Change in particle size of pectin reacted with pectinesterase isozymes from pea (Pisum sativum L.) sprout

Interfacial Behavior and Long-Term Stability of the Emulsions Stabilized by Sugar Beet Pectin-Ca2+ Complexes with Different Cross-Linking Degrees

Recent studies showed that sugar beet pectin exhibited more excellent emulsifying properties than traditional citrus peel pectin and apple pectin ascribed to the higher content of neutral sugar, protein, ferulic acid, and acetyl groups. It is precisely because of the extremely complex molecular structure of pectin that the emulsifying properties of the pectin-Ca2+ complex are still unclear. In this study, SBP-Ca2+ complexes with different cross-linking degrees were prepared. Subsequently, their interfacial adsorption kinetics, the resistance of interfacial films to external perturbances, and the long-term stability of the emulsions formed by these SBP-Ca2+ complexes were measured. The results indicated that the highly cross-linked SBP-Ca2+ complex exhibited slower interfacial adsorption kinetics than SBP alone. Moreover, compared with SBP alone, the oil-water interfacial film loaded by the highly cross-linked SBP-Ca2+ complex exhibited a lower elasticity and a poorer resistance to external perturbances. This resulted in a larger droplet size, a lower ζ-potential value, a larger continuous viscosity, and a worse long-term stability of the emulsion formed by the highly cross-linked SBP-Ca2+ complex. This study has very important guiding significance for deeply understanding the emulsification mechanism of the pectin-Ca2+ complex.

Enhancement of Oral Bioavailability of Ibandronate Through Gastroretentive Raft Forming Drug Delivery System: In Vitro and In Vivo Evaluation

Background

Bisphosphonates have very low bioavailability and cause irritation of the esophagus and stomach. This study was planned to improve the oral bioavailability of ibandronate through the formation of a raft in the stomach. Bisphosphonate-induced irritation of the esophagus and stomach is prevented by the formation of a raft.

Materials and Methods

The nanostructured raft was developed through the use of nanosized citrus pectin (NCP). The particle size of NCP was measured by zeta sizer and SEM. The percentage of NCP and the neutralization profile of raft was studied. The ibandronate, polymers, and the developed formulation were characterized by FTIR, XRD, TGA, and DSC. The release of ibandronate was studied in 0.1 N HCl, 0.5 N HCl, 1 N HCl, and simulated gastric fluid (SGF) and a cell viability study was performed using Caco-2 cells. The PPR5 formulation and Bonish 150 mg tablets were selected as test and reference formulations, respectively, for pharmacokinetic study. Twelve healthy albino rats were taken and divided into two groups using a Latin square crossover design, and the blood samples were collected for 24 hours.

Results

The SEM image showed that the particle size of NCP was 159 nm. The raft of PPR5 showed 94% NCP and 45 minutes duration of neutralization. The FTIR and XRD showed chemical stability and a uniform distribution of ibandronate in the raft. The TGA and DSC indicated the thermal stability of formulation. The release of 99.87% ibandronate at 20 minutes was observed in the SGF. The values of C _max for the reference and test formulations were 493±0.237 ng/mL and 653±0.097 ng/mL, respectively. The AUC_(0-t) of the reference and test formulations was 3708.25±3.418 ng/mL.h and 6899.25±3.467 ng/mL.h, respectively.

Conclusion

The NCP has been successfully prepared from citrus pectin and has shown effective porous raft formation. The bioavailability of the ibandronate from newly developed PPR5 was higher than the already marketed formulation.

Transcriptional responses of Arabidopsis thaliana to the bacteria-derived PAMPs harpin and lipopolysaccharide

Many plant-pathogen interactions are controlled by specific interactions between pathogen avirulence (avr) gene loci and the corresponding plant resistance R locus (gene-for-gene-hypothesis). Very often, this type of interaction culminates in a hypersensitive reaction (HR). However, recently pathogen-associated molecular patterns (PAMPs) such as flagellin or lipopolysaccharides (LPS) that are common to all bacteria have been shown to act as general elicitors of basal or innate immune responses in several plant species. Here, we summarize the genetic programs in Arabidopsis thaliana behind the LPS-induced basal response and the HR induced by harpin, respectively. Using Agilent Arabidopsis cDNA microarrays consisting of approximately 15,000 oligomers, changes in transcript accumulation of treated cells were monitored over a period of 24h after elicitor treatment. Analysis of the array data revealed significant responses to LPS (309 genes), harpin (951 genes) or both (313 genes). Concentrating our analysis on the genes encoding transcription factors, defence genes, cell wall biogenesis-related genes and signal transduction components we monitored interesting parallels, but also remarkably different expression patterns. Harpin and LPS induced an overlapping set of genes involved in cell wall biogenesis, cellular communication and signalling. The pattern of induced genes associated with cell rescue and general stress responses such as small heat-shock proteins was highly similar. In contrast, there is a striking difference regarding some of the most prominent, central components of plant defence such as WRKY transcription factors and oxidative burst-associated genes like NADPH oxidases, whose expression became apparent only after treatment with harpin. While both harpin and LPS can stimulate plant immunity in Arabidopsis, the PAMP LPS induces much more subtle host reactions at the transcriptome scale. The defence machinery induced by harpin resembles the known HR-type host responses leading to cell death after treatment with this elicitor. LPS is a weak inducer of basal resistance and induces a different pattern of genes. Strikingly the biggest overlap (40) of responding genes was found between the early harpin response (30min) and the late LPS response (24h).

Pectin methylesterase inhibitor

Pectin methylesterase (PME) is the first enzyme acting on pectin, a major component of plant cell wall. PME action produces pectin with different structural and functional properties, having an important role in plant physiology. Regulation of plant PME activity is obtained by the differential expression of several isoforms in different tissues and developmental stages and by subtle modifications of cell wall local pH. Inhibitory activities from various plant sources have also been reported. A proteinaceous inhibitor of PME (PMEI) has been purified from kiwi fruit. The kiwi PMEI is active against plant PMEs, forming a 1:1 non-covalent complex. The polypeptide chain comprises 152 amino acid residues and contains five Cys residues, four of which are connected by disulfide bridges, first to second and third to fourth. The sequence shows significant similarity with the N-terminal pro-peptides of plant PME, and with plant invertase inhibitors. In particular, the four Cys residues involved in disulfide bridges are conserved. On the basis of amino acid sequence similarity and Cys residues conservation, a large protein family including PMEI, invertase inhibitors and related proteins of unknown function has been identified. The presence of at least two sequences in the Arabidopsis genome having high similarity with kiwi PMEI suggests the ubiquitous presence of this inhibitor. PMEI has an interest in food industry as inhibitor of endogenous PME, responsible for phase separation and cloud loss in fruit juice manufacturing. Affinity chromatography on resin-bound PMEI can also be used to concentrate and detect residual PME activity in fruit and vegetable products.