Apigenin in the regulation of cholesterol metabolism and protection of blood vessels

Effect of apigenin on dynamin-related protein 1 in type 1 diabetic rats with cardiovascular complications

BACKGROUND AND OBJECTIVE

Cardiovascular complications cause increased mortality rates among diabetics. The molecular mechanisms of aberrant mitochondrial dynamics in diabetes mellitus (DM) are not fully understood. Dynamin-related protein 1 (Drp1) is thought to be a major regulator of mitochondrial fission. There is lack of studies that examined the relationship between apigenin and Drp1 expression in DM. Thus, the current study aimed to explore the expression of Drp1 in diabetic rats with cardiovascular complications, as well as to appraise the role of apigenin in modulating this expression.

METHODS

Twenty-eight adult male albino Wister rats were randomly and equally allocated into four groups: naive, streptozotocin-induced type 1 diabetic control and two apigenin-injected diabetic groups (early and late). Body weight, heart weight, blood pressure and ECG were recorded. Evaluation of blood glucose level, lipid profile and cardiac functions were measured. Determination of Drp1 mRNA expression, and histological examination of cardiac tissues from the four groups were performed.

RESULTS

Diabetic control rats developed decrease of body weight, increase of blood pressure, deterioration of the normal ECG pattern and upregulation of Drp1 mRNA expression in cardiac tissues. There was a significant correlation between the relative expression of Drp1 and all examined parameters. Apigenin-injection improved fasting blood glucose, lipid profile and cardiac function indicators (i.e., ECG parameters, CK-MB and troponin) as well as the cardiac histological structure. The decrease of Drp1 expression was more evident with early than with late apigenin-injection, however, without statistical significance.

CONCLUSIONS

Increased level of Drp1 expression in diabetic rats may be involved in the pathogenesis of diabetic cardiovascular complications. The changes that occurred in response to apigenin injection highlight its potential ameliorative effect on the diabetic cardiovascular complications and pave the route for further investigations.

Effects of apigenin on gastric cancer cells

Gastric Cancer (GC) is one of the most prevalent cancers worldwide. As the currently available therapeutic options are invasive, new and more benign options are being explored. One of which is Apigenin (Api), a natural flavonoid found in fruits and vegetables, such as celery, parsley, garlic, bell pepper and chamomile tea. Api has known anti-inflammatory, -oxidant, and -proliferative proprieties in several diseases and its potential as an anticancer compound has been explored. Here we systematize the available data regarding the effects of Api on GC cells, in terms of cell proliferation, apoptosis, Helicobacter pylori (H. pylori) infection, and molecular targets. From the literature it is possible to conclude that Api inhibits cell growth in a dose- and time-dependent manner, which is accompanied by the reduction of clone formation and induction of apoptosis. This occurs through the Akt/Bad/Bcl2/Bax axis that activates the mitochondrial pathway of apoptosis, resulting in restriction of cell proliferation. Additionally, it seems that the anti-proliferative potential of Api on GC cells is particularly relevant in a more aggressive GC phenotype but can also affect normal gastric cells. This indicate that this flavonoid must be used in low-to-moderate doses to avoid side-effects induced by disturbance of the normal epithelium. In H. Pylori-infected cells, the literature demonstrates that Api reduces inflammation by diminishing the levels of H. pylori colonization, by preventing NF-kB activation and by diminishing the production of reactive oxygen specimens (ROS). Accordingly, in GC Api seems to regulate different hallmarks of cancer, such as cell proliferation, apoptosis, cell migration, inflammation and oxidative stress, demonstrating its potential has an anti-GC compound.

Role of apigenin in targeting metabolic syndrome: A systematic review

Metabolic syndrome (MetS) is a cluster of metabolic abnormalities that has a high prevalence worldwide. Apigenin is a flavonoid present in several vegetables and fruits and has anti-inflammatory, anti-oxidant, and anti-MetS properties. This study aims to systematically review the effects of apigenin against MetS and the relevant molecular and cellular mechanisms of action, pharmacokinetics features, and potential structure-activity relationship. Electronic databases including Scopus, PubMed, Science Direct and Cochrane Library were searched for in vivo, and in vitro, and human studies with the following keywords: "apigenin" and "metabolic syndrome or insulin resistance syndrome", "fatty liver", "hypertension or blood pressure", "diabetes or blood glucose", "dyslipidemia", "heart or cardiovascular " and "obesity" in title/abstract. Data were collected from 2000 until 2021 (up to April). Only papers published in the English language were included. Forty-six full-text articles out of 1016 retrieved papers were reviewed and underwent quality assessment by investigators. Anti-obesity activity of apigenin is mainly through attenuating adipocyte differentiation by suppressing the mitotic clonal expansion and the adipogenesis-related factors. Its anti-diabetic effects can be exerted through inhibition of protein tyrosine phosphatase1B expression, maintaining the activity of anti-oxidant enzymes, reducing intracellular ROS production, cellular DNA damage, protein carbonylation, and attenuating β-cell apoptosis. Moreover, apigenin could attenuate dyslipidemia and subsequent atherosclerotic conditions through down-regulating sterol regulatory element-binding proteins (SREBP)-1c, SREBP-2, stearyl-CoA desaturase-1, and 3-hydroxy-3-methyl-glutaryl-CoA reductase. Apigenin as a dietary bioactive compound would be a promising candidate for improving MetS and its components.

Radiation-induced Testicular Damage in Mice: Protective Effects of Apigenin Revealed by Histopathological Evaluation

BACKGROUND

Radiation exposure poses a significant threat to reproductive health, particularly the male reproductive system. The testes, being highly sensitive to radiation, are susceptible to damage that can impair fertility and overall reproductive function. The study aims to investigate the radioprotective effects of apigenin on the testis through histopathological evaluation.

MATERIALS AND METHODS

This research involved utilizing a total of 40 mice, which were randomly divided into eight groups of five mice each. The groups were categorized as follows: A) negative control group, B, C, and D) administration of apigenin at three different doses (0.3 mg/kg, 0.6 mg/kg, and 1.2 mg/kg) respectively, E) irradiation group, and F, H, and I) administration of apigenin at three different doses (0.3 mg/kg, 0.6 mg/kg, and 1.2 mg/kg) in combination with irradiation. The irradiation procedure involved exposing the mice to a 2Gy X-ray throughout their entire bodies. Subsequently, histopathological assessments were conducted seven days after the irradiation process.

RESULTS

The findings indicated that radiation exposure significantly impacted the spermatogenesis system. This research provides evidence that administering apigenin to mice before ionizing radiation effectively mitigated the harmful effects on the testes. Apigenin demonstrated radioprotective properties, positively influencing various parameters, including the spermatogenesis process and the presence of inflammatory cells within the tubular spaces.

CONCLUSION

Apigenin can provide effective protection for spermatogenesis, minimize the adverse effects of ionizing radiation, and safeguard normal tissues.

Antagonism Between Gut Ruminococcus gnavus and Akkermansia muciniphila Modulates the Progression of Chronic Hepatitis B

BACKGROUND & AIMS

A long immune-tolerant (IT) phase lasting for decades and delayed HBeAg seroconversion (HBe-SC) in patients with chronic hepatitis B (CHB) increase the risk of liver diseases. Early entry into the immune-active (IA) phase and HBe-SC confers a favorable clinical outcome with an unknown mechanism. We aimed to identify factor(s) triggering IA entry and HBe-SC in the natural history of CHB.

METHODS

To study the relevance of gut microbiota evolution in the risk of CHB activity, fecal samples were collected from CHB patients (n = 102) in different disease phases. A hepatitis B virus (HBV)-hydrodynamic injection (HDI) mouse model was therefore established in several mouse strains and germ-free mice, and multiplatform metabolomic and bacteriologic assays were performed.

RESULTS

Ruminococcus gnavus was the most abundant species in CHB patients in the IT phase, whereas Akkermansia muciniphila was predominantly enriched in IA patients and associated with alanine aminotransferase flares, HBeAg loss, and early HBe-SC. HBV-HDI mouse models recapitulated this human finding. Increased cholesterol-to-bile acids (BAs) metabolism was found in IT patients because R gnavus encodes bile salt hydrolase to deconjugate primary BAs and augment BAs total pool for facilitating HBV persistence and prolonging the IT course. A muciniphila counteracted this activity through the direct removal of cholesterol. The secretome metabolites of A muciniphila, which contained small molecules structurally similar to apigenin, lovastatin, ribavirin, etc., inhibited the growth and the function of R gnavus to allow HBV elimination.

CONCLUSIONS

R gnavus and A muciniphila play opposite roles in HBV infection. A muciniphila metabolites, which benefit the elimination of HBV, may contribute to future anti-HBV strategies.

Beneficial effects of flavonoids on animal models of atherosclerosis: A systematic review and meta-analysis

Atherosclerosis is the main cause of cardiovascular diseases that seriously endanger human health. The existing treatment drugs are effective, but they have some side effects. Accumulating evidence suggests that flavonoids have attracted wide attention due to their multiple cardioprotective effects and fewer side effects. PubMed, Web of Science database, Embase, and Cochrane Library were searched for studies evaluating the effects of flavonoids against atherosclerosis. 119 studies published from August 1954 to April 2023 were included. Random-effects models were performed for synthesis. Compared with the control group, flavonoids significantly reduced longitudinal and cross-sectional plaque area. The findings indicated that flavonoids significantly reduced the concentrations of serum TC, TG, and LDL-C and increased serum HDL-C concentrations. Besides, flavonoids reduced the levels of circulating pro-inflammatory factors, including TNF-α, IL-1β, and IL-6, and increased the serum IL-10 level. This study provides evidence for the potential cardiovascular benefits of flavonoids.

Subchronic toxicity of Sideritis scardica, Lamiaceae on male Wistar rats

INTRODUCTION

Sideritisscardica, Lamiaceae, is a plant with anti-inflammatory, antirheumatic, digestive, and antimicrobial properties that is widely used in folk medicine throughout the Balkan Peninsula. The name derives from the Greek word 'sideros', meaning iron, and it is believed that the plant was also used by soldiers to heal wounds caused by cutting weapons.

LC-MS Analysis of Ginsenosides in Different Parts of Panax quinquefolius and Their Potential for Coronary Disease Improvement

Seven main ginsenosides, including ginsenoside Re, ginsenoside Rb₁, pseudoginsenoside F₁₁, ginsenoside Rb₂, ginsenoside Rb₃, ginsenoside Rd, and ginsenoside F₂, were identified by LC-QTOF MS/MS from root, leaf and flower extracts of Panax quinquefolius. These extracts promoted intersegmental vessel growth in a zebrafish model, indicating their potential cardiovascular health benefits. Network pharmacology analysis was then conducted to reveal the potential mechanisms of ginsenoside activity in the treatment of coronary artery disease. GO and KEGG enrichment analyses elucidated that G protein-coupled receptors played a critical role in VEGF-mediated signal transduction and that the molecular pathways associated with ginsenoside activity are involved in neuroactive ligand-receptor interaction, cholesterol metabolism, the cGMP-PKG signaling pathway, etc. Moreover, VEGF, FGF2, and STAT3 were confirmed as the major targets inducing proliferation of endothelial cells and driving the pro-angiogenic process. Overall, ginsenosides could be potent nutraceutical agents that act to reduce the risks of cardiovascular disease. Our findings will provide a basis to utilize the whole P. quinquefolius plant in drugs and functional foods.

Applications of Perilla frutescens Extracts in Clinical Practice

(1) Background: Perilla frutescens (L.) Britt. is an important pharmaceutical crop that remains a focus point for researchers worldwide due to its complex phytochemical constituents, medicinal effects, and nutraceutical properties. The literature data are based on animal and cell culture studies, so the clinical evidence for the therapeutic effects is poorly outlined. The aim of this review was to provide an updated and thorough understanding of Perilla frutescens applications in clinical practice using data derived from human studies, and to outline the potential directions and perspectives for further studies on this crop. (2) Methods: Medline, Embase, and Cochrane databases were used to find relevant studies. All interventional studies that evaluated the effect of Perilla frutescens in human subjects were assessed. (3) Results: The main perspectives that can be contoured from the presented literature evaluation are an important clinical effect of Perilla frutescens extracts on allergic rhinoconjuctivitis, especially in young populations, a potent hypolipemiant effect that, in conjunction with increased serum biological antioxidant potential, determines significant improvements in cognitive function and a wide variety of miscellaneous clinical effects that need further exploration. (4) Conclusions: Supplementary research is needed in order to demonstrate the therapeutic effects of Perilla frutescens in controlled clinical settings.

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.

Elucidation of active ingredients and mechanism of action of hawthorn in the prevention and treatment of atherosclerosis

Hawthorn (HT), a functional food and medicinal herb for centuries in China, has potential preventive and therapeutic effects on atherosclerosis (AS). However, the mechanisms and active ingredients of HT in the prevention and treatment of AS are unclear. This study aimed to reveal active components and mechanism of HT in the prevention and treatment of AS using UHPLC-Q-Exactive Orbitrap MS and network pharmacology. A total of 50 compounds were identified by UHPLC-Q-Exactive Orbitrap MS. Six core targets and six active compounds were obtained by network pharmacology. Apigenin, luteolin, chrysin, quercetin, oleanic acid, and corosolic acid were the active components in the prevention and treatment of AS, and core targets included SRC, HSP90AA1, MAPK3, EGFR, HRAS, and AKT1. The key signaling pathways involved are MAPK, HIF-1, NF-kappa B, PI3K-Akt, TNF, Rap1, Ras, and VEGF signaling pathways. Further molecular docking results indicated that the six active compounds had strong hydrogen bonding ability with the six core targets. On the molecular level, HT may regulate AS by controlling cell survival and proliferation, reducing the levels of enzymes HMG-CoA reductase and lipoprotein lipase and inhibiting inflammatory response. PRACTICAL APPLICATIONS: HT can serve as "medicine-food homology" for dietary supplement and exert potential preventive and therapeutic effects on AS. However, the mechanisms of HT in the prevention and treatment of AS are unclear. This study describes a rapid method of detecting and identifying the components and mechanism of HT based on LC-MS and network pharmacology, which provides a theoretical and scientific support for further application of HT and guidance for the research of other herbal medicines.

Apigenin exerts protective effect and restores ovarian function in dehydroepiandrosterone induced polycystic ovary syndrome rats: a biochemical and histological analysis

BACKGROUND

Polycystic ovarian syndrome (PCOS) is one of the major causes encouraging the elevation of androgens, obesity along with menstrual complications. Here we study the effect of Apigenin in rat model of polycystic ovarian syndrome.

METHODS

Female Sprague Dawley (SD) rats were treated with Dehydroepiandrosterone (DHEA) (6 mg/100g) opting the post-pubertal approach for developing rat model of polycystic ovarian syndrome, Metformin was used as standard. The treatments were given for 21 days along with coloproctological analysis. After the treatment regimen, the biochemical analysis was carried in plasma samples, whereas the ovaries were submitted for histopathological analysis.

RESULTS

The treatment of DHEA resulted in disturbed lipid profile and anti-oxidant status along with increased weight, ovarian diameter and cysts in rats confirming the development of PCOS. However, treatment of Apigenin showed ameliorative effect by improving the lipid profile and anti-oxidant status, the treatment also normalised the body weight, reduced ovarian diameter, cysts and restored the healthy follicles compared to control rats. The treatment of Apigenin also suppressed the levels of oestradiol and testosterone compared to control group, also, levels of progesterone were increased in Apigenin treated group of rats. The treatment of Apigenin suppressed the levels of inflammatory cytokines TNF-α and IL-6. It was observed that the effect of Apigenin were to some extent parallel to standard drug Metformin.

CONCLUSION

The findings confirmed that Apigenin ameliorates the disturbed hormonal levels, lipid profile and antioxidant status in PCOS rats.

Helichrysum italicum (Roth) G. Don and Helichrysum arenarium (L.) Moench infusions in reversing the traits of metabolic syndrome: a double-blind randomized comparative trial

Health impairments characteristic for metabolic syndrome such as increased body mass, a dysregulated lipid or glucose profile and elevated blood pressure can be reversed by appropriate lifestyle modifications. Supplementing the normal diet with herbal infusions is a promising strategy. We conducted a randomised double-blind comparative study in which participants with at least two traits of metabolic syndrome consumed an infusion of either Helichrysum italicum subsp. italicum (HI, n = 14) or Helichrysum arenarium (HA, n = 13) daily for 28 days. Anthropometric and biochemical parameters were measured at baseline, at the end of the intervention and after a 2-week washout period. HI infusion consumption had a beneficial effect on anthropometric traits; significant reductions in body weight, body mass index, and visceral and total body fat were observed. In the HA group, there was a greater reduction in serum glucose levels and an improvement in the lipid profile. In both groups, high LDL levels were measured at baseline, but two weeks after the intervention, in 84% of participants in the HA group and 71% in the HI group, the levels were within the reference range. Both interventions caused a decrease in HDL but also improved serum antioxidant properties. Consuming either infusion could thus be recommended as a simple, profitable habit for individuals with traits of metabolic syndrome.

Apigenin ameliorates di(2-ethylhexyl) phthalate-induced ferroptosis: The activation of glutathione peroxidase 4 and suppression of iron intake

Di(2-ethylhexyl) phthalate (DEHP) is a widely artificial persistent organic pollutant, the contamination of which infiltrates daily human life from many aspects, imperceptibly causing damage to multiple organs in the body, including the liver. Apigenin (APG) is widely distributed in vegetables and fruits and can relieve or prevent the injuries caused by exogenous chemicals through various pharmacological effects, such as antioxidant effects. To investigate the mechanism of DEHP-induced liver injury and the antagonistic effects of APG, we treated AML12 cells with 1 mM DEHP and/or APG. Ultrastructural morphology analysis indicated that DEHP induced typical ferroptosis-like damage. In addition, we found that DEHP exposure induced ferroptosis by enhancing reactive oxygen species (ROS) levels, disrupting iron homeostasis and lipid peroxidation, and regulating the expression of ferroptosis-related genes. Notably, supplementation with APG significantly inhibited these abnormal changes, and molecular docking further showed evidence of the activating effects of APG ligand on glutathione peroxidase 4 (GPX4). These results demonstrated that the protective effects of APG on DEHP-induced ferroptosis were achieved by activating GPX4 and suppressing intracellular iron accumulation. This information not only adds to DEHP toxicological data but also provides a basis for the practical application of APG.

Protective Roles of Apigenin Against Cardiometabolic Diseases: A Systematic Review

Apigenin is a flavonoid with antioxidant, anti-inflammatory, and anti-apoptotic activity. In this study, the potential effects of apigenin on cardiometabolic diseases were investigated in vivo and in vitro. Potential signaling networks in different cell types induced by apigenin were identified, suggesting that the molecular mechanisms of apigenin in cardiometabolic diseases vary with cell types. Additionally, the mechanisms of apigenin-induced biological response in different cardiometabolic diseases were analyzed, including obesity, diabetes, hypertension and cardiovascular diseases. This review provides novel insights into the potential role of apigenin in cardiometabolic diseases.

Natural Flavonoids Derived From Fruits Are Potential Agents Against Atherosclerosis

Atherosclerosis, as a chronic inflammatory response, is one of the main causes of cardiovascular diseases. Atherosclerosis is induced by endothelial cell dysfunction, migration and proliferation of smooth muscle cells, accumulation of foam cells and inflammatory response, resulting in plaque accumulation, narrowing and hardening of the artery wall, and ultimately leading to myocardial infarction or sudden death and other serious consequences. Flavonoid is a kind of natural polyphenol compound widely existing in fruits with various structures, mainly including flavonols, flavones, flavanones, flavanols, anthocyanins, isoflavones, and chalcone, etc. Because of its potential health benefits, it is now used in supplements, cosmetics and medicines, and researchers are increasingly paying attention to its role in atherosclerosis. In this paper, we will focus on several important nodes in the development of atherosclerotic disease, including endothelial cell dysfunction, smooth muscle cell migration and proliferation, foam cell accumulation and inflammatory response. At the same time, through the classification of flavonoids from fruits, the role and potential mechanism of flavonoids in atherosclerosis were reviewed, providing a certain direction for the development of fruit flavonoids in the treatment of atherosclerosis drugs.

|Therapeutic and preventive effects of apigenin in cerebral ischemia: a review

APG can exert various protective effects against cerebral ischemia. Moreover, APG has shown a highly promising ability to prevent cerebral ischemia in terms of regulating blood glucose, blood pressure, lipids and gut microbes.

Cardioprotective effects of phytopigments via multiple signaling pathways

BACKGROUND

Cardiovascular diseases (CVDs) are among the deadliest non-communicable diseases, and millions of dollars are spent every year to combat CVDs. Unfortunately, the multifactorial etiology of CVDs complicates the development of efficient therapeutics. Interestingly, phytopigments show significant pleiotropic cardioprotective effects both in vitro and in vivo.

PURPOSE

This review gives an overview of the cardioprotective effects of phytopigments based on in vitro and in vivo studies as well as clinical trials.

METHODS

A literature-based survey was performed to collect the available data on cardioprotective activities of phytopigments via electronic search engines such as PubMed, Google Scholar, and Scopus.

RESULTS

Different classes of phytopigments such as carotenoids, xanthophylls, flavonoids, anthocyanins, anthraquinones alleviate major CVDs (e.g., cardiac hypertrophy, atherosclerosis, hypertension, cardiotoxicities) via acting on signaling pathways related to AMPK, NF-κB, NRF2, PPARs, AKT, TLRs, MAPK, JAK/STAT, NLRP3, TNF-α, and RA.

CONCLUSION

Phytopigments represent promising candidates to develop novel and effective CVD therapeutics. More randomized, placebo-controlled clinical studies are recommended to establish the clinical efficacy of phytopigments.

Bioactivity of Dietary Polyphenols: The Role in LDL-C Lowering

Cardiovascular diseases are the leading causes of the death around the world. An elevation of the low-density lipoprotein cholesterol (LDL-C) level is one of the most important risk factors for cardiovascular diseases. To achieve optimal plasma LDL-C levels, clinal therapies were investigated which targeted different metabolism pathways. However, some therapies also caused various adverse effects. Thus, there is a need for new treatment options and/or combination therapies to inhibit the LDL-C level. Dietary polyphenols have received much attention in the prevention of cardiovascular diseases due to their potential LDL-C lowering effects. However, the effectiveness and potential mechanisms of polyphenols in lowering LDL-C is not comprehensively summarized. This review focused on dietary polyphenols that could reduce LDL-C and their mechanisms of action. This review also discussed the limitations and suggestions regarding previous studies.

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.

Apigenin exerts chemopreventive effects on lung injury induced by SiO2 nanoparticles through the activation of Nrf2

Apigenin (APG) is a flavonoid widely distributed in fruits, vegetables, and herbs, with comprehensive pharmacological effects. In this paper, we report that APG can elicit a protective effect, which is comparable to those induced by gymnoside II/n-BuOH extracts of Bletilla striata, on SiO₂-induced lung injury in vitro and in vivo. In vitro experiments showed that APG (25 μM) could restore the SiO₂-decreased A549 cell viability and lower the apoptotic rate and the production of intracellular reactive oxygen species (ROS) in A549 cells treated with nm SiO₂. Western blot results showed that APG (25 μM) could increase the level of Nuclear factor E2-related factor 2 (Nrf2) and its downstream proteins. In vivo experiments showed that APG (20 mg/kg) could potently alleviate the SiO₂-elicited lung injury by enhancing the Nrf2 expression and thereby suppressing Bax/Bcl-2 pathway. The present study suggests that APG can significantly alleviate the SiO₂-induced lung injury both in vitro and in vivo through, at least partially, activating Nrf2 expression.

An In Vitro-In Vivo Evaluation of the Antiproliferative and Antiangiogenic Effect of Flavone Apigenin against SK-MEL-24 Human Melanoma Cell Line

One of the most important class of natural compounds with successful preclinical results in the management of cancer is the flavonoids. Due to the plethora of biological activities, apigenin (4',5,7 trihydroxyflavone) is a main representant of the flavone subclass. Although the antiproliferative and antiangiogenic effects of apigenin were studied on a significant number of human and murine melanoma cell lines, in order to complete the data existing in the literature, the aim of this study is to evaluate the in vitro effect of apigenin on SK-MEL-24 human melanoma cell line as well as in vivo on tumor angiogenesis using the aforementioned cell line on the chorioallantoic membrane assay. Results have shown that in the range of tested doses, the phytocompound presents significant antiproliferative, cytotoxic, and antimigratory potential at 30 μM, respectively, 60 μM. Moreover, the phytocompound in both tested concentrations limited melanoma cell growth and migration and induced a reduced angiogenic reaction limiting melanoma cell development.

The potential protective role of apigenin against oxidative damage induced by nickel oxide nanoparticles in liver and kidney of male Wistar rat, Rattus norvegicus

Nickel oxide nanoparticles (NiONPs) are involved in several applications but still have some adverse effects. Apigenin (APG) is a widespread natural product with antioxidative, anticancer, and anti-inflammatory properties. The present work aimed to study the protective role of APG against the NiONP-induced toxicity in male Wistar rats. Rats were randomly distributed to one control group and three treated groups. The treated groups were orally administered NiONPs (100 mg/kg) alone, APG (25 mg/kg) alone, or APG 1 h before NiONPs, once daily for 28 days. Blood, liver, and kidney were collected after 7, 14, and 28 days of administration for Ni accumulation, hematological, biochemical, histological, and transmission electron microscopy (TEM) investigations. As compared to the controls, the administration of NiONPs alone significantly elevated the levels of Ni, malondialdehyde, total cholesterol, low-density lipoprotein cholesterol, creatinine, urea, blood urea nitrogen, and the activity of alanine and aspartate aminotransferases as well as the count of white blood cells. Besides, marked reductions in the activity of superoxide dismutase, and the levels of glutathione, high-density lipoprotein cholesterol, total proteins, albumin, globulin, hemoglobin, packed cell volume, and red blood cell count were reported. Histologically, the liver and kidney of rats administered NiONPs alone showed remarkable disturbances. According to TEM, subcellular alterations were observed in the liver and kidney of rats administered NiONPs alone. In contrast, APG administering before NiONPs substantially alleviated all the studied parameters. In conclusion, APG can ameliorate the NiONP-induced hepatotoxicity and nephrotoxicity in male Wistar rats.

Protection of apigenin against acrylonitrile-induced sperm and testis injury in rats: involvement of activation of ASK1-JNK/p38 signaling pathway

This study aims to clarify if apigenin (AP) could play a pivotal role in attenuating acrylonitrile (ACN)-induced sperm and testis injury by inhibiting ASK1-JNK/p38 signaling pathway. Male Sprague-Dawley rats were randomly divided into five groups: a control group (corn oil), an ACN group (ACN 46 mg kg^-1), an ACN + AP1 group (ACN + AP 117 mg kg^-1), an ACN + AP2 group (ACN + AP 234 mg kg^-1) and an ACN + AP3 group (ACN + AP 351 mg kg^-1). The ACN + AP groups were given ACN by gavage after a pretreatment with different dosages of AP for 30 min, whereas the rats in the control group received an equivalent volume of corn oil. The gavage was conducted for 6 days per week in 4 weeks. The results showed that AP reduced sperm deformity rate and DNA fragment index and attenuated the testicular injury induced by ACN. AP could also alleviate oxidative stress, downregulate ASK1-JNK/p38 signaling pathway and eventually inhibit mitochondria-mediated testicular apoptosis. In brief, AP could dampen oxidative stress thereby inhibiting testicular apoptosis mediated by ASK1-JNK/p38 signaling pathway, alleviating ACN-induced sperm and testis injury and exerting a protective effect on male reproductive system.

Apigenin Ameliorates Insulin Resistance and Lipid Accumulation by Endoplasmic Reticulum Stress and SREBP-1c/SREBP-2 Pathway in Palmitate-Induced HepG2 Cells and High-Fat Diet-Fed Mice

Insulin resistance (IR) is the common basis of diabetes and cardiovascular diseases, and its development is closely associated with lipid metabolism disorder. Flavonoids have definite chemical defense effects, including anti-inflammatory effects, anticancer effects, and antimutation effects. However, the function and mechanism of apigenin (AP, a kind of flavonoid) in IR are still unclear. In our study, intracellular fat accumulation model cells and high-fat diet (HFD)-fed model mice were established using palmitate (PA) and HFD. Mechanistically, we first demonstrated that AP could notably downregulate sterol regulatory element-binding protein 1c (SREBP-1c), sterol regulatory element-binding protein 2 (SREBP-2), fatty acid synthase, stearyl-CoA desaturase 1, and 3-hydroxy-3-methyl-glutaryl-CoA reductase in PA-induced hyperlipidemic cells and mice. Functionally, we verified that AP could markedly reduce lipid accumulation in PA-induced hyperlipidemic cells and decrease the body weight, visceral fat weight, IR, and lipid accumulation in HFD-induced hyperlipidemic mice. Besides, we showed that PA could significantly downregulate endoplasmic reticulum stress (ERS)-related proteins and inhibit ERS. Furthermore, we proved that AP could reduce blood lipids by inhibiting ERS in PA-induced hyperlipidemic cells. Meanwhile, 4-phenyl butyric acid (also called ERS alleviator), like AP, could significantly reduce blood lipids and alleviate IR in HFD-fed model mice. Therefore, we concluded that AP could substantially improve the disorder of lipid metabolism, and its mechanism might be related to the decrease of SREBP-1c, SREBP-2, and downstream genes, the inhibition of ERS, and the reduction of blood lipids and IR. SIGNIFICANCE STATEMENT: Apigenin, a nontoxic and naturally sourced flavonoid, has antihyperlipidemic properties in mice and hepatocyte. This study highlights a new mechanism of apigenin and proposes that these hypolipidemic effects are associated with the mitigation of endoplasmic reticulum stress and insulin resistance in diet-induced obesity. This study might provide translational insight into the prevention and treatment of apigenin in hyperlipidemia-related diseases.

Involvement of Muscarinic Receptors in Hypotensive and Diuretic Effects of Aqueous Soluble Fraction from Asphodelus tenuifolius Cav

Background. Asphodelus tenuifolius Cav. (Asphodelaceae) is widely used in Pakistan traditional medicine as a hypotensive and diuretic agent. Despite the cardioprotective effects described for A. tenuifolius, the mechanisms involved in its probable hypotensive and diuretic effects have never been evaluated. Firstly, different extracts from A. tenuifolius seeds were obtained, and their antioxidant profiles and chemical constituents by LC-DAD-were determined, including molecular networking by the GNPS platform. Then, to evaluate changes in blood pressure, different groups of anesthetized normotensive rats were intravenously treated with the crude extract (AT-Cr, 1-50 mg/kg), aqueous (AS-AT, 1-25 mg/kg), n-butanol (BS-AT, 1-50 mg/kg), and dichloromethane fraction (DS-AT, 1-80 mg/kg). The diuretic effects of AT-Cr, AS-AT, BS-AT, and DS-AT at 100, 200, and 300 mg/kg, p.o. doses, were also evaluated in comparison with hydrochlorothiazide (HCTZ, 10 mg/kg, p.o). The urinary volume, sodium, potassium, and pH were estimated in the sample collected for 6 h from saline-loaded rats. Using pharmacological antagonists or inhibitors, we determine the involvement of acetylcholine, prostaglandins, and nitric oxide in A. tenuifolius-induced hypotensive and diuresis action. In addition, the activities of angiotensin-converting enzyme, erythrocyte carbonic anhydrase, and renal Na+/K+/ATPase were evaluated in vitro. Acute treatment with crude extract and fractions of A. tenuifolius exhibited significant hypotensive and diuretic potential in normotensive rats. However, AS-AT produced the most potent and significant dose-dependent hypotension and diuretic effects in normotensive rats. Previous treatment with atropine significantly reduced the hypotensive and diuretic action of AS-AT, but pretreatment with indomethacin or L-NAME did not affect these effects. Moreover, the 7-day treatment with AS-AT did not reduce activities of serum angiotensin-converting enzyme, erythrocyte carbonic anhydrase, and renal Na+/K+/ATPase. AS-AT showed four major compound node clusters, which included sugars, alkaloids, nucleoside, amino acid, and glycosylated flavonoids. This research supports and extends the traditional use of A. tenuifolius as a hypotensive and diuretic agent. The results showed that AS-AT from A. tenuifolius could present compounds responsible for hypotensive and diuretic activities through the activation of muscarinic receptors.

Rationalizing the therapeutic potential of apigenin against cancer

BACKGROUND

Despite the remarkable advances made in the diagnosis and treatment of cancer during the past couple of decades, it remains the second largest cause of mortality in the world, killing approximately 9.6 million people annually. The major challenges in the treatment of the advanced stage of this disease are the development of chemoresistance, severe adverse effects of the drugs, and high treatment cost. Therefore, the development of drugs that are safe, efficacious, and cost-effective remains a 'Holy Grail' in cancer research. However, the research over the past four decades shed light on the cancer-preventive and therapeutic potential of natural products and their underlying mechanism of action. Apigenin is one such compound, which is known to be safe and has significant potential in the prevention and therapy of this disease.

AIM

To assess the literature available on the potential of apigenin and its analogs in modulating the key molecular targets leading to the prevention and treatment of different types of cancer.

METHOD

A comprehensive literature search has been carried out on PubMed for obtaining information related to the sources and analogs, chemistry and biosynthesis, physicochemical properties, biological activities, bioavailability and toxicity of apigenin.

KEY FINDINGS

The literature search resulted in many in vitro, in vivo and a few cohort studies that evidenced the effectiveness of apigenin and its analogs in modulating important molecular targets and signaling pathways such as PI3K/AKT/mTOR, JAK/STAT, NF-κB, MAPK/ERK, Wnt/β-catenin, etc., which play a crucial role in the development and progression of cancer. In addition, apigenin was also shown to inhibit chemoresistance and radioresistance and make cancer cells sensitive to these agents. Reports have further revealed the safety of the compound and the adaptation of nanotechnological approaches for improving its bioavailability.

SIGNIFICANCE

Hence, the present review recapitulates the properties of apigenin and its pharmacological activities against different types of cancer, which warrant further investigation in clinical settings.

A systematic comprehensive longitudinal evaluation of dietary factors associated with acute myocardial infarction and fatal coronary heart disease

Environmental factors, and in particular diet, are known to play a key role in the development of Coronary Heart Disease. Many of these factors were unveiled by detailed nutritional epidemiology studies, focusing on the role of a single nutrient or food at a time. Here, we apply an Environment-Wide Association Study approach to Nurses' Health Study data to explore comprehensively and agnostically the association of 257 nutrients and 117 foods with coronary heart disease risk (acute myocardial infarction and fatal coronary heart disease). After accounting for multiple testing, we identify 16 food items and 37 nutrients that show statistically significant association - while adjusting for potential confounding and control variables such as physical activity, smoking, calorie intake, and medication use - among which 38 associations were validated in Nurses' Health Study II. Our implementation of Environment-Wide Association Study successfully reproduces prior knowledge of diet-coronary heart disease associations in the epidemiological literature, and helps us detect new associations that were only marginally studied, opening potential avenues for further extensive experimental validation. We also show that Environment-Wide Association Study allows us to identify a bipartite food-nutrient network, highlighting which foods drive the associations of specific nutrients with coronary heart disease risk.

Phenolic Compounds Exerting Lipid-Regulatory, Anti-Inflammatory and Epigenetic Effects as Complementary Treatments in Cardiovascular Diseases

Atherosclerosis is the main process behind cardiovascular diseases (CVD), maladies which continue to be responsible for up to 70% of death worldwide. Despite the ongoing development of new and potent drugs, their incomplete efficacy, partial intolerance and numerous side effects make the search for new alternatives worthwhile. The focus of the scientific world turned to the potential of natural active compounds to prevent and treat CVD. Essential for effective prevention or treatment based on phytochemicals is to know their mechanisms of action according to their bioavailability and dosage. The present review is focused on the latest data about phenolic compounds and aims to collect and correlate the reliable existing knowledge concerning their molecular mechanisms of action to counteract important risk factors that contribute to the initiation and development of atherosclerosis: dyslipidemia, and oxidative and inflammatory-stress. The selection of phenolic compounds was made to prove their multiple benefic effects and endorse them as CVD remedies, complementary to allopathic drugs. The review also highlights some aspects that still need clear scientific explanations and draws up some new molecular approaches to validate phenolic compounds for CVD complementary therapy in the near future.

In vitro and in vivo activities of flavonoids – apigenin, baicalin, chrysin, scutellarin – in regulation of hypertension – a review for their possible effects in pregnancy-induced hypertension

Flavonoids and their conjugates are the most important group of natural chemical compounds in drug discovery and development. The search for pharmacological activity and new mechanisms of activity of these chemical compounds, which may inhibit mediators of inflammation and influence the structure and function of endothelial cells, can be an interesting pharmacological strategy for the prevention and adjunctive treatments of hypertension, especially induced by pregnancy. Because cardiovascular diseases have multi-factorial pathogenesis these natural chemical compounds with wide spectrum of biological activities are the most interesting source of new drugs. Extracts from one of the most popular plant used in Traditional Chinese Medicine, Scutellaria baicalensis Georgi could be a very interesting source of flavonoids because of its exact content in quercetin, apigenin, chrysin and scutellarin as well as in baicalin. These flavonoids exert vasoprotective properties and many activities such as: anti-oxidative via several pathways, anti-in-flammatory, anti-ischaemic, cardioprotective and anti-hypertensive. However, there is lack of summaries of results of studies in context of potential and future application of flavonoids with determined composition and activity. Our review aims to provide a literature survey of in vitro, in vivo and ex vivo pharmacological studies of selected flavonoids (apigenin, chrysin and scutellarin, baicalin) in various models of hypertension carried out in 2008–2018.

Lipid-lowering and antioxidative effects ofApium graveolensL. root flavonoid extracts

Apium graveolensL. root flavone extract can improve hyperlipidemia induced by high-fat emulsion diet in rats.

Anti-Oxidative and Anti-Apoptotic Effects of Apigenin on Number of Viable and Apoptotic Blastomeres, Zona Pellucida Thickness and Hatching Rate of Mouse Embryos

Background

Apigenin is a plant-derived compound belonging to the flavonoids category and bears protective effects on different cells. The aim of this study was to evaluate the effect of apigenin on the number of viable and apoptotic blastomeres, the zona pellucida (ZP) thickness and hatching rate of pre-implantation mouse embryos exposed to H₂O₂ and actinomycin D.

Materials and Methods

In this experimental study, 420 two-cell embryos were randomly divided into six groups: i. Control, ii. Apigenin, iii. H₂O₂ , iv. Apigenin+H₂O₂ , v. Actinomycin D, and vi. Apigenin+Actinomycin D. The percentage of blastocysts and hatched blastocysts was calculated. Blastocyst ZP thickness was also measured. In addition, viable blastomeres quantity was counted by Hoechst and propidium iodide staining and the number of apoptotic blastomeres was counted by TUNEL assay.

Results

The results of viable and apoptotic blastomeres quantity, the ZP thickness, and the percentage of blastocysts and hatched blastocysts were significantly more favorable in the apigenin group, rather than the control group (P<0.05). The results of the apigenin+H₂O₂ group were significantly more favorable than the H₂O₂ group (P<0.05); and the results of apigenin+actinomycin D group were significantly more favorable than actinomycin D group (P<0.05).

Conclusion

The results suggest that apigenin may protect mouse embryos against H₂O₂ and actinomycin D. So that it increases the number of viable blastomeres and decreases the number of apoptotic blastomeres, which may cause expanding the blastocysts, thinning of the ZP thickness and increasing the rate of hatching in mouse embryos.

Apigenin inhibits growth of the Plasmodium berghei and disrupts some metabolic pathways in mice

Due to the challenges in the control, prevention, and eradication of parasitic diseases like malaria, there is an urgent need to discover new therapeutic agents. Plant-derived medicines may open new ways in the field of antiplasmodial therapy. This study is aimed to investigate the toxicity and in vivo antiplasmodial activity of apigenin, a dietary flavonoid. Apigenin cytotoxicity was investigated on Huh7 cell line, brine shrimp (Artemia salina) larva, and human red blood cells. In vivo toxicity of apigenin was assessed by metabolomics approaches. Apigenin exhibited significant suppression of parasitemia in a dose-dependent manner; it suppressed Plasmodium berghei growth by 69.74%, 50.3%, and 49.23% at concentrations of 70, 35, and 15 mg/kg/day, respectively. The IC₅₀ value for apigenin after 24 hr exposure to Huh7 cells was 225 μg/ml. Apigenin did not show noticeable toxicity on A. salina and also on the membrane integrity of red blood cells. After 24 hr exposure of mice to apigenin, alterations were seen in the metabolism of glucocorticoids and mineralocorticoids, bile acid metabolism (alternative pathway), sulfur metabolism, bile acid metabolism, metabolism of estrogens and androgens, cholesterol catabolism, and biosynthesis of cholesterol. These findings indicate that apigenin has potential in vivo antiplasmodial activity against P. berghei infected mice with high selectivity against malaria, but it can disrupt some metabolic pathways in mice.

Natural Biflavonoids Modulate Macrophage-Oxidized LDL Interaction In Vitro and Promote Atheroprotection In Vivo

The accumulation of oxidized ApoB-100-containing lipoproteins in the vascular intima and its subsequent recognition by macrophages results in foam cell formation and inflammation, key events during atherosclerosis development. Agents targeting this process are considered potentially atheroprotective. Since natural biflavonoids exert antioxidant and anti-inflammatory effects, we evaluated the atheroprotective effect of biflavonoids obtained from the tropical fruit tree Garcinia madruno. To this end, the pure biflavonoid aglycones morelloflavone (Mo) and volkensiflavone (Vo), as well as the morelloflavone's glycoside fukugiside (Fu) were tested in vitro in primary macrophages, whereas a biflavonoid fraction with defined composition (85% Mo, 10% Vo, and 5% Amentoflavone) was tested in vitro and in vivo. All biflavonoid preparations were potent reactive oxygen species (ROS) scavengers in the oxygen radical absorbance capacity assay, and most importantly, protected low-density lipoprotein particle from both lipid and protein oxidation. In biflavonoid-treated macrophages, the surface expression of the oxidized LDL (oxLDL) receptor CD36 was significantly lower than in vehicle-treated macrophages. Uptake of fluorescently labeled oxLDL and cholesterol accumulation were also attenuated in biflavonoid-treated macrophages and followed a pattern that paralleled that of CD36 surface expression. Fu and Vo inhibited oxLDL-induced ROS production and interleukin (IL)-6 secretion, respectively, whereas all aglycones, but not the glucoside Fu, inhibited the secretion of one or more of the cytokines IL-1β, IL-12p70, and monocyte chemotactic protein-1 (MCP-1) in lipopolysaccharide (LPS)-stimulated macrophages. Interestingly, in macrophages primed with low-dose LPS and stimulated with cholesterol crystals, IL-1β secretion was significantly and comparably inhibited by all biflavonoid preparations. Intraperitoneal administration of the defined biflavonoid fraction into ApoE^-/- mice was atheroprotective, as evidenced by the reduction of the atheromatous lesion size and the density of T cells and macrophages infiltrating the aortic root; moreover, this treatment also lowered the circulating levels of cholesterol and the lipid peroxidation product malondialdehyde. These results reveal the potent atheroprotective effects exerted by biflavonoids on key events of the oxLDL-macrophage interphase: (i) atheroligand formation, (ii) atheroreceptor expression, (iii) foam cell transformation, and (iv) prooxidant/proinflammatory macrophage response. Furthermore, our results also evidence the antioxidant, anti-inflammatory, hypolipemiant, and atheroprotective effects of Garcinia madruno's biflavonoids in vivo.