Enhancement of antibacterial activity through phyto-fabrication of silver nanoparticles with Ficus thonningii aqueous extracts.

The World Health Organisation reports higher levels of bacterial resistance to cephalosporins and carbapenems of above 54%. The sufficient redox capabilities of Ficus thonningii phytochemicals for Ag+  reduction to Ag0 and ultimately aggregation to nucleation are exploited for the first time in attempting to enhance the antibacterial activity. Solution colour change to brown due to surface plasmon resonance phenomenon confirmed nanoparticle fabrication with a UV/Vis absorption peak at 426 nm. Fourier Transform Infrared spectra revealed functional groups (C=C at 1620-1680 cm-1 ; C=H at 1400-1600 cm-1 aromatics) for encapsulation, stabilisation, and reduction of the silver ion. The Dynamic Light Scattering technique verified F. thonningii encapsulated silver nanoparticles particle size of 57.84 nm with a negative zeta potential (-19.8 mV) as proof of stability. The surface, shape and topographical features were shown by Scanning Electron Microscopy as spherical orientations. An enhanced antimicrobial efficacy was displayed by the nanoparticles (inhibition zones of 26.1, 24.1 and 15.2 mm from 11.5, 10.6 and 6.5 mm) for Staphylococcus aureus, Streptococcus pyrogenes and Escherichia coli, respectively, compared to Flucloxacillin standard that was in the ranges of 21.5, 23.5 and 25.7 mm. The enhanced potency provides a basis for diversified approaches of generating novel drugs for treating bacterial infections.

Chitosan-Modified Cationic Amino Acid Nanoparticles as a Novel Oral Delivery System for Insulin.

In this study, chitosan-modified basic amino acid derivatives were explored as novel absorption enhancers and nanocarriers for oral insulin delivery. N-Arginine-chitosan (ACS) and N-histidine-chitosan (HCS) were successfully synthesized, and their polyelectrolyte complexes (PECs) with insulin were formed by the ordinary self-assembly method. The obtained PECs exhibited a spherical morphology with a narrow size of 205-303 nm, positive surface charge (ζ potential + 14- + 27 mV) and encapsulation efficiency of approximately 80%. The electrostatic interactions between chitosan derivatives and insulin were confirmed by molecular modeling simulation. In vitro studies demonstrated that PECs could partially protect insulin from proteolysis and degradation at 50 degrees C for at least 6 h. Compared with the insulin solution, internalization of PECs into Caco-2 cells was increased by up to 20.7-fold. Moreover, permeability was enhanced as the degrees of substitution of arginine and histidine increased. The PECs had in vivo pharmacological activities of 2.29%-5.39%, with a significant reduction of blood glucose levels in diabetic rats. These results suggested that ACS and HCS PECs hold promising potential for the oral delivery of insulin, peptides and proteins.

N-octyl-N-arginine-chitosan (OACS) micelles for gambogic acid oral delivery: preparation, characterization and its study on in situ intestinal perfusion.

CONTEXT: Gambogic acid (GA) can inhibit the growth of various cancer cells. However, the low bioavailability caused by insolubility, limits its clinical application. L-arginine is always used with GA to form a complex to obtain the higher solubility. Moreover, guanidyl group from arginine, which can facilitate the cellular uptake, was identified. OBJECTIVE: In this study, L-arginine and chitosan (CS) were used for the first time to prepare N-octyl-N-arginine CS (OACS), a novel amphiphilic carrier for GA with solubility- and absorption-enhancing functions; the characterization of the GA loaded OACS micelles (GA-OACS) and its absorption-enhancing effect were also investigated. MATERIALS AND METHODS: GA-OACS were prepared by the dialysis method. The formed micelles were characterized and evaluated by atomic force microscope (AFM), dynamic light scattering, differential scanning calorimeter (DSC), solubility test, in vitro release and in situ intestinal perfusion. RESULTS: The GA-OACS micelles were successfully prepared attaining a 35.3% drug loading and 82.2% entrapment efficiency. GA-OACS had a homogeneous particle size of 160.3 nm; +21.8 mv zeta potential with smooth continuous surface was observed by using AFM. DSC diagram suggested that GA was encapsulated in the micelles. Meanwhile, GA encapsulated in micelles exhibited a desirable slow release in vitro experiment. The solubility of GA in OACS micelles was increased up to 3.16 ± 0.13 mg/mL, 2320 times than that of free GA. The single pass perfusion showed that the absorption of GA-OACS micelles was enhanced 3.6-fold, 2.1-fold and 2.2-fold for jejunum, ileum and colon, respectively. DISCUSSION AND CONCLUSION: OACS provided excellent ability of drug loading, increasing solubility and enhanced absorption for GA, which indicated that OACS micelles as an oral drug delivery carrier may have potential research and application values.

Micelles of TPGS modified apigenin phospholipid complex for oral administration: preparation, in vitro and in vivo evaluation.

Mixed micelles were designed to increase oral bioavailability of Apigenin (Ap). The phospholipid (Ph) complex technology was exploited alongside TPGS' stabilizing effect by PEG chain sterical hindrance of the phase II enzymes. This prevented extensive metabolism of Ap while inhibiting P-glycoprotein's exocytosis. TPGS modified micelles of Ap-Ph complex (TPGS-Ap-Ph) were prepared by thin film hydration method. Ap-Ph complex was confirmed by FTIR and NMR spectroscopy while Ap, Ph and TPGS interactions were studied by surface tensiometry. TPGS-Ap-Ph micelles achieved 87.35% drug encapsulation and 12.6% drug loading showing spherical morphology 137.1 +/- 3.4 nm particle size and -12.94 mV surface charge. The negative zeta potential confirmed computer simulation predictions that PEG moieties of TPGS were at micelles surface, while hydrophobic part inserted to the phospholipid hydrophobic core by electrostatic interactions. TPGS-Ap-Ph micelles were found to be stable for more than 90 days after lyophilization. Comparing to free drug, the micelles increased intestinal absorption of Ap 2.4 fold, illustrating apparent permeation (P(app)) and absorption constant (K(a)) of 7.9 x 10(-4) and 2.05 x 10(-4) (p < 0.001) respectively. Moreover, cell culture studies showed high cellular uptake with sufficient intracellular trafficking in A549 cells. MTT assays revealed a significant cytotoxic effect by TPGS-Ap-Ph micelles. In vivo, an effective inhibition of 72.9% was achieved upon oral administration to S180 carcinoma mice compared to 19.5% by Ap-Ph complex. Altogether reflect that orally administered mixed micelles of TPGS-Ap-Ph could effectively inhibit cancer. The results present the designed micelles as a new way to improve oral bioavailability of sparingly soluble and poorly absorbed drugs.

Formulation, characterization and pharmacokinetics of Morin hydrate niosomes prepared from various non-ionic surfactants.

Morin hydrate (MH), a bioflavonoid with antioxidant and anticancer activity as well as the ability to improve the bioavailability of other drugs on their concurrent use. Three differently optimized niosomal formulations using three different non-ionic surfactants (Span 60, Span 80 and Tween 60) were achieved by (L9 (3(4))) Taguchi orthogonal array (TOA). The analysis of TOA revealed that Tween 60 Niosomes had the highest entrapment efficiency (93.4%) compared to other optimized Niosomal formulations (71-79%). In terms of MH remaining %, Tween 60 Niosomes were found to be the most stable (89%) at 4 °C over one month compared to Span 60 (56%) and Span 80 (57%) Niosomes. The release pattern in all Niosomal formulations was found to follow the Weibull model and Tween 60 Niosomes had the highest release rate. The molecular modeling simulation explained the binding of MH to the human serum albumin (HSA) by hydrogen bonds during the in vitro release process. As for the bioavailability, the AUC0-8 showed 1.3-2.7 fold increase compared to the MH solution. Ex vivo images of the excised organs showed that MH could accumulate in brain which indicates that MH-Tween 60 Niosomes might be a possible candidate to deliver hydrophobic drugs and overcome the blood-brain barrier (BBB) penetration.

Studies on lactoferrin nanoparticles of gambogic acid for oral delivery.

PURPOSE: Lactoferrin (Lf), a mammalian cationic iron-binding glycoprotein belonging to the transferrin (Tf) family, has been widely used in a variety of fields ranging from treating infant diarrhea and supporting newborn growth to food and pharmaceutical applications. In this study, Lf nanoparticles were firstly used as carriers of gambogic acid (GA) to enhance oral absorption and anti-cancer activity, hence reducing the related toxic effect. METHODS: Gambogic acid-lactoferrin nanoparticles (GL-NPs) were prepared by the nanoparticle albumin-bound (NAB) technology. The formed nanoparticles were characterized by DSC, TEM, etc. In situ intestinal perfusion experiment was performed to clarify the absorption mechanism of GL-NPs. Furthermore in vivo and in vitro anti-tumor activities of GL-NPs were also investigated. RESULTS: GL-NPs was successfully prepared with about 150 nm mean size, +20 mV ζ potential, 92.3 ± 7.2% encapsulation efficiency and 9.04 ± 0.7% DL; GL-NPs also exhibited a better stability and a desirable slow release in vitro experiment. The results of in situ intestinal perfusion showed a transformation of GA absorption from passive diffusion into active transport or facilitated diffusion by GL-NPs. MTT assay of GL-NPs showed almost an equal anti-proliferative effect with arginine solution of GA (Arg-GA) in HepG2 cell. The inhibitory rate against S180 tumor mice after oral administration of GL-NPs was up to 86.01% which was 1.39-folds of intravenous injection of Arg-GA. CONCLUSION: The in vitro results showed that the NAB technology was feasible for industrial production of Lf nanoparticles and the in vivo results proved that the effective GL-NPs is a promising approach for the oral delivery of GA. These obtained research works have also paved the preliminary way for the study of Lf as an oral drug delivery carrier.

Effect of Maillard reaction products on oxidation products in ground chicken breast.

Three amino acid-sugar solutions were adjusted to pH 8.0, heated and lyophilized prior to addition to ground chicken breast (GCB). GCB with no additives, GCB with 0.01% BHT, GCB with 0.1 or 0.2mg/g glucose heated with arginine, valine, or histidine were prepared. Thiobarbituric acid reactive substances (TBARS), volatiles determined by gas chromatography, and Hunter L*, a* and b* values were monitored over nine days. Multiple linear regression models were used to determine the effects of the studied factors on the corresponding outcome variables. a* values of GCB ranged from 1.60 to 4.90 over nine days of storage. While Maillard reaction products (MRP) lowered oxidation compared to control, no significant difference in TBARS between MRP solutions heated for 8 or 24h was found. Further, 0.1mg/g heated glucose-valine mixture decreased aldehydes up to 72.87%. Therefore, shelf-life of GCB could be extended using 0.1 or 0.2mg/g MRP.

Preparation and evaluation of berberine alginate beads for stomach-specific delivery.

The purpose of this research was to prepare floating calcium alginate beads of berberine for targeting the gastric mucosa and prolonging their gastric residence time. The floating beads were prepared by suspending octodecanol and berberine in sodium alginate (SA) solution. The suspension was then dripped into a solution of calcium chloride. The hydrophobic and low-density octodecanol enhanced the sustained-release properties and floating ability of the beads. The bead formulation was optimized for different weight ratios of octodecanol and SA and evaluated in terms of diameter, floating ability and drug loading, entrapment and release. In vitro release studies showed that the floating and sustained release time were effectively increased in gastric media by addition of octodecanol. In vivo studies with rats showed that a significant increase in gastric residence time of beads had been achieved.

Extraction, identification, and quantification of flavonoids and phenolic acids in electron beam-irradiated almond skin powder.

The effect of electron beam irradiation doses from 0 to 30 kGy on extraction yield and phenolic compounds was evaluated in almond skin phenolic extracts (ASPE). Total soluble phenols and distribution of phenolic compounds from acidified methanol ASPE and 52% methanol ASPE were quantified using Folin-Ciocalteau method, liquid chromatography with diode array and fluorescence detection, and negative ion electrospray-mass spectrometry. Electron beam irradiation increased extraction yield by as much as 23%, with the greatest increase observed in the acidified methanol ASPE. Irradiated samples extracted with acidified methanol also exhibited an increase in extractable phenols (Folin-Ciocalteau) and total HPLC-resolved phenolics at all irradiation doses. Samples extracted with 52% methanol exhibited an increase at 10 and 20 kGy, but a 31% decrease at 30 kGy. An increase in aglycones respective to their glycosides was not observed with irradiation. Therefore, the increase in phenolics was attributed to release of phenolics from their cellular matrix.

Utilization of electron beam irradiated almond skin powder as a natural antioxidant in ground top round beef.

Defatted Carmel variety almond skin powder (ASP) irradiated at 0, 10, 20, and 30 kGy was mixed with ground top round beef at 0.5% (w/w) and stored at 4 degrees C. Color stability, peroxide values (PV), conjugated dienes (CD), thiobarbituric acid reactive species (TBARS), and hexanal were determined periodically over a 2-wk period. The L values were not affected by time or treatment. Initially, the redness (a value) was higher for both the negative control with no ASP (a value of 21.83) and positive control with 0.01% BHT (a value of 22.33) compared to samples that contained the ASP (a values from 17.70 to 20.17) on day 1. This decrease in redness was attributed to the presence of the ASP. Similar to day 1, the a values were not significantly different between the 2 controls over the duration of the study. All the samples with ASP exhibited lower lipid oxidation when compared to the negative control, with greatest oxidation retardation observed at 20 and 30 kGy. Over the treatment period, a 13% to 85% reduction in PV and a 40% to 80% reduction in TBARS were observed in the sample with 30 kGy ASP compared to the negative control. Generally, PV and TBARS of samples with ASP decreased with an increase in irradiation dose. While a difference due to irradiation dose was not observed in CD and hexanal content, the values were significantly lower (P < 0.05) than the controls over time. This study demonstrates that almond skin power could be used to extend the shelf life of refrigerated ground raw beef.

Activity and nature of plasminogen activators associated with the casein micelle.

In fresh milk, plasminogen, the zymogen form of plasmin (PL), is the predominant form. Therefore, plasminogen activators (PA) can contribute significantly to PL activity in milk. Both tissue-type PA (tPA) and urokinase-type PA (uPA) exist in milk; however, contradictory findings have been reported for which type of PA is most closely associated with the casein micelles. Little is known about the factors that might lead to variations in the individual activities of the PA. The objective of this work was therefore to investigate possible factors that might affect the association of tPA and uPA with the casein micelle and their activities thereafter. Plasminogen activators were isolated from milk samples with different somatic cell counts following 2 different isolation protocols. Determination of uPA, tPA, and PL activities was carried out quantitatively following chromogenic assays using 2 different substrates, and qualitatively using specialized sodium dodecyl sulfate-PAGE. Different isolation methods and conditions led to differences in uPA, tPA, and PL activities. Urokinase-type PA activity was significantly higher in PA fractions isolated from milk with high somatic cell counts than from milk with low somatic cell counts. Activity results indicated that in pasteurized milk uPA could dissociate from the somatic cells and bind to casein. Moreover, a high level of PL in isolated PA fractions contributed to significantly enhanced PA activities. Overall, results confirmed the association of both uPA and tPA with the casein micelle; however, their amounts, activities, and molecular weights varied based on the nature of the milk and methods of separation, with uPA being the PA with greater potential to affect plasminogen activation in milk.

Degradation behavior of soy protein-wheat gluten films in simulated soil conditions.

Films containing soy protein and wheat gluten were exposed to simulated farmland soil mix over a period of 30 days and monitored for degradation. The simulated farmland soil mix (topsoil/sand/Sunshine compost/vermiculite, 59:6:25:10, wt %) was mixed and stored at ambient humidity (48-55%) and temperature (20-24 degrees C); the soil mix was constantly maintained at 15% moisture by weight. Research focused on evaluating the effectiveness of gluten and cysteine additions on biodegradable behavior in the simulated farmland soil conditions. The four types of films, soy protein (S:G 1:0); soy protein with cysteine addition (S:G 1:0 + CYS); soy protein-wheat gluten (S:G 4:1); and soy protein-wheat gluten with cysteine addition (S:G 4:1 + CYS), were prepared at pH 7. 0 for degradation studies. Soy protein-gluten film rapidly degraded with 50% weight loss in about 10 days and with up to 95% weight loss in 30 days. Tensile strength and elongation of all soy protein-gluten films significantly decreased in 3 days. However, cysteine addition delayed the degradation rate of soy protein-gluten films. Soy protein-wheat gluten film disintegrated after 20 days in the simulated farmland soil environment. These results suggest that wheat gluten and cysteine addition to soy protein-based films could delay degradation rates due to their high disulfide contents.