Morelloflavone, a biflavonoid inhibitor of migration-related kinases, ameliorates atherosclerosis in mice

The multifaceted anti-atherosclerotic properties of herbal flavonoids: A comprehensive review

Atherosclerosis (AS) is a major etiological factor underpinning a spectrum of cardiovascular diseases, leading to cerebral infarction, coronary artery disease, and peripheral vascular disease. The chronic progression of AS, spanning from initial plaque formation to the occurrence of acute cardiovascular events, underscores the complexity of AS and the challenges it presents in terms of treatment. Currently, the clinical management of AS relies predominantly on statins and proprotein convertase subtilisin/kexin type 9 inhibitors, which primarily aim to reduce low-density lipoprotein levels and have demonstrated some therapeutic efficacy. Nevertheless, due to their potential side effects, there is a pressing need to actively investigate alternative treatment approaches. Researches on natural compounds derived from herbal medicines, such as flavonoids, hold significant promise in combating AS by regulating lipid metabolism, reducing oxidative stress and inflammation, inhibiting the proliferation of vascular smooth muscle cells, modulating autophagy and additional pathways. Various targets participate in these physiological processes, encompassing acyl-CoA: cholesterol acyltransferase (ACAT), ATP citrate lyase (ACLY), nuclear factor erythroid 2-related factor 2 (Nrf2), krüppel-like factor 2 (KLF2), NOD-like receptor protein 3 (NLRP3), transcription factor EB (TFEB) and so on. This comprehensive review endeavors to synthesize and analyse the most recent findings on herbal flavonoids, shedding light on their anti-atherosclerotic potential and the underlying protective mechanisms and related-targets, which might pave the way for the development of novel drug candidates or the optimization of flavonoid-based therapies.

Cardiovascular Protective Effect of Garcinia dulcis Flower Acetone Extract in 2-Kidney-1-Clip Hypertensive Rats

Morelloflavone and camboginol are bioactive compounds purified from Garcinia dulcis (GD), which has anti-inflammatory and antihypertensive properties. The objective of this study was to examine the cardiovascular protective effect of GD flower acetone extract in 2-kidney-1-clip (2K1C) hypertensive rats. Male Wistar rats underwent 2K1C or sham operation (SO) and were housed for 4 weeks. Each group of rats, then, was further divided into 2 subgroups receiving oral administration of either 50 mg/kg BW GD extract or corn oil (vehicle) daily for 4 weeks. Noninvasive blood pressure (BP) and body weight were measured weekly throughout the study. Subsequently, the invasive measurement of arterial BP and the heart rate were determined in all anesthetized rats. The baroreceptor reflex sensitivity (BRS) was investigated by injection of either phenylephrine or sodium nitroprusside for bradycardia or tachycardia response, respectively. Histological examination of the heart and thoracic aorta was also performed in order to investigate the general morphology and the tumor necrosis factor alpha (TNF-α) expression. We found that the GD flower extract significantly diminished the BP and restored the impaired BRS. Moreover, it also decreased the TNF-α expression in the cardiac muscle and thoracic aorta of 2K1C when compared to the SO group. Taken together, our data showed that GD flower extract exhibits the cardiovascular protective effect in the 2K1C hypertensive rats.

Garcinia dulcis Extract Alleviates Inflammation in Kidney and Liver of the 2-Kidney-1-Clip Hypertensive rat

Garcinia dulcis (GD) extract possesses anti-hypertensive property that are poorly characterized. This study aimed to investigate an anti-inflammatory effect of GD flower extract in the 2-kidney-1-clip (2K1C) hypertensive compared to sham operative (SO) rat. Male Wistar rats were divided into 2 groups; the 2K1C group in which a silver clip was placed around renal artery to induce hypertension, and the SO normotensive group. Four weeks later, each group of rats were further divided into 2 subgroups, each subgroup was orally gavaged of either corn oil (vehicle) or 50 mg/kg BW GD extract daily for 4 weeks. The malondialdehyde (MDA) levels in serum, liver, and kidney were determined. Hematoxylin and eosin staining was carried out for histological examination, Periodic acid - Schiff staining for glomerular injury, Masson's trichrome staining for renal fibrosis, and immunohistochemistry for either tumor necrosis factor alpha (TNF-α) or endothelial nitric oxide synthase (eNOS) investigation. Taken together, our results demonstrated that GD flower extract decreased the MDA level in both serum and liver and kidney tissue and suppressed the expression of TNF-α in both liver and kidney of 2K1C hypertensive rats. Mesangial cell proliferation, expansion of mesangial matrix, widening Bowman's capsule space, congestion of glomerular capillary and vessel, cloudy swelling of renal tubular epithelial cell, and renal fibrosis were observed in the kidneys of 2K1C rats. Therefore, we concluded that GD flower extract can alleviate liver and kidney inflammation in which partially attenuates the glomerular injury in the 2K1C rat.

AVPCD: a plant-derived medicine database of antiviral phytochemicals for cancer, Covid-19, malaria and HIV

Serious illnesses caused by viruses are becoming the world's most critical public health issues and lead millions of deaths each year in the world. Thousands of studies confirmed that the plant-derived medicines could play positive therapeutic effects on the patients with viral diseases. Since thousands of antiviral phytochemicals have been identified as lifesaving drugs in medical research, a comprehensive database is highly desirable to integrate the medicinal plants with their different medicinal properties. Therefore, we provided a friendly antiviral phytochemical database AVPCD covering 2537 antiviral phytochemicals from 383 medicinal compounds and 319 different families with annotation of their scientific, family and common names, along with the parts used, disease information, active compounds, links of relevant articles for COVID-19, cancer, HIV and malaria. Furthermore, each compound in AVPCD was annotated with its 2D and 3D structure, molecular formula, molecular weight, isomeric SMILES, InChI, InChI Key and IUPAC name and 21 other properties. Each compound was annotated with more than 20 properties. Specifically, a scoring method was designed to measure the confidence of each phytochemical for the viral diseases. In addition, we constructed a user-friendly platform with several powerful modules for searching and browsing the details of all phytochemicals. We believe this database will facilitate global researchers, drug developers and health practitioners in obtaining useful information against viral diseases.

Garcinia kola: a critical review on chemistry and pharmacology of an important West African medicinal plant

Garcinia kola Heckel (Clusiaceae) is a tree indigenous to West and Central Africa. All plant parts, but especially the seeds, are of value in local folklore medicine. Garcinia kola is used in treatment of numerous diseases, including gastric disorders, bronchial diseases, fever, malaria and is used to induce a stimulating and aphrodisiac effect. The plant is now attracting considerable interest as a possible source of pharmaceutically important drugs. Several different classes of compounds such as biflavonoids, benzophenones, benzofurans, benzopyran, vitamin E derivatives, xanthones, and phytosterols, have been isolated from G. kola, of which many appears to be found only in this species, such as garcinianin (found in seeds and roots), kolanone (fruit pulp, seeds, roots), gakolanone (stem bark), garcinoic acid, garcinal (both in seeds), garcifuran A and B, and garcipyran (all in roots). They showed a wide range of pharmacological activities (e.g. analgesic, anticancer, antidiabetic, anti-inflammatory, antimalarial, antimicrobial, hepatoprotective and neuroprotective effects), though this has only been confirmed in animal models. Kolaviron is the most studied compound and is perceived by many studies as the active principle of G. kola. However, its research is associated with significant flaws (e.g. too high doses tested, inappropriate positive control). Garcinol has been tested under better conditions and is perhaps showing more promising results and should attract deeper research interest (especially in the area of anticancer, antimicrobial, and neuroprotective activity). Human clinical trials and mechanism-of-action studies must be carried out to verify whether any of the compounds present in G. kola may be used as a lead in the drug development.

Bioactivity of natural biflavonoids in metabolism-related disease and cancer therapies

Natural biflavonoids, such as amentoflavone, bilobetin, ginkgetin, isoginkgetin, taiwaniaflavone, morelloflavone, delicaflavone, hinokiflavone, and other derivatives (~ 40 biflavonoids), are isolated from Selaginella sp., Ginkgo biloba, Garcinia sp., and several other species of plants. They are able to exert therapeutic benefits by regulating several proteins/enzymes (PPAR-γ, CCAAT/enhancer-binding protein α [C/EBPα], STAT5, pancreatic lipase, PTP1B, fatty acid synthase, α-glucosidase [AG]) and insulin signaling pathways (via PI3K-AKT), which are linked to metabolism, cell growth, and cell survival mechanisms. Deregulated insulin signaling can cause complications of obesity and diabetes, which can lead to cognitive disorders such as Alzheimer's, Parkinson's, and dementia; therefore, the therapeutic benefits of these biflavones in these areas are highlighted. Since biflavonoids have shown potential to regulate metabolism, growth- and survival-related protein/enzymes, their relation to tumor growth and metastasis of cancer associated with angiogenesis are highlighted. The translational role of biflavones in cancer with respect to the inhibition of metabolism-related processes/pathways, enzymes, or proteins, such as STAT3/SHP-1/PTEN, kinesins, tissue kallikreins, aromatase, estrogen, protein modifiers, antioxidant, autophagy, and apoptosis induction mechanisms, are discussed. Finally, considering their observed bioactivity potential, oral bioavailability studies of biflavones and related clinical trials are outlined.

Physiological and Metabolic Effects of Yellow Mangosteen (Garcinia dulcis) Rind in Rats with Diet-Induced Metabolic Syndrome

Metabolic syndrome is a cluster of disorders that increase the risk of cardiovascular disease and diabetes. This study has investigated the responses to rind of yellow mangosteen (Garcinia dulcis), usually discarded as waste, in a rat model of human metabolic syndrome. The rind contains higher concentrations of phytochemicals (such as garcinol, morelloflavone and citric acid) than the pulp. Male Wistar rats aged 8-9 weeks were fed either corn starch diet or high-carbohydrate, high-fat diet for 16 weeks, which were supplemented with 5% freeze-dried G. dulcis fruit rind powder during the last 8 weeks. We characterised metabolic, cardiovascular, liver and gut microbiota parameters. High-carbohydrate, high-fat diet-fed rats developed abdominal obesity, hypertension, increased left ventricular diastolic stiffness, decreased glucose tolerance, fatty liver and reduced Bacteroidia with increased Clostridia in the colonic microbiota. G. dulcis fruit rind powder attenuated these changes, improved cardiovascular and liver structure and function, and attenuated changes in colonic microbiota. G. dulcis fruit rind powder may be effective in metabolic syndrome by appetite suppression, inhibition of inflammatory processes and increased fat metabolism, possibly related to changes in the colonic microbiota. Hence, we propose the use of G. dulcis fruit rind as a functional food to ameliorate symptoms of metabolic syndrome.

Ticagrelor induces paraoxonase-1 (PON1) and better protects hypercholesterolemic mice against atherosclerosis compared to clopidogrel

Ticagrelor (TIC), a P2Y purinoceptor 12 (P2Y₁₂)-receptor antagonist, has been widely used to treat patients with acute coronary syndrome. Although animal studies suggest that TIC protects against atherosclerosis, it remains unknown whether it does so through its potent platelet inhibition or through other pathways. Here, we placed hypercholesterolemic Ldlr^-/-Apobec1^-/- mice on a high-fat diet and treated them with either 25 mg/kg/day of clopidogrel (CLO) or 180 mg/kg/day of TIC for 16 weeks and evaluated the extent of atherosclerosis. Both treatments equally inhibited platelets as determined by ex vivo platelet aggregation assays. The extent of atherosclerosis, however, was significantly less in the TIC group than in the CLO group. Immunohistochemical staining and ELISA showed that TIC treatment was associated with less macrophage infiltration to the atherosclerotic intima and lower serum levels of CCL4, CXCL10, and TNFα, respectively, than CLO treatment. Treatment with TIC, but not CLO, was associated with higher serum activity and tissue level of paraoxonase-1 (PON1), an anti-atherosclerotic molecule, suggesting that TIC might exert greater anti-atherosclerotic activity, compared with CLO, through its unique ability to induce PON1. Although further studies are needed, TIC may prove to be a viable strategy in the prevention and treatment of chronic stable human atherosclerosis.

Effects of biflavonoids from Garcinia madruno on a triple transgenic mouse model of Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that is pathologically characterized by the deposition of β-amyloid (βA) peptides in senile plaques and neurofibrillary tangles in the brain. Flavonoids have recently been used to prevent and treat a variety of neurodegenerative diseases, but little is known about bioflavonoids. In this study, we evaluate whether a biflavonoid fraction (BF) exerts neuroprotective effects on an aged triple transgenic mouse mode of AD (3xTg-AD). Then, 21-24-month-old 3xTg AD mice were i.p. injected with 25mg/kg of a BF from Garcinia madruno composed of morelloflavone (65%), volkensiflavone (12%), GB 2a (11%), fukugiside (6%) and amentoflavone (0.4%) every 48h for 3 months. The BF treatment reduced βA deposition in different regions of the brain (the hippocampus, entorhinal cortex and amygdala), reduced βA1-40 and βA1-42 levels, BACE1-mediated cleavage of APP (CTFβ), tau pathology, astrogliosis and microgliosis in the brains of aged 3xTg-AD mice. Although the BF treatment weakly improved learning, animals treated with BF spent more time in the open arms of the elevated plus maze test and displayed greater risk assessment behavior than the control groups. In summary, the BF reverses histopathological hallmarks and reduces emotional disorders in the 3xTg-AD mouse model, suggesting that the biflavonoids from G. madruno represent a potential natural therapeutic option for AD if its bioavailability is improved.

Fortilin: A Potential Target for the Prevention and Treatment of Human Diseases

Fortilin is a highly conserved 172-amino-acid polypeptide found in the cytosol, nucleus, mitochondria, extracellular space, and circulating blood. It is a multifunctional protein that protects cells against apoptosis, promotes cell growth and cell cycle progression, binds calcium (Ca²⁺) and has antipathogen activities. Its role in the pathogenesis of human and animal diseases is also diverse. Fortilin facilitates the development of atherosclerosis, contributes to both systemic and pulmonary arterial hypertension, participates in the development of cancers, and worsens diabetic nephropathy. It is important for the adaptive expansion of pancreatic β-cells in response to obesity and increased insulin requirement, for the regeneration of liver after hepatectomy, and for protection of the liver against alcohol- and ER stress-induced injury. Fortilin is a viable surrogate marker for in vivo apoptosis, and it plays a key role in embryo and organ development in vertebrates. In fish and shrimp, fortilin participates in host defense against bacterial and viral pathogens. Further translational research could prove fortilin to be a viable molecular target for treatment of various human diseases including and not limited to atherosclerosis, hypertension, certain tumors, diabetes mellitus, diabetic nephropathy, hepatic injury, and aberrant immunity and host defense.

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.

Phytoconstituents and Biological Activities of Garcinia Dulcis (Clusiaceae): A Review

Garcinia dulcis (Roxb.) Kurz is a tropical fruit tree native to Southeast Asia where it has a long history of use as a traditional medicine for the treatment of ailments such as lymphatitis, parotitis, struma, scurvy, cough, and sore throat. Despite its medicinal values, this plant is not well known and rarely found nowadays. Research on the phytochemical constituents and biological activities of G. dulcis have demonstrated that various parts of the plant contain an abundance of bioactive compounds mainly xanthones and flavonoids, with significant pharmacological properties such as anti-atherosclerosis, anti-bacterial, anti-cancer, anti-hypertension, and anti-malarial. In the present review, current knowledge of the phytochemistry of G. dulcis and biological activities of its active constituents based on the available literature are summarized in order to explore application potentials and prospective research works on this plant.

Dissecting the mechanism of carotid atherosclerosis from the perspective of regulation

Carotid atherosclerosis is a chronic inflammatory disease of the arterial wall. The present study aimed to identify changes in the gene expression and regulatory factors for atherosclerotic plaques of carotid atherosclerosis from an early to an advanced stage. The original data were downloaded from the NCBI GEO database under accession no. GSE28829. Differentially expressed genes (DEGs) were detected by the Robust Multiarray Average (RMA). The enriched Gene Ontology (GO) terms and pathways for DEGs using DAVID were subsequently identified. The transcriptional and microRNA (miRNA) regulatory network were constructed for the DEGs. Cis-regulatory signals were also investigated. More genes were activated in the advanced stage compared with the early stage. IGHG1 and SPP1 were upregulated, while MYBL1 and PLD were downregulated. The upregulated genes in the advanced stage were involved in atherosclerosis‑related GO terms such as immune, vascular and cell movement homeostasis. The DEGs were significantly enriched in cell adhesion molecules (CAMs) and the focal adhesion pathway. MMP9 and CFL2 played key roles in the transcriptional regulatory network. Moreover, miR-328 was identified as one of the hubs in the miRNA regulatory network. The results may therefore be used to determine the mechanism involved in carotid atherosclerosis.

The biflavonoid morelloflavone inhibits the enzymatic and biological activities of a snake venom phospholipase A2

The biflavonoid morelloflavone has been reported as inhibitor of secretory PLA2s (phospholipases A2 from human synovial and bee venom sources); however, its capacity to interact and inhibit snake venom PLA2 activities has not been described. In this work we tested the inhibitory ability of morelloflavone on the enzymatic, anticoagulant, myotoxic and edema-inducing activities of a PLA2 isolated from Crotalus durissus cumanensis venom. The biflavonoid displayed IC50 values of 0.48 mM (95% Confidence intervals: 0.45-0.51) and 0.38 mM (95% Confidence intervals: 0.36-0.40) on the PLA2 enzymatic activity, when either aggregated or monodispersed substrates were used, respectively. In addition, morelloflavone inhibited in a time-dependent manner and irreversibly the PLA2 enzymatic activity. When mice were injected with PLA2 preincubated (preincubation assay) with 0.13, 0.63 and 1.26 mM of the biflavonoid, the myotoxic activity induced by the PLA2 was inhibited up to 63%. Nevertheless, these values decreased up to 38% when the morelloflavone was injected into muscle after PLA2. Moreover, morelloflavone inhibited, in a concentration-dependent manner, edema-forming activity of the PLA2 in the footpad. Morelloflavone also inhibited the anticoagulant activities of the PLA2 in concentration-dependent mode. In order to have insights on the mode of action of morelloflavone, intrinsic fluorescence studies were performed. Results of these assays suggest that morelloflavone interacts directly with the PLA2. These findings were supported by molecular docking results, which suggested that morelloflavone forms hydrogen bonds with residues Gly33, Asp49, Gly53 and Thr68 of the enzyme. In addition, our results suggested a π-π stacking interaction between rings A of morelloflavone with that of the residue Tyr52, and Van der Waals interactions with Gly32, His48 and Ala56. Our molecular modeling results suggest that morelloflavone may occupy part of substrate binding cleft of the PLA2. Morelloflavone is a candidate for the development of inhibitors to be used in snakebite envenomation.

The role of Src kinase in macrophage-mediated inflammatory responses

Src kinase (Src) is a tyrosine protein kinase that regulates cellular metabolism, survival, and proliferation. Many studies have shown that Src plays multiple roles in macrophage-mediated innate immunity, such as phagocytosis, the production of inflammatory cytokines/mediators, and the induction of cellular migration, which strongly implies that Src plays a pivotal role in the functional activation of macrophages. Macrophages are involved in a variety of immune responses and in inflammatory diseases including rheumatoid arthritis, atherosclerosis, diabetes, obesity, cancer, and osteoporosis. Previous studies have suggested roles for Src in macrophage-mediated inflammatory responses; however, recently, new functions for Src have been reported, implying that Src functions in macrophage-mediated inflammatory responses that have not been described. In this paper, we discuss recent studies regarding a number of these newly defined functions of Src in macrophage-mediated inflammatory responses. Moreover, we discuss the feasibility of Src as a target for the development of new pharmaceutical drugs to treat macrophage-mediated inflammatory diseases. We provide insights into recent reports regarding new functions for Src that are related to macrophage-related inflammatory responses and the development of novel Src inhibitors with strong immunosuppressive and anti-inflammatory properties, which could be applied to various macrophage-mediated inflammatory diseases.