Effects of short- and long-term use of propolis extracts on liver and kidney in rats

Propolis is widely used as a supplementary food product for its health benefits. The aim of this study was to determine the effects of commercial propolis extracts on the liver and kidney. Propolis extracts (250 mg/kgbw/day) were administered orally to adult male Wistar albino rats in solvents of ethanol, propylene glycol, water, and olive oil. Liver enzyme levels were determined biochemically in blood samples, and histopathological examinations were performed on the liver. Damage rate in both kidney tissue in the propolis-ethanol extract group increased significantly compared with the other groups after 30 and 90 days of application (p < .05). According to the results, ethanol, used as a common solvent in propolis products, may adversely affect the liver in long-term use. The data indicate that propolis-olive oil extract may be an essential alternative due to its effective and reliable properties.

Liver cancer wars: plant-derived polyphenols strike back

Liver cancer currently represents the leading cause of cancer-related death worldwide. The majority of liver cancer arises in the context of chronic inflammation and cirrhosis. Surgery, radiation therapy, and chemotherapy have been the guideline-recommended treatment options for decades. Despite enormous advances in the field of liver cancer therapy, an effective cure is yet to be found. Plant-derived polyphenols constitute a large family of phytochemicals, with pleiotropic effects and little toxicity. They can drive cellular events and modify multiple signaling pathways which involves initiation, progression and metastasis of liver cancer and play an important role in contributing to anti-liver cancer drug development. The potential of plant-derived polyphenols for treating liver cancer has gained attention from research clinicians and pharmaceutical scientists worldwide in the last decades. This review overviews hepatic carcinogenesis and briefly discusses anti-liver cancer mechanisms associated with plant-derived polyphenols, specifically involving cell proliferation, apoptosis, autophagy, angiogenesis, oxidative stress, inflammation, and metastasis. We focus on plant-derived polyphenols with experiment-based chemopreventive and chemotherapeutic properties against liver cancer and generalize their basic molecular mechanisms of action. We also discuss potential opportunities and challenges in translating plant-derived polyphenols from preclinical success into clinical applications.

Medicinal Plants in Cancer Treatment: Contribution of Nuclear Factor-Kappa B (NF-kB) Inhibitors

Nuclear factor-kappa B (NF-κB) is one of the principal inducible proteins that is a predominant transcription factor known to control the gene expression in mammals and plays a pivotal role in regulating cell signalling in the body under certain physiological and pathological conditions. In cancer cells, such as colon, breast, pancreatic, ovarian, melanoma, and lymphoma, the NF-κB pathway has been reported to be active. In cellular proliferation, promoting angiogenesis, invasion, metastasis of tumour cells and blocking apoptosis, the constitutive activity of NF-κB signalling has been reported. Therefore, immense attention has been given to developing drugs targeting NF-κB signalling pathways to treat many types of tumours. They are a desirable therapeutic target for drugs, and many studies concentrated on recognizing compounds. They may be able to reverse or standstill the growth and spread of tumours that selectively interfere with this pathway. Recently, numerous substances derived from plants have been evaluated as possible inhibitors of the NF-κB pathway. These include various compounds, such as flavonoids, lignans, diterpenes, sesquiterpenes, polyphenols, etc. A study supported by folk medicine demonstrated that plant-derived compounds could suppress NF-κB signalling. Taking this into account, the present review revealed the anticancer potential of naturally occurring compounds which have been verified both by inhibiting the NF-κB signalling and suppressing growth and spread of cancer and highlighting their mechanism of NF-κB inhibition.

Molecular alterations that precede the establishment of the hallmarks of cancer: An approach on the prevention of hepatocarcinogenesis

Chronic liver injury promotes the molecular alterations that precede the establishment of cancer. Usually, several decades of chronic insults are needed to develop the most common primary liver tumor known as hepatocellular carcinoma. As other cancer types, liver cancer cells are governed by a common set of rules collectively called the hallmarks of cancer. Although those rules have provided a conceptual framework for understanding the complex pathophysiology of established tumors, therapeutic options are still ineffective in advanced stages. Thus, the molecular alterations that precede the establishment of cancer remain an attractive target for therapeutic interventions. Here, we first summarize the chemopreventive interventions targeting the early liver carcinogenesis stages. After an integrative analysis on the plethora of molecular alterations regulated by anticancer agents, we then underline and discuss that two critical processes namely oxidative stress and genetic alterations, play the role of 'dirty work laborer' in the initial cell damage and drive the transformation of preneoplastic into neoplastic cells, respectively; besides, the activation of cellular senescence works as a key mechanism in attempting to prevent the onset and establishment of liver cancer. Whereas the detrimental effects of the binomial made up of oxidative stress and genetic alterations are either eliminated or reduced, senescence activation is promoted by anticancer agents. We argue that collectively, oxidative stress, genetic alterations, and senescence are key events that influence the fate of initiated cells and the establishment of the hallmarks of cancer.

Effect of Dietary Doses of Quercetin on Hepatic Drug Metabolizing Enzymes in Spontaneously Hypertensive Rats

BACKGROUND

Administration of quercetin (QR) has shown several health benefits in clinical and pre-clinical studies.

OBJECTIVE

This study investigates the effect of dietary doses of QR on hepatic drug metabolizing enzymes in spontaneously hypertensive rats in order to investigate the potential for herb-drug interactions.

METHODS

The activity and/or protein expression of selected cytochrome P450 (CYP) enzymes and microsomal epoxide hydrolase were measured in hepatic microsomes using specific probe substrates and/or polyclonal antibodies. Cytosolic fraction was utilized to measure protein level and activity of major antioxidant systems.

RESULTS

The doses employed in our study did not cause any significant alterations in the activity and/or protein level of CYP1A1, CYP2A6, CYP2E, and glutathione (GSH). While the activity and apoprotein levels of CYP1A2 and CYP2B1/2 were significantly reduced by the medium and high doses of QR, the activity and/or protein level of microsomal CYP3A and cytosolic GSH-S-transferase, GSH reductase, and GSH peroxidase were significantly enhanced. Activity and protein level of CYP2C9 were significantly inhibited by all doses. Only the high-dose QR resulted in significant inhibition of both microsomal and soluble epoxide hydrolase as well as induction of the antioxidant enzymes, catalase and superoxide dismutase.

CONCLUSION

This study demonstrates that dietary doses of QR may offer chemoprevention through stimulation of the endogenous antioxidant systems and inhibition of CYP enzymes involved in bioactivation of procarcinogens. However, modulation of drug metabolizing enzymes by QR could have potential for herb-drug interactions with the possibility of serious complications.

Matrine prevents the early development of hepatocellular carcinoma like lesions in rat liver

Matrine (C15H24N2O) is an alkaloid extracted from the Chinese herb Sophora flavescens that has anti-fibrotic and anti-cancer properties. The aim of the present study was to determine the chemopreventive effect of matrine on the development of primary hepatocellular carcinoma (HCC) and its possible association with the suppression of the Notch signaling pathway. The rats were randomly divided into four groups: Control, model, low-dose matrine and high-dose matrine groups. The model was established by combining a partial hepatectomy with diethylnitrosamine (DEN) + 2-acetylaminofluorene (2-AAF). Low- and high-dose matrine groups received intragastric administration of matrine (0.25 and 2.5 g/l of matrine, respectively). DEN + 2-AAF injections and hepatectomy were not performed in the control group. All rats were sacrificed 2, 4 and 7 weeks after hepatectomy. HCC-like histopathological lesions were detected using hematoxylin and eosin staining. The expression levels of α-1-fetoprotein (AFP), albumin (ALB), Notch1 and Hes1 were analyzed using immunohistochemistry. Hepatic lobule structure loss, liver tissue necrosis and inflammatory cell infiltration, and edema degeneration were observed in the model group. By contrast, hepatocyte cord structure was restored and hepatocyte edema degeneration was significantly reduced after 7 weeks of treatment with matrine. In addition, compared with the model group, matrine reduced the expression of AFP, increased the expression of ALB and reduced the expression of Notch1 and Hes1 (only for high-dose matrine; all P<0.05). The findings suggested that matrine could prevent the early development of HCC-like lesions in a rat model, possibly by modulating Notch pathway activation.

Anti-colon cancer effect of caffeic acid p-nitro-phenethyl ester in vitro and in vivo and detection of its metabolites

Caffeic acid phenethyl ester (CAPE), extracted from propolis, was proven to inhibit colon cancer. Caffeic acid p-nitro-phenethyl ester (CAPE-pNO₂), a derivative of CAPE, was determined to be an anti-platelet agent and a protector of myocardial ischaemia with more potent effects. In the present study, CAPE-pNO₂ showed stronger cytotoxic activity than CAPE. We revealed interactions between CAPE-pNO₂ and experimental cells. CAPE-pNO₂ induced apoptosis in HT-29 cells by up-regulating P53, cleaved-caspase-3, Bax, P38 and CytoC; CAPE-pNO₂ also up-regulated P21^Cip1 and P27^Kip1 and down-regulated CDK2 and c-Myc to promote cell cycle arrest in G0/G1. In xenograft studies, CAPE-pNO₂ remarkably suppressed tumour growth dose dependently and decreased the expression of VEGF (vascular endothelial growth factor) in tumour tissue. Moreover, HE staining showed that no observable toxicity was found in the heart, liver, kidney and spleen. In addition, metabolites of CAPE-pNO₂ in HT-29 cells and organs were detected. In conclusion, para-nitro may enhance the anticancer effect of CAPE by inhibiting colon cancer cell viability, inducing apoptosis and cell cycle arrest via the P53 pathway and inhibiting tumour growth and reducing tumour invasion by decreasing the expression of VEGF; additionally, metabolites of CAPE-pNO₂ showed differences in cells and organs.

Inhibition of Cytochrome P450 by Propolis in Human Liver Microsomes

Although propolis is one of the most popular functional foods for human health, there have been no comprehensive studies of herb-drug interactions through cytochrome P450 (CYP) inhibition. The purpose of this study was to determine the inhibitory effects of propolis on the activities of CYP1A2, 2A6, 2B6, 2C9, 2C19, 2D6, 2E1 and 3A4 using pooled human liver microsomes (HLMs). Propolis inhibited CYP1A2, CYP2E1 and CYP2C19 with an IC₅₀ value of 6.9, 16.8, and 43.1 μg/mL, respectively, whereas CYP2A6, 2B6, 2C9, 2D6, and 3A4 were unaffected. Based on half-maximal inhibitory concentration shifts between microsomes incubated with and without nicotinamide adenine dinucleotide phosphate, propolis-induced CYP1A2, CYP2C19, and CYP2E1 inhibition was metabolism-independent. To evaluate the interaction potential between propolis and therapeutic drugs, the effects of propolis on metabolism of duloxetine, a serotonin-norepinephrine reuptake inhibitor, were determined in HLMs. CYP1A2 and CYP2D6 are involved in hydroxylation of duloxetine to 4-hydroxy duloxetine, the major metabolite, which was decreased following propolis addition in HLMs. These results raise the possibility of interactions between propolis and therapeutic drugs metabolized by CYP1A2.

Characterization of Changes in Global Genes Expression in the Distal Colon of Loperamide-Induced Constipation SD Rats in Response to the Laxative Effects of Liriope platyphylla

To characterize the changes in global gene expression in the distal colon of constipated SD rats in response to the laxative effects of aqueous extracts of Liriope platyphylla (AEtLP), including isoflavone, saponin, oligosaccharide, succinic acid and hydroxyproline, the total RNA extracted from the distal colon of AEtLP-treated constipation rats was hybridized to oligonucleotide microarrays. The AEtLP treated rats showed an increase in the number of stools, mucosa thickness, flat luminal surface thickness, mucin secretion, and crypt number. Overall, compared to the controls, 581 genes were up-regulated and 216 genes were down-regulated by the constipation induced by loperamide in the constipated rats. After the AEtLP treatment, 67 genes were up-regulated and 421 genes were down-regulated. Among the transcripts up-regulated by constipation, 89 were significantly down-regulated and 22 were recovered to the normal levels by the AEtLP treatment. The major genes in the down-regulated categories included Slc9a5, klk10, Fgf15, and Alpi, whereas the major genes in the recovered categories were Cyp2b2, Ace, G6pc, and Setbp1. On the other hand, after the AEtLP treatment, ten of these genes down-regulated by constipation were up-regulated significantly and five were recovered to the normal levels. The major genes in the up-regulated categories included Serpina3n, Lcn2 and Slc5a8, whereas the major genes in the recovered categories were Tmem45a, Rerg and Rgc32. These results indicate that several gene functional groups and individual genes as constipation biomarkers respond to an AEtLP treatment in constipated model rats.

Dietary Doses of Sulforaphane Affect Hepatic Drug Metabolizing Enzymes in Spontaneously Hypertensive Rats

We previously demonstrated that exposure of spontaneously hypertensive rats (SHR) to dietary doses of sulforaphane (SF) results in resisting the progressive rise in blood pressure that is normally seen in these rats. This study investigates the potential effect of SF on hepatic drug metabolizing enzymes (DME) in SHR. The activity and/or protein expression of selected cytochrome P450 (CYP) enzymes and microsomal epoxide hydrolase (mEH) were measured in hepatic microsomes using specific probe substrates and/or polyclonal antibodies. Cytosolic fraction was utilized to measure protein level and activity of major antioxidant systems. The high dose SF resulted in a significant reduction of activity and apoproteins level of CYP1A2 and CYP2C9 and activities of CYP2B1/2 and mEH. No effect of SF was observed on the rest of the studied CYP enzymes. Both doses of SF resulted in a significant induction of both hepatic glutathione level and activities of superoxide dismutase and catalase. Activities of hepatic glutathione-S-transferases, glutathione reductase, and glutathione peroxidase were significantly induced only with the high dose. This study demonstrates that dietary doses of SF modulate the activity or protein expression of DME. Additionally, induction of the impaired antioxidant system in SHR may explain the blood pressure lowering effect of SF in this rat model. Copyright © 2015 John Wiley & Sons, Ltd.

Effect of Natural Polyphenols on CYP Metabolism: Implications for Diseases

Cytochromes P450 (CYPs) are a large group of hemeproteins located on mitochondrial membranes or the endoplasmic reticulum. They play a crucial role in the metabolism of endogenous and exogenous molecules. The activity of CYP is associated with a number of factors including redox potential, protein conformation, the accessibility of the active site by substrates, and others. This activity may be potentially modulated by a variety of small molecules. Extensive experimental data collected over the past decade point at the active role of natural polyphenols in modulating the catalytic activity of CYP. Polyphenols are widespread micronutrients present in human diets of plant origin and in medicinal herbs. These compounds may alter the activity of CYP either via direct interactions with the enzymes or by affecting CYP gene expression. The polyphenol-CYP interactions may significantly alter the pharmacokinetics of drugs and thus influence the effectiveness of chemical therapies used in the treatment of different types of cancers, diabetes, obesity, and cardiovascular diseases (CVD). CYPs are involved in the oxidation and activation of external carcinogenic agents, in which case the inhibition of the CYP activity is beneficial for health. CYPs also support detoxification processes. In this case, it is the upregulation of CYP genes that would be favorable for the organism. A CYP enzyme aromatase catalyzes the formation of estrone and estradiol from their precursors. CYPs also catalyze multiple reactions leading to the oxidation of estrogen. Estrogen signaling and oxidative metabolism of estrogen are associated with the development of cancer. Thus, polyphenol-mediated modulation of the CYP's activity also plays a vital role in estrogen carcinogenesis. The aim of the present review is to summarize the data collected over the last five to six years on the following topics: (1) the mechanisms of the interactions of CYP with food constituents that occur via the direct binding of polyphenols to the enzymes and (2) the mechanisms of the regulation of CYP gene expression mediated by polyphenols. The structure-activity relationship relevant to the ability of polyphenols to affect the activity of CYP is analyzed. The application of polyphenol-CYP interactions to diseases is discussed.

The effect of caffeic acid phenethyl ester analogues in a modified resistant hepatocyte model

We present a study of the chemoprotective effects of two caffeic acid phenethyl ester (CAPE)-related structures: LQM717 and LQM706. The modified resistant hepatocyte model in rats was used to study the chemoprevention of these CAPE analogues, which are inexpensive and easily obtained. In the liver cancer model used, we detected extensive necrosis and lipid peroxidation after 24 h, many altered hepatic foci, putatively preneoplastic lesions with γ-glutamyl transpeptidase staining after 30 days, and liver tumors at 12 months. We tested the effect of the CAPE analogues on necrosis, lipid peroxidation, proliferation, p65 activation, altered hepatic foci, and tumors. Both compounds exerted protective effects on lipid peroxidation, necrosis, cell proliferation, p65 activation, and preneoplastic lesions. Rats under a carcinogenic protocol showed a 52, 71.74, and 51.6% decrease in the number of preneoplastic nodules when pretreated with CAPE, LQM706, and LQM717, respectively. At 12 months after carcinogenic treatment, eight of eight rats developed liver cancer, whereas in the group of rats that received pretreatment with CAPE, LQM706, or LQM717, 62.5, 83.3, or 42.85%, respectively, had tumors. In conclusion, LQM717 has the potential to enhance chemoprotection activity much better than CAPE by markedly reducing the formation of liver cancers in this model, and this is a compound that is easy to obtain.

Caffeic acid phenethyl ester, a promising component of propolis with a plethora of biological activities: a review on its anti-inflammatory, neuroprotective, hepatoprotective, and cardioprotective effects

Caffeic acid phenethyl ester (CAPE) is an important active component of honey bee propolis that possesses a plethora of biological activities. Propolis is used safely in traditional medicine as a dietary supplement for its therapeutic benefits. This review highlights the recently published data about CAPE bioavailability, anti-inflammatory, neuroprotective; hepatoprotective and cardioprotective activities. CAPE showed promising efficacy both in vitro and in vivo studies in animal models with minimum adverse effects. Its effectiveness was demonstrated in multiple target organs. Despite this fact, it has not been yet investigated as a protective agent or a potential therapy in humans. Investigation of CAPE efficacy in clinical trials is strongly encouraged to elucidate its therapeutic benefit for different human diseases after performing full preclinical toxicological studies and gaining more insights into its pharmacokinetics.