Stability and Release Kinetics of an Advanced Gliclazide-Cholic Acid Formulation: The Use of Artificial-Cell Microencapsulation in Slow Release Targeted Oral Delivery of Antidiabetics

Introduction: In previous studies carried out in our laboratory, a bile acid (BA) formulation exerted a hypoglycaemic effect in a rat model of type-1 diabetes (T1D). When the antidiabetic drug gliclazide (G) was added to the bile acid, it augmented the hypoglycaemic effect. In a recent study, we designed a new formulation of gliclazide-cholic acid (G-CA), with good structural properties, excipient compatibility and exhibits pseudoplastic-thixotropic characteristics. The aim of this study is to test the slow release and pH-controlled properties of this new formulation. The aim is also to examine the effect of CA on G release kinetics at various pH values and different temperatures. Method: Microencapsulation was carried out using our Buchi-based microencapsulating system developed in our laboratory. Using sodium alginate (SA) polymer, both formulations were prepared: G-SA (control) and G-CA-SA (test) at a constant ratio (1:3:30), respectively. Microcapsules were examined for efficiency, size, release kinetics, stability and swelling studies at pH 1.5, pH 3, pH 7.4 and pH 7.8 and temperatures of 20 and 30 °C. Results: The new formulation is further optimised by the addition of CA. CA reduced microcapsule swelling of the microcapsules at pH 7.8 and pH 3 at 30 °C and pH 3 at 20 °C, and, even though microcapsule size remains similar after CA addition, percent G release was enhanced at high pH values (pH 7.4 and pH 7.8, p < 0.01). Conclusion: The new formulation exhibits colon-targeted delivery and the addition of CA prolonged G release suggesting its suitability for the sustained and targeted delivery of G and CA to the lower intestine

Processing and characterization of chitosan microspheres to be used as templates for layer-by-layer assembly

Chitosan (Ch) microspheres have been developed by precipitation method, cross-linked with glutaraldehyde and used as a template for layer-by-layer (LBL) deposition of two natural polyelectrolytes. Using a LBL methodology, Ch microspheres were alternately coated with hyaluronic acid (HA) and Ch under mild conditions. The roughness of the Ch-based crosslinked microspheres was characterized by atomic force microscopy (AFM). Morphological characterization was performed by environmental scanning electron microscopy (ESEM), scanning electron microscopy (SEM) and stereolight microscopy. The swelling behaviour of the microspheres demonstrated that the ones with more bilayers presented the highest water uptake and the uncoated cross-linked Ch microspheres showed the lowest uptake capability. Microspheres presented spherical shape with sizes ranging from 510 to 840 lm. ESEM demonstrated that a rougher surface with voids is formed in multilayered microspheres caused by the irregular stacking of the layers. A short term mechanical stability assay was also performed, showing that the LBL procedure with more than five bilayers of HA/Ch over Ch cross-linked microspheres provide higher mechanical stability

Screening of phytochemicals and in vitro evaluation of antibacterial and antioxidant activities of leaves, pods and bark extracts of Acacia nilotica (L.) Del

The objective of this study was to determine the phytochemical content, antibacterial activity and antioxidant activity of leaves, bark and pods of Acacia nilotica. The different extracts of acacia were evaluated for total phenolic, flavonoid and protein contents, antibacterial (agar well diffusion and broth dilution methods) and antioxidant (DPPH; 1,1-diphenyl-2-picrylhydrazyl assay) activities. The characterization and identification of phenolic compounds was carried out by Liquid Chromatography-tandem Mass Spectrometry analysis. The MS2 fragmentation pattern showed the presence of galloylated catechins and gallocatechin derivatives in tested extracts. The results indicated that all parts of the plant, but especially leaves, were effective in inhibiting the growth of antibiotic resistant strains of Escherichia coli and Salmonella species obtained from clinical and food isolates. The leaves were found to be rich in total phenolic content, proteins and high antioxidant activity as compared to pods and bark. The presence of functional groups of active compounds was confirmed by Fourier transform infrared spectroscopy (FTIR) analysis of plant extracts. It was concluded that all tested parts of A. nilotica had antibacterial and antioxidant activities. These properties might be due to the presence of high total phenolic content, proteins and/or flavonoids. Hence the extracts of leaves, bark and pods of A. nilotica represent a potential source of antibacterial and antioxidant compounds that may be used in food, agriculture and/or pharmaceutical products

Antibacterial activities and possible modes of action of acacia nilotica (L.) Del. against multidrug-resistant escherichia coli and salmonella

Medicinal plants are frequently used for the treatment of various infectious diseases. The objective of this study was to evaluate the antibacterial activity and mode of action of Acacia nilotica and the antibiogram patterns of foodborne and clinical strains of Escherichia coli and Salmonella. The mechanism of action of acacia extracts against E. coli and Salmonella was elucidated by observing morphological damages including cell integrity and cell membrane permeability, as well as changes in cell structures and growth patterns in kill-time experiments. The clinical isolates of E. coli and Salmonella were found resistant to more of the tested antibiotics, compared to food isolates. Minimum inhibitory concentration and minimum bactericidal concentration of acacia leaf extracts were in the ranges of 1.56-3.12 mg/mL and 3.12-6.25 mg/mL, respectively, whereas pods and bark extracts showed somewhat higher values of 3.12-6.25 mg/mL and 6.25-12.5 mg/mL, respectively, against all tested pathogens. The release of electrolytes and essential cellular constituents (proteins and nucleic acids) indicated that acacia extracts damaged the cellular membrane of the pathogens. These changes corresponded to simultaneous reduction in the growth of viable bacteria. This study indicates that A. nilotica can be a potential source of new antimicrobials, effective against antibiotic-resistant strains of pathogens

Antibacterial activities and possible modes of action of acacia nilotica (L.) Del. against multidrug-resistant escherichia coli and salmonella

Medicinal plants are frequently used for the treatment of various infectious diseases. The objective of this study was to evaluate the antibacterial activity and mode of action of Acacia nilotica and the antibiogram patterns of foodborne and clinical strains of Escherichia coli and Salmonella. The mechanism of action of acacia extracts against E. coli and Salmonella was elucidated by observing morphological damages including cell integrity and cell membrane permeability, as well as changes in cell structures and growth patterns in kill-time experiments. The clinical isolates of E. coli and Salmonella were found resistant to more of the tested antibiotics, compared to food isolates. Minimum inhibitory concentration and minimum bactericidal concentration of acacia leaf extracts were in the ranges of 1.56-3.12 mg/mL and 3.12-6.25 mg/mL, respectively, whereas pods and bark extracts showed somewhat higher values of 3.12-6.25 mg/mL and 6.25-12.5 mg/mL, respectively, against all tested pathogens. The release of electrolytes and essential cellular constituents (proteins and nucleic acids) indicated that acacia extracts damaged the cellular membrane of the pathogens. These changes corresponded to simultaneous reduction in the growth of viable bacteria. This study indicates that A. nilotica can be a potential source of new antimicrobials, effective against antibiotic-resistant strains of pathogens

Not Available

Not AvailableTo assess the role of phenol in flowering of litchi, an experiment was conducted at ICAR-NRC on Litchi, Muzaffarpur. Twenty desired litchi genotypes were selected and content of leaf phenol and leaf flavonoids were estimated from flowering and non-flowering trees. Results revealed that phenol content varied from 22.86 – 53.59 mg/g in flowering tree while it ranged from 10.03 – 33.7 mg/g in non-flowering tree during 2017. Among flowering genotypes phenol content was ranged from 16.51-50.35 mg/g. The highest phenol content was recorded in genotypes IC-0615590 (53.59 mg/g) whereas lowest was found in genotype IC-0615589 (22.86 mg/g) during 2017. The difference in phenol content between flowering and non-flowering tree ranged 12.74 - 66.09 %. The genotype Coll. 39 contained 66.09 % more phenol in flowering tree as compared to non-flowering trees in 2017 and IC-0615597 possessed 12.74% more phenol in flowering tree as compared to non-flowering tree during the same period. Similarly, phenol content ranged from 6.45 – 31.17 mg/g in non-flowering tree in 2018. In 2018, phenol content followed the same trend registering the maximum content in genotype IC-0615590 (50.35 mg/g) and lowest in IC-0615593 (16.51 mg/g). The difference in phenol content between flowering and non-flowering tree in 2018 ranged from 3.27 - 71.46 %. The genotype IC-0615604 possessed 71.46 % more phenol in flowering tree as compared to non-flowering tree and IC-0615593 contained 3.27 % more phenol in flowering tree as compared to non-flowering tree. In general, it was observed that the level of phenol in litchi tree varied from year to year but flowering tree always possessed more content of phenol as compared to non-flowering trees. However, the relation of flavonoids and flowering in litchi was not observed.Not Availabl