The protective effect of piperine on dextran sulfate sodium induced inflammatory bowel disease and its relation with pregnane X receptor activation

Targeting chemokine-receptor mediated molecular signaling by ethnopharmacological approaches

ETHNOPHARMACOLOGICAL RELEVANCE

Infection and inflammation are critical to global human health status and the goal of current pharmacological interventions intends formulating medications/preventives as a measure to deal with this situation. Chemokines and their cognate receptors are major regulatory molecules in many of these ailments. Natural products have been a keen source to the drug development industry, every year contributing significantly to the growing list of FDA approved drugs. A multiverse of natural resource is employed as a part of curative regimen in folk/traditional/ethnomedicine which can be employed to discover, repurpose, and design potent medications for the diseases of clinical concern.

AIM OF THE STUDY

This review aims to systematically document the ethnopharmacologically active agents targeting the infectious-inflammatory diseases through the chemokine-receptor nexus.

MATERIALS AND METHODS

Articles related to chemokine/receptor modulating ethnopharmacological anti-inflammatory, anti-infectious natural sources, bioactive compounds, and formulations have been examined with special emphasis on women related diseases. The available literature has been thoroughly scrutinized for the application of traditional medicines in chemokine associated experimental methods, their regulatory outcomes, and pertinence to women's health wherever applicable. Moreover, the potential traditional regimens under clinical trials have been critically assessed.

RESULTS

A systematic and comprehensive review on the chemokine-receptor targeting ethnopharmaceutics from the available literature has been provided. The article discusses the implication of traditional medicine in the chemokine system dynamics in diverse infectious-inflammatory disorders such as cardiovascular diseases, allergic diseases, inflammatory diseases, neuroinflammation, and cancer. On this note, critical evaluation of the available data surfaced multiple diseases prevalent in women such as osteoporosis, rheumatoid arthritis, breast cancer, cervical cancer and urinary tract infection. Currently there is no available literature highlighting chemokine-receptor targeting using traditional medicinal approach from women's health perspective. Moreover, despite being potent in vitro and in vivo setups there remains a gap in clinical translation of these formulations, which needs to be strategically and scientifically addressed to pave the way for their successful industrial translation.

CONCLUSIONS

The review provides an optimistic global perspective towards the applicability of ethnopharmacology in chemokine-receptor regulated infectious and inflammatory diseases with special emphasis on ailments prevalent in women, consecutively addressing their current status of clinical translation and future directions.

Development of chitosan lipid nanoparticles to alleviate the pharmacological activity of piperine in the management of cognitive deficit in diabetic rats

The aim of the present study was to prepare and evaluate Piperine (PP) loaded chitosan lipid nanoparticles (PP-CLNPs) to evaluate its biological activity alone or in combination with the antidiabetic drug Metformin (MET) in the management of cognitive deficit in diabetic rats. Piperine was successfully loaded on CLNPs prepared using chitosan, stearic acid, Tween 80 and Tripolyphosphate (TPP) at different concentrations. The developed CLNPs exhibited high entrapment efficiency that ranged from 85.12 to 97.41%, a particle size in the range of 59.56-414 nm and a negatively charged zeta potential values (- 20.1 to - 43.9 mV). In vitro release study revealed enhanced PP release from CLNPs compared to that from free PP suspensions for up to 24 h. In vivo studies revealed that treatment with the optimized PP-CLNPs formulation (F2) exerted a cognitive enhancing effect and ameliorated the oxidative stress associated with diabetes. PP-CLNPs acted as an effective bio-enhancer which increased the potency of metformin in protecting brain tissue from diabetes-induced neuroinflammation and memory deterioration. These results suggested that CLNPs could be a promising drug delivery system for encapsulating PP and thus can be used as an adjuvant therapy in the management of high-risk diabetic cognitive impairment conditions.

Piperine mitigates oxidative stress, inflammation, and apoptosis in the testicular damage induced by cyclophosphamide in mice

Although cyclophosphamide (CP) has been approved as an anticancer drug, its toxic effect on most organs, especially the testis, has been established. Piperine (PIP) is an alkaloid that has antioxidant, antiapoptotic, and anti-inflammatory activities. This study was investigated the protective effects of PIP on CP-induced testicular toxicity in the mice. In this experimental study, 48 adult male BALB/c mice (30-35 g) were divided into six groups (n = 8), receiving normal saline (C), 5 mg/kg of PIP (PIP5), 10 mg/kg of PIP (PIP10), 200 mg/kg of CP, 200 mg/kg of CP + PIP5, and 200 mg/kg of CP + PIP10. On the eighth day of the study, blood and testis samples were prepared for serum testosterone hormone quantification, sperm analysis, histological, and immunohistochemical assays. The results of this study showed that CP induced testicular toxicity with the decrease of sperm count, motility, and viability. Also, CP treatment caused histological structure alterations in the testis, including exfoliation, degeneration, vacuolation of spermatogenic cells, and reducing the thickness of the epithelium and the diameter of the seminiferous tubule. In addition, CP decreased glutathione (GSH) levels, increased malondialdehyde (MDA) levels, Caspase-3, and NF-κB. At the same time, PIP treatment reduced testicular histopathological abnormalities, oxidative stress, and apoptosis that were induced by CP. These results showed that PIP improved CP-induced testicular toxicity in mice, which can be related to its antioxidant, antiapoptotic, and anti-inflammatory activities.

Piperine alleviates nonalcoholic steatohepatitis by inhibiting NF-κB-mediated hepatocyte pyroptosis

PURPOSE

Nonalcoholic steatohepatitis (NASH) is the progressive form of nonalcoholic fatty liver disease (NAFLD), which has a high risk of cirrhosis, liver failure, and hepatocellular carcinoma. Piperine (Pip) is an extract of plants with powerful anti-inflammatory effects, however, the function of Pip in NASH remains elusive. Here, we aim to explore the role of Pip in NASH and to find the possible mechanisms.

METHODS

Methionine and choline-deficient (MCD) diets were used to induce steatohepatitis, methionine- and choline-sufficient (MCS) diets were used as the control. After Pip treatment, H&E staining, Oil Red O staining, hepatic triglyceride (TG) content and F4/80 expression were performed to analysis liver steatosis and inflammation; Masson's staining, COL1A1 and α-SMA were detected liver fibrosis. Lipopolysaccharide (LPS) -treated AML12 cells were used to as the cell model to induce pyroptosis. Then, pyroptosis-related proteins, IL-1β and LDH release were detected in vivo and in vitro. Finally, NF-κB inhibitor, BAY11-7082, was used to further demonstrate the mechanism of Pip in NASH.

RESULTS

The study found that Pip alleviated liver steatosis, inflammation, hepatocyte injury, and fibrosis in mice fed with MCD diets. Moreover, the pyroptosis markers (NLRP3, ASC, caspase-1 p20, and GSDMD), IL-1β and LDH release were decreased by Pip treatment. NF-κB activation was suppressed by Pip treatment and pyroptosis-related proteins were down regulated by BAY11-7082.

CONCLUSION

Pip ameliorates NASH progression, and the therapeutical effect was associated with inhibition of hepatocyte pyroptosis induced by NF-κB.

Protocatechuic acid inhibits LPS-induced mastitis in mice through activating the pregnane X receptor

Mastitis refers to the inflammation in the mammary gland caused by various reasons. Protocatechuic acid (PCA) exerts anti-inflammatory effect. However, no studies have shown the protective role of PCA on mastitis. We investigated the protective effect of PCA on LPS-induced mastitis in mice and elucidated its possible mechanism. LPS-induced mastitis model was established by injection of LPS into the mammary gland. The pathology of mammary gland, MPO activity and inflammatory cytokine production were detected to evaluate the effects of PCA on mastitis. In vivo, PCA significantly attenuated LPS-induced mammary pathological changes, MPO activity, TNF-α and IL-1β production. In vitro, the production of inflammatory cytokines TNF-α and IL-1β was significantly reduced by PCA. Furthermore, LPS-induced NF-κB activation was also inhibited by PCA. In addition, PCA was found to activate pregnane X receptor (PXR) transactivation and PCA dose-dependently increased the expression of PXR downstream molecule CYP3A4. In addition, the inhibitory effect of PCA on inflammatory cytokine production was also reversed when PXR was knocked down. In conclusion, the protective effects of PCA on LPS-induced mastitis in mice through regulating PXR.

Piperine Reduces Neoplastic Progression in Cervical Cancer Cells by Downregulating the Cyclooxygenase 2 Pathway

Cervical cancer is the fourth-most common type of cancer in the world that causes death in women. It is mainly caused by persistent infection by human papillomavirus (HPV) that triggers a chronic inflammatory process. Therefore, the use of anti-inflammatory drugs is a potential treatment option. The effects of piperine, an amino alkaloid derived from Piper nigrum, are poorly understood in cervical cancer inflammation, making it a target of research. This work aimed to investigate the antitumor effect of piperine on cervical cancer and to determine whether this effect is modulated by the cyclooxygenase 2 (PTGS2) pathway using in vitro model of cervical cancer (HeLa, SiHa, CaSki), and non-tumoral (HaCaT) cell lines. The results showed that piperine reduces in vitro parameters associated with neoplastic evolution such as proliferation, viability and migration by cell cycle arrest in the G1/G0 and G2/M phases, with subsequent induction of apoptosis. This action was modulated by downregulation of cyclooxygenase 2 (PTGS2) pathway, which in turn regulates the secretion of cytokines and the expression of mitogen-activated protein kinases (MAPKs), metalloproteinases (MMPs), and their antagonists (TIMPs). These findings indicate the phytotherapeutic potential of piperine as complementary treatment in cervical cancer.

Traditional Chinese Medicine and Natural Products: Potential Approaches for Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a rare, recurrent, and intractable inflammation obstruction of the stomach tract, usually accompanied by inflammation of cell proliferation and inflammation of the colon and carries a particular cause of inflammation. The clinical use of drugs in western countries affects IBD treatment, but various adverse effects and high prices limit their application. For these reasons, Traditional Chinese Medicine (TCM) is more advantageous in treating IBD. This paper reviews the mechanism and research status of TCM and natural products in IBD treatment by analyzing the relevant literature to provide a scientific and theoretical basis for IBD treatment.

Green Tea Extract Containing Piper retrofractum Fruit Ameliorates DSS-Induced Colitis via Modulating MicroRNA-21 Expression and NF-κB Activity

The aim of the present study was to examine the effect of green tea extract containing Piper retrofractum fruit (GTP) on dextran-sulfate-sodium (DSS)-induced colitis, the regulatory mechanisms of microRNA (miR)-21, and the nuclear factor-κB (NF-κB) pathway. Different doses of GTP (50, 100, and 200 mg/kg) were administered orally once daily for 14 days, followed by GTP with 3% DSS for 7 days. Compared with the DSS-treated control, GTP administration alleviated clinical symptoms, including the disease activity index (DAI), colon shortening, and the degree of histological damage. Moreover, GTP suppressed miR-21 expression and NF-κB activity in colon tissue of DSS-induced colitis mice. The mRNA levels of inflammatory mediators, such as tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), interleukin-1β (IL-1β), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2), were downregulated by GTP. Colonic nitric oxide (NO) and prostaglandin E2 (PGE2) production, and myeloperoxidase (MPO) activity were also lowered by GTP. Taken together, our results revealed that GTP inhibits DSS-induced colonic inflammation by suppressing miR-21 expression and NF-κB activity, suggesting that it may be used as a potential functional material for improving colitis.

Phytochemicals targeting Toll-like receptors 4 (TLR4) in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a collective term for inflammatory diseases including Crohn's disease and ulcerative colitis. Toll-like receptor 4 (TLR4) is thought to play a key role in the pathogenesis of IBD. Inhibition of TLR4 has been recognized as an effective target for the treatment of IBD. Many phytochemicals have been shown to have potential as new drugs for the treatment of IBD. This review surveyed the available literature and reports which focused on the in vivo effects of phytochemicals targeting TLR4 in different models of IBD, and clarified the significance of TLR4 as a current therapeutic target for IBD. Based on our review, we have concluded that phytochemicals targeting TLR4 are potentially effective candidates for developing new therapeutic drugs against IBD.

Neuroprotective Effects of Black Pepper and Its Bioactive Compounds in Age-Related Neurological Disorders

Age-related neurological disorders (ANDs), including neurodegenerative diseases, are multifactorial disorders whose risk increases with age. The main pathological hallmarks of ANDs include behavioral changes, excessive oxidative stress, progressive functional declines, impaired mitochondrial function, protein misfolding, neuroinflammation, and neuronal cell death. Recently, efforts have been made to overcome ANDs because of their increased age-dependent prevalence. Black pepper, the fruit of Piper nigrum L. in the family Piperaceae, is an important food spice that has long been used in traditional medicine to treat various human diseases. Consumption of black pepper and black pepper-enriched products is associated with numerous health benefits due to its antioxidant, antidiabetic, anti-obesity, antihypertensive, anti-inflammatory, anticancer, hepatoprotective, and neuroprotective properties. This review shows that black pepper's major bioactive neuroprotective compounds, such as piperine, effectively prevent AND symptoms and pathological conditions by modulating cell survival signaling and death. Relevant molecular mechanisms are also discussed. In addition, we highlight how recently developed novel nanodelivery systems are vital for improving the efficacy, solubility, bioavailability, and neuroprotective properties of black pepper (and thus piperine) in different experimental AND models, including clinical trials. This extensive review shows that black pepper and its active ingredients have therapeutic potential for ANDs.

The role of pregnane X receptor (PXR) in substance metabolism

As a member of the nuclear receptor (NR) superfamily, pregnane X receptor (PXR; NR1I2) is a ligand-activated transcription factor that plays a crucial role in the metabolism of xenobiotics and endobiotics in mammals. The tissue distribution of PXR is parallel to its function with high expression in the liver and small intestine and moderate expression in the kidney, stomach, skin, and blood-brain barrier, which are organs and tissues in frequent contact with xenobiotics. PXR was first recognized as an exogenous substance receptor regulating metabolizing enzymes and transporters and functioning in detoxification and drug metabolism in the liver. However, further research revealed that PXR acts as an equally important endogenous substance receptor in the metabolism and homeostasis of endogenous substances. In this review, we summarized the functions of PXR in metabolism of different substances such as glucose, lipid, bile acid, vitamin, minerals, and endocrines, and also included insights of the application of PXR ligands (drugs) in specific diseases.

A recent update on the use of Chinese medicine in the treatment of inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic idiopathic disease that is characterized by inflammation of the gastrointestinal tract. Proper management of IBD requires both early diagnosis and novel therapies and management programs. Many reports have suggested that Chinese medicine has unique properties favorable to the treatment of IBD. However, there are no systematic analyses on this topic.

PURPOSE

This review summarizes recent studies that assessed the effects and mechanisms of Chinese medicine in the treatment of IBD in order to fully understand the advantages of Chinese medicine in the management of IBD.

METHODS

A literature search was conducted using peer-reviewed and clinical databases, including PubMed, Web of Science, ClinicalTrials.gov, MEDLINE, EMBASE, Springer LINK, Wan-fang database, the Chinese Biomedicine Database, and the China National Knowledge Infrastructure (CNKI). Keywords used were inflammatory bowel disease (including Ulcerative colitis or Crohn's disease) and Chinese medicine. All selected articles were from 1997 to 2021, and each were assessed critically for our exclusion criteria. Studies describing the pathogenesis of IBD, the effects and mechanisms of Chinese medicine in the treatment of IBD, in particular their roles in immune regulation, intestinal flora regulation, and improvement of intestinal barrier function, were included.

CONCLUSION

This review highlights recent progress in the use of Chinese medicine in the treatment of IBD. It also provides a reference for further evaluation and exploration of the potential of classical multi-herbal Chinese medicine in the treatment of IBD.

Pharmacokinetics and Pharmacodynamic Herb-Drug Interaction of Piperine with Atorvastatin in Rats

Herbals that are widely consumed as therapeutic alternatives to conventional drugs for cardiovascular diseases, may lead to herb-drug interactions (HDIs). Atorvastatin (ATR) is drug of choice for hyperlipidemia and is extensively metabolized through CYP3A4 enzyme. Thus, we postulate that concomitant administration of ATR with piperine (PIP, potent inhibitor of CYP3A4 enzyme)/ridayarishta (RID, cardiotonic herbal formulations containing PIP) may lead to potential HDI. A simple, accurate, sensitive high-performance liquid chromatography-photodiode array detection method using Kromasil-100 C18 column, mobile phase acetonitrile: 30 mM phosphate buffer (55:45 v/v) pH 4.5 with flow rate gradient programming was developed to study the potential HDI in rats. Method was found to be linear (2-100 ng/mL) with Lower Limit of Detection (LLOD) 2 ng/mL. The precision (%CV < 15%), accuracy (-1.0 to -10% R.E) with recoveries above 90% from rat plasma of ATR and IS were obtained. The pharmacokinetic (PK) interactions studies on co-administration of ATR (8.4 mg/kg, p.o.) with PIP (35 mg/kg, p.o.), demonstrated a threefold increase in Cmax of ATR (P < 0.01) with significant increase in AUC0-t/AUC0-∞ compared to ATR alone indicating potential PK-HDI. However co-administration of RID (4.2 mL/kg, p.o.) showed less significant changes (P > 0.05) indicating low HDI. The pharmacodynamic effects/interactions study (TritonX-100 induced hyperlipidemic model in rats) suggested no significant alterations in the lipid profile on co-administration of PIP/RID with ATR, indicating that there may be no significant pharmacodynamic interactions.

Phytochemical Regulation of RNA in Treating Inflammatory Bowel Disease and Colon Cancer: Inspirations from Cell and Animal Studies

Recent studies suggest an important role for RNA, especially noncoding RNA, in inflammatory bowel disease (IBD) and colon cancer. Drug development based on regulating RNA rather than protein is a promising new area. Phytochemicals are naturally occurring plant-derived compounds with chemical diversity, biologic activity, easy availability, and low toxicity. Many phytochemicals have been shown to exert protective effects on IBD and colon cancer through modulation of RNAs. The aim of this study was to summarize the advancements of phytochemicals in regulating RNA for the treatment of IBD and colon cancer. This review involves many phytochemicals, including polyphenols, flavones, and alkaloids, which can influence various types of RNAs, including microRNA, long noncoding RNA, as well as messenger RNA, by influencing a variety of upstream molecules or regulating epigenetic processes. The limitation for many current studies is that the specific mechanisms of phytochemicals regulating RNA have not been fully uncovered. Accompanied by more identified functions of RNAs, especially noncoding RNA functions, the screening of RNA-regulating phytochemicals has presented challenges as well as opportunities for the prevention and treatment of IBD and colon cancer. SIGNIFICANCE STATEMENT: Noncoding RNAs, which constitute the majority of the human transcriptional genome, play a key role in the disease state and are considered as important therapeutic targets in inflammatory bowel disease (IBD) and colon cancer. Recent studies have shown that phytochemicals regulate the expression of many noncoding RNAs involved in IBD and colon cancer. Therefore, identifying the specific molecular mechanism of phytochemicals regulating noncoding RNA in disease models may result in novel and effective therapeutic opportunities.

Curcumin steers THP-1 cells under LPS and mTORC1 challenges toward phenotypically resting, low cytokine-producing macrophages

The persistent activation of intestinal mechanistic target of rapamycin complex 1 (mTORC1) triggered by mucosal stress has been linked to deregulation of the gut immune response resulting in intestinal inflammation and cell death. The present study investigated the regulatory properties of food-derived mTORC1 modulators, curcumin, and piperine, toward the polarization of stimulated macrophages and the differentiation of monocytes at two mTORC1 activity levels (baseline and elevated). To that end, we created stable human THP-1 monocytes exhibiting normal or constitutively active mTORC1. Curcumin or its combination with piperine, but not piperine alone, suppressed mTORC1 kinase activity, curtailed lipopolysaccharide-mediated inflammatory response of THP-1 macrophages, and repressed macrophage activation by inhibiting signaling pathways involved in M1 (mTORC1) and M2 (mTORC2 and cAMP response element binding protein) polarization. The effects of piperine in the curcumin/piperine combination were modest overall, indicating it was curcumin that modulated differentiating monocytes into acquiring a M0 macrophage phenotype characterized by low inflammatory cytokine output.

Regulation of CAR and PXR Expression in Health and Disease

Pregnane X receptor (PXR, NR1I2) and constitutive androstane receptor (CAR, NR1I3) are members of the nuclear receptor superfamily that mainly act as ligand-activated transcription factors. Their functions have long been associated with the regulation of drug metabolism and disposition, and it is now well established that they are implicated in physiological and pathological conditions. Considerable efforts have been made to understand the regulation of their activity by their cognate ligand; however, additional regulatory mechanisms, among which the regulation of their expression, modulate their pleiotropic effects. This review summarizes the current knowledge on CAR and PXR expression during development and adult life; tissue distribution; spatial, temporal, and metabolic regulations; as well as in pathological situations, including chronic diseases and cancers. The expression of CAR and PXR is modulated by complex regulatory mechanisms that involve the interplay of transcription factors and also post-transcriptional and epigenetic modifications. Moreover, many environmental stimuli affect CAR and PXR expression through mechanisms that have not been elucidated.

Piperine ameliorates insulin resistance via inhibiting metabolic inflammation in monosodium glutamate-treated obese mice

BACKGROUND

Metabolic inflammation is an essential event in obesity-induced diabetes and insulin resistance. In obesity, an increasing number of macrophages recruited into visceral adipose tissues undergo significant M₁-like polarization, secreting variable amounts of pro-inflammatory cytokines and causing insulin resistance. Piperine has excellent anti-inflammatory activities and may be used in the treatment of a variety of inflammatory diseases. In this study, we investigated the effect of piperine on adipose tissue inflammation and insulin resistance in obese mice.

METHODS

Newborn mice were subcutaneously (s.c.) injected with monosodium glutamate (MSG) to establish a diabetes model. After 24 weeks, the MSG obese mice were divided into three groups and treated with piperine (40 mg/kg/day), metformin (150 mg/kg/day) and vehicle for 10 successive weeks, respectively.

RESULTS

The obesity model was successfully established, as the body weight, insulin resistance, fasting blood glucose (FBG) and dyslipidemia were significantly increased. The 10-week administration of piperine to the obese mice not only significantly decreased the elevated FBG (Model: 6.45 ± 0.41 mM; Piperine: 4.72 ± 0.44 mM, p < 0.01), serum TC (Model: 5.66 ± 0.66 mM; Piperine: 3.55 ± 0.30 mM, p < 0.01) and TG (Model: 1.41 ± 0.08 mM; Piperine: 0.94 ± 0.05 mM, p < 0.001), but also enhanced the glucose infusion rate in the hyperglycemic clamp experiment. Meanwhile, piperine improved glucose intolerance and insulin resistance in MSG obese mice. Piperine markedly decreased the total and differential white blood cell (WBC) count, the serum levels of lipopolysaccharide (LPS) and pro-inflammatory cytokines such as galectin-3 (Gal-3) and interleukin-1β (IL-1β). Furthermore, piperine clearly down-regulated the mRNA levels of pro-inflammatory cytokines and the protein levels of M₁-like polarization marker CD11c and Gal-3 in adipose tissues. The in vitro study showed that piperine inhibited LPS-stimulated polarization of RAW 264.7 cells toward the M₁ phenotype.

CONCLUSIONS

Piperine served as an immunomodulator for the treatment of obesity-related diabetes through its anti-inflammatory effects, which might be achieved by inhibiting macrophages M₁ polarization in adipose tissues.

Piperine: A review of its biological effects

Medicinal plants have been used for years as a source of food, spices, and, in traditional medicine, as a remedy to numerous diseases. Piper nigrum, belonging to the family Piperaceae is one of the most widely used spices all over the world. It has a distinct sharp flavor attributed to the presence of the phytochemical, piperine. Apart from its use as a spice, P. nigrum is frequently used for medicinal, preservation, and perfumery purposes. Black pepper contains 2-7.4% of piperine, varying in content is associated with the pepper plant. Piperine displays numerous pharmacological effects such as antiproliferative, antitumor, antiangiogenesis, antioxidant, antidiabetic, anti-obesity, cardioprotective, antimicrobial, antiaging, and immunomodulatory effects in various in vitro and in vivo experimental trials. Furthermore, piperine has also been documented for its hepatoprotective, anti-allergic, anti-inflammatory, and neuroprotective properties. This review highlights and discusses the medicinal and health-promoting effects of piperine, along with possible mechanisms of its action in health promotion and disease prevention. In addition, the present review summarizes the recent literature related to piperine as a therapeutic agent against several diseases.

Patchouli alcohol activates PXR and suppresses the NF-κB-mediated intestinal inflammatory

ETHNOPHARMACOLOGICAL RELEVANCE

The pregnane-X-receptor (PXR) is involved in inflammatory bowel disease (IBD). Patchouli alcohol (PA) has anti-inflammatory effects; however, the effect of PA on IBD pathogenesis remains largely unknown.

AIM OF THE STUDY

The aim of the present study was to investigate the anti-inflammatory effect of PA, primarily focused on crosstalk between PA-mediated PXR activation and NF-κB inhibition.

MATERIALS AND METHODS

We evaluated the anti-inflammatory effect of PA with respect to PXR/NF-κB signalling using in vitro and in vivo models. In vitro, PA, identified as a PXR agonist, was evaluated by hPXR transactivation assays and through assessing for CYP3A4 expression and activity. NF-κB inhibition was analysed based on NF-κB luciferase assays, NF-κB-mediated pro-inflammatory gene expression, and NF-κB nuclear translocation after activation of PXR by PA. In vivo, colonic mPXR and NF-κB signalling were analysed to assess PA-mediated the protective effect against dextran sulphate sodium (DSS)-induced colitis. Furthermore, pharmacological inhibition of PXR was further evaluated by examining PA protection against DSS-induced colitis.

RESULTS

PA induced CYP3A4 expression and activity via an hPXR-dependent mechanism. PA-mediated PXR activation attenuated inflammation by inhibiting NF-κB activity and nuclear translocation. The anti-inflammatory effect of PA on NF-κB was abolished by PXR knockdown. PA prevented DSS-induced inflammation by regulating PXR/NF-κB signalling, whereas pharmacological PXR inhibition abated PA-mediated suppressive effects on NF-κB inflammation signalling.

CONCLUSIONS

PA activates PXR signalling and suppresses NF-κB signalling, consequently causing amelioration of inflammation. Our results highlight the importance of PXR-NF-κB crosstalk in colitis and suggest a novel therapeutic reagent.

Piperine, a functional food alkaloid, exhibits inhibitory potential against TNBS-induced colitis via the inhibition of IκB-α/NF-κB and induces tight junction protein (claudin-1, occludin, and ZO-1) signaling pathway in experimental mice

BACKGROUND

Inflammatory bowel disease is a chronic immunoinflammatory disease of the gastrointestinal tract. Piperine, an alkaloid, has been reported to possess antioxidant, anti-inflammatory, antiapoptotic, and antiulcer potential.

AIM

To elucidate the plausible mechanisms of action of piperine on experimental trinitrobenzenesufonic acid (TNBS)-induced colitis by assessing various biochemical, molecular, histological, and ultrastructural modifications.

METHODS

Colitis was induced in male Sprague-Dawley rats via intrarectal instillation of TNBS. Then, the rats were treated with piperine (10, 20, and 40 mg/kg, p.o.) for 14 days.

RESULTS

TNBS induced significant (p < 0.05) colonic damage, which was assessed by disease activity index, macroscopic score, and stool consistency. The administration of piperine (20 and 40 mg/kg) significantly inhibited (p < 0.05) these damages. Treatments with piperine (20 and 40 mg/kg) notably inhibited (p < 0.05) the TNBS-induced elevation of oxido-nitrosative stress (superoxide dismutase, glutathione, malondialdehyde, and nitric oxide), 5-hydroxytryptamine, and hydroxyproline content in the colon. Furthermore, colonic inducible nitric oxide synthase (iNOs), tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1β, IL-6, interferon-gamma, and cyclooxygenase-2 (COX-2) messenger RNA (mRNA) expressions were upregulated after TNBS instillation and piperine (20 and 40 mg/kg) significantly attenuated (p < 0.05) these elevated mRNA expressions. TNBS decreased the expressions of tight junction (TJ) protein (claudin-1, occludin, and zonula occludens-1 (ZO-1)) and increased the expressions of proapoptotic (caspase-1) protein. These expressions were markedly inhibited (p < 0.05) by piperine treatment. Histological and ultrastructural studies of transmission electron microscopy suggested that piperine significantly ameliorated (p < 0.05) TNBS-induced colonic aberrations.

CONCLUSION

Piperine ameliorated the progression of TNBS-induced colitis by modulating the nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor-alpha/nuclear factor-kappa B signaling pathway, thus inhibiting the overexpression of proinflammatory cytokines (TNF-α and IL's), COX-2, iNOs, oxido-nitrosative stress, and proapoptotic proteins (caspase-1) that may improve the expression of TJ protein (claudin-1, occludin, and ZO-1).

Herb-Drug Interactions and Hepatotoxicity

BACKGROUND

In recent times, herbals or phytomedicines have become very popular due to their global acceptance as a complementary and alternative remedy. While modern drugs are commercially available only after laboratory validations, clinical trials, as well as approval from drug regulatory authorities, majority of the marketed herbal products lack such scientific evidence of efficacy and safety. This results in herb or herb-drug interaction induced unfavorable clinical outcomes without crucial documentation on their temporal relations and concomitant use.

METHODS

An online literature search for peer-reviewed articles was conducted on the PubMed, Europe PMC, Medline and Google Scholar portals, using the phrases: complementary & alternative medicine, traditional Chinese medicine, herb-drug interaction, mechanisms of herb-drug interaction, herb-induced toxicity, herbal hepatotoxicity and causality, traditional medicine, viral hepatitis, etc.

Results

The retrieved data showed that globally, patients are attracted to herbal remedies with the misconception that these are completely safe and therefore, use them simultaneously with prescription drugs. Notably, there exists a potential risk of herb-drug interactions leading to some adverse side effects, including hepatotoxicity. The toxicological effect of a drug or herb is due to the inhibition of drug metabolizing enzymes (e.g., cytochrome P450), including interactions with certain prescription drugs through various mechanisms. Several cases of hepatotoxicity due to use of herbals in viral hepatitis-related liver diseases have been recently reported. However, limited experimental data and clinical evidence on herbal pharmacokinetics hamper the evaluation and reporting of adverse reactions and the underlying mechanisms.

CONCLUSION

Herb-drug interaction related morbidity is thus an emerging serious public health issue with broad implications for clinicians, pharmaceutical industries and health authorities. Nonetheless, despite increasing recognition of herb-drug interaction, a standard system for interaction prediction and evaluation is still nonexistent. This review article discusses the herb-drug interactions related hepatotoxicity and underlying mechanisms, including drug metabolizing enzymes and their regulation.

The association of pregnane X receptor activation with outcomes after liver transplantation-A retrospective study

BACKGROUND

Many complications following liver transplantation are linked to ischemia-reperfusion injury. Activation of the pregnane X receptor (PXR) has been shown to alleviate this process in animal models. The aim of this retrospective study was to investigate the effect of early activation of human PXR (hPXR) on postoperative complications and survival following liver transplantation.

METHODS

The study included deceased donor liver transplants at a single center over 6 years. Estimated hPXR activation value on day 7 (EPAV₇ ) was calculated per patient based on potency/total dose of known hPXR-activating drugs administered in the first week post-transplantation. Patients were divided into low and high hPXR activation groups based on EPAV₇ .

RESULTS

Overall, 240 liver transplants were included. Average EPAV₇ was significantly lower in patients who developed anastomotic biliary strictures (17.7 ± 5.5 vs 35.1 ± 5.7 in stricture-free patients; P = .03) and sepsis (16.4 ± 7.1 vs 34.9 ± 5.5; P = .04). Patient survival was significantly improved in the high hPXR group (5-year survival: 88.7% ± 3.8% versus 70.7% ± 5.8% [low hPXR]; P = .023). Regression analysis identified EPAV₇ as a significant independent predictor of patient survival.

CONCLUSION

hPXR activation within the first week of liver transplantation is a prognostic indicator of patient survival, possibly due to the associated lower biliary stricture and infection rates.

Piperine pretreatment attenuates renal ischemia-reperfusion induced liver injury

Background

Remote organ injury is one of the complications which are developed following ischemia-reperfusion induced acute kidney injury (AKI), dramatically increasing its mortality rate. The aim of the present study was to investigate the effect of piperine pretreatment on liver dysfunction following ischemia-reperfusion induced AKI.

Materials and methods

Acute kidney injury was induced by 30 min-bilateral renal ischemia followed by 24 h of reperfusion. To investigate liver damages, the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) enzymes were measured in plasma. In order to study oxidative stress, malondialdehyde (MDA) and ferric reducing antioxidant power (FRAP) levels were measured. Furthermore, the expression of intercellular adhesion molecule-1 (ICAM-1) mRNA along with infiltration of leukocytes in the liver tissue was measured for inflammation assessment. Histopathological damages were studied through measuring the extent of cellular fibrosis, sinusoidal dilatation, and vascular congestion in liver tissue.

Results

Following acute kidney injury, AST, ALT, and ALP levels in plasma, MDA level and ICAM-1 expression in the liver tissue, infiltration of leukocytes into the interstitium, and hepatic histopathologic damages increased significantly, while FRAP decreased. Pretreatment with piperine at 10 and 20 mg/kg body weight was able to improve these damages, such that some of them reached its value in the sham group, though piperine in the 20 mg/kg was more effective.

Conclusions

The results of this study suggest that ischemia-reperfusion induced AKI result in hepatic damages, and pretreatment with piperine can prevent development of these damages through its antioxidant and anti-inflammatory properties.

Protective effect of piperine in ischemia-reperfusion induced acute kidney injury through inhibition of inflammation and oxidative stress

Background and aim

Renal ischemia-reperfusion is associated with inflammation and oxidative stress. As a major compound in black pepper, piperine has anti-inflammatory and anti-oxidative properties. In present study, the protective effects of oral administration of piperine in renal ischemia-reperfusion (IR) induced acute kidney injuries (AKI) were investigated.

Experimental procedure

Male Wistar rats received piperine (10 or 20 mg/kg.bw) or vehicle for 10 days. The artery and vein of both kidneys were then clamped for 30 min, followed by a 24-h reperfusion period. Concentrations of creatinine and urea-nitrogen in descending aorta blood were measured, and malondialdehyde (MDA) and ferric reducing/antioxidant power (FRAP) levels were measured in kidney tissue to evaluate the oxidative stress. Inflammation was evaluated by measuring the TNF-α and ICAM-1 mRNA expression levels in renal cortical tissue using Real Time PCR method and counting leukocytes infiltration to interstitium. Further measured were tissue damages in H & E stained sections.

Results

Renal IR reduced FRAP, while increasing the plasma concentrations of creatinine and urea-nitrogen, tissue MDA level, TNF-α and ICAM-1 mRNA expressions, leukocyte infiltration and histopathologic injuries. Piperine administration significantly reduced the plasma concentrations of creatinine and urea-nitrogen, expression of pro-inflammatory factors, oxidative stress and renal histopathologic injuries. It is to be noted that 20 mg/kg dose was more effective.

Conclusion

Our results suggest piperine protects the kidney against ischemia-reperfusion induced acute kidney injuries by its anti-inflammatory and anti-oxidative properties.

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Renal ischemia-reperfusion increased the inflammation and oxidative stress parameters.

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Ischemia-reperfusion increased histopathological damages and functional parameters.

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Piperine pretreatment significantly reduced the inflammation and oxidative stress.

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Piperine administration ameliorated renal function and histopathologic damages.

An Evidence-Based Review of Medicinal Plants Used for the Treatment of Vaginitis by Avicenna in "the Canon of Medicine"

Vaginitis is one of the most common gynecological problems in reproductive age. Because of the limitations of the conventional drugs, identification of new pharmacological interventions for this disease seems to be necessary. The purpose of this article is to review the medicinal herbs mentioned for the treatment of vaginitis by the great Iranian scientist, Avicenna, in his book "the Canon of Medicine " to scientifically demonstrate their effects and their potential to be used as complementary therapies. The medicinal plants listed for vaginitis treatment in "the Canon of Medicine " were extracted. The scientific name and English common name of the given medicinal plants were searched in databases including PubMed, Scopus, and Cochrane Library until December 2017 to obtain any in vitro, animal, and clinical evidence related to vaginitis. Various pharmacological activities, including anti-inflammatory, wound healing, antimicrobial, antifungal, analgesic, and anti-prostaglandin E2, have been demonstrated for medicinal plants emphasized by Avicenna for vaginitis. Randomized controlled trials (RCTs) on Myrtus reported an improvement in the treatment of bacterial vaginosis. Four RCTs on pomegranate indicated a reduction in inflammatory factors in the patients. Medicinal herbs offered in Herbal Medicine are valuable sources for the treatment of various diseases. Effects and pharmacodynamics having been proved by conventional medicine confirm the effectiveness of these herbs. Therefore, these plants can be used in the treatment of vaginitis thanks to further clinical studies.

Plant-Derived Alkaloids: The Promising Disease-Modifying Agents for Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) represents a group of intestinal disorders with self-destructive and chronic inflammation in the digestive tract, requiring long-term medications. However, as many side effects and drug resistance are frequently encountered, safer and more effective agents for IBD treatment are urgently needed. Over the past few decades, a variety of natural alkaloids made of plants or medicinal herbs have attracted considerable interest because of the excellent antioxidant and anti-inflammatory properties; additionally, these alkaloids have been reported to reduce the colonic inflammation and damage in a range of colitic models. In this review paper, we summarize the recent findings regarding the anti-colitis activity of plant-derived alkaloids and emphasize their therapeutic potential for the treatment of IBD; obvious improvement of the colonic oxidative and pro-inflammatory status, significant preservation of the epithelial barrier function and positive modulation of the gut microbiota are the underlying mechanisms for the plant-derived alkaloids to treat IBD. Further clinical trials and preclinical studies to unravel the molecular mechanism are essential to promote the clinical translation of plant-derived alkaloids for IBD.

Activating the pregnane X receptor by imperatorin attenuates dextran sulphate sodium-induced colitis in mice

BACKGROUND AND PURPOSE

Activation of the human pregnane X receptor (PXR; NR1I2) has potential therapeutic uses for inflammatory bowel disease (IBD). Imperatorin (IMP), a naturally occurring coumarin, is the main bioactive ingredient of Angelica dahurica Radix, which is regularly used to treat the common cold and intestinal disorders. However, there are no data on the protective effects of IMP against IBD.

EXPERIMENTAL APPROACH

The effects of IMP on PXR-modulated cytochrome P450 3A4 (CYP3A4) expression were assessed using a PXR transactivation assay, a mammalian two-hybrid assay, a competitive ligand-binding assay, analysis of CYP3A4 mRNA and protein expression levels and measurement of CYP3A4 activity using a cell-based reporter gene assay and in vitro model. The inhibitory effects of IMP on NF-κB activity were evaluated by a reporter assay and NF-κB p65 nuclear translocation. The anti-IBD effects of IMP were investigated in a dextran sulphate sodium (DSS)-induced colitis mouse model. Colon inflammatory cytokines were assessed by elisa.

KEY RESULTS

IMP activated CYP3A4 promoter activity, recruited steroid receptor coactivator 1 to the ligand-binding domain of PXR and increased the expression and activity of CYP3A4. PXR knockdown substantially reduced IMP-induced increase in CYP3A4 expression. Furthermore, IMP-mediated PXR activation suppressed the nuclear translocation of NF-κB and down-regulated LPS-induced expression of pro-inflammatory genes. Nevertheless, PXR knockdown partially reduced the IMP-mediated inhibition of NF-κB. IMP ameliorated DSS-induced colitis by PXR/NF-κB signalling.

CONCLUSIONS AND IMPLICATIONS

IMP acts as a PXR agonist to attenuate DSS-induced colitis by suppression of the NF-κB-mediated pro-inflammatory response in a PXR/NF-κB-dependent manner.

Novel plant inducers of PXR-dependent cytochrome P450 3A4 expression in HepG2 cells

The cytochrome P450 3A4 (CYP3A4) is the most abundant CYP450 enzyme involved in the metabolism of endogenous products and xenobiotics, including prescription drugs and herbals. Modulation of hepatic CYP3A4 gene expression via nuclear receptors, like pregnane X receptor (PXR), is a major cause of adverse effects like drug-unresponsiveness and toxicity. In the present study, ethanol extracts of 58 medicinal plants, belonging to 27 families, were evaluated for potential activities in CYP3A4 induction in HepG2 cells by reporter gene assay. For PXR-mediated CYP3A4 induction, a 50 μg/ml concentration was used for all non-cytotoxic plants extracts. Rifampicin (10 μM) and DMSO (0.1%) were used as standard inducer and untreated (negative) control, respectively. The comparative fold-induction of CYP34A by the plant extracts in relation to the untreated control was determined. As a result, Dodonaea angustifolia (2.62 fold; P < 0.0001) was found to be the most promising inducer of CYP3A4, followed by Euphorbia tirucalli (1.95 fold; P = 0.0004), Alternanthera pungens (1.74 fold, P = 0.0035), and Ficus palmata (1.65 fold; P = 0.0097). Further phytochemical characterizations of the active plants are therefore, warranted.

Piperine ameliorates collagenase-induced Achilles tendon injury in the rat

Tendinopathy is a common clinical pathology found in athletes and workers with mixed treatment results. Piperine, a major alkaloid found in the black and long pepper, has been demonstrated to have variety of pharmacological properties such as analgesic and anti-inflammatory effects. The present study was designed to investigate the effects of piperine on collagenase-induced Achilles tendon injury. Rats were intratendineously injected with collagenase in the right Achilles tendon, followed by intragastrical administration of piperine (100 mg/kg). Morphological structure and biochemical analysis of glycosaminoglycans, hydroxyproline, collagen III, and the activity of matrix metallopeptidases in the tendon tissues were performed. Our results showed that collagenase injection resulted in clear degenerative changes in the tendon. Administration of piperine improved the morphological structure of tendon, increased glycosaminoglycans and hydroxyproline levels, and inhibited the expression and activities of MMP-2 and MMP-9. Furthermore, piperine inhibited the activation of ERK and p38 signaling pathways in injured tendon. These results indicate a beneficial role of piperine against collagenase-induced tendon injury.

Enhanced anti-tumor efficacy and mechanisms associated with docetaxel-piperine combination- in vitro and in vivo investigation using a taxane-resistant prostate cancer model

Docetaxel (DTX) is widely used for metastatic castrated resistant prostate cancer, but its efficacy is often compromised by drug resistance associated with low intracellular concentrations. Piperine (PIP) could enhance the bioavailability of other drugs via the inhibition of CYPs and P-gp activities. Thus, we hypothesize a positive effect with the DTX-PIP combination on the anti-tumor efficacy and intra-tumor DTX concentrations in taxane-resistant prostate cancer. ICR-NOD/SCID mice implanted with taxane-resistant human prostate cancer cells were administrated with saline as well as PIP and DTX separately or in combination. The tumor growth was monitored together with intra-tumor concentrations of DTX. The inhibitory effects on CYPs and P-gp were further assessed in mouse liver microsome and MDCK-MDR1 cells. Compared with DTX alone, DTX-PIP combination significantly inhibited the tumor growth (114% vs. 217%, p = 0.002) with corresponding significantly higher intra-tumor DTX concentrations (5.854 ± 5.510 ng/ml vs. 1.312 ± 0.754 ng/mg, p = 0.037). The percentage of DTX metabolism was significantly decreased from 28.94 ± 1.06% to 18.14 ± 2.22% in mouse liver microsome after administration of PIP for two weeks. DTX accumulation in MDCK-MDR1 cell was significantly enhanced in the presence of PIP. Further microarray analysis revealed that PIP inhibited P-gp as well as CYP1B1 gene expression and induced a significant gene expression change relating to inflammatory response, angiogenesis, cell proliferation, or cell migration. In conclusion, DTX-PIP combination significantly induces activity against taxane-resistant prostate tumor. Such effect appeared to be attributed to the inhibitory effect of PIP on CYPs and P-gp activity as well as gene expression changes relating to tumorigenesis and cellular responses.

High-Throughput Screening Identifies 1,4,5-Substituted 1,2,3-Triazole Analogs as Potent and Specific Antagonists of Pregnane X Receptor

Human pregnane X receptor (hPXR) is a nuclear receptor that regulates the expression of phase I and phase II drug-metabolism enzymes, as well as that of drug transporters. hPXR is a "xenobiotics sensor" and can be activated by structurally diverse compounds. The activation of hPXR by its agonists increases the clearance of xenobiotics by increasing the expression of drug-metabolism enzymes and drug transporters, possibly leading to drug toxicity, drug resistance, and other adverse drug reactions. Therefore, hPXR antagonists might attenuate agonist-mediated activation of hPXR and reduce the risk of adverse drug reactions. Several hPXR antagonists have been reported, but none of them is specific for hPXR. In this study, we present the first large-scale, unbiased, cell-based high-throughput screen to identify specific hPXR antagonists. Among the 132,975 compounds screened, we identified the 1,4,5-substituted 1,2,3-triazole analogs as potent and specific hPXR antagonists by sequentially performing primary screening, retesting, and dose-response analysis using cell-based hPXR gene reporter and receptor binding assays, as well as receptor and promoter specificity assays. The compound SJ000076745-1 is the most potent and specific hPXR antagonist in the 1,4,5-substituted 1,2,3-triazole chemical class, having a cell-based hPXR antagonist 50% inhibitory concentration (IC₅₀) value of 377 ± 16 nM and an hPXR binding inhibitory IC₅₀ value of 563 ± 40 nM.

Recent Trends in Pharmacological Activity of Alkaloids in Animal Colitis: Potential Use for Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic and disrupted inflammation of the gastrointestinal tract. IBD have two main conditions, Crohn's disease and ulcerative colitis, and have been extensively investigated in recent years. Antibiotics derived from salicylates, steroids, immunosuppressors, and anti-TNF therapy are part of the therapeutic arsenal for IBD. However, very often patients stop responding to treatments over the time. In this context, searching for alternative agents is crucial for IBD clinical management. Natural products derived from medicinal plants are an interesting therapeutic alternative, since several studies have proven effective treatments in animal models of intestinal inflammation. Several naturally occurring compounds are potent antioxidants, both as free radical scavengers and as modulators of antioxidant enzymes expression and activity. A number of natural compounds have also been proved to inhibit the release of proinflammatory cytokines, decreasing the activation of nuclear factor κB (NF-κB), which is important to the inflammatory response in IBD. The alkaloids are substances of a very diverse class of plant secondary metabolites; an extensive list of biological activities has been attributed to alkaloids, such as being anticholinergic, antitumor, diuretic, antiviral, antihypertensive, antiulcer, analgesic, and anti-inflammatory. In the present work, studies on the pharmacological activity of alkaloids in experimental models of IBD were reviewed.