Chitosan is a promising biopolymer for drug delivery systems. Because of its beneficial properties, chitosan is widely used in biomedical and pharmaceutical fields. In this review, we summarize the physicochemical and drug delivery properties of chitosan, selected studies on utilization of chitosan and chitosan-based nanoparticle composites in various drug delivery systems, and selected studies on the application of chitosan films in both drug delivery and wound healing. Chitosan is considered the most important polysaccharide for various drug delivery purposes because of its cationic character and primary amino groups, which are responsible for its many properties such as mucoadhesion, controlled drug release, transfection, in situ gelation, and efflux pump inhibitory properties and permeation enhancement. This review can enhance our understanding of drug delivery systems particularly in cases where chitosan drug-loaded nanoparticles are applied.
Background/Objectives: Viscous fibers typically reduce total cholesterol (TC) by 3-7% in humans. The cholesterol-lowering properties of the viscous fiber pectin may depend on its physico-chemical properties (viscosity, molecular weight (MW) and degree of esterification (DE)), but these are not typically described in publications, nor required by European Food Safety Authority (EFSA) with respect to its generic pectin cholesterol-lowering claim. Subjects/Methods: Here, different sources and types of well-characterized pectin were evaluated in humans. Cross-over studies were completed in mildly hyper-cholesterolemic persons receiving either 15 g/day pectin or cellulose with food for 4 weeks. Results: Relative low-density lipoprotein (LDL) cholesterol (LDL-C) lowering was as follows: citrus pectin DE-70 ¼ apple pectin DE-70 (7-10% reduction versus control)4apple pectin DE-35 ¼ citrus pectin DE-354OPF (orange pulp fiber) DE-70 and low-MW pectin DE-704citrus DE-0. In a subsequent 3-week trial with 6 g/day pectin, citrus DE-70 and high MW pectin DE-70 reduced LDL-C 6-7% versus control (without changes in TC). In both studies, high DE and high MW were important for cholesterol lowering. Source may also be important as citrus and apple DE-70 pectin were more effective than OPF DE-70 pectin. Pectin did not affect inflammatory markers high-sensitivity C-reactive protein (hsCRP) nor plasma homocysteine. Conclusions: Pectin source and type (DE and MW) affect cholesterol lowering. The EFSA pectin cholesterol-lowering claim should require a minimum level of characterization, including DE and MW.
Orthosiphon stamineus Benth. (Lamiaceae) is a valued medicinal plant in traditional folk medicine. Many pharmacological studies have demonstrated the ability of this plant to exhibit antimicrobial, antioxidant, hepatoprotection, antigenotoxic, antiplasmodial, cytotoxic, cardioactive, antidiabetic, anti-inflammatory activies. This review is a comprehensive summary of the presently available chemical, pharmacological investigations as well as the traditional and therapeutic uses of this plant. Important and different experimental data have been addressed along with a review of all phytochemicals identified in this plant, including flavonoids, terpenoids, and essential oils. O. stamineus has wide traditional and pharmacological uses in various pathophysiological conditions. Therefore, it is an attractive subject for further experimental and clinical investigations.
The immunomodulatory activity of Cassia auriculata (CA)-derived polyphenols was tested on aged rats. Rats (24-26 months old) were given CA polyphenols supplementation at doses of 25, 50, and 100 mg/kg for 28 days. Flow cytometry analysis of CA polyphenols-treated aged rats showed increased T and B cells percentage along with enhanced proliferation of splenocytes in both resting and LPS-stimulated cells. Increased percentage of pan T cells is further supported by an elevation of CD4+, CD8+, and CD4+CD25+ regulatory cells. In terms of innate immune cell activity, CA polyphenol supplementation reduced the oxidative burst activity of neutrophils in response to PMA and Escherichia coli activation. Our results collectively show that polyphenols derived from CA boost T cell immunity by increasing the number of T cells and its sensitivity towards stimulants and decreasing ROS production by neutrophils that could potentially harm multiple biological systems in aged individuals.
Phenolic Schiff bases are known for their diverse biological activities and ability to scavenge free radicals. To elucidate (1) the structure-antioxidant activity relationship of a series of thirty synthetic derivatives of 2-methoxybezohydrazide phenolic Schiff bases and (2) to determine the major mechanism involved in free radical scavenging, we used density functional theory calculations (B3P86/6-31+(d,p)) within polarizable continuum model. The results showed the importance of the bond dissociation enthalpies (BDEs) related to the first and second (BDEd) hydrogen atom transfer (intrinsic parameters) for rationalizing the antioxidant activity. In addition to the number of OH groups, the presence of a bromine substituent plays an interesting role in modulating the antioxidant activity. Theoretical thermodynamic and kinetic studies demonstrated that the free radical scavenging by these Schiff bases mainly proceeds through proton-coupled electron transfer rather than sequential proton loss electron transfer, the latter mechanism being only feasible at relatively high pH.
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