Development and characterization of polysiloxane-based gel loaded with phytoingredients encapsulated in phytosomes for scar management.

Recent research has emphasized the development of efficient drug delivery systems to facilitate the delivery of biological compounds such as polyphenols via skin absorption. Phytozomes have been employed as carriers of plant compounds in this context Hydrogen bonding between plant polyphenols and the phospholipid phosphate group enables efficient encapsulation of potent compounds for enhanced drug delivery systems. Additionally, the strong affinity of phytosomes for the skin's phospholipids enhances skin absorption. In this study, phytosomes were initially formulated using the thin-layer hydration method After optimizing the synthetic parameters, phytosomes were loaded with Resveratrol and Quercetin for enhanced delivery and skin absorption potential to assess the characteristics of the synthesized phytosomes, tests were conducted to determine particle distribution and size, zeta potential, and examine the microstructure morphology using a scanning electron microscope (SEM). Furthermore, a siloxane gel base was formulated in this study, and the stability of the physicochemical and biological properties of the final prepared nanoformulation was investigated. The results of this study indicated that the formulated phytosomes exhibit optimal characteristics for facilitating high skin penetration of resveratrol and quercetin. A high skin absorption was observed after 60 days of synthesis. Additionally, the base of the siloxane gel can play a significant role in preventing the formation of scars by reducing the passage of water vapor.

Quercetin nanocrystals for bioavailability enhancement: impact of different functional stabilizers on in vitro/in vivo drug performances.

The purpose of this study was to investigate the impact of different functional stabilizers on in vitro/in vivo drug performances after oral administration of drug nanocrystals. Quercetin nanocrystals (QT-NCs) respectively stabilized by five types of functional stabilizers, including hydroxypropyl methyl cellulose E15 (HPMC E15), poloxamer 407 (P407), poloxamer 188 (P188), D-α-tocopherol polyethylene glycol succinate (TPGS), and glycyrrhizin acid (GL), were fabricated by wet media milling technique. The particle size, morphology, physical state, drug solubility, drug dissolution in vitro, and orally pharmacokinetic behaviors of all QT-NCs were investigated. All QT-NCs with similar particle size about 200 nm were obtained by controlling milling speed and milling time. No significant differences in particles shape and crystalline nature were found for QT-NCs stabilized by different functional stabilizers. But the solubility and dissolution of QT-NCs were significantly influenced by the different functional stabilizers. The AUC0∼t of all QT-NCs after oral administration was in the following order: QT-NCs/P188 ≈ QT-NCs/HPMC E15 > QT-NCs/GL > QT-NCs/P407 ≈ QT-NCs/TPGS, and the Cmax showed an order of QT-NCs/P407 > QT-NCs/P188 ≈ QT-NCs/GL > QT-NCs/HPMC E15 > QT-NCs/TPGS. Both of QT-NCs/P407 and QT-NCs/TPGS exhibited faster oral absorption with Tmax at 0.5 h and 0.83 h, respectively, while the other three QT-NCs (QT-NCs/P188, QT-NCs/GL and QT-NCs/HPMC E15) showed a relatively slow absorption with same Tmax at 5.33 h. The longest MRT0∼t (11.72 h) and t1/2z (32.22 h) were observed for QT-NCs/HPMC E15. These results suggested that the different functional stabilizers could significantly influence on drug solubility, drug dissolution in vitro and orally pharmacokinetic behavior of QT-NCs, and it is possible to alter the drug dissolution in vitro, oral absorption and drug retention in vivo by changing the type of functional stabilizers in NCs preparation.

Highly functionalized pH-triggered supramolecular nanovalve for targeted cancer chemotherapy.

Chemotherapeutic drug delivery systems are commonly limited by their short half-lives, poor bioavailability, and unsuccessful targetability. Herein, pH-responsive hybrid NPs consist of benzimidazole-coated mesoporous silica nanoparticles (BZ-MSN) loaded with naturally occurring flavonoid quercetin (QUE-BZ-MSN). The NPs were further capped with beta-cyclodextrin (BCD) to obtain our desired BCD-QUE-BZMSN, with a zeta potential around 7.05 ± 2.37 mV and diameter about 115.2 ± 19.02 nm. The abundance of BZ onto the nanoparticles facilitates targeted quercetin chemotherapy against model lung and liver cancer cell lines. FTIR, EDX, and NMR analyses revealed evidence of possible surface functionalizations. Powder XRD analysis showed that our designed BCD-QUE-BZMSN formulation is amorphous in nature. The UV and SEM showed that our designed BCD-QUE-BZMSN has high drug entrapment efficiency and a nearly spherical morphology. In vitro, drug release assessments show controlled pH-dependent release profiles that could enhance the targeted chemotherapeutic response against mildly acidic regions in cancer cell lines. The obtained BCD-QUE-BZMSN nanovalve achieved significantly higher cytotoxic efficacy as compared to QUE alone, which was evaluated by in vitro cellular uptake against liver and lung cancer cell lines, and the cellular morphological ablation was further confirmed via inverted microscopy. The outcomes of the study imply that our designed BCD-QUE-BZMSN nanovalve is a potential carrier for cancer chemotherapeutics.

Pharmacokinetics of Dihydroquercetin after Single and Repeated Administration to Rats.

The pharmacokinetic properties of dihydroquercetin (DHQ) were studied after single and repeated (for 3 days) administration to rats in the form of a starch suspension at a dose of 25 mg/kg. Blood samples were collected using a permanent catheter in the jugular vein in 2, 5, 10, 20, and 30 min and in 1, 2, 4, and 6 h after administration. Before the repeated administration (5 min), blood sample was collected to assess the concentration of DHQ at the zero time point. Quantitative analysis was carried out by HPLC-tandem mass spectrometry. DHQ was very quickly absorbed by the gastrointestinal tract and quickly eliminated from the body. Repeated administration of DHQ did not lead to its accumulation in the body but had an effect on the enzymatic system with a subsequent increase in DHQ exposure (accumulation factor >1 by AUC after repeated administration).

Quercetin attenuates metastatic ability of human metastatic ovarian cancer cells via modulating multiple signaling molecules involved in cell survival, proliferation, migration and adhesion.

Ovarian cancer is the most deadly gynaecology related cancer due to its high metastasizing ability. Quercetin is the most abundant flavonoids received increased interest due to its anti-cancer properties. Although the anticancer property of quercetin is very well known, its anti-metastatic effect on metastatic ovarian cancer cells and their underlying molecular mechanism remains to be elucidated. Quercetin treatment at 50 µM and 75 µM concentration inhibit human metastatic ovarian cancer PA-1 cell survival and proliferation via inactivating PI3k/Akt, Ras/Raf pathways and EGFR expression. It also alters the expression of N-cadherin in PA-1 cells. Quercetin also decreases the secretion of gelatinase enzyme, proteolytic activity of MMP-2/-9, and both MMPs gene expression in metastatic ovarian cancer PA-1 cells. In addition to this quercetin inhibits the migration of PA-1 cells. Treatment of quercetin with PA-1 cells also downregulates the tight junctional molecules such as Claudin-4 and Claudin-11 while upregulates the expression of occludin. It is further validated by cell adhesion assay in which quercetin reduces the adhesion of PA-1 ovarian cancer cells. Results suggest that quercetin inhibits cell survival, proliferation, migration, and adhesion which plays crucial role in ovarian cancer metastasis. Hence, it could be a valuable therapeutic drug for the treatment and prevention of metastatic ovarian cancer.

Untargeted metabolomics reveals the mechanism of quercetin enhancing the bioavailability of ticagrelor.

Ticagrelor is a first-line clinical drug for the treatment of acute coronary syndrome, but its oral bioavailability is relatively low. Flavonoids (polyphenol compounds commonly found in plant foods) seriously affect human metabolism and health. This study compared the effects of quercetin, luteolin and catechin on the pharmacokinetic parameters of ticagrelor and found that quercetin can significantly increase the Cmax and area under the curve from time zero to 36 h (AUC0-36 ) of ticagrelor, that is, quercetin can enhance the bioavailability of ticagrelor, but luteolin and catechin cannot. The difference between the ticagrelor group and the combination of quercetin and ticagrelor was analyzed through untargeted metabolomics methods and multivariate data analysis, which identified changes in the levels of seven metabolites (deoxycholic acid, taurocholic acid, glycocholic acid, glycoursodeoxycholic acid, tryptophan, phenylalanine and kynurenine). Based on the changes of these metabolites, we found that the metabolic pathways of phenylalanine, tyrosine and tryptophan and the biosynthetic pathway of bile acids were changed. A metabolomics study revealed that quercetin improves the oral bioavailability of ticagrelor and that this might rely on changing the metabolic pathways of phenylalanine, tyrosine and tryptophan and the biosynthetic pathway of bile acids. The research results at the metabolic level provide us with a strong basis and direction for further exploring the mechanism underlying quercetin's ability to enhance the bioavailability of ticagrelor, and this may be useful for finding new agents that enhance the bioavailability.

Improving gallic acid and quercetin bioavailability by polymeric nanoparticle formulation.

The anticancer activity and pharmacokinetic properties of encapsulated polyherbal nanoparticles (gallic acid (GA) and quercetin nanocomposite) and polyherbal extract (amla and pomegranate fruit peels) in normal and DMH-induced colorectal cancer in rats were examined in this work. In normal and DMH-induced rats, a pharmacokinetic study demonstrated that polyherbal nanoparticles had a typical sustained release profile with a fourfold increase in bioavailability when compared to polyherbal extract. Based on serum-concentration profiles of polyherbal nanoparticles and polyherbal extract following oral administration, the pharmacokinetic parameters for polyherbal nanoparticles and polyherbal extract were established using a single compartmental approach. This research suggests that encapsulating GA and quercetin in polymeric nanoparticles improves their oral bioavailability and anti-colon cancer efficacy. Polymeric nanoparticles could be a novel therapeutic possibility for carcinogenesis prevention.

Rp-HPLC Determination of Quercetin in a Novel D-α-Tocopherol Polyethylene Glycol 1000 Succinate Based SNEDDS Formulation: Pharmacokinetics in Rat Plasma.

Despite its proven efficacy in diverse metabolic disorders, quercetin (QU) for clinical use is still limited because of its low bioavailability. D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS) is approved as a safe pharmaceutical adjuvant with marked antioxidant and anti-inflammatory activities. In the current study, several QU-loaded self-nanoemulsifying drug delivery systems (SNEDDS) were investigated to improve QU bioavailability. A reversed phase high performance liquid chromatography (RP-HPLC) method was developed, for the first time, as a simple and sensitive technique for pharmacokinetic studies of QU in the presence of TPGS SNEDDS formula in rat plasma. The analyses were performed on a Xterra C18 column (4.6 × 100 mm, 5 µm) and UV detection at 280 nm. The analytes were separated by a gradient system of methanol and phosphate buffer of pH 3. The developed RP-HPLC method showed low limit of detection (LODs) of 7.65 and 22.09 ng/mL and LOQs of 23.19 and 66.96 ng/mL for QU and TPGS, respectively, which allowed their determination in real rat plasma samples. The method was linear over a wide range, (30-10,000) and (100-10,000) ng/mL for QU and TPGS, respectively. The selected SNEDDS formula, containing 50% w/w TPGS, 30% polyethylene glycol 200 (PEG 200), and 20% w/w pumpkin seed oil (PSO), showed a globule size of 320 nm and -28.6 mV zeta potential. Results of the pharmacokinetic studies showed 149.8% improvement in bioavailability of QU in SNEDDS relative to its suspension. The developed HPLC method proved to be simple and sensitive for QU and TPGS simultaneous determination in rat plasma after oral administration of the new SNEDDS formula.

Preparation and Biophysical Characterization of Quercetin Inclusion Complexes with ß-Cyclodextrin Derivatives to be Formulated as Possible Nose-to-Brain Quercetin Delivery Systems.

Quercetin (Que) is a flavonoid associated with high oxygen radical scavenging activity and potential neuroprotective activity against Alzheimer's disease. Que's oral bioavailability is limited by its low water solubility and extended peripheral metabolism; thus, nasal administration may be a promising alternative to achieve effective Que concentrations in the brain. The formation of Que-2-hydroxypropylated-ß-cyclodextrin (Que/HP-ß-CD) complexes was previously found to increase the molecule's solubility and stability in aqueous media. Que-methyl-ß-cyclodextrin (Que/Me-ß-CD) inclusion complexes were prepared, characterized, and compared with the Que/HP-ß-CD complex using biophysical and computational methods (phase solubility, fluorescence and NMR spectroscopy, differential scanning calorimetry (DSC), and molecular dynamics simulations (MDS)) as candidates for the preparation of nose-to-brain Que's delivery systems. DSC thermograms, NMR, fluorescence spectroscopy, and MDS confirmed the inclusion complex formation of Que with both CDs. Differences between the two preparations were observed regarding their thermodynamic stability and inclusion mode governing the details of molecular interactions. Que's solubility in aqueous media at pH 1.2 and 4.5 was similar and linearly increased with both CD concentrations. At pH 6.8, Que's solubility was higher and positively deviated from linearity in the presence of HP-ß-CD more than with Me-ß-CD, possibly revealing the presence of more than one HP-ß-CD molecule involved in the complex. Overall, water solubility of lyophilized Que/Me-ß-CD and Que/HP-ß-CD products was approximately 7-40 times and 14-50 times as high as for pure Que at pH 1.2-6.8. In addition, the proof of concept experiment on ex vivo permeation across rabbit nasal mucosa revealed measurable and similar Que permeability profiles with both CDs and negligible permeation of pure Que. These results are quite encouraging for further ex vivo and in vivo evaluation toward nasal administration and nose-to-brain delivery of Que.

Impact of quercetin on pharmacokinetics of quetiapine: insights from in-vivo studies in wistar rats.

Quercetin (QCN) is commonly used in high doses as a dietary supplement for weight loss. Psychotic patients are at greater risk of developing obesity than the general population. The present study was designed to understand the impact of QCN on the exposure of quetiapine (QTE), an anti-psychotic drug with narrow therapeutic index and brain penetrating capability. The content of QTE in rat plasma was analyzed through liquid chromatography-tandem mass spectrometry. The results showed a significant (p < 0.05) increase in exposure of QTE (peroral dosed) in the animals pre-treated with QCN as compared to the control group. All the animals pre-treated with QCN, succumbed to death within 3-5 min of intravenous dosing of QTE (1 mg/kg). The studies in rat liver S9 fraction indicated that QCN could increase the metabolic stability of QTE by inhibiting the activity of CYP enzymes. The brain to plasma ratio of QTE increased upon QCN pre-treatment (2.6 vs 7.7), which could be attributed to P-glycoprotein inhibition at the blood-brain barrier by QCN. The current set of studies indicated that serious herb-drug interaction between QCN and QTE might occur when they are co-administered. Caution is advised for concomitant use of QCN rich dietary supplements with QTE.

Quercetin in Animal Models of Alzheimer's Disease: A Systematic Review of Preclinical Studies.

Alzheimer's disease (AD) is the leading cause of dementia worldwide. It involves progressive impairment of cognitive function. A growing number of neuroprotective compounds have been identified with potential anti-AD properties through in vitro and in vivo models of AD. Quercetin, a natural flavonoid contained in a wide range of plant species, is repeatedly reported to exert neuroprotective effects in experimental animal AD models. However, a systematic analysis of methodological rigor and the comparison between different studies is still lacking. A systematic review uses a methodical approach to minimize the bias in each independent study, providing a less biased, comprehensive understanding of research findings and an objective judgement of the strength of evidence and the reliability of conclusions. In this review, we identified 14 studies describing the therapeutic efficacy of quercetin on animal AD models by electronic and manual retrieval. Some of the results of the studies included were meta-analyzed by forest plot, and the methodological quality of each preclinical trial was assessed with SYRCLE's risk of bias tool. Our results demonstrated the consistent neuroprotective effects of quercetin on different AD models, and the pharmacological mechanisms of quercetin on AD models are summarized. This information eliminated the bias of each individual study, providing guidance for future tests and supporting evidence for further implementation of quercetin into clinical trials. However, the limitations of some studies, such as the absence of sample size calculations and low method quality, should also be noted.

Quercetin amorphous solid dispersions prepared by hot melt extrusion with enhanced solubility and intestinal absorption.

The aim of this study was to investigate the effect of amorphous solid dispersions (ASDs) on the dissolution rate and oral bioavailability of Quercetin (Que). First, we prepared the Que ASDs with various excipients using hot-melt extrusion to find the best option. X-ray diffraction (XRD), infrared spectroscopy (IR), and Raman spectroscopy were used to examine the solid formation of Que. Wetting process was studied by contact angle and solution process. The abilities of HPMC to inhibit crystallization and improve membrane permeability were demonstrated by fluorescence spectroscopy, dynamic light scattering analysis, in vitro permeability experiment and pharmacokinetics studies. Que existed as amorphous in solid dispersions, and poloxamer 188 (F68) was the best excipient for improving Que dissolution. Study on ASDs wettability proved Que ASDs improved wetting property in the presence of the F68. Furthermore, Que/F68/HPMC 1/4/3 and 1/5/2 ASDs belonged to drug-controlled diffusion; Que/F68/HPMC 1/6/1 ASDs belonged to drug/carrier-controlled diffusion; Que/F68 1/7 ASDs belonged to carrier-controlled diffusion. Addition of HPMC significantly inhibited the crystallization, improved membrane permeability and promoted drug absorption of compound Que. Que ASDs prepared enhanced solubility and intestinal absorption. Thus, Que ASDs provide a potent and efficacious formulation for Que oral administration.

Quercetin-loaded nanoparticles enhance cytotoxicity and antioxidant activity on C6 glioma cells.

Quercetin (Qu) is a natural flavonoid present in many commonly consumed food items. The dietary phytochemical quercetin prevents tumor proliferation and is a potent therapeutic cancer agent. The purpose of this study was to synthesize and characterize quercetin-loaded poly(lactic-co-glycolic acid) nanoparticles (Qu1NP, Qu2NP, and Qu3NP) with different size and encapsulation properties and to evaluate their in vitro activity on C6 glioma cells. Nanoparticles were synthesized by single emulsion solvent evaporation method. Then, particle size, zeta potential, polydispersity index and encapsulation efficiency of nanoparticles were determined. Particle size of Qu1NP, Qu2NP, and Qu3NPs were determined as 215.2 ± 6.2, 282.3 ± 7.9, and 584.5 ± 15.2 nm respectively. Treating C6 glioma cells with all nanoparticle formulations effectively inhibited the cell proliferation. Qu1NPs were showed the lowest IC50 value in 48 h with 29.9 µg/ml and achieved higher cellular uptake among other nanoparticles and Qu. Additionally, 48-h treatment with Qu1NPs significantly decreased MDA level (14.90 nmol/µg protein) on C6 glioma cells which is related to reduced oxidative stress in cells. Findings of this study revealed that quercetin's cellular uptake and anti-oxidant activity is improved by small-sized Qu1NPs in C6 glioma cells.

Synergistic anticancer action of quercetin and curcumin against triple-negative breast cancer cell lines.

Women with the breast cancer type 1 susceptibility protein (BRCA1) mutation and loss of BRCA1 expression are reported to have an increased risk of triple-negative breast cancer (TNBC). Targeting BRCA1 modulation might offer a therapeutic option to treat TNBC patients. Our studies detected that BRCA1 is poorly expressed in TNBC cell lines and highly expressed in ER+ breast cancer cell lines. To modulate BRCA1 expression, we tested two different dietary components to find out if any would induce tumor suppressor genes. We detected that quercetin and curcumin dose-dependently enhanced the BRCA1 expression. Further, a synergistic action of quercetin and curcumin was observed in modulating the BRCA1 level and in inhibiting the cell survival and migration of TNBC cell lines. Quercetin and curcumin appeared to induce BRCA1 promoter histone acetylation. Furthermore, BRCA1 knockdown induced cell survival and cell migration in ER + cells were significantly decreased by the combined treatment of quercetin and curcumin. Our present study concluded that the combination treatment of quercetin and curcumin acts synergistically to induce anticancer activity against TNBC cells by modulating tumor suppressor genes.

Study of Interactions between Amlodipine and Quercetin on Human Serum Albumin: Spectroscopic and Modeling Approaches.

The aim of this study was to analyze the binding interactions between a common antihypertensive drug (amlodipine besylate-AML) and the widely distributed plant flavonoid quercetin (Q), in the presence of human serum albumin (HSA). Fluorescence analysis was implemented to investigate the effect of ligands on albumin intrinsic fluorescence and to define the binding and quenching properties. Further methods, such as circular dichroism and FT-IR, were used to obtain more details. The data show that both of these compounds bind to Sudlow's Site 1 on HSA and that there exists a competitive interaction between them. Q is able to displace AML from its binding site and the presence of AML makes it easier for Q to bind. AML binds with the lower affinity and if the binding site is already occupied by Q, it binds to the secondary binding site inside the same hydrophobic pocket of Sudlow's Site 1, with exactly the same affinity. Experimental data were complemented with molecular docking studies. The obtained results provide useful information about possible pharmacokinetic interactions upon simultaneous co-administration of the food/dietary supplement and the antihypertensive drug.

Comparative Pharmacokinetics of Gallic Acid, Protocatechuic Acid, and Quercitrin in Normal and Pyelonephritis Rats after Oral Administration of a Polygonum capitatum Extract.

Polygonum capitatum Buch.-Ham. ex D. Don is traditionally used by Hmong for the treatment of urinary tract infections and pyelonephritis. Information regarding the pharmacokinetic behavior of the extract in the condition of pyelonephritis is lacking. In the present study, we aimed to compare the pharmacokinetic properties of gallic acid (GA), protocatechuic acid (PCA), and quercitrin (QR)-the main bioactive constituents in the herb-in normal and pyelonephritis rats. The plasma samples were collected at various time points after administration of a single dose of Polygonum capitatum extract. The plasma level of GA, PCA, and QR at the designed time points was determined by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and drug concentration versus time plots were constructed to estimate the pharmacokinetic parameters. The AUC(0-t), AUC(0-∞), MRT(0-t), and CL of GA, PCA, and QR in pyelonephritis rats was significantly different from those of the normal rats. The results indicated that the three constituents have higher rate of uptake and slower rate of elimination in the rats with pyelonephritis, suggesting altered rate and extent of drug metabolism.

Application of pH-Responsive Fucoidan/Chitosan Nanoparticles to Improve Oral Quercetin Delivery.

Polymeric nanoparticles based on fucoidan and chitosan were developed to deliver quercetin as a novel functional food. Through the polyelectrolyte self-assembly method, fucoidan/chitosan (F/C) nanoparticles were obtained with three different weight ratios (1/1, 3/1, and 5/1). The content of quercetin in the fucoidan/chitosan nanoparticles was in the range 110 ± 3 to 335 ± 4 mg·mL-1, with the increase of weight ratio of fucoidan to chitosan in the nanoparticle. Physicochemically stable nanoparticles were obtained with a particle size within the 300⁻400 nm range and surface potential higher than +30 mV for the 1F/1C ratio nanoparticle and around -30 mV for the 3F/1C and 5F/1C ratios nanoparticles. The 1F/1C ratio nanoparticle became larger and more unstable as the pH increased from 2.5 to 7.4, while the 3F/1C and 5F/1C nanoparticles retained their initial characteristics. This result indicates that the latter nanoparticles were stable along the gastrointestinal tract. The quercetin-loaded fucoidan/chitosan nanoparticles showed strong antioxidant activity and controlled release under simulated gastrointestinal environments (in particular for the 3F/1C and 5F/1C ratios), preventing quercetin degradation and increasing its oral bioavailability.

Enhanced bioactivity and efficient delivery of quercetin through nanoliposomal encapsulation using rice bran phospholipids.

BACKGROUND: Quercetin is a phenolic compound occurring in many food plants and agricultural crops. It is reported to possess various health-promoting properties. However, the poor bioavailability of quercetin, due to its low aqueous solubility and its degradation during digestion, limits its nutraceutical applications. This study aimed to encapsulate quercetin in nanoliposomes using rice-bran phospholipids for its efficient delivery and controlled release, the protection of its structural stability, and enhancement of its bioactivity. RESULTS: Nanoliposomal encapsulation of quercetin by thin film-sonication method yielded spherical nanoparticles (157.33 ± 23.78 nm) with high encapsulation efficiency (84.92 ± 0.78%). Storage stability studies showed that nanoliposomal quercetin was stable at 4 °C and 27 °C for 6 and 5 months, respectively, as indicated by unchanged antioxidant activity and quercetin retention. Nanoliposomal quercetin showed a slow, limited release pattern in simulated gastric fluid (SGF), and an initial burst release followed by a slow constant releasing pattern in simulated intestinal fluid (SIF). A 1004-fold increase in 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity was observed in quercetin nanoliposomes (SC50 = 4.04 ± 0.01 ppm) compared to non-encapsulated quercetin (SC50 = 4053.03 ± 5.61 ppm). Similarly, the anti-angiogenic activity of quercetin, as evaluated by duck embryo chorioallantoic membrane (CAM) assay, was enhanced twofold to fivefold by nanoliposomal encapsulation. CONCLUSION: This study showed that nanoliposomal encapsulation in rice-bran phospholipids enhanced the radical-scavenging and anti-angiogenic activities of quercetin. Furthermore, this study demonstrated that nanoliposomes can serve as efficient oral delivery system for quercetin. © 2018 Society of Chemical Industry.

Enriching the biological space of natural products and charting drug metabolites, through real time biotransformation monitoring: The NMR tube bioreactor.

BACKGROUND: Natural products offer a wide range of biological activities, but they are not easily integrated in the drug discovery pipeline, because of their inherent scaffold intricacy and the associated complexity in their synthetic chemistry. Enzymes may be used to perform regioselective and stereoselective incorporation of functional groups in the natural product core, avoiding harsh reaction conditions, several protection/deprotection and purification steps. METHODS: Herein, we developed a three step protocol carried out inside an NMR-tube. 1st-step: STD-NMR was used to predict the: i) capacity of natural products as enzyme substrates and ii) possible regioselectivity of the biotransformations. 2nd-step: The real-time formation of multiple-biotransformation products in the NMR-tube bioreactor was monitored in-situ. 3rd-step: STD-NMR was applied in the mixture of the biotransformed products to screen ligands for protein targets. RESULTS: Herein, we developed a simple and time-effective process, the "NMR-tube bioreactor", that is able to: (i) predict which component of a mixture of natural products can be enzymatically transformed, (ii) monitor in situ the transformation efficacy and regioselectivity in crude extracts and multiple substrate biotransformations without fractionation and (iii) simultaneously screen for interactions of the biotransformation products with pharmaceutical protein targets. CONCLUSIONS: We have developed a green, time-, and cost-effective process that provide a simple route from natural products to lead compounds for drug discovery. GENERAL SIGNIFICANSE: This process can speed up the most crucial steps in the early drug discovery process, and reduce the chemical manipulations usually involved in the pipeline, improving the environmental compatibility.

Investigation into the Emerging Role of the Basic Amino Acid L-Lysine in Enhancing Solubility and Permeability of BCS Class II and BCS Class IV Drugs.

BACKGROUND: The search for a simple and scalable approach that can improve the two key biopharmaceutical processes (solubility and permeability) for BCS Class II and BCS Class IV has still been unmet need. PURPOSE: In this study, L-lysine was investigated as a potential excipient to tackle problems with solubility and permeability. Bendazac (Class II); quercetin and rutin (Class IV) were employed. METHODS: Drugs-lysine complexes in 1:1 M ratios were prepared by co-precipitation and co-grinding; characterized for solubility, partition coefficient, DSC, FTIR, SEM, dissolution rate and permeability. Chemical stability of quercetin-lysine and rutin-lysine was studied by assessing antioxidant capacity using Trolox and CUPRAC assays. RESULTS AND CONCLUSION: Drugs-lysine salt/complexes were confirmed. Solubility enhancement factors ranged from 68- to 433-fold increases and dissolution rates were also significantly enhanced by up to 6-times, compared with drugs alone. With the exception of rutin-lysine, Papp for bendazac-lysine and quercetin-lysine enhanced by 2.3- to 4-fold. Papp for quercetin (Class IV) benefited more than bendazac (Class II) when complexed with lysine. This study warrants the use of L-lysine as a promising excipient for enhanced solubility and permeability of Class II and Class IV, providing that the solubility of the drug is ensured at 'the door step' of absorption sites.