A review on the bioavailability, bio-efficacies and novel delivery systems for piperine

Development of piperine nanoparticles stabilized by OSA modified starch through wet-media milling technique with enhanced anti-adipogenic effect in 3T3-L1 adipocytes

Piperine (PIP) has been known for its pharmacological activities with low water solubility and poor dissolution, which limits its nutritional application. The purpose of this research was to enhance PIP stability, dispersibility and biological activity by preparing PIP nanoparticles using the wet-media milling approach combined with nanosuspension solidification methods of spray/freeze drying. Octenyl succinic anhydride (OSA)-modified waxy maize starch was applied as the stabilizer to suppress aggregation of PIP nanoparticles. The particle size, redispersibility, storage stability and in vitro release behavior of PIP nanoparticles were measured. The regulating effect on adipocyte differentiation was evaluated using 3T3-L1 cell model. Results showed that PIP nanoparticles had a reduced particle size of 60 ± 1 nm, increased release rate in the simulated gastric (SGF) and intestinal fluids (SIF) and enhanced inhibition effect on adipogenesis in 3T3-L1 cells compared with free PIP, indicating that PIP-loaded nanoparticles with improved stability and anti-adipogenic property were developed successfully by combining wet-media milling and drying methods.

A Standardized Withania somnifera (Linn.) Root Extract with Piperine Alleviates the Symptoms of Anxiety and Depression by Increasing Serotonin Levels: A Double-Blind, Randomized, Placebo-Controlled Study

Background: Withania somnifera (Linn) or Ashwagandha is used in Ayurveda and other traditional medicine systems as an adaptogen and a neuroprotective supplement. Objective: The effect of Ashwagandha root extract (ARE) standardized for 2.5% full-spectrum withanolides as per The United States Pharmacopeia (USP) protocol with piperine (500 mg with 5 mg of 95% piperine) once a day (12.5 mg withanolides/day) was evaluated in individuals with mild to moderate depression and anxiety. Methods: In a randomized, double-blind placebo-controlled study, for 90 days, 70 participants were randomized to ARE (n = 34) or placebo (n = 36) once daily at night. Mean change in the Hamilton Depression Rating Scale (HDRS) and Hamilton Anxiety Rating Scale (HARS), Groningen Sleep Quality Scale (GSQS), and quality of life (QOL) from screening to days 30, 60, and 90 were evaluated. Safety was evaluated by monitoring any incidence of adverse events and laboratory parameters. Two-way analysis of variance (ANOVA) and repeated-measure ANOVA were used to compare ARE and placebo, and the changes within the group at different time points. Results: Seventy individuals were randomized and all of them completed the study. The HARS, HDRS, GSQS, and QOL scores improved significantly (p < 0.001) in all the participants taking ARE compared to placebo on days 30, 60, and 90. Anxiety and depression improved from baseline to end of the study in both groups, but the quantum of improvement was significantly higher in ARE. Serum levels of serotonin increased in ARE, but showed a decrease in placebo, the difference being statically significant (p < 0.001). Biochemical and hematological parameters remained in the normal range in all participants and ARE was well tolerated during the study. Conclusion: The results of the study suggest that 500 mg of ARE standardized for 2.5% withanolides with 5 mg piperine is beneficial in improving depression, and anxiety, by increasing serum serotonin levels. The trial was registered prospectively with the Clinical Trial Registry of India (CTRI) with the registration number CTRI/2022/05/042640, on May 18, 2022.

Piperine Improves Hyperuricemic Nephropathy by Inhibiting URAT1/GLUT9 and the AKT-mTOR Pathway

Uncontrolled hyperuricemia often leads to the development of hyperuricemic nephropathy (HN), characterized by excessive inflammation and oxidative stress. Piperine, a cinnamic acid alkaloid, possesses various pharmacological activities, such as antioxidant and anti-inflammatory effects. In this study, we intended to investigate the protective effects of piperine on adenine and potassium oxonate-induced HN mice and a uric-acid-induced injury model in renal tubular epithelial cells (mRTECs). We observed that treatment with piperine for 3 weeks significantly reduced serum uric acid levels and reversed kidney function impairment in mice with HN. Piperine (5 μM) alleviated uric acid-induced damage in mRTECs. Moreover, piperine inhibited transporter expression and dose-dependently inhibited the activity of both transporters. The results revealed that piperine regulated the AKT/mTOR signaling pathway both in vivo and in vitro. Overall, piperine inhibits URAT1/GLUT9 and ameliorates HN by inhibiting the AKT/mTOR pathway, making it a promising candidate for patients with HN.

Piperine Attenuates Bmal1-Mediated Glucose Metabolism Disorder in a Trpv1-Dependent Manner in HepG2 Cells

Piperine (PIP), a pungent alkaloid found in black pepper, has various pharmacological effects by activating the transient receptor potential vanilloid 1 (TRPV1) receptor. In this study, the regulating effect of PIP on glucose metabolism and the underlying mechanism were examined using an insulin-resistant cell model. Results showed that PIP alleviated glucosamine (GlcN)-induced glucose metabolism disorder (from 59.19 ± 1.90 to 88.36 ± 6.57%), restored cellular redox balance (from 148.43 ± 3.52 to 110.47 ± 3.52%), improved mitochondrial function (from 63.76 ± 4.87 to 85.98 ± 5.12%), and mitigated circadian disruption in HepG2 cells via the mediation of circadian clock gene Bmal1. After the knockdown of the Trpv1 gene, the modulating effect of PIP on Bmal1-mediated glucose metabolism was weakened, indicating that PIP alleviated Bmal1-involved insulin resistance and circadian misalignment in a Trpv1-dependent manner in HepG2 cells.

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.

Piperine as a Potential Nutraceutical Agent for Managing Diabetes and Its Complications: A Literature Review

The global prevalence of diabetes and its related complications has increased drastically and is currently a worldwide health challenge. There is still an urgent need for safe and effective natural products and supplements as alternative and/or adjunctive therapeutic interventions. Nowadays, people pay more and more attention to the nutritional and medicinal value of food ingredients. As one of the most widely employed spices in cooking, pepper also has novel medicinal values attributed to its main component, piperine (Pip). Pip is an amide alkaloid with pleiotropic properties such as anti-inflammatory, antioxidant, anti-cancer, and other related activities. Recently, Pip has received increasing scientific attention due to its antidiabetic and related complication properties. However, the values of existing studies are limited due to being scattered and unsystematic. The present study reviewed the therapeutic potential and possible mechanisms of Pip in diabetes and related complications, with the aim of providing promising candidates for the development of novel and effective alternative and/or adjunctive nutraceutical agents for the management of diabetes.

The influence of piperine on oxidation-induced porcine myofibrillar protein gelation behavior and fluorescent advanced glycation end products formation in model systems

This study investigated the effects of piperine on oxidation-induced porcine myofibrillar protein (MP) gelation behavior and fluorescent advanced glycation end products (fAGEs) formation. Model systems were prepared, lipid oxidation, MP gelling behavior, and fAGEs content were determined daily. The results indicated that lipid oxidation, carbonyl content, S₀, cooking loss, and tryptophan fluorescence intensity of MP significantly decreased, whereas gel strength, WHC, and whiteness markedly increased as the concentration of piperine increased (from 0 to 30 μM/g protein), indicating that piperine could reduce lipid oxidation and oxidative damage to MP. The fluorescence intensity of fAGEs markedly decreased (P < 0.05), from 93.1 ± 4.4 to 61.2 ± 3.0, as the concentration of piperine increased from 0 μM/g protein to 30 μM/g protein after 5 days of incubation. These results in model systems suggest that the presence of piperine has an important role in the inhibition of MP oxidation and fAGEs formation.

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

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

Comparative Quantification of the Phenolic Compounds, Piperine Content, and Total Polyphenols along with the Antioxidant Activities in the Piper trichostachyon and P. nigrum

India is the largest producer in the world of black pepper and it is the center of origin for Piper. The present study gives a comparative account of the chemical composition of the Piper nigrum and its wild putative parent the P. trichostachyon. Microextractions were performed and the quantification of six phenolic compounds (namely epicatechin, gallic acid, catechol, chlorogenic acid, caffeic acid, and catechin), piperine from leaves, petioles, and the fruits of both the species, were accomplished using the RP-UFLC system. The polyphenols (phenolic, flavonoid) and their antioxidant activities were also estimated. Among the six phenolic compounds studied, only three were detected and quantified. The polyphenol content correlating to the antioxidant activities was higher in the P. trichostachyon, whereas the piperine content was 108 times greater in the P. nigrum fruits. The Piper trichostachyon comparatively showed a higher content of polyphenols. The microextractions reduced the solvent consumption, the quantity of the plant material, and the amount of time used for the extraction. The first report on the TPC, TF, and the antioxidant activity of the P. trichostachyon has been described, and it also forms a scientific basis for its use in traditional medicine. The petioles of both species are good sources of phenolic compounds. A quantitative chemical analysis is a useful index in the identification and comparison of the species.

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.

Ayurvedic formulations: Potential COVID-19 therapeutics?

BACKGROUND

While Molnupiravir and Paxlovid have recently been approved for use in some countries, there are no widely available treatments for COVID-19, the disease caused by SARS-CoV-2 infection. Herbal extracts have been used to treat respiratory clinical indications by Ayurvedic medicine practitioners with minimal adverse reactions and intense research efforts are currently under way to develop some of these formulations for COVID-19 treatment.

METHODS

Literature search for in silico, in vitro, in vivo, and clinical studies on the topic of Ayurvedic formulations for potential COVID-19 treatment, in order to present the current state of current knowledge by integrating information across all systems.

RESULTS

The search yielded 20 peer reviewed articles on in silico studies examining the interaction of phytoconstituents of popular Ayurvedic formulations with SARS-CoV-2 components and its receptors; five articles on preclinical investigations of the ability of selected Ayurvedic formulations to inhibit functions of SARS-CoV-2 proteins; and 51 completed clinical trials on the efficacy of using Ayurvedic formulations for treatment of mild to moderate COVID-19. Clinical data was available from 17 of the 51 trials. There was a considerable overlap between formulations used in the in silico studies and the clinical trials. This finding was unexpected as there is no clearly stated alignment between studies and the traditional pathway to drug discovery- basic discovery leading to in vitro and in vivo proof of concept, followed by validation in clinical trials. This was further demonstrated in the majority of the in silico studies where focus was on potential antiviral mechanisms, while the clinical trials were focused on patient recovery using oral treatments. In all 17 clinical trials where data was available, Ayurvedic treatments lead to a shorter period to recovery in participants with COVID-19.

CONCLUSION

The most commonly used Ayurvedic treatments for management of respiratory symptoms associated with SARS-CoV-2 infection appear to have prophylactic and/or therapeutic properties. It would be of particular interest to assess synergistic and concomitant systemic effects and antiviral activities of individual phytoconstituents and their combinations in the Ayurvedic treatments.

Biofilm and hyphal inhibitory synergistic effects of phytoactives piperine and cinnamaldehyde against Candida albicans

Oral candidiasis, the most common mycotic infection of the human oral cavity is non-life-threatening yet if untreated may advance as systemic infections. Ability of Candida albicans to adapt sessile lifestyle imparts resistance to drugs and host immunity. Consequently, due to limited effectiveness of conventional antifungal treatment, novel therapeutic strategies are required. In the present study, synergistic interaction of phytochemicals, piperine and cinnamaldehyde against the biofilm and hyphal of C. albicans was evaluated. Minimum inhibitory concentration (MIC) and biofilm inhibitory concentration (BIC) of piperine and cinnamaldehyde against C. albicans were analysed through microbroth dilution assay and crystal violet staining method, respectively. Combinatorial biofilm and hyphal inhibitory effect were investigated through checkerboard assay. In vitro results were validated through gene expression analysis. BIC of piperine and cinnamaldehyde was determined to be 32 µg/mL and 64 µg/mL, respectively. Interaction between these two phytocomponents was found to be synergistic and six different synergistic antibiofilm combinations were identified. Microscopic analysis of biofilm architecture also evidenced the biofilm and surface adherence inhibitory potential of piperine and cinnamaldehyde combinations. Phenotypic switching between yeast and hyphal morphological forms was influenced by synergistic combinations. qPCR analysis corroborated the results of in vitro activities. nrg1 and trp1, the negative transcriptional regulators of filamentous growth were upregulated whereas other genes that are involved in biofilm formation, filamentous growth, adhesion etc were found to be downregulated. These proficient phytochemical combinations provide a new therapeutic avenue for the treatment of biofilm associated oral candidiasis and to combat the recurrent infections due to antibiotic resistance.

Piperine Improves Lipid Dysregulation by Modulating Circadian Genes Bmal1 and Clock in HepG2 Cells

Metabolic disorders are closely associated with the dysregulation of circadian rhythms. Many bioactive components with lipid metabolism-regulating effects have been reported to function through circadian clock-related mechanisms. As the main pungent principle of black pepper, piperine (PIP) has been demonstrated to possess anti-obesity bioactivity by affecting hepatic lipid metabolism-related factors. However, whether the circadian clock genes Bmal1 and Clock are involved in the protective effect of PIP against lipid metabolism disorders remains unknown. In this work, oleic acid (OA) induced lipid accumulation in HepG2 cells. The effect of PIP on redox status, mitochondrial functions, and circadian rhythms of core clock genes were evaluated. Results revealed that PIP alleviated circadian desynchrony, ROS overproduction, and mitochondrial dysfunction. A mechanism study showed that PIP could activate the SREBP-1c/PPARγ and AMPK/AKT-mTOR signaling pathways in a Bmal1/Clock-dependent manner in HepG2 cells. These results indicated that Bmal1 and Clock played important roles in the regulating effect of PIP on hepatic lipid homeostasis.

Capsaicin Attenuates Oleic Acid-Induced Lipid Accumulation via the Regulation of Circadian Clock Genes in HepG2 Cells

As the major component in red chili peppers, capsaicin is useful in the prevention of lipid metabolism disorders. In this study, the attenuation effect of capsaicin on oleic acid (OA)-induced lipid accumulation in HepG2 cells was evaluated with respect to circadian clock gene expressions. Lipid profiles, including triacylglycerols, total cholesterols, high-density lipoproteins, low-density lipoproteins, and aspartate aminotransferase content, were measured using enzymatic assay kits. The mitochondrial membrane potential, cellular redox status, and lipid droplet morphology were also determined using different assay kits and staining methods. The mRNA and protein expressions of core circadian clock genes and major lipometabolism-related factors were assessed using RT-qPCR and western blotting. Results showed that 50 μM capsaicin alleviated the circadian desynchrony and inhibited OA-induced ROS overproduction (from 166.44 ± 12.63% to 119.90 ± 5.43%) and mitochondrial dysfunction (from 0.60 ± 0.08 to 0.83 ± 0.09, represented by the red/green fluorescence ratio) in HepG2 cells. The amelioration effect of capsaicin on OA-induced lipid accumulation was weakened after Bmal1-knockdown, demonstrating that the rhythmic expression of the circadian clock gene is involved in the regulation process of capsaicin in lipid metabolism.