Formulation and evaluation of chitosan-based nanogel for oral delivery of diosmin.

The bioactive flavonoid diosmin (DSN) has a variety of biological activities, excellent therapeutic activity, however, it has a number of biopharmaceutical problems that limit its advantages. The present study aims to develop chitosan-based nanogels (NGs) as drug-delivery platforms for DSN and characterize them using physicochemical methods. DSN-loaded NGs were prepared using the ionic gelation method and particle size (PS), poly-dispersity index (PDI), zeta potential (ZP), loading efficiency (LE) and loading capacity (LC) of 113.07±12.62nm, 0.266±0.08, 22.32± 0.56 mV, 81.56±2.65% and 10.25±1.43% were obtained, respectively. Transmission electron microscopy analysis of DSN-loaded NGs also revealed that the PS ranged from 100 to 200nm, which is comparable to the outcomes of the dynamic light scattering technique. The NGs swelled in pH 6.8 and pH 7.4 buffers and was easily eroded at pH 1.2 and pH 4.5. DSN was released from NGs in acidic buffers by a Fickian process and this release was followed by both swelling and erosion. According to stability experiments, the PS, ZP and PDI at 25oC and 40oC did not significantly change after 90 days. In conclusion, the NGs system proved very effective at delivering DSN orally.

Determination of Diosmin in Pharmaceutical Products with Chemically Modified Voltammetric Sensors.

In this paper, the electrochemical behavior of two types of sensors based on modified screen-printed electrodes (one screen-printed electrode based on carbon (SPCE) and another screen-printed electrode modified with Prussian Blue (PB/SPCE)) was studied with the aim of sensitive detection of diosmin, an active pharmaceutical compound from the class of flavonoids. The scan electron microscopy technique was used for the morphological characterization of PB/SPCE. The preliminary analysis assessed the electrochemical behavior of SPCE and PB/SPCE in KCl solution and in a double solution of potassium ferrocyanide-potassium chloride. It was shown that the active area of PB/SPCE is superior to the one of SPCE, the greater sensitivity being related with the presence of the electroactive modifier. Similarly, in the case of diosmin detection, the PB/SPCE sensor detect more sensitivity the diosmin due to the electrocatalytic effect of PB. From the study of the influence of reaction rate on the sensor's electrochemical response, it was shown that the detection process is controlled by the adsorption process, the degree of surface coverage with electroactive molecules being higher in the case of PB/SPCE. From the PB/SPCE calibration curve, it wasdetermined that it has high sensitivity and low detection and quantification limit values (limit of detection 5.22 × 10-8 M). The applicability of the PB/SPCE sensor was confirmed by sensitive analysis of diosmin in pharmaceutical products. The voltammetric method is suitable for the detection and quantification of diosmin in pharmaceutical products. The method is simple, accurate, and quick and can be used in routine analysis in the examination of the quality of pharmaceutical products and other types of samples.

Repurposing of FDA-approved drugs against active site and potential allosteric drug-binding sites of COVID-19 main protease.

The novel coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) still has serious negative effects on health, social life, and economics. Recently, vaccines from various companies have been urgently approved to control SARS-CoV-2 infections. However, any specific antiviral drug has not been confirmed so far for regular treatment. An important target is the main protease (Mpro ), which plays a major role in replication of the virus. In this study, Gaussian and residue network models are employed to reveal two distinct potential allosteric sites on Mpro that can be evaluated as drug targets besides the active site. Then, Food and Drug Administration (FDA)-approved drugs are docked to three distinct sites with flexible docking using AutoDock Vina to identify potential drug candidates. Fourteen best molecule hits for the active site of Mpro are determined. Six of these also exhibit high docking scores for the potential allosteric regions. Full-atom molecular dynamics simulations with MM-GBSA method indicate that compounds docked to active and potential allosteric sites form stable interactions with high binding free energy (∆Gbind ) values. ∆Gbind values reach -52.06 kcal/mol for the active site, -51.08 kcal/mol for the potential allosteric site 1, and - 42.93 kcal/mol for the potential allosteric site 2. Energy decomposition calculations per residue elucidate key binding residues stabilizing the ligands that can further serve to design pharmacophores. This systematic and efficient computational analysis successfully determines ivermectine, diosmin, and selinexor currently subjected to clinical trials, and further proposes bromocriptine, elbasvir as Mpro inhibitor candidates to be evaluated against SARS-CoV-2 infections.

Thermodynamics of the Interaction between the Spike Protein of Severe Acute Respiratory Syndrome Coronavirus-2 and the Receptor of Human Angiotensin-Converting Enzyme 2. Effects of Possible Ligands.

Since the end of 2019, the coronavirus SARS-CoV-2 has caused more than 1000000 deaths all over the world and still lacks a medical treatment despite the attention of the whole scientific community. Human angiotensin-converting enzyme 2 (ACE2) was recently recognized as the transmembrane protein that serves as the point of entry of SARS-CoV-2 into cells, thus constituting the first biomolecular event leading to COVID-19 disease. Here, by means of a state-of-the-art computational approach, we propose a rational evaluation of the molecular mechanisms behind the formation of the protein complex. Moreover, the free energy of binding between ACE2 and the active receptor binding domain of the SARS-CoV-2 spike protein is evaluated quantitatively, providing for the first time the thermodynamics of virus-receptor recognition. Furthermore, the action of different ACE2 ligands is also examined in particular in their capacity to disrupt SARS-CoV-2 recognition, also providing via a free energy profile the quantification of the ligand-induced decreased affinity. These results improve our knowledge on molecular grounds of the SARS-CoV-2 infection and allow us to suggest rationales that could be useful for the subsequent wise molecular design for the treatment of COVID-19 cases.

Ultrasound-Assisted Extraction of Taxifolin, Diosmin, and Quercetin from Abies nephrolepis (Trautv.) Maxim: Kinetic and Thermodynamic Characteristics.

Extraction behaviors of the 3 flavonoids taxifolin, diosmin, and quercetin have been investigated in Abies nephrolepis leaves and bark. The following operation parameters-ethanol volume fraction, liquid-solid ratio, temperature, ultrasound irradiation power and time, and ultrasound frequency-were varied to study their effect on the yield of the 3 flavonoids during extraction. The results showed that a low extraction efficiency occurred at 293.15 K due to slow kinetics, while the situation was significantly improved at 333.15 K. The kinetic data for the extraction yields of the 3 flavonoids achieved good fits by the first-order kinetic model. From the thermodynamic analysis results, we realized that the ultrasound-assisted extraction of taxifolin, diosmin, and quercetin from the leaves and bark of A. nephrolepis was a spontaneous and endothermic process in which the disorder increased (ΔG0 < 0, ΔH0 > 0, and ΔS0 > 0). According to the response surface methodology (RSM) analysis, under the optimal operation conditions (ethanol concentration of 50%, liquid-solid ratio of 20 mL/g, frequency of 45 kHz, extraction time of 39.25 min, ultrasound irradiation power of 160 W and temperature of 332.19 K), the total yield of the 3 flavonoids were 100.93 ± 4.01 mg/g from the leaves of A. nephrolepis (with 31.03 ± 1.51 mg/g, 0.31 ± 0.01 mg/g, 69.59 ± 2.57 mg/g for taxifolin, diosmin, and quercetin, respectively), and under the optimal operation conditions (ethanol concentration of 50%, liquid-solid ratio of 20 mL/g, frequency of 45 kHz, extraction time of 36.80 min, ultrasound irradiation power of 150 W and temperature of 328.78 K), 16.05 mg/g ± 0.38 mg/g were obtained from the bark of A. nephrolepis (with 1.44 ± 0.05 mg/g, 0.47 ± 0.01 mg/g, 14.14 ± 0.38 mg/g for taxifolin, diosmin, and quercetin, respectively), which were close to the prediction values.

Preparation, evaluation and pharmacokinetics of diosmin herbosome in beagle dogs.

Diosmin is one of the most widely used phlebotonic drugs, but its poor bioavailability has restricted its usage. The aim of this study was to formulate a complex Diosmin with phospholipids (75% in PC, in 1:2 molar ratios) and to evaluate for solubility, drug content, X-ray diffraction (XRD), differential scanning calorimetry (DSC) and in vitro dissolution study. Further to test the bioavailability of both the complex and Alvenor⌖ in beagle dogs and compare pharmacokinetic parameters. Diosmin herbosome was found to be more soluble than both pure diosmin and Alvenor⌖. The complex contained 71.94% drug content. DSC thermograms and XRD also proved the claim of the complexation. The dissolution profile of diosmin herbosome and Alvenor⌖ in water-ethanol medium showed an increase of the dissolution for diosmin herbosome. Comparison of plasma concentration and main pharmacokinetic parameters of diosmin herbosome treated and Alvenor⌖ treated dogs showed a higher Cmax for the complex with longer elimination half-life. The complexation of diosmin with phospholipids can be potentially used in enhancing the absorption and solubility, consequently increasing the bioavailability of the drug.

Role of Diosmin in protection against the oxidative stress induced damage by gamma-radiation in Wistar albino rats.

The benchmark of this study is to evaluate the radio protective efficiency of diosmin, a natural citrus flavone of hesperidin derivative on radiation-induced damage in wistar albino rats. Rats orally administered two diosmin doses (100 and 200 mg/kg body wt.) for a month (every other day) prior to exposure to high gamma radiation single dose (8Gy) or cumulative dose (10Gy). To evaluate the radio protective efficiency of diosmin various biochemical estimations, histopathological alterations as well as comet assay and caspase-3 activity for assessment of apoptosis were performed. Results indicated that radiation-induced decline in the levels of antioxidant parameters (SOD and GSH), increased lipid peroxidation, DNA damage and apoptosis were improved by pre-administration of diosmin. Diosmin dose (200 mg/kg body wt.) restored the antioxidant status to near normal and reduced lipid peroxidation, DNA and tissue damage. These results were confirmed by histopathological examinations, which showed that pre-administration of diosmin protected the liver and kidney of albino rats against gamma-irradiation induced damage. Hence, it has been illustrated that diosmin might be an effective radio protector against radiation-induced damage in rats. Moreover, diosmin alone pretreated group did not show any biochemical alterations or DNA damage indicating the protective nature of the drug.

Combating atherosclerosis with targeted Diosmin nanoparticles-treated experimental diabetes.

Diabetes with poor glycemic control is accompanying with an increased risk of disease namely atherosclerotic cardiovascular. Diosmin (DSN), which is obtained from citrus fruit used to assist the treatment of hemorrhoids or chronic venous atherosclerosis diseases, has an antioxidant, anti-hyperglycemic and anti-inflammatory effect. DSN is characterized by poor water solubility which limits its absorption by the gastrointestinal tract. To overcome this limitation, this study was designed to increase DSN bioavailability and solubility, through its loading on polymeric matrix; hydroxypropyl starch (HPS) and Poly lactide-glycolide-chitin (PLGA/chitin) to prepare Diosmin nanoparticles (DSN-NPs). Two methods were used to prepare DSN- NPs; Emulsion-solvent evaporation and Acid-base neutralization followed by further assessment on diabetes induced atherosclerosis The study was conducted on 50 animals assigned into 5 groups with 10 animals in each group: Group I: Normal rats received only normal saline, Group II: Diabetic rats, Group III: diabetic rats received oral DSN, Group IV: diabetic rats received DSN loaded HPS, Group V: diabetic rats received DSN loaded PLGA/chitin. Levels of total cholesterol, triglycerides, HDL-cholesterol, insulin, MDA and NO. plasminogen activator inhibitor-1 PAI-1), Paraoxonase-1(PON1), transforming growth factor-ß1 (TGF-ß1), NF-Ò¡B and Ang II were estimated. Our study revealed that, there was statistically significant difference between DSN treated group compared with DSN loaded HPS treated group and DSN loaded PLGA/chitin. Furthermore, the results obtained clearly disclosed no statistically significant difference between DSN loaded PLGA/chitin and control group exhibited DSN loaded PLGA/chitin has the higher ability to counteract the atherosclerosis factors induced by diabetes in all rats.

Diosmin Nanocrystal-Loaded Wafers for Treatment of Diabetic Ulcer: In Vitro and In Vivo Evaluation.

This work aimed at loading of diosmin nanocrystals into alginate-based wafers for treatment of highly exuding diabetic ulcer in rats using topical route of administration. For this purpose, different formulation variables and preparation techniques to enhance the flexibility and adhesion properties of the prepared sodium alginate (SA) wafers were carried out. The prepared wafers were characterized regarding hydration capacity, bioadhesion, scanning electron microscope, and Fourier-transform infrared spectroscopy. Efficacy of treating diabetic ulcer was studied using diabetic-induced rat model using streptozotocin. Results obtained showed that using SA:gelatin with 1.5%/1.5% w/w gave acceptable wafers with a sustained release of diosmin over 8 h. A complete re-epithelialization, well-organized dermal layers, well-formed granulation tissue, and mature collagen bundles were observed in treated rats. It was concluded that combination of gelatin with SA provided an excellent wafer as a promising medicated wound dressing holding diosmin nanocrystals while maintaining its stability.

Comparative Bioavailability of Two Diosmin Formulations after Oral Administration to Healthy Volunteers.

Diosmin is a flavonoid commonly found in citrus fruits, largely used as adjuvant treatment for circulatory disorders, including chronic venous insufficiency (CVI) and hemorrhoids. Following oral administration, diosmin is not directly absorbed but must first be hydrolyzed into its aglycone, diosmetin, which is then absorbed into the systemic circulation. The aim of the current cross-over clinical study was to assess the pharmacokinetic profile of µSmin® Plus, a micronized diosmin flavonoid complex standardized in diosmin and formulated with a buffering agent (tested formulation). The study compared this to unformulated micronized diosmin (reference), in 16 healthy volunteers. Plasma samples were analyzed by HPLC-MS and plasma diosmetin concentration was measured after deconjugation with ß-glucuronidase. For the tested formulation area under the curve (AUC0-t), and maximum plasma and time concentration (Cmax; tmax) were found to be 298.4 ± 163.7, 50.3 ± 22.6 and 2.2 ± 2.9, respectively. AUC0-t and Cmax of the reference were 31.9 ± 100.4 and 2.4 ± 1.9, respectively. The tested formulation showed higher plasmatic concentrations of diosmetin in comparison to those obtained after the administration of unformulated micronized diosmin. The relative bioavailability was 9.4 greater for the tested formulation than in micronized diosmin. In conclusion, our data indicate that µSmin® Plus was rapidly and well absorbed into systemic circulation and may therefore be ideally suitable to deliver diosmin in human interventional trials.

In vitro effects of diosmin, naringenin, quercetin and indole-3-carbinol on fish hepatic CYP1A1 in the presence of clotrimazole and dexamethasone.

Phytochemicals are widely present in fruits, vegetables and other plants and have great health benefits owing to their antioxidant properties. They are naturally found in the aquatic environment as well as discharged from sewage treatment plants after their large consumption. Little is known about their impact on fish; particularly in light of their interactions with pharmaceuticals. Therefore, this study was designed to determine the effects of diosmin, naringenin, quercetin and idole-3-carbinol on CYP1A-dependent 7-ethoxyresorufin-O-deethylase (EROD) activity on rainbow trout hepatic microsomes in the presence of two pharmaceuticals: clotrimazole and dexamethasone. The interactions between the phytochemicals and pharmaceuticals used in this study were determined using a combination index. Hepatic microsomes were exposed to two concentrations (1-or 50 µM) of phytochemicals and pharmaceuticals separately and in combinations. Singly, clotrimazole inhibited EROD activity 40% and 90% of control, while dexamethasone did not. Naringenin and diosmin inhibited EROD activity alone up to 90% and 55% respectively, but activities were further inhibited in the presence of either pharmaceutical. The preliminary study of combinations of clotrimazole with phytochemicals primarily showed synergistic effects. While EROD activity was not inhibited in the presence of quercetin or indole-3-carbinol, significant and synergistic inhibition was detected when either of these was combined with clotrimazole or dexamethasone.

Spectroscopic and structural studies of the diosmin monohydrate and anhydrous diosmin.

Diosmin, a flavone glycoside frequently used in therapy of various veins diseases in monohydrate form, exhibits poor solubility in water and low bioavailability. Due to the fact that the anhydrous forms of drugs generally have better bioavailability than the corresponding hydrates, the aim of this study was to analyze the conversion of diosmin monohydrate (DSNM) to anhydrous diosmin (DSNA) that occurs upon heating. The mechanism of this transformation was examined as well as advanced structural studies of each form were performed using 13C CP/MAS SSNMR, DSC, FT-IR and PXRD techniques. Spectroscopic findings were supported by CASTEP-DFT calculations of NMR and IR parameters. The pathway of reversible transformation was specified as follows: DSNM upon heating for 24h at temperature up to 110°C losses non-crystalline water and converts into metastable form (DSNM*) that turns into DSNA during heating at temperature 140°C for next 24h. Under room temperature DSNA spontaneously absorbs moisture from air and turns into a DSNM within 72h. The detailed analysis of CP kinetic parameters (T1ρI) revealed presence of metastable, intermediate form of diosmin (DSNM*) and allowed its characterization. The results are essential for further studies comparing dissolution and bioavailability of DSNM and DSNA. The study provided an understanding of the conversion pathway of the diosmin monohydrate into its anhydrate form when it is exposed to increased temperature.

Diosmin/essential oil combination for dermal photo-protection using a lipoid colloidal carrier.

Solar irradiation induces skin inflammatory processes causing deleterious effects like premature ageing. In this study, the designed lipoid colloidal carrier (LCC) was loaded with Diosmin in combination with different essential oils, to be used as a topical photo-protective preparation. To investigate the ability of the essential oils to potentiate Diosmin effects, the Diosmin/essential oil-loaded LCCs (LCC2, LCC3 and LCC4) were compared to the Diosmin-loaded LCC (LCC1). The incorporated essential oils were those of Rosmarinus officinalis, Zingiber officinale or Vitis vinifera in LCC2, LCC3 and LCC4, respectively. All the LCCs had particle size (PS) values ranging from 121.1 to 144.3nm with uniform distribution and, zeta potential (Z) values around 30mV. Also, they all had high drug encapsulation efficiencies. LCC1 had the lowest anti-oxidant and in-vitro sun-blocking effect (p<0.05). In-vivo photo-protective studies showed that all the formulated LCCs had a skin protective effect when compared to the positive control (p<0.05); however LCC1 had the lowest anti-erythemal and anti-wrinkling effect. Histological studies proved the efficacy of the designed LCCs as skin anti-photoageing, with LCC1 showing the lowest anti-inflammatory and anti-wrinkling effect, while LCC2 had the highest anti-wrinkling effect. These results indicated that the suggested Diosmin/essential oil combinations improved the anti-oxidant, sun-blocking and anti-photoageing effects of Diosmin. After one year of storage, the LCCs showed satisfactory physical stability. This study presents the designed LCCs as safe and effective nano-structured dermal care products containing 'all-natural' components.

Pharmacokinetic Profile of µSMIN Plus™, a new Micronized Diosmin Formulation, after Oral Administration in Rats.

Diosmin is a naturally occurring flavonoid present in citrus fruits and other plants belonging to the Rutaceae family. It is used for the treatment of chronic venous insufficiency (CVI) for its pheblotonic and vaso-active properties, safety and tolerability as well. The aim of the current in vivo study was to investigate the pharmacokinetic profile of a branded micronized diosmin (µSMIN Plus™) compared with plain micronized diosmin in male Sprague-Dawley rats. After oral administration by gastric gavage, blood samples were collected via jugular vein catheters at regular time intervals from baseline up to 24 hours. Plasma concentrations were assessed by LC/MS. For each animal, the following pharmacokinetic parameters were calculated using a non-compartmental analysis: maximum plasma drug concentration (Cmax), time to reach Cmax (Tmax), area under the plasma concentration-time curve (AUC0-last), elimination half-life (t½), and relative oral bioavailability (%F). The results of the current study clearly showed an improvement in the pharmacokinetic parameters in animals treated with µSMIN Plus™ compared with animals treated with micronized diosmin. In particular, µSMIN Plus™ showed a 4-fold increased bioavailability compared with micronized diosmin. In conclusion, the results from the current study provided a preliminary pharmacokinetic profile for µSMIN Plus™, which may represent a new tool for CVI management.

Effects of Citrus Flavonoids Against Microvascular Damage Induced by Hypoperfusion and Reperfusion in Rat Pial Circulation.

OBJECTIVE: The aim of the present study was to investigate the in vivo protective effects of hesperidin or diosmin or apigenin on damage induced by transient BCCAO and reperfusion. METHODS: Rat pial microcirculation was observed through a closed cranial window, using fluorescence microscopy. Pial arterioles were classified in five orders according to the Strahler's method. RESULTS: After 30 BCCAO and 60 minutes reperfusion, rats showed decreased arteriolar diameter, microvascular leakage, leukocyte adhesion, and reduction in capillary perfusion. Hesperidin and diosmin abolished the reduction in arteriolar diameter, while higher dose apigenin induced dilation by 21.7 ± 2.0% in order three arterioles RE. Nitric oxide synthase inhibition attenuated significantly hesperidin or diosmin or apigenin's effects on arteriolar diameter. Moreover, all these substances reduced microvascular leakage as well as leukocyte adhesion in dose-related manner, while capillary perfusion was protected. Furthermore, reduction in infarcted area and decrease in ROS production were observed. CONCLUSIONS: Hesperidin, diosmin, and apigenin showed dose-related protective effects on hypoperfusion-reperfusion injury, causing nitric oxide release and attenuating tissue edema and leukocyte adhesion.

Electrospinning of diosmin from aqueous solutions for improved dissolution and oral absorption.

A nanofibrous membrane carrier for nearly water insoluble drug diosmin was formulated. The aim of this study was to evaluate the drug release and dissolution properties in an aqueous buffer of pH 7.8, and to compare the suitability of the drug carrier with the available drug forms and screen diosmin absorption extent. The membranes were produced from HPC/PVA/PEO-drug water solutions and then evaluated by SEM and DSC measurements. The results showed that diosmin was incorporated within the nanofibers in an amorphous state, and/or as a solid dispersion. The results of in vitro release experiments excerpt a very fast release of the drug, followed by the formation of an over saturated solution and partial precipitation of the drug (a "spring" effect). The enormous increases in dissolution of the drug from a nanofibrous carrier, compared to a micronized and crystalline form, was achieved. The in vivo bioavailability study carried out on rats showed higher initial drug plasma levels and higher AUC values after administration of the nanofibrous drug formulation, compared to the micronized form. The results of the study demonstrated that the improvement of the diosmin in vitro dissolution also brought the enhanced in vivo absorption extent of the drug.

Development of novel polymer-stabilized diosmin nanosuspensions: in vitro appraisal and ex vivo permeation.

Scanty solubility and permeability of diosmin (DSN) are perpetrators for its poor oral absorption and high inter-subject variation. This article investigated the potential of novel DSN nanosuspensions to improve drug delivery characteristics. Bottom-up nanoprecipitation technique has been employed for nanosuspension development. Variables optimized encompassed polymeric stabilizer type, DSN: stabilizer ratio, excess stabilizer removal, spray drying, and mannitol incorporation. In vitro characterization included particle size (PS), infrared spectroscopy (IR), differential scanning calorimetry (DSC), X-ray powder diffraction (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM), and dissolution profile. Ex vivo permeation was assessed in rats using non-everted sac technique and HPLC. Optimal DSN nanosuspension (DSN:hydroxypropylmethyl cellulose HPMC 2:1) was prepared with acid base neutralization technique. The formula exhibited the lowest PS (336 nm) with 99.9% drug loading and enhanced reconstitution properties after mannitol incorporation. SEM and TEM revealed discrete, oval drug nanocrystals with higher surface coverage with HPMC compared to MC. DSN nanosuspension demonstrated a significant enhancement in DSN dissolution (100% dissolved) compared to crude drug (51%). Permeation studies revealed 89% DSN permeated from the nanosuspension after 120 min compared to non-detected amounts from drug suspension. Conclusively, novel DSN nanosuspension could successful improve its dissolution and permeation characteristics with promising consequences of better drug delivery.

Diosmin binding to human serum albumin and its preventive action against degradation due to oxidative injuries.

Diosmin is a glycosylated polyphenolic compound, commonly found in fruits and vegetables, which is utilized for the pharmacological formulation of some drugs. The interactions of diosmin to human serum albumin have been investigated by fluorescence, UV-visible, FTIR spectroscopy, native electrophoresis and protein-ligand docking studies. The fluorescence studies indicate that the binding site of the additive involves modifications of environment around Trp214 at the level of subdomain IIA. Combining the curve-fitting results of infrared Amide I' band, the modifications of protein secondary structure have been estimated, indicating a decrease in α-helix structure following flavonoid binding. Data obtained by fluorescence and UV-visible spectroscopy, FTIR experiments and molecular modeling afforded a clear picture of the association mode of diosmin to HSA, suggesting that the primary binding site of diosmin is located in Sudlow's site I. Computational mapping confirms this observation suggesting that the possible binding site of diosmin is located in the hydrophobic cavity of subdomain IIA, whose microenvironment is able to help and stabilize the binding of the ligand in non-planar conformation. Moreover the binding of diosmin to HSA significantly contributes to protect the protein against degradation due to HCLO and Fenton reaction.

Lyophilized phytosomal nanocarriers as platforms for enhanced diosmin delivery: optimization and ex vivo permeation.

Diosmin (DSN) is an outstanding phlebotonic flavonoid with a tolerable potential for the treatment of colon and hepatocellular carcinoma. Being highly insoluble, DSN bioavailability suffers from high inter-subject variation due to variable degrees of permeation. This work endeavored to develop novel DSN loaded phytosomes in order to improve drug dissolution and intestinal permeability. Three preparation methods (solvent evaporation, salting out, and lyophilization) were compared. Nanocarrier optimization encompassed different soybean phospholipid (SPC) types, different solvents, and different DSN:SPC molar ratios (1:1, 1:2, and 1:4). In vitro appraisal encompassed differential scanning calorimetry, infrared spectroscopy, particle size, zeta potential, polydispersity index, transmission electron microscopy, drug content, and in vitro stability. Comparative dissolution studies were performed under sink versus non-sink conditions. Ex vivo intestinal permeation studies were performed on rats utilizing noneverted sac technique and high-performance liquid chromatography analysis. The results revealed lyophilization as the optimum preparation technique using SPC and solvent mixture (Dimethyl sulphoxide:t-butylalchol) in a 1:2 ratio. Complex formation was contended by differential scanning calorimetry and infrared data. Optimal lyophilized phytosomal nanocarriers (LPNs) exhibited the lowest particle size (316 nm), adequate zeta-potential (-27 mV), and good in vitro stability. Well formed, discrete vesicles were revealed by transmission electron microscopy, drug content, and in vitro stability. Comparative dissolution studies were performed. LPNs demonstrated significant enhancement in DSN dissolution compared to crude drug, physical mixture, and generic and brand DSN products. Permeation studies revealed 80% DSN permeated from LPNs via oxygenated rat intestine compared to non-detectable amounts from suspension. In this study, LPNs (99% drug loading) could be successfully tailored for DSN with improved dissolution and permeation characteristics, which is promising for lowering the influence of exogenous factors and increasing drug delivery.

[Study on chemical constituents of Hyssopus cuspidatus].

OBJECTIVE: To study the chemical constituents of Hyssopus cuspidatus. METHODS: Compounds were isolated and purified by extraction and different kinds of column chromatography. Their structures were determined on the basis of the physicochemical properties and spectral analysis. RESULTS: Six compounds were identified as caffeic acid methyl ester (1), luteolin 7-O-alpha-L-rhamnopyranosyl (1 --> 6)-beta-D-glucopyranoside (2), luteolin 7-O-beta-D-glucuronide (3), diosmin (4), acacetin 7-O-alpha-L-rhamnopyranosyl(1 --> 6)-beta-D-glucopyranoside (5) and rosmarinic acid (6). CONCLUSION: Compounds 1, 4 and 6 are isolated from this plant for the first time, and compounds 2, 3 and 5 are firstly obtained from Hyssopus genus.