Piperine, a Bioactive Component of Pepper Spice Exerts Therapeutic Effects on Androgen Dependent and Androgen Independent Prostate Cancer Cells

Recent advances in dietary androgen receptor inhibitors

As a nuclear transcription factor, the androgen receptor (AR) plays a crucial role not only in normal male sexual differentiation and growth of the prostate, but also in benign prostatic hyperplasia, prostatitis, and prostate cancer. Multiple population-based epidemiological studies demonstrated that prostate cancer risk was inversely associated with increased dietary intakes of green tea, soy products, tomato, and so forth. Therefore, this review aimed to summarize the structure and function of AR, and further illustrate the structural basis for antagonistic mechanisms of the currently clinically available antiandrogens. Due to the limitations of these antiandrogens, a series of natural AR inhibitors have been identified from edible plants such as fruits and vegetables, as well as folk medicines, health foods, and nutritional supplements. Hence, this review mainly focused on recent experimental, epidemiological, and clinical studies about natural AR inhibitors, particularly the association between dietary intake of natural antiandrogens and reduced risk of prostatic diseases. Since natural products offer multiple advantages over synthetic antiandrogens, this review may provide a comprehensive and updated overview of dietary-derived AR inhibitors, as well as their potential for the nutritional intervention against prostatic disorders.

Promising Approaches in Plant-Based Therapies for Thyroid Cancer: An Overview of In Vitro, In Vivo, and Clinical Trial Studies

Thyroid cancer, particularly undifferentiated tumors, poses a significant challenge due to its limited response to standard therapies. The incidence of thyroid cancer, predominantly differentiated carcinomas, is on the rise globally. Anaplastic thyroid carcinoma (ATC), though rare, is highly aggressive and challenging to treat. Therefore, this study aimed to collect data and explore alternative treatments, focusing on the efficacy of photodynamic therapy (PDT) combined with natural compounds as well as the potential role of phytochemicals, including quercetin, kaempferol, apigenin, genistein, daidzein, naringenin, hesperitin, anthocyanidins, epigallocatechin gallate (EGCG), resveratrol, ellagic acid, ferulic acid, caffeic acid, curcumin, saponins, ursolic acid, indole-3-carbinol (I3C), capsaicin, and piperine in thyroid cancer treatment. PDT, utilizing sensitizers activated by tumor-directed light, demonstrates promising specificity compared to traditional treatments. Combining PDT with natural photosensitizers, such as hypericin and genistein, enhances cytotoxicity against thyroid carcinoma cells. This literature review summarizes the current knowledge on phytochemicals and their anti-proliferative effects in in vitro and in vivo studies, emphasizing their effectiveness and mechanism of action as a novel therapeutic approach for thyroid cancers, especially those refractory to standard treatments.

A combined in vitro and molecular dynamics simulation studies unveil the molecular basis of the anticancer potential of piperine targeting AKT1 against prostate cancer

The present study investigates the activity of the natural compound piperine on prostate cancer cell line (PC-3), followed by exploring its mechanistic inhibition on the RAC-alpha serine/threonine-protein kinase (AKT1) protein. The 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay showed that after 24 hrs of exposure to piperine (15 µmol/ml), cell viability fell to 50% compared to the standard drug flutamide (SDF) (51 µmol/ml) with a lower IC50 concentration. However, the Dual acridine orange/ethidium bromide (AO/EtBr) staining demonstrated that, as compared to the SDF, piperine caused substantial cellular death in PC-3 cells, presumably by triggering DNA fragmentation. In addition, compared to untreated cells, the proportion of the sub-G0/G1 and G2/M stages population increased considerably in piperine-treated cells. The cell cycle's sub-G0/G1 and G2/M phases were also arrested in piperine-treated cells compared to the SDF in cell cycle analysis. Based on our systems pharmacology and molecular docking studies, AKT1 is predicted as a potential target against piperine. The complementary charge between AKT1 and piperine was emphasized in the transient ligand-protein binding interaction in molecular dynamic modeling over 100 ns, and stable hydrogen bond interaction between Lys268 and Ser205 amino acid residues of the active pocket was hypothesized. Overall, the findings from our in vitro and MD simulations provide insights into the mechanism of piperine targeting AKT1 and offer a possible candidate for future prostate cancer therapeutic development.Communicated by Ramaswamy H. Sarma.

Investigating the structural basis of piperine targeting AKT1 against prostate cancer through in vitro and molecular dynamics simulations

AkT1, significantly impacts many tumours cell functions, like transcription, apoptosis, glucose metabolism, cell proliferation, and cell migration. For tumours to develop and spread, aberrant activation of AKT1 is essential. Therefore, a major focus of molecularly targeted PCa treatment is AKT1. The present study investigates the effect of piperine compared to SDF using in-vitro studies, viz colony formation assay, comet assay and AKT1 gene expression studies using human PCa cell line PC3. A cluster of approximately at least 50 cells constitutes a colony. The clonogenic assay showed that the number and size of colonies significantly decreased when treated with compounds (SDF and piperine) in comparison to the untreated cells which effectively proliferated to form more colonies. Piperine treatment showed significant inhibition of colony formation than SDF. Effective genotoxicity was observed in piperine-treated PC3 cells with an increased Tail length of 120 µm and it was moderately observed in SDF with a Tail length of 30 µm treated on PC3 cells. The control group did not show any considerable genotoxicity with a Tail length of 6 µm. Our data, both in vitro and in silico, suggested that piperine would be a good starting point for developing novel drugs for the treatment of PCa. The downstream functions of Akt1 may be inhibited by these effects, which could impede the proliferation of PCa cells. High stability of the piperine-AKT1 complex was found by the MD simulation. Higher hydrophilic residues like Lys268 and Ser205 at the active pocket may be the cause of the binding stability. Overall, the observed results confirmed the anti-PCa effect of piperine by causing effective DNA damage and proved to be genotoxic in nature against the human PCa. These effects may impede the downstream activities of Akt1 and result in PCa cell growth regression.Communicated by Ramaswamy H. Sarma.

Anticancer Potential of the Principal Constituent of Piper nigrum, Piperine: A Comprehensive Review

Black pepper's main component, piperine, is a phytochemical that gives the spice its distinctively pungent flavor, which has made it a staple in human diets for decades and a widely used food item. In addition to its use as a culinary component and preservation agent, it is also employed in traditional medicine for a diverse range of objectives, a practice that has been substantiated by existing scientific investigations on its physiological impacts in the majority of instances. Piperine contains various bioactive effects, such as antibacterial activity, in addition to several physiological benefits that could help overall human health, such as immunomodulatory, hepatoprotective, antioxidant, antimetastatic, anticancer, and many more properties that have been established. Clinical trials revealed that this phytochemical has exceptional antioxidant, anticancer, and drug availability-enhancing properties, as well as immunomodulatory potential. The different components of evidence indicate the therapeutic potential of piperine and underscore the importance of incorporating it into both broad health-promoting interventions and supplementary treatment pharmaceutical formulations. This inclusion can enhance the bioavailability of other therapeutic medications, including those used in chemotherapy.

Advanced application of nanotechnology in active constituents of Traditional Chinese Medicines

Traditional Chinese Medicines (TCMs) have been used for centuries for the treatment and management of various diseases. However, their effective delivery to targeted sites may be a major challenge due to their poor water solubility, low bioavailability, and potential toxicity. Nanocarriers, such as liposomes, polymeric nanoparticles, inorganic nanoparticles and organic/inorganic nanohybrids based on active constituents from TCMs have been extensively studied as a promising strategy to improve the delivery of active constituents from TCMs to achieve a higher therapeutic effect with fewer side effects compared to conventional formulations. This review summarizes the recent advances in nanocarrier-based delivery systems for various types of active constituents of TCMs, including terpenoids, polyphenols, alkaloids, flavonoids, and quinones, from different natural sources. This review covers the design and preparation of nanocarriers, their characterization, and in vitro/vivo evaluations. Additionally, this review highlights the challenges and opportunities in the field and suggests future directions for research. Nanocarrier-based delivery systems have shown great potential in improving the therapeutic efficacy of TCMs, and this review may serve as a comprehensive resource to researchers in this field.

Salinomycin mediated therapeutic targeting of circulating stem like cell population in oral cancer

CD44+ circulating tumor stem cells (CTSCs) have been significantly associated with aggressiveness, resistance and poor prognosis of oral cancer patients. Thus, targeted elimination of these CTSCs could be a new conceptual framework for enhancing the therapeutic outcome of patients. Docking of potential investigational molecules and simulation results identified Salinomycin as a potential lead compound that could effectively inhibit CD44 receptor. To assess the cytotoxic effect, immuno-magnetically sorted circulatory CD44+ cells were subjected to increasing concentrations of 5FU, Cisplatin and Salinomycin. Salinomycin demonstrated significant cytotoxic effect towards the CD44+ subpopulation in a dose and time dependent manner. Further the effect of these compounds was investigated on apoptosis, cell cycle, signaling pathways and gene expression profiles using Muse^TM flow cytometer and Real-Time PCR. It was observed that mRNA expression patterns of CD44v6, Nanog, AKT1, CDKN2A and β-catenin of Salinomycin treated CD44+ cells. Moreover, Salinomycin significantly induced programmed cell death by inducing G2/M cell cycle arrest and inhibiting MAPK/PI3K pathways in this chemo-resistant population. Thus, this study demonstrated the potential of Salinomycin to target the chemo-resistant circulating CD44 population by attenuating its proliferation and survival.Communicated by Ramaswamy H. Sarma.

Research Trend and Detailed Insights into the Molecular Mechanisms of Food Bioactive Compounds against Cancer: A Comprehensive Review with Special Emphasis on Probiotics

In an attempt to find a potential cure for cancer, scientists have been probing the efficacy of the food we eat and its bioactive components. Over the decades, there has been an exponentially increasing trend of research correlating food and cancer. This review explains the molecular mechanisms by which bioactive food components exhibit anticancer effects in several cancer models. These bioactive compounds are mainly plant based or microbiome based. While plants remain the primary source of these phytochemicals, little is known about probiotics, i.e., microbiome sources, and their relationships with cancer. Thus, the molecular mechanisms underlying the anticancer effect of probiotics are discussed in this review. The principal mode of cell death for most food bioactives is found to be apoptosis. Principal oncogenic signaling axes such as Akt/PI3K, JAK/STAT, and NF-κB seem to be modulated due to these bioactives along with certain novel targets that provide a platform for further oncogenic research. It has been observed that probiotics have an immunomodulatory effect leading to their chemopreventive actions. Various foods exhibit better efficacy as complete extracts than their individual phytochemicals, indicating an orchestrated effect of the food components. Combining bioactive agents with available chemotherapies helps synergize the anticancer action of both to overcome drug resistance. Novel techniques to deliver bioactive agents enhance their therapeutic response. Such combinations and novel approaches are also discussed in this review. Notably, most of the food components that have been studied for cancer have shown their efficacy in vivo. This bolsters the claims of these studies and, thus, provides us with hope of discovering anticancer agents in the food that we eat.

Phytochemicals in Inhibition of Prostate Cancer: Evidence from Molecular Mechanisms Studies

Prostate cancer is one of the leading causes of death for men worldwide. The development of resistance, toxicity, and side effects of conventional therapies have made prostate cancer treatment become more intensive and aggressive. Many phytochemicals isolated from plants have shown to be tumor cytotoxic. In vitro laboratory studies have revealed that natural compounds can affect cancer cell proliferation by modulating many crucial cellular signaling pathways frequently dysregulated in prostate cancer. A multitude of natural compounds have been found to induce cell cycle arrest, promote apoptosis, inhibit cancer cell growth, and suppress angiogenesis. In addition, combinatorial use of natural compounds with hormone and/or chemotherapeutic drugs seems to be a promising strategy to enhance the therapeutic effect in a less toxic manner, as suggested by pre-clinical studies. In this context, we systematically reviewed the currently available literature of naturally occurring compounds isolated from vegetables, fruits, teas, and herbs, with their relevant mechanisms of action in prostate cancer. As there is increasing data on how phytochemicals interfere with diverse molecular pathways in prostate cancer, this review discusses and emphasizes the implicated molecular pathways of cell proliferation, cell cycle control, apoptosis, and autophagy as important processes that control tumor angiogenesis, invasion, and metastasis. In conclusion, the elucidation of the natural compounds' chemical structure-based anti-cancer mechanisms will facilitate drug development and the optimization of drug combinations. Phytochemicals, as anti-cancer agents in the treatment of prostate cancer, can have significant health benefits for humans.

Combination Anticancer Therapies Using Selected Phytochemicals

Cancer is still one of the most widespread diseases globally, it is considered a vital health challenge worldwide and one of the main barriers to long life expectancy. Due to the potential toxicity and lack of selectivity of conventional chemotherapeutic agents, discovering alternative treatments is a top priority. Plant-derived natural products have high potential in cancer treatment due to their multiple mechanisms of action, diversity in structure, availability in nature, and relatively low toxicity. In this review, the anticancer mechanisms of the most common phytochemicals were analyzed. Furthermore, a detailed discussion of the anticancer effect of combinations consisting of natural product or natural products with chemotherapeutic drugs was provided. This review should provide a strong platform for researchers and clinicians to improve basic and clinical research in the development of alternative anticancer medicines.

Gambogic Acid and Piperine Synergistically Induce Apoptosis in Human Cholangiocarcinoma Cell via Caspase and Mitochondria-Mediated Pathway

Most cholangiocarcinoma (CCA) patients undergo chemotherapy as a therapeutic approach due to the disease's frequently late diagnosis. However, because CCA is resistant to currently available treatments, the prognosis for this cancer is still quite poor. Combination therapy has emerged as a novel and promising strategy in cancer treatment, as monotherapy frequently results in tumor recurrence and drug resistance. Gambogic acid has been shown to have a synergism with other compounds in combating certain cancer cells. Moreover, piperine has been shown to improve the efficacy of numerous chemotherapy drugs and other anticancer natural substances. However, no research has been done on the combination of these two compounds in the treatment of bile duct cancer. In this study, the cytotoxic activity was determined by using the MTT assay, and then, the combined effect was assessed by using the combination index (CI). We found that the combination of gambogic acid and piperine inhibited cell viability more effectively than either treatment alone, and it also demonstrated a synergistically cytotoxic effect against CCA cells. Interestingly, the findings allowed the use of lower concentrations of gambogic acid in cancer treatment when combined with piperine, which could reduce its adverse effect on normal cholangiocytes. Furthermore, the combination of the two compounds increased CCA cell death by inducing apoptosis via both the extrinsic and intrinsic or mitochondria-mediated pathways, as determined by caspase-3, -8, and -9 activity and the reduction of mitochondrial transmembrane potential (ΔΨm). It is possible that the use of these two natural compounds together could be a promising strategy for the treatment of bile duct cancer.

Molecular and pharmacological aspects of piperine as a potential molecule for disease prevention and management: evidence from clinical trials

BACKGROUND

Piperine is a type of amide alkaloid that exhibits pleiotropic properties like antioxidant, anticancer, anti-inflammatory, antihypertensive, hepatoprotective, neuroprotective and enhancing bioavailability and fertility-related activities. Piperine has the ability to alter gastrointestinal disorders, drug-metabolizing enzymes, and bioavailability of several drugs. The present review explores the available clinical and preclinical data, nanoformulations, extraction process, structure-activity relationships, molecular docking, bioavailability enhancement of phytochemicals and drugs, and brain penetration properties of piperine in the prevention, management, and treatment of various diseases and disorders.

MAIN BODY

Piperine provides therapeutic benefits in patients suffering from diabetes, obesity, arthritis, oral cancer, breast cancer, multiple myeloma, metabolic syndrome, hypertension, Parkinson's disease, Alzheimer's disease, cerebral stroke, cardiovascular diseases, kidney diseases, inflammatory diseases, and rhinopharyngitis. The molecular basis for the pleiotropic activities of piperine is based on its ability to regulate multiple signaling molecules such as cell cycle proteins, anti-apoptotic proteins, P-glycoprotein, cytochrome P450 3A4, multidrug resistance protein 1, breast cancer resistance protein, transient receptor potential vanilloid 1 proinflammatory cytokine, nuclear factor-κB, c-Fos, cAMP response element-binding protein, activation transcription factor-2, peroxisome proliferator-activated receptor-gamma, Human G-quadruplex DNA, Cyclooxygenase-2, Nitric oxide synthases-2, MicroRNA, and coronaviruses. Piperine also regulates multiple signaling pathways such as Akt/mTOR/MMP-9, 5'-AMP-activated protein kinase-activated NLR family pyrin domain containing-3 inflammasome, voltage-gated K+ current, PKCα/ERK1/2, NF-κB/AP-1/MMP-9, Wnt/β-catenin, JNK/P38 MAPK, and gut microbiota.

SHORT CONCLUSION

Based on the current evidence, piperine can be the potential molecule for treatment of disease, and its significance of this molecule in the clinic is discussed.

GRAPHICAL ABSTRACT

Anticancer Applications and Pharmacological Properties of Piperidine and Piperine: A Comprehensive Review on Molecular Mechanisms and Therapeutic Perspectives

Piperine and piperidine are the two major alkaloids extracted from black pepper (Piper nigrum); piperidine is a heterocyclic moiety that has the molecular formula (CH₂)₅NH. Over the years, many therapeutic properties including anticancer potential of these two compounds have been observed. Piperine has therapeutic potential against cancers such as breast cancer, ovarian cancer, gastric cancer, gliomal cancer, lung cancer, oral squamous, chronic pancreatitis, prostate cancer, rectal cancer, cervical cancer, and leukemia. Whereas, piperidine acts as a potential clinical agent against cancers, such as breast cancer, prostate cancer, colon cancer, lung cancer, and ovarian cancer, when treated alone or in combination with some novel drugs. Several crucial signalling pathways essential for the establishment of cancers such as STAT-3, NF-κB, PI3k/Aκt, JNK/p38-MAPK, TGF-ß/SMAD, Smac/DIABLO, p-IκB etc., are regulated by these two phytochemicals. Both of these phytochemicals lead to inhibition of cell migration and help in cell cycle arrest to inhibit survivability of cancer cells. The current review highlights the pharmaceutical relevance of both piperine and piperidine against different types of cancers.

Therapeutic spectrum of piperine for clinical practice: a scoping review

Translation of traditional knowledge of herbs into a viable product for clinical use is still an uphill task. Piperine, a pungent alkaloid molecule derived from Piper nigrum and Piper longum possesses diverse pharmacological effects. Traditionally, pepper is used for arthritis, bronchitis, gastritis, diarrhea, snake bite, menstrual pain, fever, and bacterial infections, etc. The anti-inflammatory, antioxidant and immunomodulatory actions of piperine are the possible mechanisms behind its therapeutic potential. Various in-silico and experimental studies have shown piperine as a possible promising molecule in coronavirus disease (COVID-19), ebola, and dengue due to its immunomodulatory and antiviral activities. The other important clinical applications of piperine are due to its bio enhancing effect on drugs, by modulating, absorption in the gastrointestinal tract, altering activities of transporters like p-glycoprotein substrates, and modulating drug metabolism by altering the expression of cytochrome P450 or UDP-glucuronosyltransferase enzymes. Piperine attracted clinicians in treating patients with arthritis, metabolic syndrome, diabetes, skin infections, gastric and liver disorders. This review focused on systematic, evidence-based insight into the use of piperine in clinical settings and mechanistic details behind its therapeutic actions. Also, highlights a number of clinical trials of piperine at various stages exploring its clinical application in cancer, neurological, respiratory, and viral disease, etc.

Prostate cancer: Therapeutic prospect with herbal medicine

Prostate cancer (PCa) is a major cause of morbidity and mortality in men worldwide. A geographic variation on the burden of the disease suggested that the environment, genetic makeup, lifestyle, and food habits modulate one's susceptibility to the disease. Although it has been generally thought to be an older age disease, and awareness and timely execution of screening programs have managed to contain the disease in the older population over the last decades, the incidence is still increasing in the population younger than 50. Existing treatment is efficient for PCa that is localized and responsive to androgen. However, the androgen resistant and metastatic PCa are challenging to treat. Conventional radiation and chemotherapies are associated with severe side effects in addition to being exorbitantly expensive. Many isolated phytochemicals and extracts of plants used in traditional medicine are known for their safety and diverse healing properties, including many with varying levels of anti-PCa activities. Many of the phytochemicals discussed here, as shown by many laboratories, inhibit tumor cell growth and proliferation by interfering with the components in the pathways responsible for the enhanced proliferation, metabolism, angiogenesis, invasion, and metastasis in the prostate cells while upregulating the mechanisms of cell death and cell cycle arrest. Notably, many of these agents simultaneously target multiple cellular pathways. We analyzed the available literature and provided an update on this issue in this review article.

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Prostate cancer in a major cause of death in older population worldwide.

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Efficacies of current treatment options are limited in many cases.

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Phytochemicals and extracts isolated from plants show anti-prostate cancer activity with unique mechanisms.

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Certain phytochemicals alone or in combination with current chemotherapy show therapeutic promise.

Immunometabolism modulation, a new trick of edible and medicinal plants in cancer treatment

The edible and medicinal plants (EMPs) are becoming an abundant source for cancer prevention and treatment since the natural and healthy trend for modern human beings. Currently, there are more than one hundred species of EMPs widely used and listed by the national health commission of China, and most of them indicate immune or metabolic regulation potential in cancer treatment with numerous studies over the past two decades. In the present review, we focused on the metabolic influence in immunocytes and tumor microenvironment, including immune response, immunosuppressive factors and cancer cells, discussing the immunometabolic potential of EMPs in cancer treatment. There are more than five hundred references collected and analyzed through retrieving pharmacological studies deposited in PubMed by medical subject headings and the corresponding names derived from pharmacopoeia of China as a sole criterion. Finally, the immunometabolism modulation of EMPs was sketch out implying an immunometabolic control in cancer treatment.

Protective effect of the association of curcumin with piperine on prostatic lesions: New perspectives on BPA-induced carcinogenesis

Bisphenol A (BPA) is a chemical agent which can exert detrimental effects on the male reproductive system, especially the prostate gland. In this study we described the efficacy of the dietary agent curcumin, alone or combined with piperine, to suppress the impact of BPA on the prostate. Adult gerbils were divided into nine experimental groups (n = 7 each group), regarding control (water and oil), exposed to BPA (50 μg/kg/day in water) or curcumin (100 mg/kg) and/or piperine (20 mg/kg). To evaluate the effects of the phytotherapic agents, the other groups received oral doses every two days, BPA plus curcumin (BCm), piperine (BP), and curcumin + piperine (BCmP). BPA promoted prostatic inflammation and morphological lesions in ventral and dorsolateral prostate lobes, associated with an increase in androgen receptor-positive cells and nuclear atypia, mainly in the ventral lobe. Curcumin and piperine helped to minimize these effects. BPA plus piperine or curcumin showed a reduction in nuclear atypical phenotype, indicating a beneficial effect of phytochemicals. Thus, these phytochemicals minimize the deleterious action of BPA in prostatic lobes, especially when administered in association. The protective action of curcumin and piperine consumption is associated with weight loss, anti-inflammatory potential, and control of prostate epithelial cell homeostasis.

Naturally occurring heterocyclic anticancer compounds

Naturally occurring heterocyclic scaffolds are key ingredients for the development of various therapeutics employed for biomedical applications. Heterocyclic pharmacophores are widely disseminated and have been befallen in almost all categories of drugs for the alleviation of myriad ailments including diabetes, neurodegenerative, psychiatric, microbial infections, disastrous cancers etc. Countless fused heterocyclic anticancerous templates are reported to display antimetabolite, antioxidant, antiproliferative, cytostatic etc. pharmacological actions via targeting different signaling pathways (cell cycle, PI-3kinase/Akt, p53, caspase extrinsic pathway etc.), overexpressive receptors (EGRF, HER2, EGF, VEGF etc.) and physiological enzymes (topoisomerase I and II, cyclin dependent kinase etc.). A compiled description on various natural sources (plants, microbes, marine) containing anticancer agents comprising heterocyclic ring specified with presence of nitrogen (vincristine, vinblastine, indole-3-carbinol, meridianins, piperine, lamellarins etc.), oxygen (paclitaxel, halichondrin B, quercetin, myricetin, kaempferol etc.) and sulphur atoms (brugine, fucoidan, carrageenan etc.) are displayed here along with their molecular level cytotoxic action and therapeutic applications.

Anti-inflammatory and antioxidant effects of nanoformulations composed of metal-organic frameworks delivering rutin and/or piperine natural agents

Plant-derived natural medicines have been extensively studied for anti-inflammatory or antioxidant properties, but challenges to their clinical use include low bioavailability, poor solubility in water, and difficult-to-control release kinetics. Nanomedicine may offer innovative solutions that can enhance the therapeutic activity and control release kinetics of these agents, opening the way to translating them into the clinic. Two agents of particular interest are rutin (Ru), a flavonoid, and piperine (Pip), an alkaloid, which exhibit a range of pharmacological activities that include antioxidant and anti-inflammatory effects. In this work, nanoformulations were developed consisting of two metal–organic frameworks (MOFs) with surface modifications, Ti-MOF and Zr-MOF, each of them loaded with Ru and/or Pip. Both MOFs and nanoformulations were characterized and evaluated in vivo for anti-inflammatory and antioxidant effects. Loadings of ∼17 wt.% for a single pro-drug and ∼27 wt.% for dual loading were achieved. The release patterns for Ru and or Pip followed two stages: a zero-order for the first 12-hour stage, and a second stage of stable sustained release. At pH 7.4, the release patterns best fit to zero-order and Korsmeyer–Peppas kinetic models. The nanoformulations had enhanced anti-inflammatory and antioxidant effects than any of their elements singly, and those with Ru or Pip alone showed stronger effects than those with both agents. Results of assays using a paw edema model, leukocyte migration, and plasma antioxidant capacity were in agreement. Our preliminary findings indicate that nanoformulations with these agents exert better anti-inflammatory and antioxidant effects than the agents in their free form.

Phytochemistry and therapeutic potential of black pepper [Piper nigrum (L.)] essential oil and piperine: a review

Background

Black pepper [Piper nigrum (L.), Family: Piperaceae] is used traditionally for the treatment of various diseases including; cough, cold, dyspnea throat diseases, intermittent fever, dysentery, stomachache, worms and piles. The pharmacological potential of black pepper is due to the presence of metabolites like phenolic compounds, alkaloids, flavonoids, carotenoids, terpenoids, etc. The multipurpose use of black pepper dried seeds has several other beneficial health effects that also received in the light of traditional as well as current medicine perspectives. The review aims to discuss the botany, phytochemical constituents, and pharmacological properties of piperine and black pepper essential oil (BPEO).

Results

Phytochemical analyses have described the main chemical constituents of black pepper, including carbohydrates, proteins, calcium, magnesium, potassium, iron, vitamin C, tannins, flavonoids and carotenoids. The volatile oil content ranges from 0.4 to 7 % in dried berries. The major constituents of BPEO are sabinene, 3-carene, D-limonene, α-pinene, caryophyllene, β-phellandrene, α-phellandrene, α-thujene, and β-bisabolene. Additionally, piperine is the naturally occurring and principal bioactive alkaloid constituent of black pepper owing to its potential therapeutic properties, including cerebral brain functioning and increased nutrient absorption. The BPEO has several biological roles, including antioxidant, anti-inflammatory, anticancer, anti-obesity, antidepressant, antidiabetic, antimicrobial, gastroprotective, and insecticidal activities.

Conclusions

This review examines and presents the appropriate evidence on black pepper and its traditional uses as well as biological activities of BPEO and piperine. Although several previous reports showed diverse biological effects for piperine and bioactive constitutes of BPEO. Thus, minimal investigations were conducted using animal models, and many of these studies also lacked appropriate experimental setting like doses, control details. Hence, future studies are necessary to understand the mechanism of piperine, BPEO, bioactive constituents and their effects upon their use by animal models and humans with the proper experimental procedure which we can facilitate the protection of human health from several diseases.

Biang E, T. Tchinda A, Djomeni Dzeufiet DP, Agbor GA. Cafeteria Diet-Induced Metabolic and Cardiovascular Changes in Rats: The Role of Piper nigrum Leaf Extract

BACKGROUND

Cafeteria diet is known to induce excessive body fat accumulation (obesity) that could cause metabolic and cardiovascular changes and even death. The increase in prevalence over time and the failure in treatment options make obesity a real public health problem. The present study assessed the preventive effect of the hydro-ethanolic extract of the Piper nigrum leaf on the development of metabolic and cardiovascular changes in cafeteria diet fed Wistar rats.

METHODS

Thirty-six male rats were divided into 5 groups of 6 rats each: a normal control group (Nor.), a negative control group (Neg.), two groups administered different doses of extract in mg/kg (E250 and E500), and a group administered atorvastatin 10 mg/kg (Ator., reference drug). The animals were fed with experimental diets (standard and cafeteria) for a period of 5 weeks. Food and water intake were assessed daily, and the body weight assessed weekly. At the end of the feeding, plasma lipid profile and markers of hepatic and renal function were assessed. Furthermore, the relative weights of the adipose tissue and the organs were assessed. The liver, kidneys, and heart homogenates were assessed for markers of oxidative stress while the aorta was histopathologically examined.

RESULTS

Cafeteria diet-induced weight gain of 30% and increased triglyceride, total cholesterol, and low-density lipoprotein cholesterol level of more than 50%. Equally, an increase in the relative weight of accumulated adipose tissues of more than 90%, oxidative stress, and alteration in the organ structure were visible in cafeteria diet fed rats (Neg). Treatment with P. nigrum extract significantly prevented weight gain, dyslipidemia, oxidative stress, and alteration in the architecture of the aorta. The effect of P. nigrum extract was comparable to that of the reference drug.

CONCLUSION

Piper nigrum leaf may prevent weight gain and possess cardioprotective activity with a strong antioxidant activity.

Comparative binding analysis of noscapine and piperine with tRNA: A structural perturbation and energetic study

In this study, we have exploring the binding mechanisms of the two anticancer alkaloid noscapine (NOS) and piperine (PIP) with tRNA using different spectroscopy and computational method. Absorbance and emission spectra revealed that both the drugs show strong binding with tRNA, where NOS intercalate between the base pairs of tRNA and PIP binds in the groove of tRNA. Competitive binding study and steady state anisotropy further confirms the intercalative mode of binding between NOS and tRNA and groove binding in PIP-tRNA complex. The observed thermodynamic parameters suggested that NOS-tRNA complex formation is endothermic and entropy driven, however it was exothermic, and enthalpy driven in case of PIP-tRNA complex. CD and time resolved fluorescence studies show the structural perturbations and conformational change in tRNA structure with NOS as well as PIP. Molecular docking studies are comparable with experimental results and further confirmed that the hydrophobic interactions involved in the NOS-tRNA binding, whereas hydrogen binding and van der Waals interactions play important role in the PIP-tRNA complex formation. This study can be useful to understand the potential binding and resultant tRNA damage by alkaloids and deigned new target specific anticancer drug.

Overview of the Anticancer Potential of the "King of Spices" Piper nigrum and Its Main Constituent Piperine

The main limits of current anticancer therapy are relapses, chemoresistance, and toxic effects resulting from its poor selectivity towards cancer cells that severely impair a patient's quality of life. Therefore, the discovery of new anticancer drugs remains an urgent challenge. Natural products represent an excellent opportunity due to their ability to target heterogenous populations of cancer cells and regulate several key pathways involved in cancer development, and their favorable toxicological profile. Piper nigrum is one of the most popular spices in the world, with growing fame as a source of bioactive molecules with pharmacological properties. The present review aims to provide a comprehensive overview of the anticancer potential of Piper nigrum and its major active constituents-not limited to the well-known piperine-whose undeniable anticancer properties have been reported for different cancer cell lines and animal models. Moreover, the chemosensitizing effects of Piper nigrum in association with traditional anticancer drugs are depicted and its toxicological profile is outlined. Despite the promising results, human studies are missing, which are crucial for supporting the efficacy and safety of Piper nigrum and its single components in cancer patients.

Piperine Inhibits TGF-β Signaling Pathways and Disrupts EMT-Related Events in Human Lung Adenocarcinoma Cells

Background: Piperine, an amide extracted from the Piper spices, exhibits strong anti-tumor properties. However, its effect on the epithelial–mesenchymal transition (EMT) process has never been investigated. Herein, we evaluate the toxic effect of piperine on lung adenocarcinoma (A549), breast adenocarcinoma (MDA-MB-231) and hepatocellular carcinoma (HepG2) cell lines, as well as its ability to inhibit EMT-related events induced by TGF-β1 treatment. Methods: The cell viability was investigated by MTT assay. Protein expression was evaluated by Western blot. Gene expression was monitored by real-time PCR. Zymography assay was employed to detect metalloproteinase (MMP) activity in conditioned media. Cell motility was assessed by the wound-healing and phagokinetic gold sol assays. Results: The results revealed that piperine was cytotoxic in concentrations over 100 µM, showing IC50 values for HepG2, MDA-MB-231 and A549 cell lines of 214, 238 and 198 µM, respectively. In order to investigate whether piperine would reverse the TGF-β1 induced-EMT, the A549 cell line was pretreated with sublethal concentrations of the natural amide followed by the addition of TGF-β1. Besides disrupting EMT-related events, piperine also inhibited both ERK 1/2 and SMAD 2 phosphorylation. Conclusions: These results suggest that piperine might be further used in therapeutic strategies for metastatic cancer and EMT-related disorders.

The Antiglycation Effect of Monomethyl Branched Chained Fatty Acid and Phytochemical Compounds and their Synergistic Effect on Obesity Related Colorectal Cancer Cell Panel

Background and aims: monomethyl branched chain fatty acids (mmBCFA) and phytochemicals including: Hydroxycitric Acid, Chlorogenic Acid and Piperine have been considered as an interesting agent for researches due to their role in diabetes and cancer. The present study examines the antiglycation effect of mmBCFA and phytochemicals and investigate their Synergistic effect on different colorectal cancer cell lines.

Methods: This study was carried out by using murine monocyte-macrophage cell line and Methylglyoxal (MGO) to enhance the glycation process, furthermore to examine the antiproliferative effect of both the mmBCFA and phytochemicals we use Sulforhodamine B (SRB) assay against obesity related-colorectal cancer cell line panel.

Results: Both phytochemicals and mmBCFA have a higher antiglycation effect than Aminoguanidine (AMG) significantly, moreover, all of the phytochemicals and mmBCFA have antiproliferative against SW620, CACO2 and SW480, nevertheless none of these agents was equipotent to Cisplatin, furthermore, the synergetic effect observed only when we co-incubate Piperine with mmBCFA.

Conclusions: phytochemicals such as Hydroxycitric Acid, Chlorogenic Acid and Piperine and mmBCFA could be used as treatment to prevents the accumulation of advanced glycation end-products (AGEs) in diabetes. Furthermore, the co-incubation between these compounds can inhibit cancer growth, as alternative therapeutic strategy against obesity related-colorectal cancer.

Effective Targeting of Colon Cancer Cells with Piperine Natural Anticancer Prodrug Using Functionalized Clusters of Hydroxyapatite Nanoparticles

Targeted drug delivery offers great opportunities for treating cancer. Here, we developed a novel anticancer targeted delivery system for piperine (Pip), an alkaloid prodrug derived from black pepper that exhibits anticancer effects. The tailored delivery system comprises aggregated hydroxyapatite nanoparticles (HAPs) functionalized with phosphonate groups (HAP-Ps). Pip was loaded into HAPs and HAP-Ps at pH 7.2 and 9.3 to obtain nanoformulations. The nanoformulations were characterized using several techniques and the release kinetics and anticancer effects investigated in vitro. The Pip loading capacity was >20%. Prolonged release was observed with kinetics dependent on pH, surface modification, and coating. The nanoformulations fully inhibited monolayer HCT116 colon cancer cells compared to Caco2 colon cancer and MCF7 breast cancer cells after 72 h, whereas free Pip had a weaker effect. The nanoformulations inhibited ~60% in HCT116 spheroids compared to free Pip. The Pip-loaded nanoparticles were also coated with gum Arabic and functionalized with folic acid as a targeting ligand. These functionalized nanoformulations had the lowest cytotoxicity towards normal WI-38 fibroblast cells. These preliminary findings suggest that the targeted delivery system comprising HAP aggregates loaded with Pip, coated with gum Arabic, and functionalized with folic acid are a potentially efficient agent against colon cancer.

Two Natural Alkaloids Synergistically Induce Apoptosis in Breast Cancer Cells by Inhibiting STAT3 Activation

Breast cancer has become a worldwide threat, and chemotherapy remains a routine treatment. Patients are forced to receive continuous chemotherapy and suffer from severe side effects and poor prognosis. Natural alkaloids, such as piperine (PP) and piperlongumine (PL), are expected to become a new strategy against breast cancer due to their reliable anticancer potential. In the present study, cell viability, flow cytometry, and Western blot assays were performed to evaluate the suppression effect of PP and PL, alone or in combination. Data showed that PP and PL synergistically inhibited breast cancer cells proliferation at lower doses, while only weak killing effect was observed in normal breast cells, indicating a good selectivity. Furthermore, apoptosis and STAT3 signaling pathway-associated protein levels were analyzed. We demonstrated that PP and PL in combination inhibit STAT3 phosphorylation and regulate downstream molecules to induce apoptosis in breast cancer cells. Taken together, these results revealed that inactivation of STAT3 was a novel mechanism with treatment of PP and PL, suggesting that combination application of natural alkaloids may be a potential strategy for prevention and therapy of breast cancer.

Ionic Liquid Green Assembly-Mediated Migration of Piperine from Calf-Thymus DNA: A New Possibility of the Tunable Drug Delivery System

Biocompatible surface-active ionic liquid (SAIL) was used first to study the deintercalation process of a well-known natural compound piperine (PIP) as an anticancer drug, obtained from PIP-calf thymus DNA (ctDNA) complex under controlled experimental conditions. In this study, we have been exploring the interaction of PIP in SAIL (1-butyl-3-methylimidazolium octyl sulfate ionic liquid ([C₄mim][C₈OSO₃])), ctDNA, and deintercalation of PIP from the PIP-ctDNA complex through SAIL micelle using various spectroscopic techniques. Absorption, emission, and lifetime decay measurements provide strong evidence of the relocation of PIP molecules from ctDNA to SAIL micelle. Fluorescence quenching and steady-state fluorescence anisotropy were employed to examine the exact location of PIP in different media. Moreover, the surface tension technique was also employed to confirm the release of PIP molecules from the PIP-ctDNA complex in the presence of SAIL. Circular dichroism analysis suggested that SAIL micelle does not perturb the ctDNA structure, which supported the fact that SAIL micelle can be used as a safe vehicle for PIP. Overall, the study highlighted a novel strategy for deintercalation of drug using SAIL because the release of the drug can be controlled over a period by varying the concentration and composition of the SAIL.

Piperine-A Major Principle of Black Pepper: A Review of Its Bioactivity and Studies

Piperine is the main compound present in black pepper, and is the carrier of its specific pungent taste, which is responsible for centuries of human dietary utilization and worldwide popularity as a food ingredient. Along with the application as a food ingredient and food preservative, it is used in traditional medicine for many purposes, which has in most cases been justified by modern scientific studies on its biological effects. It has been confirmed that piperine has many bioactive effects, such as antimicrobial action, as well as many physiological effects that can contribute to general human health, including immunomodulatory, hepatoprotective, antioxidant, antimetastatic, antitumor, and many other activities. Clinical studies demonstrated remarkable antioxidant, antitumor, and drug availability-enhancing characteristics of this compound, together with immunomodulatory potential. All these facts point to the therapeutic potential of piperine and the need to incorporate this compound into general health-enhancing medical formulations, as well as into those that would be used as adjunctive therapy in order to enhance the bioavailability of various (chemo)therapeutic drugs.

Piperine: role in prevention and progression of cancer

Cancer is among the leading causes of death worldwide. Several pharmacological protocols have been developed in order to block tumor progression often showing partial efficacy and severe counterproductive effects. It is now conceived that a healthy lifestyle coupled with the consumption of certain phytochemicals can play a protective role against tumor development and progression. According to this vision, it has been introduced the concept of "chemoprevention". This term refers to natural agents with the capability to interfere with the tumorigenesis and metastasis, or at least, attenuate the cancer-related symptoms. Piperine (1-Piperoylpiperidine), a main extract of Piper longum and Piper nigrum, is an alkaloid with a long history of medicinal use. In fact, it exhibits a variety of biochemical and pharmaceutical properties, including chemopreventive activities without significant cytotoxic effects on normal cells, at least at doses < of 250 µg/ml. The aim of this review is to discuss the relevant molecular and cellular mechanisms underlying the chemopreventive action of this natural alkaloid.

ROS-Mediated Cancer Cell Killing through Dietary Phytochemicals

Reactive oxygen species (ROS) promote carcinogenesis by inducing genetic mutations, activating oncogenes, and raising oxidative stress, which all influence cell proliferation, survival, and apoptosis. Cancer cells display redox imbalance due to increased ROS level compared to normal cells. This unique feature in cancer cells may, therefore, be exploited for targeted therapy. Over the past few decades, natural compounds have attracted attention as potential cancer therapies because of their ability to maintain cellular redox homeostasis with minimal toxicity. Preclinical studies show that bioactive dietary polyphenols exert antitumor effects by inducing ROS-mediated cytotoxicity in cancer cells. These bioactive compounds also regulate cell proliferation, survival, and apoptotic and antiapoptotic signalling pathways. In this review, we discuss (i) how ROS is generated and (ii) regulated and (iii) the cell signalling pathways affected by ROS. We also discuss (iv) the various dietary phytochemicals that have been implicated to have cancer therapeutic effects through their ROS-related functions.

Phytochemical and pharmacological attributes of piperine: A bioactive ingredient of black pepper

Plants are vital for the wellbeing of humankind in a variety of ways. Some plant extracts contain antimicrobial properties that can treat different pathogens. Most of the world's population relies on medicinal plants and natural products for their primary health care needs. Therefore, there is a growing interest in natural products, medicinal plants, and traditional medicine along with a desire to design and develop novel plant-based pharmaceuticals. These plant-based pharmaceuticals may address the concerns of reduced efficacy of synthetic antibiotics due to the emergence of drug-resistant pathogens. In this regard, some plant extracts from black pepper (Piper nigrum) with antimicrobial properties, including piperine, have the potential to be used as natural dietary supplements together with modern therapeutic approaches. This review highlights possible applications of piperine as the active compound in the fields of rational drug design and discovery, pharmaceutical chemistry, and biomedicine. We discuss different extraction methods and pharmacological effects of the analyzed substance to pave the way for further research strategies and perspectives towards the development of novel herbal products for better healthcare solutions.

Sensitive detection of Piper nigrum L. adulterants by a novel screening approach based on qPCR

The spice made from the fruits of Piper nigrum L. (Piperaceae) has high economic value since the beginnings of international trade. Because its price has been increasing, adulterations with papaya seeds, cayenne pepper and maize flour were reported. These have been screened by methodologies dedicated to the detection of single adulterants lacking sensitivity and specificity. Herein we propose a specific, highly-sensitive, high-throughput and affordable qPCR-based methodology for the detection of P. nigrum contaminants (Carica papaya, Zea mays and Capsicum annuum) using plant DNA barcodes trnL and psbA-trnH. The method enables the specific detection of contaminants in a short time with low limits of detection (LOD₆ values of 1, 2 and 10 Haploid Genome Equivalents). A market survey (29 samples) revealed 41% of samples contaminated, though about ¾ at very low levels indicating accidental contamination. The proposed tool will contribute to the improvement of quality of this much traded spice.

Hesperidin, piperine and bee venom synergistically potentiate the anticancer effect of tamoxifen against breast cancer cells

Despite advances in cancer treatment, breast cancer remains one of the main life threatening diseases in women. Most anti-breast cancer drugs cause severe health complications and multidrug resistance. Although, some natural products, such as hesperidin (Hes), piperine (Pip) and bee venom (BV), showed anti-breast cancer effect when used separately, their combined effect together or with the anti-cancer drug tamoxifen (Tam) has not yet been studied. Herein, we hypothesized that these three natural products could potentiate the therapeutic effect of Tam when used together. First, we studied the cytotoxic effect of Hes, Pip, and BV on MCF7 and T47D cells using MTT assay and found reasonable IC₅₀ comparable to that of Tam. Second, we checked the effect of all combinations (n = 67 for each cell line, prepared as non-constant ratio from fractions of IC₅₀ of the four compounds) and found enhanced anti-proliferative effects on MCF7 and T47D and synergistic effect, revealed by combination index (CI) values below one. Next, the best 5 combinations with lowest Tam doses and CI but with highest cell death were selected for further molecular analysis in comparison to single-drug treatment. All single- and combined-treated groups showed a significant increase in apoptosis (indicated by upregulated mRNA level of the pro-apoptotic marker Bax and downregulated mRNA level of the anti-apoptotic marker Bcl2) and a significant decrease in mRNA level of the two breast cancer related receptors EGFR and ERα, with the best effect in combined groups especially that contained the 4 compounds, as compared to vehicle-treated group. Moreover, Pip, BV and all combinations, except Tam + Hes group, arrested MCF7 and T47D in G2/M phase of cell cycle, while Tam and/or Hes caused G0/G1 phase arrest. These results indicate that Hes, Pip and BV synergistically enhance the anti-cancer effect of Tam and could be used as safe adjuvant/vehicle to Tam in treatment of breast cancer after further confirmatory in vivo investigations.

Diverged Effects of Piperine on Testicular Development: Stimulating Leydig Cell Development but Inhibiting Spermatogenesis in Rats

Background: Piperine is the primary pungent alkaloid isolated from the fruit of black peppercorns. Piperine is used frequently in dietary supplements and traditional medicines. The objective of the present study was to investigate the effects of piperine on the testis development in the pubertal rat.

Methods: Piperine (0 or 5 or 10 mg/kg) was gavaged to 35-day-old male Sprague-Dawley rats for 30 days. Serum levels of testosterone (T), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were measured. The development of adult Leydig cell population was also analyzed 65 days postpartum. For in vitro studies, immature Leydig cells were isolated from 35-day-old male rats and treated with 50 μM piperine in the presence of different steroidogenic stimulators/substrates for 24 h.

Results: Thirty-day treatment of rats with piperine significantly increased serum T levels without affecting LH concentrations. However, piperine treatment reduced serum FSH levels. Consistent with increase in serum T, piperine increased Leydig cell number, cell size, and multiple steroidogenic pathway proteins, including steroidogenic acute regulatory protein, cholesterol side-chain cleavage enzyme, 3β-hydroxysteroid dehydrogenase 1, 17α-hydroxylase/20-lyase, and steroidogenic factor 1 expression levels. Piperine significantly increased the ratio of phospho-AKT1 (pAKT1)/AKT1, phosphos-AKT2 (pAKT2)/AKT2, and phospho-ERK1/2 (pERK1/2)/ERK1/2 in the testis. Interestingly, piperine inhibited spermatogenesis. Piperine in vitro also increased androgen production and stimulated cholesterol side-chain cleavage enzyme and 17α-hydroxylase/20-lyase activities in immature Leydig cells.

Conclusion: Piperine stimulates pubertal Leydig cell development by increasing Leydig cell number and promoting its maturation while it inhibits spermatogenesis in the rat. ERK1/2 and AKT pathways may involve in the piperine-mediated stimulation of Leydig cell development.

Piperine depresses the migration progression via downregulating the Akt/mTOR/MMP‑9 signaling pathway in DU145 cells

Piperine, an alkaloid derived from natural products, has been demonstrated to exert antitumor activities in vivo and in vitro. However, its anti-tumor effect has not yet been illustrated in the prostate cancer (PCa) metastatic process. Thus, the present study explored the influence of piperine on PCa and the underlying molecular mechanism. Cell migration was detected via the Transwell chamber model. Total protein was identified by western blot analysis. The data revealed that piperine markedly repressed cell proliferation and migration, and induced apoptosis in PCa DU145. In addition, LY294002, an protein kinase B (Akt) inhibitor, greatly suppressed the expression level of phospho (p)-Akt, matrix metalloproteinase (MMP)-9 and p-mammalian target of rapamycin (mTOR), suggesting that the activation of the Akt/mTOR/MMP-9 signaling pathway may participate in regulating cell migration in PCa. Furthermore, piperine reduced the expression of p-Akt, MMP-9 and p-mTOR. Together, these data indicated that piperine may serve as a promising novel therapeutic agent to better overcome PCa metastasis.

Cancer Chemoprevention and Piperine: Molecular Mechanisms and Therapeutic Opportunities

Cancer is a genetic disease characterized by unregulated growth and dissemination of malignantly transformed neoplastic cells. The process of cancer development goes through several stages of biochemical and genetic alterations in a target cell. Several dietary alkaloids have been found to inhibit the molecular events and signaling pathways associated with various stages of cancer development and therefore are useful in cancer chemoprevention. Cancer chemoprevention has long been recognized as an important prophylactic strategy to reduce the burden of cancer on health care system. Cancer chemoprevention assumes the use of one or more pharmacologically active agents to block, suppress, prevent, or reverse the development of invasive cancer. Piperine is an active alkaloid with an excellent spectrum of therapeutic activities such as anti-oxidant, anti-inflammatory, immunomodulatory, anti-asthmatic, anti-convulsant, anti-mutagenic, antimycobacterial, anti-amoebic, and anti-cancer activities. In this article, we made an attempt to sum up the current knowledge on piperine that supports the chemopreventive potential of this dietary phytochemical. Many mechanisms have been purported to understand the chemopreventive action of piperine. Piperine has been reported to inhibit the proliferation and survival of many types of cancer cells through its influence on activation of apoptotic signaling and inhibition of cell cycle progression. Piperine is known to affect cancer cells in variety of other ways such as influencing the redox homeostasis, inhibiting cancer stem cell (CSC) self-renewal and modulation of ER stress and autophagy. Piperine can modify activity of many enzymes and transcription factors to inhibit invasion, metastasis, and angiogenesis. Piperine is a potent inhibitor of p-glycoprotein (P-gp) and has a significant effect on the drug metabolizing enzyme (DME) system. Because of its inhibitory influence on P-gp activity, piperine can reverse multidrug resistance (MDR) in cancer cells and acts as bioavailability enhancer for many chemotherapeutic agents. In this article, we emphasize the potential of piperine as a promising cancer chemopreventive agent and the knowledge we collected in this review can be applied in the strategic design of future researches particularly human intervention trials with piperine.

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.

Antiobesity potential of Piperonal: promising modulation of body composition, lipid profiles and obesogenic marker expression in HFD-induced obese rats

Background

Black pepper or Piper nigrum is a well-known spice, rich in a variety of bioactive compounds, and widely used in many cuisines across the world. In the Indian traditional systems of medicine, it is used to treat gastric and respiratory ailments. The purpose of this investigation is to study the antihyperlipidemic and antiobesity effects of piperonal in high-fat diet (HFD)-induced obese rats.

Methods

Piperonal, an active constituent of Piper nigrum seeds, was isolated and confirmed by HPLC, ¹H and ¹³C NMR spectroscopy. Male SD rats were fed on HFD for 22 weeks; Piperonal was supplemented from the 16th week as mentioned in the experimental design. Changes in body weight and body composition were measured by TOBEC, bone mineral composition and density were measured by DXA, and adipose tissue distribution was measured by 7 T–MRI. Plasma levels of glucose, insulin, insulin resistance and lipid profiles of plasma, liver and kidney, adipocyte hormones and liver antioxidants were evaluated using standard kit methods. Expression levels of adipogenic and lipogenic genes, such as PPAR-γ, FAS, Fab-4, UCP-2, SREBP-1c, ACC, HMG-COA and TNF-α were measured by RT-PCR. Histopathological examination of adipose and liver tissues was also carried out in experimental rats.

Results

HFD substantially induced body weight, fat%, adipocyte size, circulatory and tissue lipid profiles. It elevated the plasma levels of insulin, insulin resistance and leptin but decreased the levels of adiponectin, BMC and BMD. Increased expression of PPAR-γ, FAS, Fab-4, UCP-2, SREBP-1c, ACC, and TNF-α was noticed in HFD-fed rats. However, supplementation of piperonal (20, 30 and 40 mg/kg b.wt) for 42 days considerably and dose-dependently attenuated the HFD-induced alterations, with the maximum therapeutic activity being noticed at 40 mg/kg b.wt.

Conclusions

Piperonal significantly attenuated HFD-induced body weight and biochemical changes through modulation of key lipid metabolizing and obesogenic genes. Our findings demonstrate the efficacy of piperonal as a potent antiobesity agent, provide scientific evidence for its traditional use and suggest the possible mechanism of action.

Anticarcinogenic Effect of Spices Due to Phenolic and Flavonoid Compounds-In Vitro Evaluation on Prostate Cells

This study shows the effects of spices, and their phenolic and flavonoid compounds, on prostate cell lines (PNT1A, 22RV1 and PC3). The results of an MTT assay on extracts from eight spices revealed the strongest inhibitory effects were from black pepper and caraway seed extracts. The strongest inhibitory effect on prostatic cells was observed after the application of extracts of spices in concentration of 12.5 mg·mL^-1. An LC/MS analysis identified that the most abundant phenolic and flavonoid compounds in black pepper are 3,4-dihydroxybenzaldehyde and naringenin chalcone, while the most abundant phenolic and flavonoid compounds in caraway seeds are neochlorogenic acid and apigenin. Using an MTT assay for the phenolic and flavonoid compounds from spices, we identified the IC₅₀ value of ~1 mmol·L^-1 PNT1A. The scratch test demonstrated that the most potent inhibitory effect on PNT1A, 22RV1 and PC3 cells is from the naringenin chalcone contained in black pepper. From the spectrum of compounds assessed, the naringenin chalcone contained in black pepper was identified as the most potent inhibitor of the growth of prostate cells.

Reversible Testicular Toxicity of Piperine on Male Albino Rats

Background:

Piperine was widely used in traditional medicine for inducing sterility and abortion.

Objective:

To evaluate the effect of the piperine on testis of male albino rats

Materials and Methods:

Adult male rats were divided into four groups (n = 12). Group I (control): Rats were given vehicle p.o. i.e. 0.5% carboxymethyl cellulose in normal saline daily for 60 days, Group II (ED): Rats received piperine at a dose of 10 mg/kg body weight (b.w.) daily, Group III (E4D): Rats received piperine at a dose of 10 mg/kg b.w. on every 4^th day, Group IV (E7D): Rats received piperine at a dose of 10 mg/kg b.w. on every 7^th day. Half of the animals from each group were sacrificed after the treatment period (60 days), and the remaining were kept for drug-free withdrawal period (60 days) and then sacrificed.

Results:

Piperine significantly decreased the reproductive organ weights in groups ED and E4D. Piperine induced hormonal imbalance by altering the serum levels of follicle-stimulating hormone, luteinizing hormone, sex hormone binding globulin, serum, and testicular testosterone in groups ED and E4D. Furthermore, piperine decreased the activity of germ cell markers and Leydig cellular steroidogenic enzymes in the groups ED and E4D after 60 days. All the above-altered values returned to normal levels after withdrawal period. Histopathological findings also supported the above findings.

Conclusion:

From the above data, it can be concluded that piperine could be a good lead molecule for the development of reversible oral male contraceptive.

SUMMARY

Piperine was employed for the contraceptive purposes in traditional medicine

Piperine significantly impaired the spermatogenesis by decreasing the testicular hormone synthesis in groups ED and E4D

Piperine disrupted the testicular antioxidant system by promoting the ROS production and hydroxyl radical generation in rat testis in groups ED and E4D

Histopathological evidence supported the disruption of spermatogenesis by piperine

All the effects of piperine after the treatment period (i.e. 60 days) were back to normal after the withdrawal period (i.e., after 120 days).

The use of natural products to target cancer stem cells

The cancer stem cell hypothesis has been used to explain many cancer complications resulting in poor patient outcomes including induced drug resistance, metastases to distant organs, and tumor recurrence. While the validity of the cancer stem cell model continues to be the cause of much scientific debate, a number of putative cancer stem cell markers have been identified making studies concerning the targeting of cancer stem cells possible. In this review, a number of identifying properties of cancer stem cells have been outlined including properties contributing to the drug resistance and metastatic potential commonly observed in supposed cancer stem cells. Due to cancer stem cells' numerous survival mechanisms, the diversity of cancer stem cell markers between cancer types and tissues, and the prevalence of cancer stem cell markers among healthy stem and somatic cells, it is likely that currently utilized treatments will continue to fail to eradicate cancer stem cells. The successful treatment of cancer stem cells will rely upon the development of anti-neoplastic drugs capable of influencing many cellular mechanisms simultaneously in order to prevent the survival of this evasive subpopulation. Natural compounds represent a historically rich source of novel, biologically active compounds which are able to interact with a large number of cellular targets while limiting the painful side-effects commonly associated with cancer treatment. A brief review of select natural products that have been demonstrated to diminish the clinically devastating properties of cancer stem cells or to induce cancer stem cell death is also presented.

Assessing the anticancer effects associated with food products and/or nutraceuticals using in vitro and in vivo preclinical development-related pharmacological tests

This review is part of a special issue entitled "Role of dietary pattern, foods, nutrients and nutraceuticals in supporting cancer prevention and treatment" and describes a pharmacological strategy to determine the potential contribution of food-related components as anticancer agents against established cancer. Therefore, this review does not relate to chemoprevention, which is analysed in several other reviews in the current special issue, but rather focuses on the following: i) the biological events that currently represent barriers against the treatment of certain types of cancers, primarily metastatic cancers; ii) the in vitro and in vivo pharmacological pre-clinical tests that can be used to analyse the potential anticancer effects of food-related components; and iii) several examples of food-related components with anticancer effects. This review does not represent a catalogue-based listing of food-related components with more or less anticancer activity. By contrast, this review proposes an original pharmacological strategy that researchers can use to analyse the potential anticancer activity of any food-related component-e.g., by considering the crucial characteristics of cancer biological aggressiveness. This review also highlights that cancer patients undergoing chemotherapy should restrict the use of "food complements" without supervision by a medical nutritionist. By contrast, an equilibrated diet that includes the food-related components listed herein would be beneficial for cancer patients who are not undergoing chemotherapy.