Possible molecular targets for therapeutic applications of caffeic acid phenethyl ester in inflammation and cancer

Caffeic Acid Phenethyl Ester (CAPE): Biosynthesis, Derivatives and Formulations with Neuroprotective Activities

Neurodegenerative disorders are characterized by a progressive process of degeneration and neuronal death, where oxidative stress and neuroinflammation are key factors that contribute to the progression of these diseases. Therefore, two major pathways involved in these pathologies have been proposed as relevant therapeutic targets: The nuclear transcription factor erythroid 2 (Nrf2), which responds to oxidative stress with cytoprotecting activity; and the nuclear factor NF-κB pathway, which is highly related to the neuroinflammatory process by promoting cytokine expression. Caffeic acid phenethyl ester (CAPE) is a phenylpropanoid naturally found in propolis that shows important biological activities, including neuroprotective activity by modulating the Nrf2 and NF-κB pathways, promoting antioxidant enzyme expression and inhibition of proinflammatory cytokine expression. Its simple chemical structure has inspired the synthesis of many derivatives, with aliphatic and/or aromatic moieties, some of which have improved the biological properties. Moreover, new drug delivery systems increase the bioavailability of these compounds in vivo, allowing its transcytosis through the blood-brain barrier, thus protecting brain cells from the increased inflammatory status associated to neurodegenerative and psychiatric disorders. This review summarizes the biosynthesis and chemical synthesis of CAPE derivatives, their miscellaneous activities, and relevant studies (from 2010 to 2023), addressing their neuroprotective activity in vitro and in vivo.

The natural iron chelators' ferulic acid and caffeic acid rescue mice's brains from side effects of iron overload

Studies have shown that iron accumulation in the brain leads to neurogenic disorders. Novel iron chelating agents such as natural remedies are useful to decrease the side effects of iron in the brain. In addition, flavones and polyphenols are capable of chelating metals. In the current study, we evaluated the iron chelating capacity of ferulic acid and caffeic acid in the brain tissues of iron-overloaded mice. The mice received iron dextran intraperitoneally four times a week for 6 weeks. Next, blood samples were taken from the mice. In addition, brain tissues were excised for tissue staining as well as total iron and catalase (CAT) activity assessment. Ferulic acid and caffeic acid significantly decreased iron content in both brain and serum samples. Ferulic acid decreased iron by 50 and 51% more than the iron dextran-treated mice and by 43 and 2% more than desferal (DFO)-treated mice in serum and brain, respectively. In addition, caffeic acid reduced iron 57% more than the iron-treated group and 49 and 2% more than the desferal-treated group in the serum and brain, respectively. The catalase activity decreased with the increase in iron. By administering natural compounds, the catalase activity was increased equal to that of the control group. Thus, ferulic acid and caffeic acid might be possible natural iron chelators for brain iron overload therapy.

Hybrid molecules based on caffeic acid as potential therapeutics: A focused review

Caffeic acid-based compounds possess a high degree of structural diversity and show a variety of pharmacological properties, providing a useful framework for the discovery of new therapeutic agents. They are well-known analogues of antioxidants found in many natural products and synthetic compounds. The present review surveys the recent developments in structure-activity relationships (SAR) and mechanism of action (MOA) of various caffeic acid-containing compounds that play important roles in the design and synthesis of new bioactive molecules with antioxidant, antidiabetic, antiviral, antibacterial, anticancer, anti-inflammatory, and other properties. This review should provide inspiration to scientists in the research fields of organic synthesis and medicinal chemistry related to the development of new antioxidants with versatile therapeutic potential.

An Insight into Anticancer Effect of Propolis and Its Constituents: A Review of Molecular Mechanisms

Propolis is a natural compound collected by honeybees from different parts of plants. Honeybees produce a sticky component besides honey by mixing the tree resin and other botanical sources with saliva called propolis or bee glue. Propolis was traditionally used as a wound healing substance, cosmetic, medicine, and many other conditions. Till now, there is no definite curable treatment for most cancers and chemotherapeutic drugs and drugs used for targeted therapies have serious side effects. According to a recent research, natural products are becoming increasingly essential in cancer prevention. Natural products are a great source of potential therapeutic agents, especially in the treatment of cancer. Previous studies have reported that the presence of caffeic acid phenethyl ester (CAPE), artepillin C, and chrysin is responsible for the anticancer potential of propolis. Most of the previous studies suggested that propolis and its active compounds inhibit cancer progression by targeting multiple signaling pathways including phosphoinositide 3-kinases (PI3K)/Akt and mitogen-activated protein kinase (MAPK) signaling molecules, and induce cell cycle arrest. Induction of apoptosis by propolis is mediated through extrinsic and intrinsic apoptotic pathways. The aim of this review is to highlight and summarize the molecular targets and anticancer potential of propolis and its active compounds on cell survival, proliferation, metastasis, and apoptosis in cancer cells.

Therapeutic Implications of Caffeic Acid in Cancer and Neurological Diseases

Caffeic acid (CA) is found abundantly in fruits, vegetables, tea, coffee, oils, and more. CA and its derivatives have been used for many centuries due to their natural healing and medicinal properties. CA possesses various biological and pharmacological activities, including antioxidant, anti-inflammatory, anticancer, and neuroprotective effects. The potential therapeutic effects of CA are mediated via repression and inhibition of transcription and growth factors. CA possesses potential anticancer and neuroprotective effects in human cell cultures and animal models. However, the biomolecular interactions and pathways of CA have been described highlighting the target binding proteins and signaling molecules. The current review focuses on CA’s chemical, physical, and pharmacological properties, including antioxidant, anti-inflammatory, anticancer, and neuroprotective effects. We further described CA’s characteristics and therapeutic potential and its future directions.

A comprehensive insight into the molecular and cellular mechanisms of the effects of Propolis on preserving renal function: a systematic review

BACKGROUND

The present systematic review is conducted, focusing on the existing evidence of Propolis's effects due to its various health benefits, mainly antioxidant and anti-inflammatory properties on preserving renal function.

METHODS

A systematic search of PubMed, Scopus, Embase, ProQuest, and Google Scholar was undertaken for relevant papers published from the start until January 2021.

RESULTS

This review revealed that Propolis affects fasting blood sugar (FBS), postprandial blood glucose, advanced glycation end products (AGEs) concentrations, malondialdehyde (MDA) levels, urinary concentrations of reactive oxygen metabolites (Tbars), total oxidant status (TOS), oxidative stress index (OSI), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) formation favorably. The findings on hemoglobin A1C (HbA1C), insulin, homeostasis model assessment of insulin resistance (HOMA-IR), β-cell function (HOMA-β), quantitative insulin sensitivity check index (QUICKI), and lipid profile were controversial. Moreover, a significant reduction in renal nuclear factor kappa B (NF-κB), serum immunoglobulins, renal ED-1+ cells, and urinary monocyte chemoattractant protein-1 (MCP-1) following Propolis supplementation has been reported, while the results on interleukin-6 (IL-6), tumor necrosis factor α (TNF-α), nitric oxide (NO), nitric oxide synthetase (NOS), and high sensitivity C-reactive protein (hs-CRP) were controversial. Furthermore, included studies showed its anti- proteinuria and kidney restoring effects.

CONCLUSION

In this review, both human and animal studies provide us evidences that Propolis could potentially improve the glycemic status, oxidative stress, renal tissue damage, and renal function. Further studies are needed to determine the underlying mechanisms.

Therapeutic Effects and Safe Uses of Plant-Derived Polyphenolic Compounds in Cardiovascular Diseases: A Review

Polyphenols have long been recognized as health-promoting entities, including beneficial effects on cardiovascular disease, but their reputation has been boosted recently following a number of encouraging clinical studies in multiple chronic pathologies, that seem to validate efficacy. Health benefits of polyphenols have been linked to their well-established powerful antioxidant activity. This review aims to provide comprehensive and up-to-date knowledge on the current therapeutic status of polyphenols having sufficient heed towards the treatment of cardiovascular diseases. Furthermore, data about the safety profile of highly efficacious polyphenols has also been investigated to further enhance their role in cardiac abnormalities. Evidence is presented to support the action of phenolic derivatives against cardiovascular pathologies by following receptors and signaling pathways which ultimately cause changes in endogenous antioxidant, antiplatelet, vasodilatory, and anti-inflammatory activities. In addition, in vitro antioxidant and pre-clinical and clinical experiments on anti-inflammatory as well as immunomodulatory attributes of polyphenols have revealed their role as cardioprotective agents. However, an obvious shortage of in vivo studies related to dose selection and toxicity of polyphenols makes these compounds a suitable target for clinical investigations. Further studies are needed for the development of safe and potent herbal products against cardiovascular diseases. The novelty of this review is to provide comprehensive knowledge on polyphenols safety and their health claims. It will help researchers to identify those moieties which likely exert protective and therapeutic effects towards cardiovascular diseases.

Investigation of the anti-inflammatory effects of caffeic acid phenethyl ester in a model of λ-Carrageenan-induced paw edema in rats

In the present study, it is aimed to evaluate the effects of caffeic acid phenethyl ester (CAPE) against acute paw inflammation induced by carragenan (Carr) at macro and micro levels. Therefore, in this study, 1 hour after administering intraperitoneal of indomethacin (Ind) or CAPE (10 and 30 mg/kg body weight) to Sprague Dawley rats, Carr was injected intraplantarly into their right paws. The paw volumes of the rats were measured with a plethysmometer until the 4th hour. Also, X-ray and thermal camera images were taken to determine edema and temperature changes. At the end of the study, after the paw tissues and serums were taken, oxidative stress and inflammation status were determined using biochemical, molecular, and western blot techniques. In addition, lipid and protein profiles in paw tissue were determined using HPTLC and electrophoresis methods. The results depicted that a high dose of CAPE against Carr-induced inflammation may be almost as effective as Ind used as reference.

Caffeic acid phenethyl ester inhibits the growth of bladder carcinoma cells by upregulating growth differentiation factor 15

BACKGROUND

Caffeic acid phenethyl ester (CAPE), a bioactive component of propolis, has beneficial effects on cancer prevention. Growth differentiation factor 15 (GDF15) is an antitumor gene of bladder cancer. Therefore, this study investigated the anti-cancer effect of CAPE on bladder carcinoma cells and related mechanisms.

METHODS

The expressions of GDF15, N-myc downstream-regulated gene 1 (NDRG1), and maspin, and the activations of ERK, JNK, p38, and AMPKα1/2 in human bladder cells after gene transfection or knockdown were determined by immunoblot, RT-qPCR, and reporter assays. The assays of 5-ethynyl-2'-deoxyuridine (EdU), CyQUANT cell proliferation, and Matrigel invasion, and the xenograft animal study were used to assess the cell proliferation, invasion, and tumorigenesis.

RESULTS

GDF15 expression in epithelial cells was negatively correlated with neoplasia in vitro. Also, GDF15 exhibits in bladder fibroblasts and smooth muscle cells. CAPE-induced expressions of NDRG1 and maspin decreased cell proliferation and invasion of bladder carcinoma cells in a GDF15-dependent manner in vitro. The xenograft animal study suggesting CAPE attenuated tumor growth in vivo. CAPE increased phosphorylation of ERK, JNK, p38, and AMPKα1/2 to modulate the GDF15 expressions. Pretreatments with ERK, JNK, or p38 inhibitors partially inhibited the CAPE effects on the inductions of GDF15, NDRG1, or maspin. Knockdown of AMPKα1/2 attenuated the CAPE-induced GDF15 expression and cell proliferation in bladder carcinoma cells.

CONCLUSIONS

Our findings indicate that CAPE is a promising agent for anti-tumor growth in human bladder carcinoma cells via the upregulation of GDF15.

A novel caffeic acid derivative prevents renal remodeling after ischemia/reperfusion injury

Acute kidney disease due to renal ischemia/reperfusion (I/R) is a major clinical problem without effective therapies. The injured tubular epithelial cells may undergo epithelial-mesenchymal transition (EMT). It will loss epithelial phenotypes and express the mesenchymal characteristics. The formation of scar tissue in the interstitial space during renal remodeling is caused by the excessive accumulation of extracellular matrix components and induced fibrosis. This study investigated the effect of caffeic acid ethanolamide (CAEA), a novel caffeic acid derivative, on renal remodeling after injury. The inhibitory role of CAEA on EMT was determined by western blotting, real-time PCR, and immunohistochemistry staining. Treating renal epithelial cells with CAEA in TGF-β exposed cell culture successfully maintained the content of E-cadherin and inhibited the expression of mesenchymal marker, indicating that CAEA prevented renal epithelial cells undergo EMT after TGF-β exposure. Unilateral renal I/R were performed in mice to induce renal remodeling models. CAEA can protect against I/R-induced renal remodeling by inhibiting inflammatory reactions and consecutively inhibiting TGF-β-induced EMT, characterized by the preserved E-cadherin expression and alleviated α-SMA and collagen expression, as well as the alleviated of renal fibrosis. We also revealed that CAEA may exhibits biological activity by targeting TGFBRI. CAEA may antagonize TGF-β signaling by interacting with TGFBR1, thereby blocking binding between TGF-β and TGFBR1 and reducing downstream signaling, such as Smad3 phosphorylation. Our data support the administration of CAEA after I/R as a viable method for preventing the progression of acute renal injury to renal fibrosis.

Co-delivery of quercetin and caffeic-acid phenethyl ester by polymeric nanoparticles for improved antitumor efficacy in colon cancer cells

AIM

This study aimed to synthesise quercetin- caffeic-acid phenethyl ester (CAPE)-co-loaded poly(lactic-co-glycolic-acid) (PLGA) nanoparticles (QuCaNP) and investigate their anti-cancer activity on human colorectal carcinoma HT-29 cells.

METHODS

QuCaNPs were synthesised using single-emulsion (o/w) solvent evaporation method. Particle size, zeta potential, polydispersity index, in vitro release profile, and surface morphology of QuCaNPs were determined. Cytotoxicity, anti-migration, anti-proliferation and apoptotic activities of QuCaNPs were studied.

RESULTS

Mean diameter of QuCaNP was 237.8 ± 9.670 nm, with a polydispersity index (PDI) of 0.340 ± 0.027. Encapsulation efficiency was 74.28% (quercetin) and 65.24% (CAPE). Particle size and drug content of QuCaNP remained stable for 30 days at -20 °C. The half-maximal inhibitory concentration (IC₅₀) values of QuCaNP-treated HT-29 cells were calculated as 11.2 µg/mL (24 h) and 8.2 µg/mL (48 h). QuCaNP treatment increased mRNA levels of caspase-3 (2.38 fold) and caspase-9 (2-fold) and expressions of key proteins in the intrinsic apoptosis pathway in HT-29 cells.

CONCLUSION

Overall, our results demonstrated QuCaNPs exhibits improved anti-cancer activity on HT-29 cells.

Antioxidant effect of caffeic acid phenethyl ester in experimentally induced periodontitis

OBJECTIVES

The aim of the present study was to evaluate the antioxidant effect of systemically administered caffeic acid phenethyl ester (CAPE) in periodontitis.

MATERIALS AND METHODS

Forty rats were randomly divided into four groups: control, lipopolysaccharide-induced experimental periodontitis (LPS), CAPE 5: LPS+5 μmol/kg/day CAPE, and CAPE 10: LPS+10 μmol/kg/day CAPE. Following lipopolysaccharide-induced experimental periodontitis, CAPE was administered intraperitoneally for 28 days. Gingival and serumal total antioxidant status (TAS) and total oxidant status (TOS) were analyzed by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Gingival tissue TAS was significantly higher with CAPE application compared with the LPS group and was highest in the CAPE 10 group (p<0.05). Gingival tissue TOS was highest in the LPS group, and both of the CAPE dosages decreased the gingival tissue TOS, with the highest decrease in the CAPE 10 group (p<0.05). The differences were not significant for serumal TAS or TOS levels (p>0.05).

CONCLUSIONS

The effect of CAPE on increased TAS and decreased TOS levels in inflamed gingival tissue indicates the antioxidant therapeutic potential of CAPE in periodontitis.

CLINICAL RELEVANCE

Within the limitations of this study, CAPE may be suggested as an effective host modulator agent for reducing oxidative stress in gingival tissue and might be considered as an adjunctive therapy in periodontitis.

Defensive impact of propolis against CCl4 actuated rats' testicular damage

Objective:

The paper’s primary goal is to report the devastating impact of carbon tetrachloride (CCl₄) on rat testicular tissue and the possible protecting function of propolis against CCl₄ based on its free radical scavenging and inflammatory relief properties.

Materials and Methods:

A total of 24 adult male albino rats had been classified into four groups (six rats/group). Rats of group 1 served as control, whereas groups 2–4 received propolis (200 mg/kg/day), CCl₄ (3 ml/kg/day), and propolis/CCl₄, respectively. After 4 weeks, the collected sera were applied for the estimation of lipid profile and sex hormones. Also, histopathological picture, malondialdehyde, and tumor necrosis factor alpha (TNFα) gene profile was measured in collected testicular tissues.

Results:

The present information revealed a noteworthy change (p < 0.05) in lipid profile, decrease in testicular weight, testosterone, antioxidants values along with a prominent increase (p < 0.05) in estradiol, lipid peroxidation values, and expression of TNFα in rats administrated with CCl₄ compared to control. Moreover, the histopathological profile showed the degeneration of the epithelium. Interestingly, propolis attenuated the destructive effect of CCl₄ on rat testes.

Conclusion:

The examined dose of propolis reduced oxidation, and inflammatory reactions resulted from CCl₄ exposure and proved that it might have a helpful part in free radicals interceded diseases.

Phytophospholipid Complex of Caffeic Acid: Development, In vitro Characterization, and In Vivo Investigation of Antihyperlipidemic and Hepatoprotective Action in Rats

Caffeic acid (CA), a hydroxycinnamic acid possessing a variety of pharmacological activities, has caused a growing interest for the treatment of hyperlipidemia and associated conditions. This work endeavored to develop a novel formulation of CA-Phospholipon® 90H complex (CA-PC) using a solvent evaporation method. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transform infrared spectrophotometry (FTIR), and powder X-ray powder diffraction (PXRD) was carried to confirm the formation of CA-PC. The CA-PC was functionally evaluated in terms of solubility, in vitro and ex vivo drug release, and in vivo bioavailability and efficacy studies. SEM, DSC, FTIR, and XRD studies indicated the physical interaction of CA with Phospholipon® 90H to form a complex. Dynamic light scattering (DLS) studies described particle size of 168 ± 3.9 nm with a monodisperse distribution (PDI 0.17) and a negative zeta-potential of - 16.6 ± 2.1 mV. The phospholipid complex significantly improved (4.2-fold) the solubility of CA. In vitro and ex vivo dissolution studies of the formulated CA-PC revealed a significantly higher release compared with the pure CA. The pharmacokinetic study of CA-PC in rats demonstrated a significant increase (4.79-fold) in oral bioavailability when compared with pure CA as well. Additionally, a significant improvement in serum lipid profile, serum liver biomarker enzyme levels and, restoration of hepatic tissue architecture to normal, in high-fat diet (HFD) induced hyperlipidemic model was obtained upon CA-PC administration when compared with pure CA. These findings indicated that CA-PC would serve as an effective and promising formulation for CA delivery with improved antihyperlipidemic and hepatoprotective activity.Graphical abstract.

Neuroprotective Potential of Caffeic Acid Phenethyl Ester (CAPE) in CNS Disorders: Mechanistic and Therapeutic Insights

Neurological disorders like Alzheimer's disease (AD), Parkinson's disease (PD), stroke, amyotrophic lateral sclerosis (ALS), Huntington's disease (HD), epilepsy, traumatic brain injury (TBI), depression, and anxiety are responsible for thousands of deaths worldwide every year. With the increase in life expectancy, there has been a rise in the prevalence of these disorders. Age is one of the major risk factors for these neurological disorders, and with the aged population set to rise to 1.25 billion by 2050, there is a growing concern to look for new therapeutic molecules to treat age-related diseases. Caffeic acid phenethyl ester (CAPE) is a molecule obtained from a number of botanical sources, such as the bark of conifer trees as well as propolis which is extracted from beehives. Though CAPE remains relatively unexplored in human trials, it possesses antioxidant, anti-inflammatory, antimitogenic, and anti-cancer activities, as shown by preclinical studies. Apart from this, it also exhibits tremendous potential for the treatment of neurological disorders through the modulation of multiple molecular pathways and attenuation of behavioural deficits. In the present article, we have reviewed the therapeutic potential of CAPE and its mechanisms in the treatment of neurological disorders.

Caffeic acid phenethyl ester mitigates cadmium-induced hepatotoxicity in mice: Role of miR-182-5p/TLR4 axis

Cadmium (Cd), an environmental pollutant, is evidenced to cause hepatotoxicity. In this study, the potential protective effect of caffeic acid phenethyl ester (CAPE) on cadmium-induced liver damage was investigated. Forty male mice were treated daily with either CdCl₂ (1.5 mg/kg body weight (b.w.), gavage) or CAPE (10 μmol/kg b.w., gavage) or both for 4 weeks. CAPE administration significantly reduced Cd level and liver and body weight, and increased AST, ALT and ALP level. Moreover, CAPE prevented CdCl₂-induced oxidative stress via PI3K/Akt/mTOR pathway and inhibited apoptosis by regulating apoptosis markers. CAPE also suppressed the CdCl₂-induced inflammation by reducing the inflammatory mediators, including TNF-α, IL-6 and IL-1β. Furthermore, CAPE alleviated CdCl₂-induced reduction of TLR4. It should be noted that this effect was achieved by targeting miR-182-5p, and CAPE improved miR-182-5p level. The improvement of the liver tissue histopathology by CAPE confirmed the biochemical data. These results show for the first time that miR-182-5p/TLR4 axis involved in CAPE's protection against CdCl₂-induced hepatotoxicity, and may provide novel insights into the treatment of cadmium-related diseases.

Safety assessment of a newly synthesized copolymer for micellar delivery of hydrophobic caffeic acid phenethyl ester

Caffeic acid phenethyl ester (CAPE), a major pharmacologically active component of poplar type propolis, is known for its proapoptotic, anti-inflammatory, antioxidant, antiviral, and enzyme inhibiting activities. The aim of this study was to perform an in vitro and in vivo safety assessment of a micellar system based on a newly synthesized copolymer, consisting of polyglycidol and poly(allyl glycidyl ether) (C₁₂-PAGE-PG) as a drug delivery platform for CAPE. The in vitro studies on HepG2 and L929 cells by MTT and LDH assays after treatment with the empty and CAPE-loaded micelles showed no cytotoxic effects of the empty micelles and retained cytotoxic activity of CAPE loaded in the micelles. No hemolysis or stimulation of mouse lymphocytes or macrophages was observed in vitro. In vivo hematological, biochemical, and histological assays on rats, treated with the empty (2580 and 5160 µg/kg) or CAPE-loaded (375 and 750 µg CAPE/kg) micelles did not reveal pathological changes of any of the parameters assayed after 14-days' treatment. In conclusion, initial toxicological data characterize C₁₂-PAGE-PG as a non-toxic and promising copolymer for development of micellar drug delivery systems, particularly for a hydrophobic active substance as CAPE.

Targeting the JAK/STAT Signaling Pathway Using Phytocompounds for Cancer Prevention and Therapy

Cancer is a prevalent cause of mortality around the world. Aberrated activation of Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathway promotes tumorigenesis. Natural agents, including phytochemicals, exhibit potent anticancer activities via various mechanisms. However, the therapeutic potency of phytoconstituents as inhibitors of JAK/STAT signaling against cancer has only come into focus in recent days. The current review highlights phytochemicals that can suppress the JAK/STAT pathway in order to impede cancer cell growth. Various databases, such as PubMed, ScienceDirect, Web of Science, SpringerLink, Scopus, and Google Scholar, were searched using relevant keywords. Once the authors were in agreement regarding the suitability of a study, a full-length form of the relevant article was obtained, and the information was gathered and cited. All the complete articles that were incorporated after the literature collection rejection criteria were applied were perused in-depth and material was extracted based on the importance, relevance, and advancement of the apprehending of the JAK/STAT pathway and their relation to phytochemicals. Based on the critical and comprehensive analysis of literature presented in this review, phytochemicals from diverse plant origins exert therapeutic and cancer preventive effects, at least in part, through regulation of the JAK/STAT pathway. Nevertheless, more preclinical and clinical research is necessary to completely comprehend the capability of modulating JAK/STAT signaling to achieve efficient cancer control and treatment.

Withanone and caffeic acid phenethyl ester are predicted to interact with main protease (Mpro) of SARS-CoV-2 and inhibit its activity

The recent novel coronavirus, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2/2019-nCoV) has caused a large number of deaths around the globe. There is an urgent need to understand this new virus and develop prophylactic and therapeutic drugs. Since drug development is an expensive, intense and time-consuming path, timely repurposing of the existing drugs is often explored wherein the research avenues including genomics, bioinformatics, molecular modeling approaches offer valuable strengths. Here, we have examined the binding potential of Withaferin-A (Wi-A), Withanone (Wi-N) (active withanolides of Ashwagandha) and Caffeic Acid Phenethyl Ester (CAPE, bioactive ingredient of propolis) to a highly conserved protein, M^pro of SARS-CoV-2. We found that Wi-N and CAPE, but not Wi-A, bind to the substrate-binding pocket of SARS-CoV-2 M^pro with efficacy and binding energies equivalent to an already claimed N3 protease inhibitor. Similar to N3 inhibitor, Wi-N and CAPE were interacting with the highly conserved residues of the proteases of coronaviruses. The binding stability of these molecules was further analyzed using molecular dynamics simulations. The binding free energies calculated using MM/GBSA for N3 inhibitor, CAPE and Wi-N were also comparable. Data presented here predicted that these natural compounds may possess the potential to inhibit the functional activity of SARS-CoV-2 protease (an essential protein for virus survival), and hence (i) may connect to save time and cost required for designing/development, and initial screening for anti-COVID drugs, (ii) may offer some therapeutic value for the management of novel fatal coronavirus disease, (iii) warrants prioritized further validation in the laboratory and clinical tests.

Communicated by Ramaswamy H. Sarma

Caffeic Acid Phenethyl Ester Effects: In Silico Study of its Osteoimmunological Mechanisms

Background:

Biological system complexity impedes the drug target identification by biological experiments. Thus drugs, rather than acting on target site only, can interact with the entire biological system. Study of this phenomenon, known as network pharmacology, provides grounds for biological target identification of new drugs or acts as a foundation for the discovery of new targets of present drugs. No publication is available on the interaction network of CAPE.

Aim:

This study was aimed at the investigation of the candidate targets and possible interactions of caffeic acid phenethyl ester (CAPE) involved in its osteoimmunological effects.

Methods:

This study encompasses the investigation of candidate targets and possible interactions of CAPE by analyzing through PASS Prediction and constructing a biological network of CAPE.

Results:

In response to input (CAPE), PASS Prediction generated a network of 1723 targets. While selecting the probability to be active (Pa) value greater than 0.7 brought forth only 27 targets for CAPE. Most of these targets predicted the therapeutic role of CAPE as an osteoimmunological agent. Apart from this, this network pharmacology also identified 10 potential anti-cancer targets for CAPE, out of which 7 targets have been used efficiently in developing potent osteoimmunological drugs.

Conclusion:

This study provides scientific prediction of the mechanisms involved in osteoimmunological effects of CAPE, presenting its promising use in the development of a natural therapeutic agent for the pharmaceutical industry. CAPE targets identified by web-based online databases and network pharmacology need additional in silico assessment such as docking and MD simulation studies and experimental verification to authenticate these results.

A novel nanoparticle loaded with methyl caffeate and caffeic acid phenethyl ester against Ralstonia solanacearum—a plant pathogenic bacteria

Developing a novel agent and understanding the interaction model between multipolymer nanoparticles and bacteria could be worthwhile to induce the protection of crops with the prevalence of frequent hazards because of the use of pesticides and chemical resistance. Unlike metal nanoparticles, multipolymer nanoparticles have bacteriostatic properties against Ralstonia solanacearum that can trigger bacterial wilt by infecting the plant. Therefore, a novel poly(lactic-co-glycolic acid) nanoparticle containing caffeic acid phenethyl ester (CAPE) and methyl caffeate (MC) was prepared with the sustained-release property (for 10 d at pH 6.5); here, 50% of the cumulative release rate was achieved. It was observed that the cytomembrane of R. solanacearum was jeopardized by the nanoparticle by the creation of large holes on the bacterial surface. The nanoparticle has an approximate EC₅₀ value of 0.285 mg mL⁻¹ with active pharmaceutical ingredients (APIs), while the drug dosage could be reduced by 2/3. Furthermore, to reveal the possible mechanism of interaction between the multipolymer nanoparticles and bacteria, a formidable inhibition effect was observed; the pathogenicity-related genes, namely, phcA, phcB, pehC, egl, pilT, and polA, of R. solanacearum were downregulated by 1/2, 1/42, 1/13, 1/6, 1/2, and 1/8, respectively, showing significant effects on the major virulence-related genes. Hence, a novel nanoparticle with excellent antibacterial and sustained-release properties has been prepared, possessing the potential to replace chemical pesticides and serve as a new control strategy for mulberry blight disease.

Developing a novel agent and understanding an interaction model between multipolymer nanoparticles and bacteria could be worthwhile to induce the protection of crops with the prevalence of frequent hazards because of the use of chemical pesticides.

Cardioprotective effect of caffeic acid phenethyl ester on cardiac contusion following blunt chest trauma in rats

We investigated the effects of caffeic acid phenethyl ester (CAPE) on cardiac damage after blunt chest injury. Forty male adult Wistar albino rats were divided into four groups; control, cardiac contusion, cardiac contusion + CAPE, and CAPE. CAPE, 10 mmol/kg, was administered intraperitoneally for 7 days following cardiac contusion. Heart tissue and blood were obtained at the end of the experimental period. Cardiac histopathology was determined using hematoxylin & eosin (H & E) staining. Expression of tumor necrosis factor-alpha (TNF-α) in cardiomyocytes was determined using immunohistochemistry. Cardiac apoptosis was determined using the TUNEL method. Serum creatine kinase (CK), creatine kinase-muscle/brain (CK-MB) and lactate dehydrogenase (LDH) levels were determined using spectrophotometric methods. The serum cardiac troponin I (C-TI) level was measured using the ELISA method. Myofibril loss was detected in the cardiomyocytes of the cardiac contusion group. Increased apoptosis and TNF-α expression were observed in the cardiac contusion group compared to the control group. Increased CK, CK-MB, LDH and C-TI levels were found in the cardiac contusion group. We found that CAPE administration improved myocardial function. Compared to the cardiac contusion group, CK, CK-MB, LDH and C-TI levels decreased significantly in the cardiac contusion + CAPE group. Administration of CAPE significantly inhibited apoptosis and cardiac TNF-α expression. Our findings demonstrate the therapeutic effects of CAPE for cardiac contusion damage after blunt chest trauma.

Assessment of the Antigenotoxic Activity of Poly(d,l-lactic- co-glycolic acid) Nanoparticles Loaded with Caffeic Acid Phenethyl Ester Using the Ames Salmonella/Microsome Assay

In the present study, the antigenotoxic activity of poly(d,l-lactic- co-glycolic acid) (PLGA) nanoparticles (NPs) loaded with caffeic acid phenethyl ester (CAPE) was investigated in comparison to free CAPE using the Ames Salmonella/microsome assay. Additionally, to elucidate the impacts of the type of solvent effect on antigenotoxic activity, the following systems were tested: CAPE in water (poor solvent), ethyl alcohol (good solvent), and PLGA NPs (unknown). The effect of the NP system on solubility was investigated for the first time by assessing the antigenotoxic potential. In this study, the CAPE/PLGA NPs were synthesized using an oil-in-water (o/w) single-emulsion solvent evaporation method with an average size of 206.2 ± 1.2 nm, ζ potential of -19.8 ± 2.5 mV, encapsulation efficiency of 87.2 ± 2.5%, and drug loading of 53.3 ± 1.8%. According to the results of the antigenotoxic activity, the highest antimutagenic activity in both applied strains was found for CAPE in ethanol, and the lowest activity was detected for CAPE in water. Our study has shown that NP systems exhibit high antigenotoxic activity, which is similar to the results of CAPE dissolved in ethanol. These results have shown that NP systems increase biological activity of hydrophobic substances by increasing their solubility and that the use of PLGA instead of organic solvents in drug production may provide an increase in their medical utility.

Use of UHPLC-TripleQ with synthetic standards to profile anti-inflammatory hydroxycinnamic acid amides in root barks and leaves of Lycium barbarum

Hydroxycinnamic acid amides (HCAA) are the secondary metabolites ubiquitously exist in flowering plants, formed by condensation between hydroxycinnamates and mono or polyamines. HCAA species not only serve multiple functions in plant growth and development, but also exert significant positive effects on human health. In this study, we combined organic synthesis and UPHLC-TripleQ-MS/MS specifically targeting at HCAA species. The method was fully validated with respect to specificity, linearity, intra- and inter-day precision and accuracy, limit of detection (LOD), limit of quantification (LOQ), recovery, and reproducibility. We applied this method to identify and quantify HCAAs from the root barks and leaves of Lycium barbarum. HCAA species were reported in leaves for the first time, and 10 new HCAA species were further identified in root barks in addition to the ones reported in the literature. We also examine anti-inflammatory properties of identified HCAAs species. Seven HCAA compounds had a potent NO inhibitory effect with IC₅₀ as low as 2.381 μM (trans-N-caffeoyl phenethylamine). Our developed method largely improved analytical sensitivity of HCAAs species that potentially contributes to plant metabolomics studies.

Bush mint (Hyptis suaveolens) and spreading hogweed (Boerhavia diffusa) medicinal plant extracts differentially affect activities of CYP1A2, CYP2D6 and CYP3A4 enzymes

ETHNO-PHARMACOLOGICAL RELEVANCE

Hyptis suaveolens (L) Poit and Boerhavia diffusa Linn are medicinal herbal plants commonly found in the tropics and sub-tropics. They are used to treat various conditions among them boils, dyslipidaemia, eczema, malaria, jaundice and gonorrhoea. Thus, the herbal medicinal extracts are now found as part of some commercial herbal formulations. There has not been adequate characterization of these medicinal herbs on their effects on drug metabolising enzymes.

AIM OF THE STUDY

To investigate the effects of extracts of Hyptis suaveolens (HS) and Boerhavia diffusa (BD) on activity of drug metabolising enzymes, CYP1A2, CYP2D6 and CYP3A4, as well predict their potential for herb-drug interaction. A secondary aim was to identify constituent compounds such as polyphenolics, in the crude extract preparations of Hyptis suaveolens and Boerhavia diffusa and measure them for activity.

MATERIALS AND METHODS

CYP450 inhibition assays using recombinant CYP450 (rCYP) and fluorescence screening employing individual isozymes (CYP1A2, CYP2D6 and CYP3A4) were used to determine reversible- and time-dependent inhibition (TDI) profiles of extracts of Hyptis suaveolens and Boerhavia diffusa. Inhibition kinetic parameters, K_i and K_inact were also estimated. UPLC-MS employing a Synapt G2 (ESI negative) coupled to a PDA detector was used to identify polyphenolic compounds in crude extracts of Hyptis suaveolens and Boerhavia diffusa.

RESULTS

The inhibitory potency of Hyptis suaveolens and Boerhavia diffusa extracts varied among the different enzymes, with CYP1A2 (3.68 ± 0.10µg/mL) being the least inhibited by HS compared to CYP2D6 (1.39 ± 0.01µg/mL) and CYP3A4 (2.36 ± 0.57µg/mL). BD was most potent on CYP3A4 (7.36 ± 0.94µg/mL) compared to both CYP2D6 (17.79 ± 1.02µg/mL) and CYP1A2 (9.48 ± 0.78µg/mL). Extracts of Hyptis suaveolens and Boerhavia diffusa exhibited TDIs on all CYPs. The most prominent phenolic candidates identified in both medicinal herbs using UPLC-MS analysis included caffeic acid, rutin, quercetin, citric acid, ferulic acid and gluconic acid. These phenolic compounds are thought to potentially give HS and BD their therapeutic effects and inhibitory characteristics affecting CYP450 activities. In vivo predictions showed the potential for HS and BD extracts to cause significant interactions if co-administered with other medications.

CONCLUSIONS

The study reveals that crude aqueous extracts of HS and BD potentially inhibit drug metabolising isozymes CYP1A2, CYP2D6 and CYP3A4 in a reversible and time-dependent manner. Thus care should be taken when these extracts are co-administered with drugs that are substrates of CYP1A2, CYP2D6 and CYP3A4.

Phytotherapeutics: The Emerging Role of Intestinal and Hepatocellular Transporters in Drug Interactions with Botanical Supplements

In herbalism, botanical supplements are commonly believed to be safe remedies, however, botanical supplements and dietary ingredients interact with transport and metabolic processes, affecting drug disposition. Although a large number of studies have described that botanical supplements interfere with drug metabolism, the mode of their interaction with drug transport processes is not well described. Such interactions may result in serious undesired effects and changed drug efficacy, therefore, some studies on interaction between botanical supplement ingredients and drug transporters such as P-gp and OATPs are described here, suggesting that the interaction between botanical supplements and the drug transporters is clinically significant.

Induction of G 2 /M arrest and apoptosis through mitochondria pathway by a dimer sesquiterpene lactone from Smallanthus sonchifolius in HeLa cells

Dimer sesquiterpene lactones (SLs), uvedafolin and enhydrofolin, against four monomer SLs isolated from yacon, Smallanthus sonchifolius, leaf were the most cytotoxic substances on HeLa cells (IC₅₀ values 2.96–3.17 μM at 24 hours). However, the cytotoxic mechanism of dimer SL has not been elucidated yet. Therefore, in this study, we clarified the in vitro cytotoxic mechanism of uvedafolin on the HeLa cells, and evaluated the cytotoxicity against NIH/3T3 cells which were used as normal cells. In consequence, the dimer SLs had low toxicity for the NIH/3T3 cells (IC₅₀ 4.81–4.98 μM at 24 hours) and then the uvedafolin mediated cell cycle arrest at the G₂/M phase and induced apoptosis on the HeLa cells evidenced by appearance of a subG1 peak. Uvedafolin induced apoptosis was attributed to caspase-9 and caspase-3/7 activities. An effectively induced apoptosis pathway was demonstrated from mitochondria membrane potential change and cytochrome c release to cytosol. These results reveal that uvedafolin induced apoptosis via the mitochondria pathway. The present results indicate the potential of uvedafolin as a leading compound of new anticancer agents.

Induction of Cell Cycle Arrest and Apoptotic Response of Head and Neck Squamous Carcinoma Cells (Detroit 562) by Caffeic Acid and Caffeic Acid Phenethyl Ester Derivative

Natural polyphenols have been observed to possess antiproliferative properties. The effects, including apoptotic potential of bioactive phenolic compounds, caffeic acid (CA) and its derivative caffeic acid phenethyl ester (CAPE), on cell proliferation and apoptosis in human head and neck squamous carcinoma cells (HNSCC) line (Detroit 562) were investigated and compared. Cancer cells apoptosis rates and cell cycle arrests were analysed by flow cytometry. Exposure to CA and CAPE was found to result in a dose-dependent decrease in the viability of Detroit 562 cells at different levels. CA/CAPE treatment did significantly affect the viability of Detroit 562 cells (MTT results). CAPE-mediated loss of viability occurred at lower doses and was more pronounced, with the concentrations which inhibit the growth of cells by 50% estimated at 201.43 μM (CA) and 83.25 μM (CAPE). Dead Cell Assay with Annexin V labelling demonstrated that CA and CAPE treatment of Detroit 562 cells resulted in an induction of apoptosis at 50 μM and 100 μM doses. The rise of mainly late apoptosis was observed for 100 μM dose and CA/CAPE treatment did affect the distribution of cells in G0/G1 phase. A combination of different phenolic compounds, potentially with chemotherapeutics, could be considered as an anticancer drug.

Long-chain bases from sea cucumber mitigate endoplasmic reticulum stress and inflammation in obesity mice

Endoplasmic reticulum (ER) stress and inflammation can induce hyperglycemia. Long-chain bases (LCBs) from sea cucumber exhibit antihyperglycemic activities. However, their effects on ER stress and inflammation are unknown. We investigated the effects of LCBs on ER stress and inflammatory response in high-fat, fructose diet-induced obesity mice. Reactive oxygen species and free fatty acids were measured. Inflammatory cytokines in serum and their mRNA expressions in epididymal adipose tissues were investigated. Hepatic ER stress-related key genes were detected. c-Jun NH₂-terminal kinase and nuclear factor κB inflammatory pathways were also evaluated in the liver. Results showed that LCBs reduced serum and hepatic reactive oxygen species and free fatty acids concentrations. LCBs decreased serum proinflammatory cytokines levels, namely interleukin (IL)-1β, tumor necrosis factor-α, IL-6, macrophage inflammatory protein 1, and c-reactive protein, and increased anti-inflammatory cytokine IL-10 concentration. The mRNA and protein expressions of these cytokines in epididymal adipose tissues were regulated by LCBs as similar to their circulatory contents. LCBs inhibited phosphorylated c-Jun NH₂-terminal kinase and inhibitor κ kinase β, and nuclear factor κB nuclear translocation. LCBs also inhibited mRNA expression of ER stress markers glucose regulated protein, activating transcription factor 6, double-stranded RNA-activated protein kinase-like endoplasmic reticulum kinase, and X-box binding protein 1, and phosphorylation of eukaryotic initiation factor-α and inositol requiring enzyme 1α. These results indicate that LCBs can alleviate ER stress and inflammatory response. Nutritional supplementation with LCBs may offer an adjunctive therapy for RE stress-associated inflammation.

Biological actions and molecular effects of resveratrol, pterostilbene, and 3'-hydroxypterostilbene

Stilbenes are a class of polyphenolic compounds, naturally found in a wide variety of dietary sources such as grapes, berries, peanuts, red wine, and some medicinal plants. There are several well-known stilbenes including trans-resveratrol, pterostilbene, and 3′-hydroxypterostilbene. The core chemical structure of stilbene compounds is 1,2-diphenylethylene. Recently, stilbenes have attracted extensive attention and interest due to their wide range of health-beneficial effects such as anti-inflammation, -carcinogenic, -diabetes, and -dyslipidemia activities. Moreover, accumulating in vitro and in vivo studies have reported that stilbene compounds act as inducers of multiple cell-death pathways such as apoptosis, cell cycle arrest, and autophagy for chemopreventive and chemotherapeutic agents in several types of cancer cells. The aim of this review is to highlight recent molecular findings and biological actions of trans-resveratrol, pterostilbene, and 3′-hydroxypterostilbene.