Paeonol exhibits anti-tumor effects by apoptotic and anti-inflammatory activities in 7,12-dimethylbenz(a)anthracene induced oral carcinogenesis

Usnic acid attenuates 7,12-dimethylbenz[a] anthracene (DMBA) induced oral carcinogenesis through inhibiting oxidative stress, inflammation, and cell proliferation in male golden Syrian hamster model

In this study, we investigated the chemopreventive efficacy of usnic acid (UA), an effective secondary metabolite component of lichens, against 7,12-dimethylbenz[a]anthracene (DMBA)-induced oral squamous cell carcinoma (OSCC) in the hamster model. Initially, the buccal pouch carcinogenesis was induced by administering 0.5% DMBA to the HBP (hamster buccal pouch) region about three times a week until the 10th week. Then, UA was orally treated with different concentrations (25, 50, 100 mg/kg b.wt) on alternative days of DMBA exposure, and the experimental process ended in the 16th week. After animal experimentation, we observed 100% tumor incidence with well-differentiated OSCC, dysplasia, and hyperplasia lesions in the DMBA-induced HBP region. Furthermore, the UA treatment of DMBA-induced hamster effectively inhibited tumor growth. In addition, UA upregulated antioxidant levels, interfered with the elevated lipid peroxidation by-product of thiobarbituric acid reactive substances, and changed the activities of the liver detoxification enzyme (Phase I and II) in DMBA-induced hamsters. Furthermore, immunohistochemical staining of inflammatory markers (iNOS and COX-2) and proliferative cell markers (cyclin-D1 and PCNA) were upregulated in the buccal pouch part of hamster animals induced with DMBA. Notably, the oral administration of UA significantly suppressed these markers during DMBA-induced hamsters. Collectively, our findings revealed that UA exhibits antioxidant, anti-inflammatory, antitumor, and apoptosis-inducing characteristics, demonstrating UA's protective properties against DMBA-induced HBP carcinogenesis.

Paeonol repurposing for cancer therapy: From mechanism to clinical translation

Paeonol (PAE) is a natural phenolic monomer isolated from the root bark of Paeonia suffruticosa that has been widely used in the clinical treatment of some inflammatory-related diseases and cardiovascular diseases. Much preclinical evidence has demonstrated that PAE not only exhibits a broad spectrum of anticancer effects by inhibiting cell proliferation, invasion and migration and inducing cell apoptosis and cycle arrest through multiple molecular pathways, but also shows excellent performance in improving cancer drug sensitivity, reversing chemoresistance and reducing the toxic side effects of anticancer drugs. However, studies indicate that PAE has the characteristics of poor stability, low bioavailability and short half-life, which makes the effective dose of PAE in many cancers usually high and greatly limits its clinical translation. Fortunately, nanomaterials and derivatives are being developed to ameliorate PAE's shortcomings. This review aims to systematically cover the anticancer advances of PAE in pharmacology, pharmacokinetics, nano delivery systems and derivatives, to provide researchers with the latest and comprehensive information, and to point out the limitations of current studies and areas that need to be strengthened in future studies. We believe this work will be beneficial for further exploration and repurposing of this natural compound as a new clinical anticancer drug.

The effect of herbal medicine in innate immunity to Candida albicans

Candida albicans (C. albicans) is an opportunistic pathogenic fungus that often causes mucosal and systemic infections. Several pattern recognition receptors (PRRs), such as Toll-like receptors (TLRs) and C-type lectin receptors (CLRs), have been implicated in the host recognition of C. albicans. These PRRs recognize the pathogen-associated molecular patterns (PAMPs) of C. albicans to activate innate immune cells, thereby rapidly inducing various inflammatory responses by activating intracellular signaling cascades. Herbal medicine and its active components deserve priority development due to their low toxicity and high antibacterial, antiviral and antifungal activities. This review discussed the activities of herbal compounds against C. albicans and their related mechanisms, especially their regulatory role on innate immune cells such as neutrophils, macrophages, and dendritic cells (DCs) implicated in C. albicans infections. Our work aims to find new therapeutic drugs and targets to prevent and treat diseases caused by C. albicans infection with the mechanisms by which this fungus interacts with the innate immune response.

Anticancer and antioxidant profiling effects of Nerolidol against DMBA induced oral experimental carcinogenesis

The objective of this study is to examine the chemopreventive effects of Nerolidol (NER) on hamster buccal pouch carcinogenesis (HBC) induced by 7,12-dimethylbenz(a)anthracene (DMBA) in male golden Syrian hamsters. In this study, oral squamous cell carcinoma was developed in the buccal pouch of an oral painted hamster with 0.5% DMBA in liquid paraffin three times weekly for 12 weeks. To assess DMBA-induced hamster buccal tissue carcinogenesis, biochemical endpoints such as Phase I and II detoxification enzymes, antioxidants, lipid peroxidation (LPO) by-products, and renal function markers, as well as histopathological examinations, were used. Furthermore, the immunohistochemical studies of interleukin-6 were investigated to find the inflammatory link in the HBC carcinogenesis. In our results, DMBA alone exposed hamsters showed 100% tumor growth, altered levels of antioxidants, detoxification agents, LPO, and renal function identifiers as compared to the control hamsters. The outcome in  present biochemical, histopathological, and immunohistochemistry studies has been found a reverse in NER-treated hamsters against the tumor. This study concluded that NER modulated the biochemical profiles (antioxidants, detoxification, LPO, and renal function markers) and inhibited tumor development in DMBA induced oral carcinogenesis.

The role of dietary flavonoids for modulation of ATP binding cassette transporter mediated multidrug resistance

Flavonoids are widely existing compounds with enormous pharmacological effects from food and medicine. However, the low bioavailability in intestinal absorption and metabolism limits their clinical application. Intestinal efflux ABC (ATP binding cassette) transporters, including P-glycoprotein (P-gp), breast cancer resistance protein (BCRP) and multidrug resistance-associated proteins (MRPs), act as "pumping doors" to regulate the efflux of flavonoids from intestinal epithelial cells into the intestinal cavity or the systemic circulation. The present review describes the critical effect of ABC transporters involved in the efflux of flavonoids which depend on its efflux direction. And the role of flavonoids for modulation of intestinal ABC transporters was emphasized and several examples were given. We summarized that the resistance effect of flavonoid-mediated multidrug on ABC transporters may influence the bioavailability of drugs, bioactive ingredients and/or toxic compounds upon dietary uptake. Meanwhile, flavonoids functionalized as reversing agents of the ABC transporter may be an important mechanism for unexpected food-drug, food-toxin or food-food interactions. The overview also indicates that elucidation of the action and mechanism of the intestinal metabolic enzymes-efflux transporters coupling will lay a foundation for improving the bioavailability of flavonoids <i>in vivo</i> and increasing their clinical efficacy.

Paeonol suppresses lipid formation and promotes lipid degradation in adipocytes

Paeonol can regulate a variety of physiological and pathological processes such as thrombosis, oxidative stress, inflammation and atherosclerosis. However, its potential role and underlying mechanisms in obesity and lipid metabolism remain to be elucidated. In the present study, 3T3-L1 cells were differentiated and collected on days 4, 6 and 8. The expression levels of fatty-acid-binding protein 4 (FABP4) and microRNA (miR)-21 were detected using reverse transcription-quantitative PCR and western blot analyses. Cell viability was assessed using a Cell Counting Kit-8 assay. A miR-21 mimic was constructed and transfected into 3T3-L1 preadipocytes. Adipocyte differentiation was detected using Oil Red O staining. The proteins CD36, glucose transporter 4, peroxisome proliferator-activated receptor γ (PPAR-γ) and adipocyte protein 2 (Ap2) were detected using western blot analysis. The expression levels of FABP4 and miR-21 were increased in differentiated 3T3-L1 cells. Paeonol exhibited no effects on cell activity, whereas it inhibited the expression levels of miR-21 in the 3T3-L1 differentiated adipocytes. Paeonol suppressed the differentiation of 3T3-L1 adipocytes and its effect was partially reversed by the overexpression of miR-21. In addition, paeonol promoted the lipid degradation of 3T3-L1 adipocytes, increased the expression levels of PPAR-γ and Ap2, and suppressed triglyceride synthesis in these cells. These effects were partially reversed by the overexpression of miR-21. In conclusion, the findings of the present study indicated that paeonol may exert protective effects against lipid formation and promote lipid degradation in adipocytes. These data provide evidence of the regulatory effect of paeonol on adipocyte differentiation and highlight its pathological significance.

Paeonol Induces Protective Autophagy in Retinal Photoreceptor Cells

Background: Retinal photoreceptor (RP) cells are widely involved in retina-related diseases, and oxidative stress plays a critical role in retinal secondary damage. Herein, we investigated the effectiveness and potential mechanisms of autophagy of paeonol (Pae) in terms of oxidation resistance. Methods: The animal model was induced by light damage (LD) in vivo, whereas the in vitro model was established by H₂O₂ stimulation. The effectiveness of Pae was evaluated by hematoxylin and eosin, terminal deoxynucleotidyl transferase dUTP nick end labeling assay, immunofluorescence, transmission electron microscopy, electroretinogram, and Western blot analysis in vivo, and the underlying mechanisms of Pae were assessed by Cell Counting Kit-8 assay, reactive oxygen species (ROS) assay, and Western blot analysis in 661W cells. We mainly evaluated the effects of Pae on apoptosis and autophagy. Results: Increased apoptosis of the LD-induced and decreased autophagy of RPs were mitigated by Pae treatment. Pea, which increased the expression of mitochondrial functional protein cytochrome c, reversed the decreased cell viability and autophagy induced by oxidative stress in 661W cells. Experiments showed that autophagy was downregulated in PINK1/Parkin dependent and the BNIP3L/Nix dependent pathways under H₂O₂ stimulation and was upregulated by Pae treatment. Pae increased the cell viability and reduced ROS levels through autophagy. Conclusion: Pretreatment with Pae preserved RP cells by enhancing autophagy, which protected retinal function.

Paeonol protects melanocytes against hydrogen peroxide-induced oxidative stress through activation of Nrf2 signaling pathway

Oxidative stress plays a pivotal role in the pathogenesis of vitiligo. Paeonol, a phenolic compound found in the root bark of Cortex Moutan, has been suggested to have therapeutic effects on various diseases through nuclear factor Nrf2 mediated antioxidant pathways. However, the therapeutic effects of paeonol on vitiligo have not been investigated. In this study, we investigated whether paeonol could protect melanocytes against oxidative stress through Nrf2 activation. Hydrogen peroxide (H₂ O₂ ) was used to mimic the oxidative stress. PIG1 cells were pretreated with paeonol for 24 h, and then were treated with H₂ O₂ for 24 h. To detect the role of Nrf2, siRNA method was used to knockdown the Nrf2 expression. After that, cell viability, melanin content, tyrosinase activity, intracellular reactive oxygen species, antioxidant enzymes activities, nuclear translocation of Nrf2, and mRNA expression of Nrf2 downstream antioxidant genes were detected. Paeonol improved cell viability and melanogenesis in PIG1 cells treated with H₂ O₂ . Paeonol also alleviated oxidative stress by restoring the activities of superoxide dismutase, catalase, and glutathione peroxidase. Paeonol promoted Nrf2 nuclear translocation and the expression of its downstream-regulated antioxidative genes under oxidative stress. Furthermore, Nrf2 knockdown by siRNA abolished the protective effects of paeonol on PIG1 cells against oxidative damage. Paeonol protected melanocytes against H₂ O₂ -induced oxidative stress by Nrf2 mediated antioxidant pathways. Paeonol is a potential therapeutic drug for vitiligo.

Stem cell-derived exosomes: Role in the pathogenesis and treatment of atherosclerosis

Atherosclerosis (AS) is a chronic inflammatory vascular disease characterized by the accumulation of lipids and inflammatory debris in large arteries, high morbidity, and AS-related disease mortality. AS is a complex process, involving endothelial cell dysfunction and inflammation, smooth muscle cell proliferation, and macrophage activation. However, the currently available therapies for AS are not ideal, thus requiring development of novel treatment strategies. Exosomes are bi-lipid membranous extracellular containing multifarious cargo, such as proteins, lipids, micro ribonucleic acid (miRNAs), messenger RNAs, and long non-coding RNAs. Moreover, exosomes reportedly participate in various AS processes. Specifically, stem cell-derived exosomes can regulate the occurrence and development of AS, exhibiting the ability to overcome the limitations associated with AS treatment and stem cell therapy. In this paper, we review the pathological mechanism of AS and discuss the role of exosomes and stem cell-derived exosomes in AS progression. We conclude by suggesting new therapeutic strategies for treating AS with stem cell-derived exosomes in the hope of improving the clinical treatment of AS.

Chemistry, pharmacokinetics, pharmacology and recent novel drug delivery systems of paeonol

Paeonol is a bioactive phenol present in Dioscorea japonica, Paeonia suffruticosa and Paeonia lactiflora. It is reported for various pharmacological activities.

AIM

To review chemistry, pharmacokinetics, pharmacological activities as well as various formulations of paeonol.

MATERIALS AND METHODS

A literature search was done using different search terms for paeonol by using different scientific databases like PubMed, Scopus and ProQuest. Scientific papers published during the period 1969 to 2019 were comprehensively reviewed.

KEY FINDINGS

Researchers have synthesized methoxy, ethoxy, piperazine, chromonylthiazolidine, phenol-phenylsulfonyl, alkyl ether, aminothiazole, tryptamine hybrids and paeononlsilatie derivatives to enhance the stability of paeonol. These derivatives were synthesized and evaluated for in vitro series of biological activities like anti-inflammatory, tyrosinase inhibitory, neuroprotective, anticancer and antiviral activity. Regardless of valuable therapeutic potential, the clinical use of paeonol is restricted due to poor water solubility, low oral bioavailability, low stability and high volatility at room temperature. To enhance the bioavailability of paeonol various formulations are prepared and evaluated for its activity. Paeonol formulations can be categorized as conventional-tablets, topical gel and hydrogel; polymeric delivery system-microparticles, microsponges, dendrimers, nanocapsules, polymeric nanoparticles, nanospheres; lipid-based delivery systems-microemulsion, self-micro-emulsifying drug delivery, liposome, transethosomes, ethosomes, niosomes, proniosomes, lipid-based nanoparticles and nanoemulsion of paeonol.

SIGNIFICANCE

Paeonol has a potential to be developed as a techno-commercial product with respect to its multi-faceted pharmacological properties. Even though in vitro and in vivo studies have been reported the important activities of paeonol, its commercial utilization requires extensive safety and efficacy data.

Paeonol Attenuates Methotrexate-Induced Cardiac Toxicity in Rats by Inhibiting Oxidative Stress and Suppressing TLR4-Induced NF-κB Inflammatory Pathway

Methotrexate (MTX) is a commonly used chemotherapeutic agent. Oxidative stress and inflammation have been proved in the development of MTX toxicity. Paeonol is a natural phenolic compound with various pharmacological activities including antioxidant and anti-inflammatory properties. The aim of the present study was to evaluate the protective effect of paeonol against MTX-induced cardiac toxicity in rats and to evaluate the various mechanisms that underlie this effect. Paeonol (100 mg/kg) was administered orally for 10 days. MTX cardiac toxicity was induced at the end of the fifth day of the experiment, with or without paeonol pretreatment. MTX-induced cardiac damage is evidenced by a distortion in the normal cardiac histological structure, with significant oxidative and nitrosative stress shown as a significant increase in NADPH oxidase-2, malondialdehyde, and nitric oxide levels along with a decrease in reduced glutathione concentration and superoxide dismutase activity compared to the control group. MTX-induced inflammatory effects are evidenced by the increased cardiac toll-like receptor 4 (TLR4) mRNA expression and protein level as well as increased cardiac tumor necrosis factor- (TNF-) α and interleukin- (IL-) 6 levels along with increased nuclear factor- (NF-) κB/p65 immunostaining. MTX increased apoptosis as shown by the upregulation of cardiac caspase 3 immunostaining. Paeonol was able to correct the oxidative and nitrosative stress as well as the inflammatory and apoptotic parameters and restore the normal histological structure compared to MTX alone. In conclusion, paeonol has a protective effect against MTX-induced cardiac toxicity through inhibiting oxidative and nitrosative stress and suppressing the TLR4/NF-κB/TNF-α/IL-6 inflammatory pathway, as well as causing an associated reduction in the proapoptotic marker, caspase 3.

Macrophage migration inhibitory factor of Syrian golden hamster shares structural and functional similarity with human counterpart and promotes pancreatic cancer

Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine that increasingly is being studied in cancers and inflammatory diseases. Though murine models have been instrumental in understanding the functional role of MIF in different pathological conditions, the information obtained from these models is biased towards a specific species. In experimental science, results obtained from multiple clinically relevant animal models always provide convincing data that might recapitulate in humans. Syrian golden hamster (Mesocricetus auratus), is a clinically relevant animal model for multiple human diseases. Hence, the major objectives of this study were to characterize the structure and function of Mesocricetus auratus MIF (MaMIF) and finally evaluate its effect on pancreatic tumor growth in vivo. Initially, the recombinant MaMIF was cloned, expressed and purified in a bacterial expression system. The MaMIF primary sequence, biochemical properties, and crystal structure analysis showed greater similarity with human MIF. The crystal structure of MaMIF illustrates that it forms a homotrimer as known in human and mouse. However, MaMIF exhibits some minor structural variations when compared to human and mouse MIF. The in vitro functional studies show that MaMIF has tautomerase activity and enhances activation and migration of hamster peripheral blood mononuclear cells (PBMCs). Interestingly, injection of MaMIF into HapT1 pancreatic tumor-bearing hamsters significantly enhanced the tumor growth and tumor-associated angiogenesis. Together, the current study shows a structural and functional similarity between the hamster and human MIF. Moreover, it has demonstrated that a high level of circulating MIF originating from non-tumor cells might also promote pancreatic tumor growth in vivo.

Paeonol: pharmacological effects and mechanisms of action

Paeonia suffruticosa possesses various medicinal benefits and has been used extensively in traditional oriental medicine for thousands of years. Paeonol is the main component isolated from the root bark of Paeonia suffruticosa. The pharmacological effects of Paeonia suffruticosa are mostly attributed to paeonol. Paeonol injection has been successfully applied in China for nearly 50 years for inflammation/pain-related indications. Currently, the dosage forms of paeonol approved by China Food and Drug Administration include tablet, injection, and external preparations such as ointment and adhesive plaster. So far, the clinical applications of paeonol are mainly focusing on the anti-inflammatory activity. Studies of other pharmacological activities of paeonol are developing rapidly, and which may play an important role in the future. Besides, substantial mechanisms of pharmacological action of paeonol have been clarified in recent years. In this review, we summarize the pharmacological effects anti-inflammatory, neuroprotective, anti-tumor, anti-cardiovascular diseases and associated mechanisms of action of paeonol up to date.