation and bone-resorbing activity of osteoclasts differentiated from RAW264.7 cells in a concentration-dependent manner. Furthermore, hydroxychavicol decreased the expression of osteoclast-specific genes, including cathepsin K, MMP-9, and dendritic cell-specific transmembrane protein (DC-STAMP). For mechanistic studies, hydroxychavicol suppressed RANKL-induced expression of major transcription factors, including the nuclear factor of activated T-cells 1 (NFATc1), c-Fos, and c-Jun. At the early stage of osteoclast differentiation, hydroxychavicol blocked the phosphorylation of NF-κB subunits (p65 and Iκβα). This blockade led to the decrease of nuclear translocation of p65 induced by RANKL. In addition, the anti-osteoclastogenic effect of hydroxychavicol was confirmed by the inhibition of TRAP-positive multinucleated differentiation from human peripheral mononuclear cells (PBMCs). In conclusion, hydroxychavicol inhibits osteoclastogenesis by abrogating RANKL-induced NFATc1 expression by suppressing the NF-κB signaling pathway in vitro.

Hydroxychavicol as a potential anticancer agent (Review)

Piper betle leaves are widely cultivated in Malaysia, India, Indonesia and Thailand. They have been used as a traditional medicine for centuries due to their medicinal properties, including antioxidant, antiproliferative, antibacterial, antifungal and anti-inflammatory properties, which are attributable to their high phenolic contents. Hydroxychavicol (HC), a primary constituent of P. betle leaves, is known to possess antiproliferative activity at micromolar doses on various cancer cell lines of different origins while leaving normal cells unharmed. The present review summarises the mechanisms of action of HC reported in the literature, reviews the scope of work done thus far and outlines the direction of future research on the potential of HC as an anticancer agent. PubMed, Scopus and Web of Science were searched using the keywords (hydroxychavicol OR 4-allylpyrocatechol OR 4-allylcatechol) AND (cancer OR carcinogenesis OR tumour OR carcinoma) to acquire research articles. In vitro studies reported several possible mechanisms for the chemopreventive effects of HC against cancer cell lines, including chronic myelogenous leukaemia (CML), prostate, glioma, breast and colorectal cancers, while in vivo studies encompassed investigations on Ehrlich ascites carcinoma cells in Swiss albino mice and a CML mouse model. These studies suggest that HC exerts its anticancer effect via the modulation of mitochondrial membrane potential and the c-Jun N-terminal kinase, mitogen-activated protein kinase and endoplasmic reticulum-unfolded protein responses pathways and the generation of reactive oxygen species. In summary, future research should focus on combinations of HC with other anticancer drugs and testing in animal models to evaluate its bioavailability, potency and tissue and dose selectivity.

Coagulation System Activation for Targeting of COVID-19: Insights into Anticoagulants, Vaccine-Loaded Nanoparticles, and Hypercoagulability in COVID-19 Vaccines

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), also known as COVID-19, is currently developing into a rapidly disseminating and an overwhelming worldwide pandemic. In severe COVID-19 cases, hypercoagulability and inflammation are two crucial complications responsible for poor prognosis and mortality. In addition, coagulation system activation and inflammation overlap and produce life-threatening complications, including coagulopathy and cytokine storm, which are associated with overproduction of cytokines and activation of the immune system; they might be a lead cause of organ damage. However, patients with severe COVID-19 who received anticoagulant therapy had lower mortality, especially with elevated D-dimer or fibrin degradation products (FDP). In this regard, the discovery of natural products with anticoagulant potential may help mitigate the numerous side effects of the available synthetic drugs. This review sheds light on blood coagulation and its impact on the complication associated with COVID-19. Furthermore, the sources of natural anticoagulants, the role of nanoparticle formulation in this outbreak, and the prevalence of thrombosis with thrombocytopenia syndrome (TTS) after COVID-19 vaccines are also reviewed. These combined data provide many research ideas related to the possibility of using these anticoagulant agents as a treatment to relieve acute symptoms of COVID-19 infection.

Arecoline induces heart injure via Fas/Fas ligand apoptotic pathway in heart of Sprague-Dawley rat

Habitual chewing of areca nut increases the risk of cardiovascular disease mortality, but less report demonstrate the toxic mechanism of areca nut on heart. To investigate toxicity of areca nut on cardiomyocytes, we induced the heart injury with arecoline to evaluate the acute damage of areca nut on heart. Different concentrations of are coline (lowdosage: 5 mg/kg/day and high dosage 50 mg/kg/day) were injected into Sprague-Dawley rat via intra-peritoneal method for 21 days to create negative effects of arecoline on cardiomyocyte. Themyocardial architecture of the rat heart was observed. The arecoline-induced apoptotic proteins were analysed via western blotting. The myocardialarchitecture of heart was injured with arecoline and TUNEL stain was also shown are coline-induced cardiac apoptosis. Arecoline promoted the protein expression of both Fas dependent snd mitochondrial dependent apoptosis. In summary, arecoline induces cardiac toxicity and apoptosis by inducing both death receptor and mitochondria-dependent apoptotic pathways on heart.

The Role of Essential Oils and Their Main Compounds in the Management of Cardiovascular Disease Risk Factors

Cardiovascular diseases (CVDs) are a global health burden that greatly impact patient quality of life and account for a huge number of deaths worldwide. Despite current therapies, several side effects have been reported that compromise patient adherence; thus, affecting therapeutic benefits. In this context, plant metabolites, namely volatile extracts and compounds, have emerged as promising therapeutic agents. Indeed, these compounds, in addition to having beneficial bioactivities, are generally more amenable and present less side effects, allowing better patient tolerance. The present review is an updated compilation of the studies carried out in the last 20 years on the beneficial potential of essential oils, and their compounds, against major risk factors of CVDs. Overall, these metabolites show beneficial potential through a direct effect on these risk factors, namely hypertension, dyslipidemia and diabetes, or by acting on related targets, or exerting general cellular protection. In general, monoterpenic compounds are the most studied regarding hypotensive and anti-dyslipidemic/antidiabetic properties, whereas phenylpropanoids are very effective at avoiding platelet aggregation. Despite the number of studies performed, clinical trials are sparse and several aspects related to essential oil’s features, namely volatility and chemical variability, need to be considered in order to guarantee their efficacy in a clinical setting.

Hydroxychavicol, a polyphenol from Piper betle leaf extract, induces cell cycle arrest and apoptosis in TP53-resistant HT-29 colon cancer cells

This study aims to elucidate the antiproliferative mechanism of hydroxychavicol (HC). Its effects on cell cycle, apoptosis, and the expression of c-Jun N-terminal kinase (JNK) and P38 mitogen-activated protein kinase (MAPK) in HT-29 colon cancer cells were investigated. HC was isolated from Piper betle leaf (PBL) and verified by high-performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR), and gas chromatography-mass spectrometry (GC-MS). The cytotoxic effects of the standard drug 5-fluorouracil (5-FU), PBL water extract, and HC on HT-29 cells were measured after 24, 48, and 72 h of treatment. Cell cycle and apoptosis modulation by 5-FU and HC treatments were investigated up to 30 h. Changes in phosphorylated JNK (pJNK) and P38 (pP38) MAPK expression were observed up to 18 h. The half maximal inhibitory concentration (IC₅₀) values of HC (30 μg/mL) and PBL water extract (380 μg/mL) were achieved at 24 h, whereas the IC₅₀ of 5-FU (50 μmol/L) was obtained at 72 h. Cell cycle arrest at the G₀/G₁ phase in HC-treated cells was observed from 12 h onwards. Higher apoptotic cell death in HC-treated cells compared to 5-FU-treated cells (P<0.05) was observed. High expression of pJNK and pP38 MAPK was observed at 12 h in HC-treated cells, but not in 5-FU-treated HT-29 cells (P<0.05). It is concluded that HC induces cell cycle arrest and apoptosis of HT-29 cells, with these actions possibly mediated by JNK and P38 MAPK.

Stimulation of MMP-9 of oral epithelial cells by areca nut extract is related to TGF-β/Smad2-dependent and -independent pathways and prevented by betel leaf extract, hydroxychavicol and melatonin

BACKGROUND

There are 200-600 million betel quid (BQ) chewers in the world. BQ increases oral cancer risk. Matrix metalloproteinase-9 (MMP-9) is responsible for matrix degradation, cancer invasion and metastasis. Whether areca nut extract (ANE), a BQ component, stimulates MMP-9 secretion, and the related signaling pathways awaits investigation.

RESULTS

ANE (but not arecoline) stimulated MMP-9 production of gingival keratinocytes and SAS cancer epithelial cells. ANE stimulated TGF-β1, p-Smad2, and p-TAK1 protein expression. ANE-induced MMP-9 production/expression in SAS cells can be attenuated by SB431542 (ALK5/Smad2 inhibitor), 5Z-7-Oxozeaenol (TAK1 inhibitor), catalase, PD153035 (EGFR tyrosine kinase inhibitor), AG490 (JAK inhibitor), U0126 (MEK/ERK inhibitor), LY294002 (PI3K/Akt inhibitor), betel leaf (PBL) extract, and hydroxychavicol (HC, a PBL component), and melatonin, but not by aspirin.

CONCLUSIONS

AN components contribute to oral carcinogenesis by stimulating MMP-9 secretion, thus enhancing tumor invasion/metastasis. These events are related to reactive oxygen species, TGF-β1, Smad2-dependent and -independent signaling, but not COX. These signaling molecules can be biomarkers of BQ carcinogenesis. PBL, HC and melatonin and other targeting therapy can be used for oral cancer treatment.

METHODS

ANE-induced MMP-9 expression/secretion of oral epithelial cells and related TGF-β1, Smad-dependent and -independent signaling were studied by MTT assay, RT-PCR, western blotting, immunofluorescent staining, and ELISA.

Protective Effects of Phenylpropanoids and Phenylpropanoid-rich Essential Oils on the Cardiovascular System

BACKGROUND

Cardiovascular diseases are the leading cause of global mortality with a tendency to increase due to population ageing as well as an increase in associated risk factors. Although current therapies improve survival rates, they are associated with several side effects, thus justifying the development of novel preventive and/or therapeutic approaches. In this way, plant metabolites such as essential oils have emerged as promising agents due to their biological effects.

OBJECTIVE

Bearing in mind that several essential oils are characterized by high amounts of phenylpropanoids, which may play a crucial role in the activity of these volatile extracts, a comprehensive and systematic review focusing on the cardiovascular effects of phenylpropanoid-rich essential oils is presented.

METHODS

Popular search engines including PubMed, Science Direct, Scopus and Google Scholar were consulted and papers from 2000 onwards were selected. Non-volatile phenylpropanoids were not considered in this review.

RESULTS

A compilation of the current knowledge on this thematic pointed out beneficial effects for volatile phenylpropanoids namely hypotensive, vasorelaxant, antiplatelet aggregation, antidyslipidaemic and antidiabetic, as well as protective properties against ischemia/reperfusion injury and heart hypertrophy.

CONCLUSION

A better understanding of the protective effects of phenylpropanoids on the cardiovascular system is presented, thus paving the way towards future research on plant-based therapies for cardiovascular diseases.

Antibacterial Activity of Loloh (Traditional Balinese Medicine) Decoction Water and Squeeze Water of betel Leaf against Bacteria Streptococcus pyogenes causes of sore throat

Sore throat is a respiratory infection caused by a bacterial infection of Streptococcus pyogenes. Betel leaf is used for loloh (traditional medicine) which has antimicrobial activity. The purpose of this study was to determine the content of active compounds and the antibacterial activity of the boiled water and juice of betel leaf against Streptococcus pyogenes. Explorative research using GC-MS method was used to identify and determine the abundance (content) of active compounds from loloh while the experimental research with the Randomized Post Test Only Control Group Design was carried out by treating the samples in four groups those are the negative control group with distilled water, the positive control group with 30 μg vancomycin, the treatment group with boiled water of betel leaf and betel leaf juice water to prove the antibacterial activity of loloh. The antibacterial activity data of the study results were analyzed statistically nonparametric through the Kruskal-Wallis test. The results showed that the betel leaf boiled water contained 0.472% hydroxicavicol active compound and had an average antibacterial activity of 6.50±0.224 mm against Streptococcus pyogenes bacteria. Whilst the juice of betel leaves did not contain active compounds and had no antibacterial activity.

Anti-Inflammatory Effects of 5α,8α-Epidioxycholest-6-en-3β-ol, a Steroidal Endoperoxide Isolated from Aplysia depilans, Based on Bioguided Fractionation and NMR Analysis

Sea hares of Aplysia genus are recognized as a source of a diverse range of metabolites. 5α,8α-Endoperoxides belong to a group of oxidized sterols commonly found in marine organisms and display several bioactivities, including antimicrobial, anti-tumor, and immunomodulatory properties. Herein we report the isolation of 5α,8α-epidioxycholest-6-en-3β-ol (EnP(5,8)) from Aplysia depilans Gmelin, based on bioguided fractionation and nuclear magnetic resonance (NMR) analysis, as well as the first disclosure of its anti-inflammatory properties. EnP(5,8) revealed capacity to decrease cellular nitric oxide (NO) levels in RAW 264.7 macrophages treated with lipopolysaccharide (LPS) by downregulation of the Nos2 (inducible nitric oxide synthase, iNOS) gene. Moreover, EnP(5,8) also inhibited the LPS-induced expression of cyclooxygenase-2 (COX-2), interleukin 6 (IL-6), and tumor necrosis factor alpha (TNF-α) at the mRNA and protein levels. Mild selective inhibition of COX-2 enzyme activity was also evidenced. Our findings provide evidence of EnP(5,8) as a potential lead drug molecule for the development of new anti-inflammatory agents.

Aspirin eugenol ester inhibits agonist-induced platelet aggregation in vitro by regulating PI3K/Akt, MAPK and Sirt 1/CD40L pathways

Aspirin eugenol ester (AEE) was a promising drug candidate for treating inflammation, pain and fever and preventing cardiovascular diseases with fewer side effects than its precursors. Previous researches indicated that AEE could markedly inhibit agonist-induced platelet aggregation in vitro and ex vivo, however, the anti-platelet aggregation mechanisms of AEE remain to be defined. Here, AEE in vitro effects on agonist-induced granule-secretion, intercellular Ca²⁺ mobilization and thromboxane A₂ (TXA₂) generation were examined. Vasodilator-stimulated phosphoprotein (VASP), mitogen-activated protein kinase (MAPK), Akt, Sirt 1 and CD40L expressions were also studied. In agonist-activated platelets in vitro, AEE markedly attenuated granule secretion markers (P-selectin expression and ATP release), intercellular Ca²⁺ mobilization and thromboxane B₂ (TXB₂) formation. AEE also attenuated CD40L activation, suppressed extracellular-signal-regulated protein kinase 2 (ERK2), c-Jun N-terminal kinase 1 (JNK1) and Akt phosphorylation, and recovered Sirt1 expression, but the activation of p38, VASP^Ser157 and VASP^Ser239, and the levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) were not affected by AEE. Overall, this study demonstrates that AEE inhibits agonist-induced platelet aggregation in vitro by regulating PI3K/Akt, MAPK and Sirt 1/CD40L pathways.

Effects of Piper betle fractionated extracts on inhibition of Streptococcus mutans and Streptococcus intermedius

The overgrowth of certain strains of normal flora in oral cavity can cause many kinds of oral infections or diseases such as carries, periodontitis, and gingivitis. Prevention and treatment of these diseases are usually achieved by chemical antiseptics. However, these chemicals are found as negative impacts of human health hazards and accession of microbial resistance. The present study explores the potential of Piper betle extracts on inhibition of two oral pathogenic bacteria; Streptococcus mutans DMST 41283 and Streptococcus intermedius DMST 42700. P. betle demonstrated significantly higher inhibitory activity against both pathogenic strains than Acacia catechu, Camellia sinensis, Coccinia grandis, Solanum indicum, and Streblus asper. Among fractionated extracts of P. betle from several solvents, the extract from ethyl acetate (Pb-EtOAc) possessed the widest inhibition zone of 11.0 ± 0.1 and 11.3 ± 0.4 mm against both bacterial strains, respectively. Pb-EtOAc showed the same minimum inhibitory concentration of 0.5 mg/mL against both strains, whereas its minimum bactericidal concentrations were 2.0 and 0.5 mg/mL against S. mutans and S. intermedius, respectively. HPLC analysis demonstrated that the major active compound of Pb-EtOAc was 4-allylpyrocatechol. It was found that the killing kinetics of Pb-EtOAc against both test strains were time and dose dependent. Scanning electron microscopy micrographs showed the morphological changes and depletion of the tested pathogens indicating cell destruction after exposure to Pb-EtOAc. It is confirmed that Pb-EtOAc is potentially effective against both oral pathogens and might be used as natural alternative agents in prevention and treatment of oral infections caused by oral pathogenic bacteria.

Biological Properties of Some Volatile Phenylpropanoids

Plants and their extracts are the new field of interest for many scientists and also of some pharmaceutical industries. In order to provide more information for their usage in the prevention and treatment of diseases many clinical trials and researches are being carried out. In this review the biological activities and the mechanism of action of volatile phenylpropanoids (PPs) found in essential oils (EOs) are presented. The aim of this overview is to show that volatile PPs found in EOs can exert many of the biological activities which are generally attributed to EOs. Almost all of the PPs possess antimicrobial, anti-inflammatory and anticancer activities. These are related to the different substitution of the phenylpropane molecule. For each isolated group not only one, but more pharmacological activities can be credited.

Natural Products for Antithrombosis

Thrombosis is considered to be closely related to several diseases such as atherosclerosis, ischemic heart disease and stroke, as well as rheumatoid arthritis, hyperuricemia, and various inflammatory conditions. More and more studies have been focused on understanding the mechanism of molecular and cellular basis of thrombus formation as well as preventing thrombosis for the treatment of thrombotic diseases. In reality, there is considerable interest in the role of natural products and their bioactive components in the prevention and treatment of thrombosis related disorders. This paper briefly describes the mechanisms of thrombus formation on three aspects, including coagulation system, platelet activation, and aggregation, and change of blood flow conditions. Furthermore, the natural products for antithrombosis by anticoagulation, antiplatelet aggregation, and fibrinolysis were summarized, respectively.

Baicalein inhibits agonist- and tumor cell-induced platelet aggregation while suppressing pulmonary tumor metastasis via cAMP-mediated VASP phosphorylation along with impaired MAPKs and PI3K-Akt activation

Recently, the importance of platelet activation in cancer metastasis has become generally accepted. As a result, the development of new platelet inhibitors with minimal adverse effects is now a promising area of targeted cancer therapy. Baicalein is a functional ingredient derived from the root of Scutellaria baicalensis Georgi, a plant used intraditional medicine. The pharmacological effects of this compound including anti-oxidative and anti-inflammatory activities have already been demonstrated. However, its effects on platelet activation are unknown. We therefore investigated the effects of baicalein on ligand-induced platelet aggregation and pulmonary cancer metastasis. In the present study, baicalein inhibited agonist-induced platelet aggregation, granule secretion markers (P-selectin expression and ATP release), [Ca(2+)]i mobilization, and integrin αIIbβ3 expression. Additionally, baicalein attenuated ERK2, p38, and Akt activation, and enhanced VASP phosphorylation. Indeed, baicalein was shown to directly inhibit PI3K kinase activity. Moreover, baicalein attenuated the platelet aggregation induced by C6 rat glioma tumor cells in vitro and suppressed CT26 colon cancer metastasis in mice. These features indicate that baicalein is a potential therapeutic drug for the prevention of cancer metastasis.

Antiplatelet effect of catechol is related to inhibition of cyclooxygenase, reactive oxygen species, ERK/p38 signaling and thromboxane A2 production

Catechol (benzenediol) is present in plant-derived products, such as vegetables, fruits, coffee, tea, wine, areca nut and cigarette smoke. Because platelet dysfunction is a risk factor of cardiovascular diseases, including stroke, atherosclerosis and myocardial infarction, the purpose of this study was to evaluate the anti-platelet and anti-inflammatory effect of catechol and its mechanisms. The effects of catechol on cyclooxygenase (COX) activity, arachidonic acid (AA)-induced aggregation, thromboxane B2 (TXB2) production, lactate dehydrogenase (LDH) release, reactive oxygen species (ROS) production and extracellular signal-regulated kinase (ERK)/p38 phosphorylation were determined in rabbit platelets. In addition, its effect on IL-1β-induced prostaglandin E2 (PGE2) production by fibroblasts was determined. The ex vivo effect of catechol on platelet aggregation was also measured. Catechol (5-25 µM) suppressed AA-induced platelet aggregation and inhibited TXB2 production at concentrations of 0.5-5 µM; however, it showed little cytotoxicity and did not alter U46619-induced platelet aggregation. Catechol (10-50 µM) suppressed COX-1 activity by 29-44% and COX-2 activity by 29-50%. It also inhibited IL-1β-induced PGE2 production, but not COX-2 expression of fibroblasts. Moreover, catechol (1-10 µM) attenuated AA-induced ROS production in platelets and phorbol myristate acetate (PMA)-induced ROS production in human polymorphonuclear leukocytes. Exposure of platelets to catechol decreased AA-induced ERK and p38 phosphorylation. Finally, intravenous administration of catechol (2.5-5 µmole/mouse) attenuated ex vivo AA-induced platelet aggregation. These results suggest that catechol exhibited anti-platelet and anti-inflammatory effects, which were mediated by inhibition of COX, ROS and TXA2 production as well as ERK/p38 phosphorylation. The anti-platelet effect of catechol was confirmed by ex vivo analysis. Exposure to catechol may affect platelet function and thus cardiovascular health.

Hydroxychavicol, a betel leaf component, inhibits prostate cancer through ROS-driven DNA damage and apoptosis

Dietary phytochemicals are excellent ROS-modulating agents and have been shown to effectively enhance ROS levels beyond toxic threshold in cancer cells to ensure their selective killing while leaving normal cells unscathed. Here we demonstrate that hydroxychavicol (HC), extracted and purified from Piper betel leaves, significantly inhibits growth and proliferation via ROS generation in human prostate cancer, PC-3 cells. HC perturbed cell-cycle kinetics and progression, reduced clonogenicity and mediated cytotoxicity by ROS-induced DNA damage leading to activation of several pro-apoptotic molecules. In addition, HC treatment elicited a novel autophagic response as evidenced by the appearance of acidic vesicular organelles and increased expression of autophagic markers, LC3-IIb and beclin-1. Interestingly, quenching of ROS with tiron, an antioxidant, offered significant protection against HC-induced inhibition of cell growth and down regulation of caspase-3, suggesting the crucial role of ROS in mediating cell death. The collapse of mitochondrial transmembrane potential by HC further revealed the link between ROS generation and induction of caspase-mediated apoptosis in PC-3 cells. Our data showed remarkable inhibition of prostate tumor xenografts by ~72% upon daily oral administration of 150mg/kg bw HC by quantitative tumor volume measurements and non-invasive real-time bioluminescent imaging. HC was well-tolerated at this dosing level without any observable toxicity. This is the first report to demonstrate the anti-prostate cancer efficacy of HC in vitro and in vivo, which is perhaps attributable to its selective prooxidant activity to eliminate cancer cells thus providing compelling grounds for future preclinical studies to validate its potential usefulness for prostate cancer management.

Areca nut components affect COX-2, cyclin B1/cdc25C and keratin expression, PGE2 production in keratinocyte is related to reactive oxygen species, CYP1A1, Src, EGFR and Ras signaling

AIMS

Chewing of betel quid (BQ) increases the risk of oral cancer and oral submucous fibrosis (OSF), possibly by BQ-induced toxicity and induction of inflammatory response in oral mucosa.

METHODS

Primary gingival keratinocytes (GK cells) were exposed to areca nut (AN) components with/without inhibitors. Cytotoxicity was measured by 3-(4,5-dimethyl- thiazol- 2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. mRNA and protein expression was evaluated by reverse transcriptase-polymerase chain reaction (RT-PCR) and western blotting. PGE2/PGF2α production was measured by enzyme-linked immunosorbent assays.

RESULTS

Areca nut extract (ANE) stimulated PGE2/PGF2α production, and upregulated the expression of cyclooxygenase-2 (COX-2), cytochrome P450 1A1 (CYP1A1) and hemeoxygenase-1 (HO-1), but inhibited expression of keratin 5/14, cyclinB1 and cdc25C in GK cells. ANE also activated epidermal growth factor receptor (EGFR), Src and Ras signaling pathways. ANE-induced COX-2, keratin 5, keratin 14 and cdc25C expression as well as PGE2 production were differentially regulated by α-naphthoflavone (a CYP 1A1/1A2 inhibitor), PD153035 (EGFR inhibitor), pp2 (Src inhibitor), and manumycin A (a Ras inhibitor). ANE-induced PGE2 production was suppressed by piper betle leaf (PBL) extract and hydroxychavicol (two major BQ components), dicoumarol (a

NAD(P)H

Quinone Oxidoreductase--NQO1 inhibitor) and curcumin. ANE-induced cytotoxicity was inhibited by catalase and enhanced by dicoumarol, suggesting that AN components may contribute to the pathogenesis of OSF and oral cancer via induction of aberrant differentiation, cytotoxicity, COX-2 expression, and PGE2/PGF2α production.

CONCLUSIONS

CYP4501A1, reactive oxygen species (ROS), EGFR, Src and Ras signaling pathways could all play a role in ANE-induced pathogenesis of oral cancer. Addition of PBL into BQ and curcumin consumption could inhibit the ANE-induced inflammatory response.

Relationship between Platelet PPARs, cAMP Levels, and P-Selectin Expression: Antiplatelet Activity of Natural Products

Platelets are no longer considered simply as cells participating in thrombosis. In atherosclerosis, platelets are regulators of multiple processes, with the recruitment of inflammatory cells towards the lesion sites, inflammatory mediators release, and regulation of endothelial function. The antiplatelet therapy has been used for a long time in an effort to prevent and treat cardiovascular diseases. However, limited efficacy in some patients, drug resistance, and side effects are limitations of current antiplatelet therapy. In this context, a large number of natural products (polyphenols, terpenoids, alkaloids, and fatty acids) have been reported with antiplatelet activity. In this sense, the present paper describes mechanisms of antiplatelet action of natural products on platelet P-selectin expression through cAMP levels and its role as peroxisome proliferator-activated receptors agonists.

All in the name of flavour, fragrance & freshness: commonly used smokeless tobacco preparations in & around a tertiary hospital in India

BACKGROUND & OBJECTIVES

There is a general misconception that smokeless tobacco particularly sweetened and flavoured paan masala and gutkas are safe to use. The present study was undertaken with the objective of highlighting the deceptive and aggressive marketing techniques adopted by the manufacturers of smokeless tobacco preparations exploiting cultural, social and religious values. Another object was to highlight the lack of transparency in terms of content, weight, quality control and warning.

METHODS

All empty pouches of the used paan masalas, gutka, khaini or surti in and around a tertiary care hospital at east Delhi were collected. Their constituents were studied as per written declaration by the manufacturers on each packet. Information on net weight, cost, presence and type of warning, and quality assurance on each brand provided on side of the packets was noted.

RESULTS

A total of 1136 pouches of 33 brands/varieties were collected. Most of the gutka preparations contained tobacco, betel nut, unknown flavouring agents, undeclared spices and heavy metals. Warning regarding the harmful effect of tobacco was written in 90.9 per cent of brands with 81.8 per cent in English language only in minute font. Contents of the products were mentioned in 84.8 per cent of brands and only 27.3 per cent of those mentioned the net weight of the ingredients.

INTERPRETATION & CONCLUSIONS

Seemingly 'innocuous' tobacco preparations in the form of paan masalas, gutka, khaini, surti or mouth fresheners contain various harmful substance like tobacco, betel nut, sugar coated fennel, saccharine, heavy metals like silver, unknown flavouring agents and undeclared spices in unknown quantities. Lack of transparency in terms of content, weight, quality control and warning is duping unsuspecting consumers.

Antiplatelet effect of phloroglucinol is related to inhibition of cyclooxygenase, reactive oxygen species, ERK/p38 signaling and thromboxane A2 production

Platelet dysfunction is a major risk factor of cardiovascular diseases such as atherosclerosis, stroke and myocardial infarction. Many antiplatelet agents are used for prevention and treatment of these diseases. In this study, phloroglucinol (2.5-25 μM) suppressed AA-induced platelet aggregation and thromboxane B(2) (TXB(2)) production, but not U46619-induced platelet aggregation. Phloroglucinol (100-250 μM) showed little cytotoxicity to platelets. Phloroglucinol inhibited the COX-1 and COX-2 activities by 45-74% and 49-72% respectively at concentrations of 10-50 μM. At concentrations of 1 and 5 μM, phloroglucinol attenuated the AA-induced ROS production in platelets by 30% and 53%, with an IC(50) of 13.8 μM. Phloroglucinol also inhibited the PMA-stimulated ROS production in PMN. Preincubation of platelets by phloroglucinol (10-25 μM) markedly attenuated the AA-induced ERK and p38 phosphorylation. Intravenous administration of phloroglucinol (2.5 and 5 μmol/mouse) suppressed the ex vivo AA-induced platelet aggregation by 57-71%. Phloroglucinol administration also elevated the mice tail bleeding time. Moreover, phloroglucinol inhibited the IL-1β-induced PGE(2) production in pulp fibroblasts. These results indicate that antiplatelet and anti-inflammatory effects of phloroglucinol are related to inhibition of COX, ROS and TXA2 production as well as ERK/p38 phosphorylation in platelets. Phloroglucinol further suppress PMA-induced ROS production in PMN. The antiplatelet effect of phloroglucinol was confirmed by ex vivo study. Clinically, the consumption of phloroglucinol-containing food/natural products as nutritional supplement may be helpful to cardiovascular health. Phloroglucinol has potential pharmacological use.

Chewing areca nut increases the risk of coronary artery disease in Taiwanese men: a case-control study

Background

Areca nut chewing has been reported to be associated with obesity, metabolic syndrome, hypertension, and cardiovascular mortality in previous studies. The aim of this study was to examine whether chewing areca nut increases the risk of coronary artery disease (CAD) in Taiwanese men.

Methods

This study is a hospital-based case-control study. The case patients were male patients diagnosed in Taiwan between 1996 and 2009 as having a positive Treadmill exercise test or a positive finding on the Thallium-201 single-photon emission computed tomography myocardial perfusion imaging. The case patients were further evaluated by coronary angiography to confirm their CAD. Obstructive CAD was defined as a ≥ 50% decrease in the luminal diameter of one major coronary artery. The patients who did not fulfill the above criteria of obstructive CAD were excluded.

The potential controls were males who visited the same hospital for health check-ups and had a normal electrocardiogram but no history of ischemic heart disease or CAD during the time period that the case patients were diagnosed. The eligible controls were randomly selected and frequency-matched with the case patients based on age. Multiple logistic regression analyses were used to estimate the odds ratio of areca nut chewing and the risk of obstructive CAD.

Results

A total of 293 obstructive CAD patients and 720 healthy controls, all men, were analyzed. Subjects who chewed areca nut had a 3.5-fold increased risk (95% CI = 2.0-6.2) of having obstructive CAD than those without, after adjusting for other significant covariates. The dose-response relationship of chewing areca nut and the risk of obstructive CAD was also noted. After adjusting for other covariates, the 2-way additive interactions for obstructive CAD risk were also significant between areca nut use and cigarette smoking, hypertension and dyslipidemia.

Conclusions

Long-term areca nut chewing was an independent risk factor of obstructive CAD in Taiwanese men. Interactive effects between chewing areca nut and cigarette smoking, hypertension, and dyslipidemia were also observed for CAD risk. Further exploration of their underlying mechanisms is necessary.

In vitro antifungal activity of hydroxychavicol isolated from Piper betle L

Background

Hydroxychavicol, isolated from the chloroform extraction of the aqueous leaf extract of Piper betle L., (Piperaceae) was investigated for its antifungal activity against 124 strains of selected fungi. The leaves of this plant have been long in use tropical countries for the preparation of traditional herbal remedies.

Methods

The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of hydroxychavicol were determined by using broth microdilution method following CLSI guidelines. Time kill curve studies, post-antifungal effects and mutation prevention concentrations were determined against Candida species and Aspergillus species "respectively". Hydroxychavicol was also tested for its potential to inhibit and reduce the formation of Candida albicans biofilms. The membrane permeability was measured by the uptake of propidium iodide.

Results

Hydroxychavicol exhibited inhibitory effect on fungal species of clinical significance, with the MICs ranging from 15.62 to 500 μg/ml for yeasts, 125 to 500 μg/ml for Aspergillus species, and 7.81 to 62.5 μg/ml for dermatophytes where as the MFCs were found to be similar or two fold greater than the MICs. There was concentration-dependent killing of Candida albicans and Candida glabrata up to 8 × MIC. Hydroxychavicol also exhibited an extended post antifungal effect of 6.25 to 8.70 h at 4 × MIC for Candida species and suppressed the emergence of mutants of the fungal species tested at 2 × to 8 × MIC concentration. Furthermore, it also inhibited the growth of biofilm generated by C. albicans and reduced the preformed biofilms. There was increased uptake of propidium iodide by C. albicans cells when exposed to hydroxychavicol thus indicating that the membrane disruption could be the probable mode of action of hydroxychavicol.

Conclusions

The antifungal activity exhibited by this compound warrants its use as an antifungal agent particularly for treating topical infections, as well as gargle mouthwash against oral Candida infections.

Olive tree wood phenolic compounds with human platelet antiaggregant properties

Oleuropein and (+)-cycloolivil are natural polyphenolic compounds with a significant radical scavenging activity present in olive tree. We have investigated the antiaggregant effects of oleuropein and (+)-cycloolivil isolated from an ethyl acetate extract of olive tree wood. Oleuropein and (+)-cycloolivil reduced the ability of thrombin to stimulate platelet aggregation. Both compounds reduced thrombin-evoked Ca(2+) release and entry to a similar extent to hydroxytyrosol. This effect was greater in platelets from patients with type 2 diabetes mellitus than in controls. Thrombin-, thapsigargin- and 2,5-di-(tert-butyl)-1,4-hydroquinone (TBHQ)-evoked protein tyrosine phosphorylation, which is involved in Ca(2+) signalling and platelet aggregation, is inhibited by oleuropein and (+)-cycloolivil. oleuropein and (+)-cycloolivil are natural oxygen radical scavengers that reduce thrombin-induced protein tyrosine phosphorylation, Ca(2+) signalling and platelet aggregation. These observations suggest that oleuropein and (+)-cycloolivil may prevent thrombotic complications associated to platelet hyperaggregability and be the base for the development of antiaggregant therapeutic strategies.

Strategies for antiplatelet targets and agents

Platelets play a key role in thrombosis and haemostasis, which can be either beneficial or deleterious depending on the circumstance. Antiplatelet therapy is the 'cornerstone' in the prevention and treatment of thrombotic diseases. Platelet activation is a complex process known as transmembrane signaling which then serves to activate the platelet via a cascade of biochemical interactions. Currently available strategies of antiplatelet therapy are generally based on the signaling pathway of platelet activation, which possess the characters that mono-agent, mono-target, and mainly irreversible inhibition. Therefore, both established and novel antiplatelet agents have their own pros and cons and such problems as resistance, drug-drug interaction, discontinuation and monitoring, etc. have been appeared. Due to the problems existing in current antiplatelet agents, future new strategies for antiplatelet targets, agent-developing and treatment might probably include three aspects: targeting the factors associated with platelet hyperactivity, developing novel antiplatelet agents with multiple targets, mild and reversible properties from natural products, and keeping healthy lifestyle and emphasizing prevention.