In vitro cytotoxic and in silico activity of piperine isolated from Piper nigrum fruits Linn

Piperine enhances doxorubicin sensitivity in triple-negative breast cancer by targeting the PI3K/Akt/mTOR pathway and cancer stem cells

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer that lacks an actionable target with limited treatment options beyond conventional chemotherapy. Therapeutic failure is often encountered due to inherent or acquired resistance to chemotherapy. Previous studies implicated PI3K/Akt/mTOR signaling pathway in cancer stem cells (CSCs) enrichment and hence chemoresistance. The present study aimed at investigating the potential effect of piperine (PIP), an amide alkaloid isolated from Piper nigrum, on enhancing the sensitivity of TNBC cells to doxorubicin (DOX) in vitro on MDA-MB-231 cell line and in vivo in an animal model of Ehrlich ascites carcinoma solid tumor. Results showed a synergistic interaction between DOX and PIP on MDA-MB-231 cells. In addition, the combination elicited enhanced suppression of PI3K/Akt/mTOR signaling that paralleled an upregulation in this pathway's negative regulator, PTEN, along with a curtailment in the levels of the CSCs surrogate marker, aldehyde dehydrogenase-1 (ALDH-1). Meanwhile, in vivo investigations demonstrated the potential of the combination regimen to enhance necrosis while downregulating PTEN and curbing PI3K levels as well as p-Akt, mTOR, and ALDH-1 immunoreactivities. Notably, the combination failed to change cleaved poly-ADP ribose polymerase levels suggesting a pro-necrotic rather than pro-apoptotic mechanism. Overall, these findings suggest a potential role of PIP in decreasing the resistance to DOX in vitro and in vivo, likely by interfering with the PI3K/Akt/mTOR pathway and CSCs.

Discovery of potential epidermal growth factor receptor inhibitors from black pepper for the treatment of lung cancer: an in-silico approach

A tyrosine kinase receptor known as epidermal growth factor receptor (EGFR) is one of the main tumour markers in many cancer types and also plays a crucial role in cell proliferation, differentiation, angiogenesis, and apoptosis, which is a result of the auto-phosphorylations (kinase activity enhancement) that trigger signals involved in different cellular processes. Due to the discovery that non-small cell lung cancer (NSCLC) is a cause of this kinase activity enhancement, so far, several inhibitors have been tested against EGFR, but the side effects of these inhibitors necessitate an urgent measure to come up with an inhibitor that will be more specific to the cancer cells and not affect self-cells. This study was conducted to evaluate the efficacy of 37 compounds derived from Piper nigrum against EGFR using computer-aided drug design. Based on molecular docking, induced-fit docking, calculation of free binding energy, pharmacokinetics, QSAR prediction, and MD simulation. We propose five (5) lead compounds (clarkinol A, isodihydrofutoquinol B, Burchellin, kadsurin B, and lancifolin C) as a novel inhibitor, with clarkinol A demonstrating the highest binding affinity (-7.304 kcal/mol) with EGFR when compared with the standard drug (erlotinib). They also showed significant moderation for parameters investigated for a good pharmacokinetic profile, with a reliable R2 coefficient value predicted using QSAR models. The MD simulation of clarkinol A was found to be stable within the EGFR binding pocket throughout the 75 ns simulation run time. The findings showed that clarkinol A derived from Piper nigrum is worth further investigation and consideration as a possible EGFR inhibitor for the treatment of lung cancer.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40203-024-00197-1.

Current trends in natural products for the treatment and management of dementia: Computational to clinical studies

The number of preclinical and clinical studies evaluating natural products-based management of dementia has gradually increased, with an exponential rise in 2020 and 2021. Keeping this in mind, we examined current trends from 2016 to 2021 in order to assess the growth potential of natural products in the treatment of dementia. Publicly available literature was collected from various databases like PubMed and Google Scholar. Oxidative stress-related targets, NF-κB pathway, anti-tau aggregation, anti-AChE, and A-β aggregation were found to be common targets and pathways. A retrospective analysis of 33 antidementia natural compounds identified 125 sustainable resources distributed among 65 families, 39 orders, and 7 classes. We found that families such as Berberidaceae, Zingiberaceae, and Fabaceae, as well as orders such as Lamiales, Sapindales, and Myrtales, appear to be important and should be researched further for antidementia compounds. Moreover, some natural products, such as quercetin, curcumin, icariside II, berberine, and resveratrol, have a wide range of applications. Clinical studies and patents support the importance of dietary supplements and natural products, which we will also discuss. Finally, we conclude with the broad scope, future challenges, and opportunities for field researchers.

Piperine improves the sensitivity of osteosarcoma cells to doxorubicin by inducing apoptosis and inhibiting the PI3K/AKT/GSK-3β pathway

BACKGROUND

Osteosarcoma is a primary bone malignancy associated with the highest incidence rate. Chemotherapy for osteosarcoma has not substantially changed, and survival of patients with metastatic tumours has reached a plateau. Doxorubicin (DOX) is a broad-spectrum anti-osteosarcoma drug; however, its application is limited due to its high cardiotoxicity. Piperine (PIP) has been verified to drive certain cancer cell death and increases chemosensitivity of DOX. However, the effects of PIP in promoting the chemosensitivity of osteosarcoma to DOX have not been studied.

METHODS

We examined the combined effect of PIP and DOX on U2OS and 143B osteosarcoma cells. CCK-8 assays, scratch assays, flow cytometry analysis, and western blotting were performed. Furthermore, the effect of PIP combined with DOX on osteosarcoma tumours was observed in vivo using nude mice.

RESULTS

PIP can increase the chemosensitivity of U2OS and 143B cells to DOX. Both in vitro and in vivo results showed the dramatic inhibition of cell proliferation and tumour growth by the combined therapy group compared to monotherapy groups. Apoptosis analysis revealed that PIP augments DOX-induced cell apoptosis by upregulating BAX and P53 expression, as well as reducing Bcl-2 expression. Furthermore, PIP also attenuated the initiation of the PI3K/AKT/GSK-3β signaling pathway in osteosarcoma cells by altering the expression levels of P-AKT, P-PI3K and P-GSK3β.

CONCLUSIONS

This study revealed for the first time that PIP can potentiate the sensitivity and cytotoxicity of DOX during osteosarcoma therapy in vitro and in vivo, which probably achieved by inhibiting the PI3K/AKT/GSK-3β signalling pathway.

Piperine ameliorates ischemic stroke-induced brain injury in rats by regulating the PI3K/AKT/mTOR pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Piperine (PIP), a main active component isolated from Piper nigrum L., exerts neuroprotective effects in a rat model of ischemic stroke (IS). However, studies on the effects of PIP on neuroprotection and autophagy after IS are limited.

AIM OF THE STUDY

This study aimed to prove the protective effects of PIP against brain IS and elucidate its underlying mechanisms.

MATERIALS AND METHODS

Specific pathogen-free male Sprague-Dawley rats were selected to establish a permanent middle cerebral artery occlusion model. The experiment was randomly divided into six groups: sham group, model group, PIP intervention group (10, 20, and 30 mg/kg group), and nimodipine group (Nimo group, 12 mg/kg). Neurological function score, postural reflex score, body swing score, balance beam test, and grip strength test were used to detect behavioral changes of rats. The area of cerebral infarction was detected by TTC staining, and the number and morphological changes of neurons were observed by Nissl and HE staining. In addition, the ultrastructure of hippocampal dentate gyrus neurons was observed using a transmission electron microscope. Western blot was used to detect the expression of PI3K/AKT/mTOR signaling pathway proteins and autophagy-related proteins, namely, Beclin1 and LC3, in the hippocampus and cortex. Cell experiments established an in vitro model of oxygen-glucose deprivation (OGD) with the HT22 cell line to verify the mechanism. The experiment was divided into five groups: control group, OGD group, OGD + PIP 20 μg/mL group, OGD + PIP 30 μg/mL group, and OGD + PIP 40 μg/mL group. CCK-8 was used to measure cell activity, and Western blot was used to measure the expression of PI3K/AKT/mTOR signaling pathway proteins and autophagy-related proteins (Beclin1 and LC3).

RESULTS

Compared with the model group, the neurological function scores, body swing scores, and postural reflex scores of rats in the 10, 20, and 30 mg/kg PIP intervention groups and Nimo groups decreased, whereas the balance beam score and grip test scores increased (all p < 0.05). After 10, 20, and 30 mg/kg PIP and Nimo intervention, the cerebral infarction area of pMCAO rats was reduced (p < 0.01), and Nissl and HE staining results showed that the number of neurons survived in the 30 mg/kg PIP and Nimo intervention groups increased. Cell morphology and structure were significantly improved (p < 0.05). Most of the hippocampal dentate gyrus neurons and their organelles gradually returned to normal in the 30 mg/kg PIP and Nimo intervention groups, with less neuronal damage. The expression levels of p-mTOR, p-AKT, and p-PI3K in the hippocampus and cortex of the 30 mg/kg PIP and Nimo intervention groups decreased, whereas the expression level of PI3K increased (all p < 0.05). In addition, the expression level of autophagy-related proteins, namely, Beclin1 and LC3-II, in the 30 mg/kg PIP and Nimo intervention groups decreased (all p < 0.05). Results of CCK-8 showed that after 1 h of OGD, the 30 and 40 μg/mL PIP intervention groups had higher cell viability than the OGD group (p < 0.01). Western blot results showed that compared with the OGD group, the expression level of p-mTOR, p-AKT, and p-PI3K in the 30 and 40 μg/mL PIP intervention groups decreased, and the expression level of PI3K increased (all p < 0.05). Moreover, the expression level of autophagy-related proteins, namely, Beclin1 and LC3-II, in the 30 and 40 μg/mL PIP intervention groups decreased (all p < 0.05).

CONCLUSIONS

This study shows that PIP is a potential compound with neuroprotective effects. PIP can inhibit the PI3K/AKT/mTOR pathway and autophagy. Its inhibition of autophagy is possibly related to modulating the PI3K/AKT/mTOR pathway. These findings provide new insights into the use of PIP for the treatment of IS and its underlying mechanism.

Immunity against COVID-19: Potential role of Ayush Kwath

SARS-CoV-2 infection associated respiratory disease- COVID-19 has evolved into a pandemic but, being a new form of virus, pathogenesis of disease causation is not fully understood and drugs and vaccines against this virus are still being tested so that no effective drugs or vaccines have been advised by regulatory authority. In this context, the Ministry of AYUSH, Government of India has recommended 'Ayush Kwath' to improve the immunity and combat the infection. Our objective of this literature review is to review the role of immunity in pathogenesis of COVID-19 and role of Ayush Kwath against the virus and regulation of immunity. Current review was conducted using a search of available literature on COVID-19 and immunity, Vyadhikshamatwa, Ayurveda and COVID-19, Rasayana, Coronavirus, SARS-CoV-2, immunomodulatory effects of medicinal plants; Tulsi/Holy Basil/Ocimum sanctum, Dalchini/Cinnamon/Cinnamomum zeylanicum, Sunthi/Ginger/Zingiber officinale and Marich/Black Pepper/Piper nigrum. Ayurveda, being an ancient science have both medicinal and cultural values and had stimulated our kitchen and influenced what we ate in different seasons and the remedies we used for common ailments. Herbs such as Tulsi, Marich, Sunthi, Dalchini are the most commonly used and easily available drugs in home. Thus, Ayush Kwath due to its immune-modulatory, antiviral, anti-oxidant, anti-inflammatory, anti-platelet, anti-atherosclerotic, hepato-protective, reno-protective properties; seems to be effective in immuno-regulation for controlling viral infections like COVID-19. Further pre-clinical and clinical trials need to be done for the evaluation of safety and efficacy of this polyherbal formulation.

Piperine analogs arrest c-myc gene leading to downregulation of transcription for targeting cancer

G-quadruplex (G4) structures are considered a promising therapeutic target in cancer. Since Ayurveda, Piperine has been known for its medicinal properties. Piperine shows anticancer properties by stabilizing the G4 motif present upstream of the c-myc gene. This gene belongs to a group of proto-oncogenes, and its aberrant transcription drives tumorigenesis. The transcriptional regulation of the c-myc gene is an interesting approach for anticancer drug design. The present study employed a chemical similarity approach to identify Piperine similar compounds and analyzed their interaction with cancer-associated G-quadruplex motifs. Among all Piperine analogs, PIP-2 exhibited strong selectivity, specificity, and affinity towards c-myc G4 DNA as elaborated through biophysical studies such as fluorescence emission, isothermal calorimetry, and circular dichroism. Moreover, our biophysical observations are supported by molecular dynamics analysis and cellular-based studies. Our study showed that PIP-2 showed higher toxicity against the A549 lung cancer cell line but lower toxicity towards normal HEK 293 cells, indicating increased efficacy of the drug at the cellular level. Biological evaluation assays such as TFP reporter assay, quantitative real-time PCR (qRT- PCR), and western blotting suggest that the Piperine analog-2 (PIP-2) stabilizes the G-quadruplex motif located at the promoter site of c-myc oncogene and downregulates its expression. In conclusion, Piperine analog PIP-2 may be used as anticancer therapeutics as it affects the c-myc oncogene expression via G-quadruplex mediated mechanism.

Inhibition of α-glucosidase and α-amylase by herbal compounds for the treatment of type 2 diabetes: A validation of in silico reverse docking with in vitro enzyme assays

BACKGROUND

α-Amylase and α-glucosidase are important therapeutic targets for the management of type 2 diabetes mellitus. The inhibition of these enzymes decreases postprandial hyperglycemia. In the present study, compounds found in commercially available herbs and spices were tested for their ability to inhibit α-amylase and α-glucosidase. These compounds were acetyleugenol, apigenin, cinnamic acid, eriodictyol, myrcene, piperine, and rosmarinic acid.

METHODS

The enzyme inhibitory nature of the compounds was evaluated using in silico docking analysis with Maestro software and was further confirmed by in vitro α-amylase and α-glucosidase biochemical assays.

RESULTS

The relationships between the in silico and in vitro results were well correlated; a more negative docking score was associated with a higher in vitro inhibitory activity. There was no significant (P > .05) difference between the inhibition constant (K_i ) value of acarbose, a widely prescribed α-glucosidase and α-amylase inhibitor, and those of apigenin, eriodictyol, and piperine. For α-amylase, there was no significant (P > .05) difference between the K_i value of acarbose and those of apigenin, cinnamic acid, and rosmarinic acid. The effect of the herbal compounds on cell viability was assessed with the sulforhodamine B (SRB) assay in C2C12 and HepG2 cells. Acetyleugenol, cinnamic acid, myrcene, piperine, and rosmarinic acid had similar (P > .05) IC₅₀ values to acarbose.

CONCLUSIONS

Several of the herbal compounds studied could regulate postprandial hyperglycemia. Using herbal plants has several advantages including low cost, natural origin, and easy cultivation. These compounds can easily be consumed as teas or as herbs and spices to flavor food.

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.

The Influence of Piperine on the Radioprotective Effect of Curcumin in Irradiated Human Lymphocytes

Objectives

Ionizing radiation (IR) induces DNA damage in normal cells, leading to genotoxicity. The radioprotective effects of co-treatment with curcumin and piperine were investigated against genotoxicity induced by IR in human normal lymphocytes.

Materials and Methods

Human blood samples were pretreated with curcumin at different concentrations (5, 10, and 25 μg/mL) and/or piperine (2.5 μg/mL) and then were exposed to IR at a dose 1.5 Gy. The radioprotective effects of curcumin and piperine were assessed by micronucleus (MN) assay.

Results

Curcumin and piperine reduced the percentage of MN induced by IR in lymphocytes. Piperine alone significantly reduced genotoxicity induced by IR as compared to curcumin alone at all concentrations. An additive radioprotective effect was observed with combination of piperine and curcumin at the low concentration of 5 μg/mL, while this synergistic effect was not observed with curcumin at the higher concentrations of 10 and 25 μg/mL.

Conclusion

Piperine has a potent radioprotective effect at low concentration as compare to curcumin. However, an additive radioprotective effect was observed with co-treatment with piperine and curcumin at low concentration, while piperine increased the percentage of MN in normal lymphocytes when co-treated with curcumin at higher concentration.

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.

Synthesis, docking and anticancer activity of azo-linked hybrids of 1,3,4-thia-/oxadiazoles with cyclic imides

A series of novel analogues based on a diazole-imide pharmacophore were synthesized by diazotizing substituted 1,3,4-thia-/oxadiazol-2-amines and subsequently coupling the resulting diazonium salts with N-substituted cyclic imides. The resulting compounds C1 to C28 were characterized by various spectral methods, viz. IR, NMR and mass spectroscopy. All the synthesized compounds were tested against two human cancer cell lines: human breast adenocarcinoma cell line MCF-7 and colorectal adenocarcinoma cell line HT-29. Among the synthesized compounds, C14 (2-(4-chloro-3-((5-(4-nitrophenyl)-1,3,4-thiadiazol-2-yl)diazenyl)phenyl)-4,5,6,7-tetrahydro-1H-isoindole-1,3(2H)-dione) emerged as a potential candidate against both MCF-7 and HT-29 with [Formula: see text] values of 0.09 ± 0.02 [Formula: see text]M and 0.11 ± 0.03 [Formula: see text]M, respectively. Similarly, compound C16 displayed highest anticancer activity against MCF-7 cell line with [Formula: see text] = 0.07 ± 0.02 [Formula: see text]M. Target fishing (inverse docking) using ChemMapper server identified EGFR tyrosine and CDK2 kinases as high priority targets for this pharmacophore. Computational docking (AutoDock 4.2) was used to analyse the interactions between the target proteins and active compounds.

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.