Quality assessment and Q-markers discovery in Citri Sarcodactylis Fructus by integrating serum pharmacochemistry and network pharmacology.

INTRODUCTION: Citri Sarcodactylis Fructus (CSF), a common fruit and traditional Chinese medicine (TCM), has been hindered in its further development and research owing to the lack of comprehensive and specific quality evaluation standards. OBJECTIVE: This study aimed to establish clear TCM quality standards related to the therapeutic mechanisms of CSF and to provide a basis for subsequent research and development. METHODS: Ultra-high performance liquid chromatography coupled with hybrid quadrupole-orbitrap high-resolution mass spectrometry (UPLC-Q-orbitrap HRMS) technology was used to comprehensively identify CSF components and explore their absorbance levels in rat serum. Network pharmacology research methods were employed to investigate the potential mechanisms of action of the identified components in the treatment of major clinical diseases. Subsequently, a combination of HPLC chromatographic fingerprinting for qualitative analysis and multi-index content determination was used to evaluate the detectability of the identified quality markers (Q-markers). RESULTS: Twenty-six prototype components were tentatively characterized in rat serum. Network pharmacology analysis showed six effective components, namely 7-hydroxycoumarin, isoscopoletin, diosmin, hesperidin, 5,7-dimethoxycoumarin, and bergapten, which played important roles in the treatment of chronic gastritis, functional dyspepsia, peptic ulcer, and depression and were preliminarily identified as Q-markers. The results of content determination in 15 batches of CSF indicated significant differences in the content of medicinal materials from different origins. However, compared with the preliminarily determined Q-markers, all six components could be measured and were determined as Q-markers of CSF. CONCLUSION: The chemical Q-markers obtained in this study could be used for effective quality control of CSF.

Comparison of the effects of methylprednisolone, hyperbaric oxygen and hesperidin + diosmin on the facial nerve injury: an experimental animal model.

BACKGROUND: Necessity of new and alternative treatments in traumatic facial nerve injury. AIMS/OBJECTIVE: In this experimental study, we aimed to evaluate the histopathologic and functional effects of methylprednisolone, hyperbaric oxygen and hesperidin + diosmin treatments on traumatic facial nerve regeneration in rats. METHODS: After facial nerve injury, five groups were formed with eight rats in each group: Group 1 (negative control), 2 (operation), 3 (corticosteroid), 4 (hyperbaric oxygen), 5 (hesperidin + diosmin). Blink reflex of rats evaluated a day after the operation and at the first, second and third weeks. Facial nerve samples from sacrificed animals were examined under a light microscope. RESULTS: According to our results, in group 4; axonal degeneration and vascular congestion were significantly lower than group 2 and 3, and myelin sheath thickness was significantly higher than group 3. In group 5; axonal degeneration was significantly lower than group 2 and vascular congestion was significantly lower than group 2 and 3. In terms of functional recovery; there was no statistically significant difference between the groups. CONCLUSIONS AND SIGNIFICANCE: It has been shown that both hyperbaric oxygen and hesperidin + diosmin treatments have positive effects on facial nerve regeneration. Both treatments may be good alternatives for ameliorating traumatic nerve injury, but these treatment modalities need to be further explored.

Diosmin and Bromelain Stimulate Glutathione and Total Thiols Production in Red Blood Cells.

Diosmin and bromelain are bioactive compounds of plant origin with proven beneficial effects on the human cardiovascular system. We found that diosmin and bromelain slightly reduced total carbonyls levels and had no effect on TBARS levels, as well as slightly increased the total non-enzymatic antioxidant capacity in the RBCs at concentrations of 30 and 60 µg/mL. Diosmin and bromelain induced a significant increase in total thiols and glutathione in the RBCs. Examining the rheological properties of RBCs, we found that both compounds slightly reduce the internal viscosity of the RBCs. Using the MSL (maleimide spin label), we revealed that higher concentrations of bromelain led to a significant decrease in the mobility of this spin label attached to cytosolic thiols in the RBCs, as well as attached to hemoglobin at a higher concentration of diosmin, and for both concentrations of bromelain. Both compounds tended to decrease the cell membrane fluidity in the subsurface area, but not in the deeper regions. An increase in the glutathione concentration and the total level of thiol compounds promotes the protection of the RBCs against oxidative stress, suggesting that both compounds have a stabilizing effect on the cell membrane and improve the rheological properties of the RBCs.

Nephroprotective Effect of Diosmin against Cisplatin-Induced Kidney Damage by Modulating IL-1ß, IL-6, TNFα and Renal Oxidative Damage.

Cisplatin (CP) is a platinum compound of the alkylating agent class that is used for the treatment of various types of cancer. However, CP treatments in cancer patients are accountable for nephrotoxicity, as it is a major adverse effect. Hence, this research study was proposed to investigate the nephroprotective effect of diosmin, a flavonoid glycoside of hesperidin derivatives against cisplatin-induced kidney damage. Wistar rats received a single intraperitoneal (i.p) injection of CP (7.5 mg/kg, i.p) to induce nephrotoxicity. The administration of CP significantly (p < 0.001) increased the markers of kidney function test (creatinine, blood urea nitrogen, and uric acid) and demonstrated histopathological changes in the kidney of the CP-treated nephrotoxic group. In addition, the CP-treated nephrotoxic group demonstrated a significant (p < 0.001) increase in lipid peroxidation (LPO) levels and depleted activities of reduced glutathione (GSH), glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD) and catalase (CAT).However, diosmin (100 and 200 mg/kg) treatments significantly reduced the elevated levels of kidney function test parameters and restored structural changes in the kidney (p < 0.001). The administration of diosmin (100 and 200 mg/kg) significantly (p < 0.001) reduced LPO levels, increased GSH content and showed improvements in the activities of GPx, GR, SOD and CAT. The markers of inflammatory cytokines such as IL-1ß, IL-6 and TNFα significantly (p < 0.001) increased in the CP-treated nephrotoxic group, whereas diosmin (100 and 200 mg/kg) treatments significantly (p < 0.001) reduced the elevated levels of these cytokines. The findings of this research demonstrate the nephroprotective effect of diosmin against CP-induced kidney damage. Therefore, we conclude that diosmin may be used as a supplement in the management of nephrotoxicity associated with CP treatments in cancer patients.

The Effect of Hesperidin and Diosmin Individually or in Combination on Metabolic Profile and Neuropathy among Diabetic Patients with Metabolic Syndrome: A Randomized Controlled Trial.

Current evidence supports the association of metabolic syndrome (MetS) with neuropathy. Limited data are available on proper strategies to control metabolic disorders and neuropathy among patients with type2 diabetes mellitus (T2DM). We aimed to determine hesperidin and diosmin efficacy individually and in combination among T2DM patients with neuropathy and meet MetS criteria. In this parallel-group designed trial, 129 T2DM patients with MetS and neuropathy were recruited and randomized to receive their oral hypoglycemics with either hesperidin (1g/day), or diosmin (1g/day), or combination of both or oral hypoglycemics without intervention for 12 weeks. Diabetic neuropathy was evaluated using Michigan Neuropathy Screening Instrument (MNSI) at baseline and after trial. Anthropometric parameters, blood glucose and lipid profile were also assessed before and after the intervention using paired student t-test within groups. The trial is registered at clinicaltrials.gov as NCT05243238. By completion of the trial duration, both hesperidin and diosmin groups showed significant reduction in blood glucose, triglycerides (TGs) and low density lipoprotein (LDL) from baseline (p<0.05). However, the magnitude of improvement in metabolic components significantly increased with hesperidin and diosmin combination. Although MNSI scores improved significantly in both groups, the reduction was more significant with the combination of hesperidin and diosmin. Moreover, the change in MNSI score was significantly correlated with the improvement in metabolic profile components including LDL, TGs and fasting blood glucose. Oral supplementation of hesperidin and diosmin was associated with improvement in metabolic syndrome and diabetic neuropathy and the combination of both was superior in efficacy.

Diosmin, a citrus fruit-derived phlebotonic bioflavonoid protects rats from chronic kidney disease-induced loss of bone mass and strength without deteriorating the renal function.

Kidney Disease Improving Global Outcomes (KDIGO) 2017 Clinical Practice Guideline has recommended treatment decisions for patients with chronic kidney disease (CKD) with osteoporosis and/or high risk of fracture. Bisphosphonates, the first-line anti-osteoporosis drugs have the concern of worsening kidney functions. Moreover, despite impaired bone formation in CKD patients, teriparatide, the formation-stimulating drug is not recommended. Thus, there is an urgent need for safe and effective treatment of osteoporosis in CKD patients. Here, in CKD rats, we tested the osteoprotective effect of diosmin, a citrus-derived bioflavonoid used as a phlebotonic in chronic venous insufficiency and has a renoprotective effect. CKD was developed by 5/6th nephrectomy and diosmin at the human equivalent dose (100 mg kg-1) did not advance renal failure but reduced blood pressure to the level of sham control. Fibroblast growth factor-23 and parathyroid hormone were increased in CKD and diosmin suppressed both. CKD reduced bone mass and deteriorated the microarchitecture of trabecular bones, and diosmin maintained both to control levels. Bone formation and strength were impaired in the CKD and diosmin maintained these levels to control levels. Nanoindentation of bone showed that diosmin significantly increased tissue hardness over the control. Diosmetin, the metabolic surrogate of diosmin had comparable pharmacokinetic profiles between the control and CKD groups. Furthermore, diosmetin (50 mg kg-1) protected against CKD-induced bone loss. These data suggest that diosmin and its metabolic surrogate, diosmetin protect against CKD-induced osteopenia. Since diosmin has no renal adverse effect and protected bone mass and strength in CKD rats, we propose assessing its anti-osteoporosis effect in CKD patients.

Lymphotonic activity of Ruscus extract, hesperidin methyl chalcone and vitamin C in human lymphatic smooth muscle cells.

OBJECTIVE: Besides actions including their venotonic, anti-inflammatory, and anti-oxidant effects, venoactive drugs are expected to act on edema via their action on lymphatics. The objective of this study was to evaluate the effect of the combination of Ruscus, hesperidin methyl chalcone and Vitamin C (Ruscus/HMC/Vit C) on intracellular calcium mobilization and contraction of human lymphatic smooth muscle cells (LSMCs) to better characterize the mechanism of its lymphotonic activity. METHODS: Calcium mobilization was evidenced by videomicroscopy analysis of the fluorescence emitted by a specific Ca2+ sensitive dye and measured after injection of Ruscus/HMC/Vit C at 0.1, 0.3, 1.0, and 3.0 mg/mL into LSMCs. RESULTS: Ruscus/HMC/Vit C induced a strong and reproducible concentration-dependent calcium mobilization in LSMCs. On the contrary, another venoactive drug used as comparator, micronized purified flavonoid fraction (MPFF), did not induce calcium mobilization whatever the tested concentration. CONCLUSION: Although alternative mechanisms of action may result in potential lymphotonic effects, the efficacy of lymphotonic products is nonetheless related to their stimulating effect on the contractile activity of the smooth muscle cells surrounding lymphatic vessels. In the light of the results obtained in this study, the direct effect of Ruscus/HMC/Vit C on LSMC contraction may partially explain its clinical efficacy on lymphotonic activity, as has been observed in terms of objective signs of edema as reported in the recent guidelines on chronic venous disease.

The Growth Suppression Activity of Diosmin and PGV-1 Co-Treatment on 4T1 Breast Cancer Targets Mitotic Regulatory Proteins.

OBJECTIVE: We aim to enhance the effectiveness of curcumin analog PGV-1 through co-treatment with diosmin, a citrus flavonoid, on 4T1 cells and evaluate the molecular targets underlying its effect on the cell cycle. METHODS: Cytotoxic effects were performed by MTT assay against 4T1 cells. The May Grünwald-Giemsa staining was used to observe cell cycle arrest. The senescence was assayed with SA-ß-gal staining. Bioinformatic studies were utilized to discover protein targets of PGV-1 and diosmin on triple-negative breast cancer (TNBC) using SwissTargetPrediction, then exploration of protein targets was performed using the TCGA dataset via the UALCAN website. Kaplan-Meier was performed using GraphPad with data from the TCGA dataset via Oncoln. Using MOE 2010, we conducted the binding affinity between PGV-1 and diosmin to protein targets. RESULTS: PGV-1 and diosmin showed cytotoxic effect with IC50 values of 9 µM and 389 µM, respectively, and the combined cytotoxic assay exhibited a synergistic effect with a combination index (CI) of <1. PGV-arrested 4T1 cells in pro-metaphase and induced mitotic catastrophe, while the combination of diosmin with PGV-1 increased the number of mitotic catastrophes. The SA-ß-gal assay revealed that both compounds were capable of inducing senescence in 4T1 cells. Study bioinformatics and molecular docking showed that PGV-1 and diosmin target cell cycle regulatory proteins in TNBC, namely CDK1, KIF11, and AURKA. Thus, the combination of diosmin and PGV-1 modulating the cell cycle that causes senescence and catastrophic death of 4T1 cancer cells is related to the inhibition of these cell cycle proteins. CONCLUSION: Diosmin enhances the cytotoxic effect of PGV-1 synergistically on 4T1 cancer cells, which correlates to the increasing senescence and mitotic catastrophe. The synergistic effect of the co-treatment is likely to target AURKA, CDK1, and KIF11. The combination of PGV-1 and diosmin performs a potential as a combinatorial anticancer drug for TNBC.

Anticancer and Anti-inflammatory Effect of Diosmin against Dalton Ascitic Lymphoma Induced Leukemia.

Cancer is the world's biggest health problem and cancer-induced mortality happened all over the planet after the heart disease. The present study was to scrutinize the anti-leukemia effect of diosmin against Dalton Ascitic Lymphoma (DAL) induced leukemia in mice. DAL cell was used for induction the solid tumor. Body weight, life spans, tumor volume and mean survival time was estimated. Antioxidant, biochemical and pro-inflammatory cytokines were estimated. Diosmin showed the cell viability effect at dose dependent manner against the both cell lines. DAL induced solid tumor mice showed the decreased body weight, mean survival days, non viable cell count and increased the tumor volume, viable cell count and diosmin significantly (p < 0.001) reverse the effect of DAL. Diosmin significantly (p < 0.001) altered the hematological, differential leukocytes, antioxidant, biochemical, pro-inflammatory cytokines at dose dependently. Collectively, we can say that diosmin might alter the DAL induced abnormality via antioxidant and anti-inflammatory effects.

Diosmin Mitigates Cyclophosphamide Induced Premature Ovarian Insufficiency in Rat Model.

The current study was designed to investigate the protective role of diosmin against cyclophosphamide-induced premature ovarian insufficiency (POI). Female Swiss albino rats received a single intraperitoneal dose of cyclophosphamide (200 mg/kg) followed by 8 mg/kg/day for the next 15 consecutive days either alone or in combination with oral diosmin at 50 or 100 mg/kg. Histopathological examination of ovarian tissues, hormonal assays for follicle stimulating hormone (FSH), estradiol (E2), and anti-Mullerian hormone (AMH), assessment of the oxidative stress status, as well as measurement of the relative expression of miRNA-145 and its target genes [vascular endothelial growth factor B (VEGF-B) and regulator of cell cycle (RGC32)] were performed. Diosmin treatment ameliorated the levels of E2, AMH, and oxidative stress markers. Additionally, both low and high diosmin doses significantly reduced the histopathological alterations and nearly preserved the normal ovarian reserve. MiRNA-145 expression was upregulated after treatment with diosmin high dose. miRNA-145 target genes were over-expressed after both low and high diosmin administration. Based on our findings, diosmin has a dose-dependent protective effect against cyclophosphamide-induced ovarian toxicity in rats.

Diosmin restores the skin barrier by targeting the aryl hydrocarbon receptor in atopic dermatitis.

BACKGROUND: Atopic dermatitis (AD) is an inflammatory chronic skin disease that is characterized by the dysfunction or lack of skin barrier proteins. Recent studies have proposed that the pharmacological upregulation of skin barrier proteins is an effective treatment for AD. Aryl hydrocarbon receptor (AhR) is a transcription factor that positively regulates the expression of skin barrier proteins upon its activation. PURPOSE: This study aimed to identify AhR agonists from phytochemicals and investigate its effect on skin barrier restoration as well as its mechanisms of action in AD. STUDY DESIGN: A publicly available assay database and HaCaT cells stably transduced with a luciferase gene driven by an AhR-target gene promoter (CYP1A1) were used to screen for the activity of AhR agonists from phytochemicals. Normal human epidermal keratinocytes (NHEKs) and a human skin equivalent (HSE) model were used to investigate the effect of AhR agonists on skin restoration and its underlying mechanisms. METHODS: A Gaussia luciferase assaywas performed to screen for AhR agonist activity. Western blotting, qRT-PCR analysis, immunofluorescence, drug affinity responsive target stability assay, and siRNA-mediated AhR knockdown were performed in NHEKs. Hematoxylin and eosin staining was performed to measure epidermal thickness in the HSE model. RESULTS: Diosmin, a potential AhR agonist derived from natural products, upregulated the expression of skin barrier proteins (filaggrin and loricrin) and their upstream regulator (OVOL1) in NHEKs. Diosmin treatment also increased epidermal thickness in the HSE model. In addition, incubating NHEKs with diosmin restored the expression of skin barrier proteins and mRNAs that were suppressed by Th2 cytokines and inhibited STAT3 phosphorylation that was induced by Th2 cytokines. Diosmin also upregulated the expression of NQO1, a negative regulator of STAT3. Immunofluorescence results showed that diosmin stimulated AhR nuclear translocation, and the drug affinity responsive target stability assay revealed that this phytochemical directly bound to AhR. Furthermore, AhR knockdown abolished diosmin-induced filaggrin and loricrin expression. CONCLUSION: These results suggest that diosmin is a potential treatment for AD that targets AhR.

Protective effects of hesperidin and diosmin against acrylamide-induced liver, kidney, and brain oxidative damage in rats.

Acrylamide (AA) is a heat-induced toxin formed during thermal processing of many commonly consumed foods, including meat products, French fries, potato crisps, bread, cereals, cookies, and coffee. There is thus potentially high dietary exposure of humans to AA, which can induce significant oxidative stress. Hesperidin (HS) and diosmin (DS) are flavone glycosides that have antioxidant properties. The aim of this study was to investigate the protective effects of HS and DS against AA toxicity. Fifty-six adult male Wistar albino rats were divided into seven groups. The first group was orally administered 0.5% (w/v) dimethyl sulfoxide (DMSO) and considered as the control group. The second and third groups were orally administered 10 mg/kg/day of HS or DS, respectively. The fourth group received 20 mg/kg/day of AA orally for 14 days. The fifth and sixth groups were given 10 mg/kg/day of HS or DS, respectively, followed by AA. The seventh group was given both HS and DS after AA administration. AA intoxication significantly (p ≤ 0.05) increased serum levels of liver function enzymes (ALT, AST, and ALP), kidney function products (urea and creatinine), oxidative DNA damage marker (OHdG), proinflammatory markers (TNF-α, IL-1ß, and IL-6), lipid peroxidation marker (malondialdehyde), and nitric oxide (NO). On the other hand, it significantly (p ≤ 0.05) decreased levels of reduced glutathione (GSH) in the liver, kidney, and brain. The activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT) in the liver, kidney, and brain tissues were also reduced. HS and DS supplementation prevented lipid peroxidation, normalized the serum parameters altered by AA, and enhanced the tissue concentrations and activities of antioxidant biomarkers. It could be concluded that HS and DS have potent protective effects against oxidative stress, lipid peroxidation, and DNA damage induced by AA toxicity in rats.

The chondroprotective effect of diosmin on human articular chondrocytes under oxidative stress.

Excessive oxidative stress, which can amplify inflammatory responses, is involved in the pathologic progression of knee osteoarthritis. Diosmin is known to possess a variety of biological functions such as antiinflammatory and antioxidant activities. We therefore demonstrated the chondroprotective potentials of diosmin on human articular chondrocytes under oxidative stress. The cytotoxicity of diosmin (5, 10, 50, and 100 µM) to chondrocytes was first evaluated. Subsequently, the cells were treated with diosmin (5 and 10 µM) after hydrogen peroxide (H2 O2 ) exposure. We found that the cytotoxicity of diosmin occurred in a dose-dependent manner (10, 50, and 100 µM), and low-dose diosmin (5 µM) slightly impaired cell viability. Diosmin supplementations (5 and 10 µM) did not show beneficial effects on mitochondrial activity, cytotoxicity, proliferation, and survival and the cell senescence was ameliorated in H2 O2 -exposed chondrocytes. On the other hand, diosmin down-regulated the mRNA levels of iNOS, COX-2, IL-1ß, COL1A1, MMP-3, and MMP-9; up-regulated TIMP-1 and SOX9; and improved COL2A1 in chondrocytes under oxidative stresses. Furthermore, diosmin also regulated glutathione reductase and glutathione peroxidase of H2 O2 -exposed chondrocytes. In conclusion, diosmin displayed a remarkable antiinflammatory effect compared with the antioxidant capacity on human chondrocytes. Diosmin can maintain the homeostasis of extracellular matrix of articular cartilage.

A nutraceutical composition containing diosmin and hesperidin has osteogenic and anti-resorptive effects and expands the anabolic window of teriparatide.

A combination of diosmin and hesperidin (9:1 ratio) is marketed as a dietary supplement/nutraceutical for cardiovascular health. We studied the skeletal effect of this combination (90% diosmin and 10% hesperidin, henceforth named as DH). We showed that a) in rats with femur osteotomy, DH stimulated callus bone regeneration, b) in growing rats, DH promoted peak bone mass achievement and c) in OVX rats rendered osteopenic, DH completely restored femur trabecular bones and strength along with the increases in surface referent bone formation and serum osteogenic marker. Furthermore, DH suppressed bone resorption in OVX rats as well as in OVX rats treated with teriparatide (human parathyroid hormone 1-34) but did not affect the osteoanabolic effect of teriparatide. These data suggested that DH could prolong the anabolic window of teriparatide. To understand the mechanism of DH action, we performed pharmacokinetic studies and observed that upon its oral administration the only circulating metabolites was diosmetin (the aglycone form of diosmin) while none of the two input flavanones were detectable. Accordingly, subsequent experiments with diosmetin revealed that it was a selective estrogen receptor-ß agonist that stimulated osteoblast differentiation and suppressed sclerostin the anti-osteoblastogenic Wnt antagonist. Taken together, our study defined a positive skeletal effect of DH.

[Diosmin in the treatment of venous disease: pharmacokinetics and pharmacodynamics (in Russian only)]. / Diosmin v lechenii venoznoi patologii: osnovy farmakokinetiki i farmakodinamiki.

The issues of absorption, bacterial intestinal metabolism and hepatic metabolism of diosmin are described. The main metabolites of the drug and the ways of their elimination are indicated. The article describes the main therapeutic targets and mechanisms of influence on the course of disease including effect on the venous wall tone and permeability, lymphatic drainage, inflammation and oxidative stress.

Protective Effects of Micronized Purified Flavonoid Fraction (MPFF) on a Novel Experimental Model of Chronic Venous Hypertension.

OBJECTIVES: To assess protective effects of micronized purified flavonoid fraction (MPFF) on microcirculation in an original chronic model of hind limb venous hypertension with low blood flow in small animals. METHODS: Vein ligatures were performed on male hamsters, as follows: A-right femoral vein; A + B-right femoral vein and its right branch; A + C-right femoral vein and its left branch; A + B + C-right femoral and its right and left branches; D-external right iliac vein. In sham operated groups, similar vascular dissections were performed without ligatures. Superficial (epigastric) and central (jugular) venous pressure evaluations were made during a 10 week period. Hamsters subjected to A + B + C and D ligatures were selected for leukocyte rolling and sticking, functional capillary density (FCD), and venular and arteriolar diameter observations. D ligature was selected to evaluate pharmacological treatment efficacy. MPFF (100 mg/kg), concomitant active flavonoids of MPFF (diosmetin, hesperidin, linarin, and isorhoifolin) (10 mg/kg), diosmin (100 mg/kg) or drug vehicle were administered orally during 2 weeks before vein ligature and 6 weeks thereafter. RESULTS: A, A + B and A + C models maintained venous return through collaterals. From the 2nd to the 10th weeks after vein ligatures, A + B + C and D models elicited a progressive increase of superficial venous pressure (3.83 ± 0.65 vs. 8.56 ± 0.72 mmHg, p < .001 and 4.13 ± 0.65 vs. 9.35 ± 0.65 mmHg, p < .001, respectively) with significant changes to the microcirculation. As D model significantly increased superficial venous pressure without affecting central venous pressure, it was used to evaluate the long-term effects of treatment. Compared with vehicle, MPFF, concomitant active flavonoids of MPFF, and diosmin, significantly decreased leukocyte-endothelium interaction and prevented FCD reduction. Only MPFF significantly prevented venular enlargement as observed in the vehicle treated group. CONCLUSION: MPFF was more effective than diosmin in improving all microvascular variables. The superiority of MPFF over diosmin alone can be explained by the synergistic beneficial effects of the association between diosmin and active flavonoids of MPFF.

The Benefits of the Citrus Flavonoid Diosmin on Human Retinal Pigment Epithelial Cells under High-Glucose Conditions.

We investigate diosmin for its effect on the ARPE-19 human retinal pigment epithelial cells exposed to high glucose, a model of diabetic retinopathy (DR). After incubation for 4 days with a normal (5 mmol/L) concentration of D-glucose, ARPE-19 cells were exposed separately to normal or high concentrations of D-glucose (30 mmol/L) with or without diosmin at different concentrations (0.1, 1, 10 µg/mL) for another 48 h. Next, we assessed cell viability, reactive oxygen species (ROS) generation and antioxidant enzyme activities. In order to examine the underlying molecular mechanisms, we meanwhile analyzed the expressions of Bax, Bcl-2, total and phosphorylated JNK and p38 mitogen-activated protein kinase (MAPK). Diosmin dose dependently enhanced cell viability following high glucose treatment in ARPE-19 cells. The activities of superoxide dismutase and glutathione peroxidase, as well as the levels of reduced glutathione were decreased, while it was observed that levels of ROS in high glucose cultured ARPE-19 cells increased. High glucose also disturbed Bax and Bcl-2 expression, interrupted Bcl-2/Bax balance, and triggered subsequent cytochrome c release into the cytosol and activation of caspase-3. These detrimental effects were ameliorated dose dependently by diosmin. Furthermore, diosmin could abrogate high glucose-induced apoptosis as well as JNK and P38 MAPK phosphorylation in ARPE-19 cells. Our results suggest that treatment ARPE-19 cells with diosmin halts hyperglycemia-mediated oxidative damage and thus this compound may be a candidate for preventing the visual impairment caused by DR.

Antihyperglycaemic action of diosmin, a citrus flavonoid, is induced through endogenous ß-endorphin in type I-like diabetic rats.

Diosmin is one of the flavonoids contained in citrus and has been demonstrated to improve glucose metabolism in diabetic disorders. However, the mechanism(s) of diosmin in glucose regulation remain obscure. Therefore, we investigated the potential mechanism(s) for the antihyperglycaemic action of diosmin in streptozotocin-induced diabetic rats (STZ-diabetic rats). Diosmin lowered hyperglycaemia in a dose-dependent manner in STZ-diabetic rats. This action was inhibited by naloxone at a dose sufficient to block opioid receptors. Additionally, we determined the changes in plasma ß-endorphin-like immunoreactivity (BER) using enzyme-linked immunosorbent assay (ELISA). Diosmin also increased BER dose-dependently in the same manner. Repeated treatment of STZ-diabetic rats with diosmin for 1 week resulted in an increase in the expression of the glucose transporter subtype 4 (GLUT 4) in the soleus muscle and a reduction in the expression of phosphoenolpyruvate carboxykinase (PEPCK) in the liver. These effects were also inhibited by naloxone at a dose sufficient to block opioid receptors. Bilateral adrenalectomy in STZ-diabetic rats eliminated the actions of diosmin, including both the reduction in hyperglycemia and the elevation of plasma BER. In conclusion, our results suggest that diosmin may act on the adrenal glands to enhance the secretion of ß-endorphin, which can stimulate the opioid receptors to attenuate hepatic gluconeogenesis and increase glucose uptake in soleus muscle, resulting in reduced hyperglycemia in STZ-diabetic rats.

Evaluation of protective effects of diosmin (a citrus flavonoid) in chemical-induced urolithiasis in experimental rats.

Context There have not been any conclusive studies of the effects of diosmin, a modified flavanone glycoside obtained from Teucrium gnaphalodes L'Her (Lamiaceae), on urolithiasis. Objective To evaluate anti-urolithiatic effects of diosmin in ammonium chloride and ethylene glycol-induced renal stone in experimental animals. Materials and methods Thirty Sprague-Dawley were divided into five groups (n=6) receiving the following treatments, respectively, p.o. for 15 consecutive days: distilled water, 0.75% v/v ethylene glycol + 2% w/v ammonium chloride, 0.75% v/v ethylene glycol + 2% w/v ammonium chloride + cystone® 750 mg/kg, 0.75% v/v ethylene glycol + 2% w/v ammonium chloride + diosmin 10 mg/kg or 0.75% v/v ethylene glycol + 2% w/v ammonium chloride + diosmin 20 mg/kg. Different biomarkers of urolithiasis in urine and serum were evaluated and histopathological examination of kidney was done. Results Animals treated with diosmin (both 10 and 20 mg/kg) had significantly (p < 0.005) decreased in kidney weight, urinary pH, total urinary protein, urinary calcium, phosphorus, serum potassium, sodium, magnesium, creatinine, uric acid and blood urea nitrogen levels and significantly (p < 0.005) increased in urinary volume, urinary magnesium, potassium, sodium, creatinine, uric acid and serum calcium levels in comparison to animals treated with ethylene glycol and ammonium chloride. However, results were better with diosmin 20 mg/kg in comparison to the control group. Conclusion Diosmin (10 and 20 mg/kg) has very good anti-urolithiatic activity similar to the standard drug cystone®.

Synergistic effects of diosmetin with erythromycin against ABC transporter over-expressed methicillin-resistant Staphylococcus aureus (MRSA) RN4220/pUL5054 and inhibition of MRSA pyruvate kinase.

Increasing prevalence of methicillin-resistant Staphylococcus aureus (MRSA) worldwide with limited therapeutic options is a growing public health concern. Natural products have been shown to possess antibacterial actions against MRSA. Flavonoids from natural products have been shown to possess antibacterial actions against MRSA by antagonizing its resistance mechanisms. Diosmin and diosmetin are natural flavonoids found in a variety of citrus fruits. The aim of this study was to investigate whether diosmin and diosmetin could inhibit the growth of MRSA and the in vitro enzymatic activity of a newly discovered MRSA drug target, pyruvate kinase (PK). By using a panel of MRSA strains with known resistant mechanisms, neither diosmin nor diosmetin was shown to possess direct antibacterial activities against all tested MRSA strains. However, in checkerboard assay, we found that diosmetin together with erythromycin, could synergistically inhibit the growth of ABC-pump overexpressed MRSA-RN4220/pUL5054, and time kill assay also showed that the antibacterial activities of diosmetin with erythromycin were bactericidal. Diosmetin was further shown to significantly suppress the MRSA PK activities in a dose dependent manner. In conclusion, the inhibition of MRSA PK by diosmetin could lead to a deficiency of ATP and affect the bacterial efflux pump which might contribute to the antibacterial actions of diosmetin against MRSA.