Preventive effect of apigenin against isoproterenol-induced apoptosis in cardiomyoblasts

Structure Optimization of Natural Product Catalpol to Obtain Novel and Potent Analogs against Heart Failure

Heart failure (HF) is a major global health threat, characterized by high morbidity and mortality. Targeting cardiac hypertrophy has been identified as a potential therapy for HF, with current treatments showing limited efficacy. Our research aims to address this limitation by exploring new structural classes of therapeutic agents. Starting from the natural product catalpol, we designed a series of novel catalpol analogs to break through the structural limitations of natural analogs, improve the anti-HF efficacy and metabolic properties. Among these, compound JZ19 exhibited remarkable efficacy in both myocardial cell injury assays and in an isoproterenol-induced murine HF model, outperforming catalpol. Our findings indicate that JZ19 potently reversed cardiac function by modulating the PI3K-AKT-GSK3β pathway, a key regulator of hypertrophy and apoptosis. Moreover, JZ19 showed favorable pharmacokinetic properties and safety. Overall, our results provide direct pharmacologic evidence supporting the further development of JZ19 as novel HF therapeutics by inhibiting cardiac hypertrophy and apoptosis.

Cardioprotective Potential of d-limonene against Isoproterenol induced Myocardial Infarction in Rats

d-limonene is a type of colorless liquid hydrocarbon that falls under the category of cyclic monoterpene. It is the component found in the oil extracted from fruit peels. Isoproterenol, a synthetic β-adrenergic agonist, was administered to rats to induce myocardial injury by increasing heart rate and myocardial oxygen demand, leading to ischemia and oxidative stress. This study aims to investigate the properties of d limonene, against myocardial infarction induced by isoprenaline (ISO) in rats. Male Sprague Dawley rats were treated with d-limonene (200 & 400 mg/kg, p.o) daily for 28 days and administered ISO (85 mg/kg, s.c) on the 29th and 30th days at an interval of 24 hr to induce myocardial injury. Morphological and antioxidant parameters, biochemical markers, lipid profile, troponin-I, cardiac ATPase, heart mitochondrial, and lysosomal enzymes were assayed followed by histopathological screening. Rats treated with isoproterenol (85 mg/kg, s.c), administered twice at an interval of 24 h on 29th and 30th day showed a significant change in morphological and antioxidant parameters, biochemical markers, lipid profile, troponin-I, cardiac ATPase, heart mitochondrial, lysosomal enzymes activities and transcription factor (TNF-α/IL-6/NF-kB) expression. Pretreatment with d-limonene (200 and 400 mg/kg, p.o) for 28 days followed by ISO administration on 29th and 30th day significantly reversed the effects of isoproterenol-induced ischemic changes. Moreover, the biochemical results were validated by histopathological findings. The research indicates that d-limonene demonstrates cardioprotective potential against isoproterenol-induced myocardial infarction. This is attributed to its antioxidant properties, stabilization of myocardial membranes, improved scavenging of free radicals, and inhibition of membrane lipid peroxidation.

Apigenin: A Bioflavonoid with a Promising Role in Disease Prevention and Treatment

Apigenin is a powerful flavone compound found in numerous fruits and vegetables, and it offers numerous health-promoting benefits. Many studies have evidenced that this compound has a potential role as an anti-inflammatory and antioxidant compound, making it a promising candidate for reducing the risk of pathogenesis. It has also been found to positively affect various systems in the body, such as the respiratory, digestive, immune, and reproductive systems. Apigenin is effective in treating liver, lung, heart, kidney, neurological diseases, diabetes, and maintaining good oral and skin health. Multiple studies have reported that this compound is capable of suppressing various types of cancer through the induction of apoptosis and cell-cycle arrest, suppressing cell migration and invasion, reduction of inflammation, and inhibiting angiogenesis. When used in combination with other drugs, apigenin increases their efficacy, reduces the risk of side effects, and improves the response to chemotherapy. This review broadly analyzes apigenin's potential in disease management by modulating various biological activities. In addition, this review also described apigenin's interaction with other compounds or drugs and the potential role of nanoformulation in different pathogeneses. Further extensive research is needed to explore the mechanism of action, safety, and efficacy of this compound in disease prevention and treatment.

PEG-modified nano liposomes co-deliver Apigenin and RAGE-siRNA to protect myocardial ischemia injury

Ischemic heart disease (IHD) is a cardiac disorder in which myocardial damage occurs as a result of myocardial ischemia and hypoxia. Evidence suggests that oxidative stress and inflammatory responses are critical in the development of myocardial ischemia. Therefore, the combination of antioxidant and anti-inflammatory applications is an effective strategy to combat ischemic heart disease. In this paper, polyethylene glycol (PEG)-modified cationic liposomes were used as carriers to deliver apigenin (Apn) with small interfering RNA (siRNA) targeting the receptor for glycosylation end products (RAGE) (siRAGE) into cardiomyocytes to prevent myocardial ischemic injury through antioxidant and anti-inflammatory effects. Our results showed that we successfully prepared cationic PEG liposomes loaded with Apn and siRAGE (P-CLP-A/R) with normal appearance and morphology, particle size and Zeta potential, and good encapsulation rate, drug loading and in vitro release degree. In vitro, P-CLP-A/R was able to prevent oxidative stress injury in H9C2 cells, downregulate the expression of RAGE, reduce the secretion of cellular inflammatory factors and inhibit apoptosis through the RAGE/NF-κB pathway; In vivo, P-CLP-A/R was able to prevent arrhythmia and myocardial pathological injury, and reduce apoptosis and the area of necrotic myocardium in rats. In conclusion, P-CLP-A/R has a protective effect on myocardial ischemic injury and is expected to be a potential drug for the prevention of ischemic heart disease in the future.

Implication of MAPK, Lipocalin-2, and Fas in the protective action of liposomal resveratrol against isoproterenol-induced kidney injury

Background and Objective

Isoproterenol (ISO) is a non-selective β-adrenergic receptor agonist. It can be used to treat bradycardia and cardiogenic shock. Despite its usefulness, the overstimulation of β-receptors by ISO can cause "cardiorenal syndrome," a term used to describe heart and kidney damage. Resveratrol (RES), a natural polyphenol, has marked anti-inflammatory and antioxidant activities. The present work was designed to study the protective efficacy of liposomal resveratrol (L-RES) against ISO-induced kidney injury.

Materials and Methods

The kidney injury was induced in rats by administering ISO (50 mg/kg, s.c.) twice a week for 2 weeks. RES and L-RES were administered at a dose (20 mg/kg/ day, p.o.) along with ISO for 2 weeks. Inflammatory and apoptotic biomarkers were analyzed, which were validated using histochemical analysis.

Results

ISO caused renal dysfunction, which manifested as elevated urea, creatinine and uric acid, besides cystatin c and MAPK protein overexpression. In addition, ISO induced gene expression of Fas and lipocalin-2 and provoked genomic DNA fragmentation in renal tissues as compared with the control group. Histological examination confirmed morphological alterations of the kidney tissues obtained from the ISO group. Concurrent treatment of either RES or L-RES with ISO significantly ameliorated kidney damage as demonstrated by the improvement of all measured parameters with the best results for L-RES. The histopathological findings were correlated with the above biochemical parameters.

Conclusion

L-RES could be a promising approach for the prevention of kidney injury induced by ISO, most likely via the downregulation of MAPK, cystatin c, Fas, and lipocalin-2.

Hepatoprotective effect of p-Coumaric acid against KBrO3 -induced apoptosis in HepG2 cells

In the present study, we investigated the effect of the p-Coumaric acid (PCA), a phenolic acid, on potassium bromate (KBrO3 ) induced oxidative damage, Ras/Raf/MEK signaling, and apoptosis in HepG2 cells. Our findings showed that PCA-treated cells prevented cytotoxicity compared with KBrO3- treated cells. Furthermore, KBrO3 -induced oxidative stress and lipid peroxidation was attenuated by PCA and it also increased the antioxidant levels such as SOD, CAT, and GPX. Additionally, PCA inhibited the KBrO3 -induced DNA damage in HepG2 cells. Moreover, PCA treatment suppressed the activation of Ras/Raf/MEK signaling and increased the expression of PRDX-1. In addition, PCA prevented the KBrO3 -induced apoptosis cascade by altering the expression of proapoptotic, Bax, caspase-3, and antiapoptotic, Bcl-2 proteins. The present study proves that PCA inhibited the KBrO3 -induced oxidative stress, DNA damage, and apoptotic signaling cascade in HepG2 cells.

Toll-like receptor 4: A potential therapeutic target for multiple human diseases

The immune response plays a pivotal role in the pathogenesis of diseases. Toll-like receptor 4 (TLR4), as an intrinsic immune receptor, exhibits widespread in vivo expression and its dysregulation significantly contributes to the onset of various diseases, encompassing cardiovascular disorders, neoplastic conditions, and inflammatory ailments. This comprehensive review centers on elucidating the architectural and distributive characteristics of TLR4, its conventional signaling pathways, and its mode of action in diverse disease contexts. Ultimately, this review aims to propose novel avenues and therapeutic targets for clinical intervention.

Anti-photoaging effect and mechanism of flexible liposomes co-loaded with apigenin and doxycycline

Prolonged exposure to UV light can lead to photo-ageing of the skin. Therefore, the development and application of anti-photoaging drugs is urgent. In this study, we co-loaded apigenin (Apn) and doxycycline (Doc), a broad-spectrum inhibitor of matrix metalloproteinases (MMPs), into flexible liposomes to exert anti-photoaging effects by combating oxidative stress, anti-inflammation, reducing the activation of MMPs and preventing collagen loss. The results showed that we prepared a flexible liposome (A/D-FLip) containing Apn and Doc. Its appearance, particle size and Zeta potential were normal and it had good encapsulation efficiency, drug loading, in vitro release and transdermal efficiency. In cellular experiments, A/D-FLip could inhibit oxidative stress damage, reduce inflammatory factors and decrease the activation of MMPs in Human immortalized keratinocytes (HaCaT) cells; in animal experiments, A/D-FLip could inhibit skin damage and reduce skin collagen loss by decreasing the activation of MMPs, thus inhibiting skin photoaging in mice. In conclusion, A/D-FLip has good anti-photoaging effects and it has the potential to become an effective skin care product or drug against UV damage and skin photoaging in the future.

Pharmacological and Molecular Insight on the Cardioprotective Role of Apigenin

Apigenin is a naturally occurring dietary flavonoid found abundantly in fruits and vegetables. It possesses a wide range of biological properties that exert antioxidant, anti-inflammatory, anticancer, and antibacterial effects. These effects have been reported to be beneficial in the treatment of atherosclerosis, stroke, hypertension, ischemia/reperfusion-induced myocardial injury, and diabetic cardiomyopathy, and provide protection against drug-induced cardiotoxicity. These potential therapeutic effects advocate the exploration of the cardioprotective actions of apigenin. This review focuses on apigenin, and the possible pharmacological mechanisms involved in the protection against cardiovascular diseases. We further discuss its therapeutic uses and highlight its potential applications in the treatment of various cardiovascular disorders. Apigenin displays encouraging results, which may have implications in the development of novel strategies for the treatment of cardiovascular diseases. With the commercial availability of apigenin as a dietary supplement, the outcomes of preclinical studies may provide the investigational basis for future translational strategies evaluating the potential of apigenin in the treatment of cardiovascular disorders. Further preclinical and clinical investigations are required to characterize the safety and efficacy of apigenin and establish it as a nutraceutical as well as a therapeutic agent to be used alone or as an adjuvant with current drugs.

Mitochondrial Effects of Common Cardiovascular Medications: The Good, the Bad and the Mixed

Mitochondria are central organelles in the homeostasis of the cardiovascular system via the integration of several physiological processes, such as ATP generation via oxidative phosphorylation, synthesis/exchange of metabolites, calcium sequestration, reactive oxygen species (ROS) production/buffering and control of cellular survival/death. Mitochondrial impairment has been widely recognized as a central pathomechanism of almost all cardiovascular diseases, rendering these organelles important therapeutic targets. Mitochondrial dysfunction has been reported to occur in the setting of drug-induced toxicity in several tissues and organs, including the heart. Members of the drug classes currently used in the therapeutics of cardiovascular pathologies have been reported to both support and undermine mitochondrial function. For the latter case, mitochondrial toxicity is the consequence of drug interference (direct or off-target effects) with mitochondrial respiration/energy conversion, DNA replication, ROS production and detoxification, cell death signaling and mitochondrial dynamics. The present narrative review aims to summarize the beneficial and deleterious mitochondrial effects of common cardiovascular medications as described in various experimental models and identify those for which evidence for both types of effects is available in the literature.

Cardioprotective potential of the antioxidant-rich bioactive fraction of Garcinia pedunculata Roxb. ex Buch.-Ham. against isoproterenol-induced myocardial infarction in Wistar rats

This Study aimed to characterise the phenolic compounds in Garcinia pedunculata extract and assess their potential antioxidant activity as well as its cardioprotective potential in isoproterenol-induced cardiac hypertrophy in an experimental animal model. In vitro antioxidant properties were determined using DPPH, ABTS, FRAP, PMD assays. In vitro lipid peroxidation experiment was also performed with heart tissues. Cardioprotective and cardiotoxicity effects were determined using the cell line studies. The cardioprotective effect of GP was assessed in a rat model of isoproterenol-(ISO-) induced cardiac hypertrophy by subcutaneous administration. Heart weight/tail length ratio and cardiac hypertrophy indicators were reduced after oral administration of GP. Additionally, GP reduced oxidative stress and heart inflammation brought on by ISO. In H9c2 cells, the antihypertrophic and anti-inflammatory effects of the extract of GP were seen in the presence of ISO, which were further supported by the in vivo observations. This study makes a compelling case for the possibility that supplementing with dried GP fruit can prevent heart hypertrophy by reducing oxidative stress and inflammation.

Main active components of Si-Miao-Yong-An decoction (SMYAD) attenuate autophagy and apoptosis via the PDE5A-AKT and TLR4-NOX4 pathways in isoproterenol (ISO)-induced heart failure models

Heart failure (HF), the main cause of death in patients with many cardiovascular diseases, has been reported to be closely related to the complicated pathogenesis of autophagy, apoptosis, and inflammation. Notably, Si-Miao-Yong-An decoction (SMYAD) is a traditional Chinese medicine (TCM) used to treat cardiovascular disease; however, the main active components and their relevant mechanisms remain to be discovered. Based on our previous ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS) results, we identified angoriside C (AC) and 3,5-dicaffeoylquinic acid (3,5-DiCQA) as the main active components of SMYAD. In vivo results showed that AC and 3,5-DiCQA effectively improved cardiac function, reduced the fibrotic area, and alleviated isoproterenol (ISO)-induced myocarditis in rats. Moreover, AC and 3,5-DiCQA inhibited ISO-induced autophagic cell death by inhibiting the PDE5A/AKT/mTOR/ULK1 pathway and inhibited ISO-induced apoptosis by inhibiting the TLR4/NOX4/BAX pathway. In addition, the autophagy inhibitor 3-MA was shown to reduce ISO-induced apoptosis, indicating that ISO-induced autophagic cell death leads to excess apoptosis. Taken together, the main active components AC and 3,5-DiCQA of SMYAD inhibit the excessive autophagic cell death and apoptosis induced by ISO by inhibiting the PDE5A-AKT and TLR4-NOX4 pathways, thereby reducing myocardial inflammation and improving heart function to alleviate and treat a rat ISO-induced heart failure model and cell heart failure models. More importantly, the main active components of SMYAD will provide new insights into a promising strategy that will promote the discovery of more main active components of SMYAD for therapeutic purposes in the future.

In Vivo and In Vitro Cardioprotective Effect of Gossypin Against Isoproterenol-Induced Myocardial Infarction Injury

The aim of the study was to examine the protective effects and possible mechanism of gossypin against isoproterenol (ISO)-mediated myocardial damage in vivo and H9c2 cell damage in vitro. H9c2 cells were categorized into five groups. Viability was evaluated with MTT and LDH release in H9c2 cells. Apoptotic parameter analysis was performed with cytochrome c (Cyt-c), caspase-3 (CASP-3), and BCL2/Bax mRNA expression levels. In vivo, gossypin was administered orally to mice at doses of 5, 10, and 20 mg/kg for 7 days. ISO groups were injected with isoproterenol (150 mg/kg) subcutaneously (on 8th and 9th) for 2 days. Afterward, lactate dehydrogenase (LDH), creatine kinase-MB (CK-MB) levels and Troponin-I (Tn-I) amount from their serum, oxidative stress parameters superoxide dismutase (SOD) activity, glutathione (GSH) and malondialdehyde (MDA) levels, and tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1 β), and NF-kB mRNA expression levels with inflammatory markers from heart tissue were evaluated. In addition, IL-1B, BCL-2, and cas-3 immunohistochemical staining was performed from heart tissue and TNF-a level was measured by ELISA method. Administration of Gossypin protected the cells by dose-dependent, eliminating the reduced cell viability and increased LDH release of ISO in H9c2 cells. In mice serum analyses, increased LDH, CK-MB levels, and Tn-I levels were normalized by gossypin. ISO administration in heart tissue is regulated by gossypin with increased SOD activity, GSH amount, TNF-α, IL-6, IL-1β, and NF-kB mRNA expression levels and decreased MDA amount. Overall, the present results demonstrated that gossypin has a potential cardioprotective treatment for ischemic heart disease on in vivo and in vitro.

Current Status and Future Perspectives on Therapeutic Potential of Apigenin: Focus on Metabolic-Syndrome-Dependent Organ Dysfunction

Metabolic syndrome and its associated disorders such as obesity, insulin resistance, atherosclerosis and type 2 diabetes mellitus are globally prevalent. Different molecules showing therapeutic potential are currently available for the management of metabolic syndrome, although their efficacy has often been compromised by their poor bioavailability and side effects. Studies have been carried out on medicinal plant extracts for the treatment and prevention of metabolic syndrome. In this regard, isolated pure compounds have shown promising efficacy for the management of metabolic syndrome, both in preclinical and clinical settings. Apigenin, a natural bioactive flavonoid widely present in medicinal plants, functional foods, vegetables and fruits, exerts protective effects in models of neurological disorders and cardiovascular diseases and most of these effects are attributed to its antioxidant action. Various preclinical and clinical studies carried out so far show a protective effect of apigenin against metabolic syndrome. Herein, we provide a comprehensive review on both in vitro and in vivo evidence related to the promising antioxidant role of apigenin in cardioprotection, neuroprotection and renoprotection, and to its beneficial action in metabolic-syndrome-dependent organ dysfunction. We also provide evidence on the potential of apigenin in the prevention and/or treatment of metabolic syndrome, analysing the potential and limitation of its therapeutic use.

Protective effects of apigenin on altered lipid peroxidation, inflammation, and antioxidant factors in methotrexate-induced hepatotoxicity

Methotrexate (MTX) is used as an effective chemotherapeutic agent against autoimmune diseases and tumors. Oxidative stress and inflammation are involved in the pathogenesis of MTX-induced damage. This study aimed at examining the ameliorating effects of apigenin (API) as a natural antioxidant on MTX-induced hepatotoxicity. The rats were classified into four groups: group I: normal saline-treated, group II: MTX-treated (20 mg/kg, ip, single dose at day 7), group III: MTX + API-treated (20 mg/kg, po), and group IV: API-treated. API was administrated for 9 days. Alanine aminotransferase (ALT), alkaline phosphatase (ALP), and aspartate aminotransferase (AST) were used as biochemical factors of MTX-induced hepatic injury. In hepatic tissues, the levels of malondialdehyde (MDA), nitric oxide (NO), glutathione (GSH), and activities of antioxidant enzymes such as catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD) as oxidative stress markers along with inflammatory factors such as tumor necrosis factor-alpha (TNF-α) and interleukin 1 beta (IL-1β) were assessed. Our results showed that MTX administration significantly increased ALP, ASP, ALT, MDA, NO, TNF-α, and IL-1β levels and significantly decreased antioxidant factors such as GSH, CAT, GPx, and SOD. The API pretreatment group showed a significant rise in hepatic antioxidant markers, besides significant reductions in the serum levels of AST, ALT, and ALP and hepatic content of MDA, TNF-α, NO, and IL-1β. In addition, the hepatoprotective effect of API was confirmed by histological evaluation of the liver. API can prevent MTX-induced hepatotoxicity through mitigation of oxidative stress and inflammation.

Dietary Flavonoids in p53-Mediated Immune Dysfunctions Linking to Cancer Prevention

The p53 protein plays a central role in mediating immune functioning and determines the fate of the cells. Its role as a tumor suppressor, and in transcriptional regulation and cytokine activity under stress conditions, is well defined. The wild type (WT) p53 functions as a guardian for the genome, while the mutant p53 has oncogenic roles. One of the ways that p53 combats carcinogenesis is by reducing inflammation. WT p53 functions as an anti-inflammatory molecule via cross-talk activity with multiple immunological pathways, such as the major histocompatibility complex I (MHCI) associated pathway, toll-like receptors (TLRs), and immune checkpoints. Due to the multifarious roles of p53 in cancer, it is a potent target for cancer immunotherapy. Plant flavonoids have been gaining recognition over the last two decades to use as a potential therapeutic regimen in ameliorating diseases. Recent studies have shown the ability of flavonoids to suppress chronic inflammation, specifically by modulating p53 responses. Further, the anti-oxidant Keap1/Nrf2/ARE pathway could play a crucial role in mitigating oxidative stress, leading to a reduction of chronic inflammation linked to the prevention of cancer. This review aims to discuss the pharmacological properties of plant flavonoids in response to various oxidative stresses and immune dysfunctions and analyzes the cross-talk between flavonoid-rich dietary intake for potential disease prevention.

Protective effect of alpha-pinene against isoproterenol-induced myocardial infarction through NF-κB signaling pathway

Monoterpenes present in the essential oils exhibit anti-inflammatory properties. In this study, we investigated the preventive effect of alpha-pinene (AP), a monoterpene, against isoproterenol (ISO)-induced myocardial infarction and inflammation in Wistar rats. Male Wistar rats were pretreated with AP (50 mg/kg body weight (bw)) administration for 21 days and ISO (85 mg/kg bw) was administered subcutaneously for last two consecutive days (20th day and 21st day). We noticed that there was an increased activity of cardiac marker enzymes in ISO-treated rats. We also observed that elevated levels of lipid peroxidative indices decreased activities of antioxidant status in plasma, erythrocyte, and heart tissue in ISO-induced rats. Furthermore, ISO-treated rats showed an increase in the levels of inflammatory mediators like tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the serum. Besides, we confirmed the upregulated expression of TNF-α, IL-6, and nuclear factor kappa-light-chain-enhancer of activated B cells in ISO-induced rat heart tissue. Conversely, we found that AP pretreatment significantly decreased levels of cardiac markers like serum cardiac troponin T and cardiac troponin I, lipid peroxidative markers, and restored antioxidants status in ISO-treated rats. Besides, AP administration attenuated ISO-induced inflammatory marker expression. The present findings demonstrated that AP significantly protects the myocardium and exerts cardioprotective and anti-inflammatory effects in experimental rats.

Galangin Attenuates Isoproterenol-Induced Inflammation and Fibrosis in the Cardiac Tissue of Albino Wistar Rats

Galangin (GA) is an active flavonoid of the rhizome of Alpinia galanga that belongs to the ginger family. GA exhibit potent anti-inflammatory properties. Therefore, we evaluated the preventive effects of GA against isoproterenol (ISO)-induced inflammation and myocardial fibrosis in male albino Wistar rats. We found that GA (1 mg/kg b.wt.) pretreatment attenuated the ISO-mediated (5 mg/kg b.wt. for 14 consecutive days) elevation of heart rate, activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), creatine kinase (CK), creatine kinase-MB (CKMB) in the rat serum. We also noticed that GA prevented the ISO-mediated cardiac markers i.e. cardiac troponin T and I (cTnT and cTnI) expression in the serum of rats. Further, GA pretreatment prevented ISO-mediated lipid peroxidation and diminished blood pressure and loss of antioxidants status in the heart tissue of ISO treated rats. In addition, GA treatment modulates ISO-induced alterations the expressions of tissue inhibitor of metalloproteinases-1 (TIMP-1), p-AKT, glycogen synthase kinase-3β (p-GSK-3β) and peroxisome proliferators-activated receptor-γ (PPAR-γ) in the heart tissue. Furthermore, molecular analysis (PCR array and western blot) revealed that GA pretreatment prevented inflammation and fibrosis related gene expression pattern in ISO-induced rats. Taken together, the results indicate the cardioprotective effect of GA against ISO-induced inflammation and fibrosis. The antioxidant and anti-inflammatory potential of GA could be considered for its cardioprotective effect in the ISO-treated rats.

The Inhibitory Effect of Flavonoid Aglycones on the Metabolic Activity of CYP3A4 Enzyme

Flavonoids are natural compounds that have been extensively studied due to their positive effects on human health. There are over 4000 flavonoids found in higher plants and their beneficial effects have been shown in vitro as well as in vivo. However, data on their pharmacokinetics and influence on metabolic enzymes is scarce. The aim of this study was to focus on possible interactions between the 30 most commonly encountered flavonoid aglycones on the metabolic activity of CYP3A4 enzyme. 6β-hydroxylation of testosterone was used as marker reaction of CYP3A4 activity. Generated product was determined by HPLC coupled with diode array detector. Metabolism and time dependence, as well as direct inhibition, were tested to determine if inhibition was reversible and/or irreversible. Out of the 30 flavonoids tested, 7 significantly inhibited CYP3A4, most prominent being acacetin that inhibited 95% of enzyme activity at 1 µM concentration. Apigenin showed reversible inhibition, acacetin, and chrysin showed combined irreversible and reversible inhibition while chrysin dimethylether, isorhamnetin, pinocembrin, and tangeretin showed pure irreversible inhibition. These results alert on possible flavonoid–drug interactions on the level of CYP3A4.