Synthesis, characterization and evaluation of antioxidant properties of catechin hydrate nanoparticles

A pH-sensitive silica nanoparticles for colon-specific delivery and controlled release of catechin: Optimization of loading efficiency and in vitro release kinetics

Catechin is a naturally occurring flavonoid of the flavan-3-ol subclass with numerous biological functions; however, these benefits are diminished due to several factors, including low water solubility and degradation in the stomach's harsh environment. So, this study aimed to develop an intelligent catechin colon-targeting delivery system with a high loading capacity. This was done by coating surface-decorated mesoporous silica nanoparticles with a pH-responsive enteric polymer called Eudragit®-S100. The pristine wormlike mesoporous silica nanoparticles (< 100 nm) with high surface area and large total pore volume were effectively synthesized and modified with the NH2 group using the post-grafting strategy. Various parameters, including solvent polarity, catechin-carrier mass ratio, and adsorption time, were studied to improve the loading of catechin into the aminated silica nanoparticles. Next, the negatively charged Eudragit®-S100 was electrostatically coated onto the positively charged aminated nanocarriers to shield the loaded catechin from the acidic environment of the stomach (pH 1.9) and to facilitate site-specific delivery in the acidic environment of the colon (pH 7.4). The prepared nanomaterials were evaluated using several methods, including The Brauner-Emmett-Teller, surface area analyzer, zeta sizer, Field Emission Scanning Electron Microscope, Powder X-Ray Diffraction, Fourier Transform Infrared Spectroscopy, Energy-Dispersive X-ray Spectroscopy, and Differential Scanning Calorimetry. In vitro dissolution studies revealed that Eudragit®-S100-coated aminated nanomaterials prevented the burst release of the loaded catechin in the acidic environment, with approximately 90% of the catechin only being released at colonic pH (pH > 7) with a supercase II transport mechanism. As a result, silica nanoparticles coated with Eudragit®-S100 would provide an innovative and promising approach in targeted nanomedicine for the oral delivery of catechin and related medicines for treating diseases related to the colon, such as colorectal cancer and irritable bowel syndrome.

Effects of Processing Conditions and Simulated Digestion In Vitro on the Antioxidant Activity, Inhibition of Xanthine Oxidase and Bioaccessibility of Epicatechin Gallate

The bioactivity and gastrointestinal stability of epicatechin gallate (ECG) may be affected by processing conditions. Results showed that the antioxidant ability and inhibitory activity on xanthine oxidase (XO) of ECG were higher at low pH values. Appropriate microwave and heating treatments improved the antioxidant (the scavenging rate increased from 71.75% to 92.71% and 80.88% under the microwave and heating treatments) and XO inhibitory activity (the inhibitory rate increased from 47.11% to 56.89% and 51.85% at the microwave and heating treatments) of ECG. The treated ECG led to a more compact structure of XO. Moreover, there may be synergistic antioxidant and inhibitory effects between ECG and its degradation products. The bioaccessibility of ECG after simulated digestion was untreated > microwave > heating, and the microwave-treated ECG still had good XO inhibitory activity after digestion. These findings may provide some significant information for the development of functional foods enriched in catechins.

Chitosan Nanoparticles: A Versatile Platform for Biomedical Applications

Chitosan is a biodegradable and biocompatible natural polymer that has been extensively explored in recent decades. The Food and Drug Administration has approved chitosan for wound treatment and nutritional use. Furthermore, chitosan has paved the way for advancements in different biomedical applications including as a nanocarrier and tissue-engineering scaffold. Its antibacterial, antioxidant, and haemostatic properties make it an excellent option for wound dressings. Because of its hydrophilic nature, chitosan is an ideal starting material for biocompatible and biodegradable hydrogels. To suit specific application demands, chitosan can be combined with fillers, such as hydroxyapatite, to modify the mechanical characteristics of pH-sensitive hydrogels. Furthermore, the cationic characteristics of chitosan have made it a popular choice for gene delivery and cancer therapy. Thus, the use of chitosan nanoparticles in developing novel drug delivery systems has received special attention. This review aims to provide an overview of chitosan-based nanoparticles, focusing on their versatile properties and different applications in biomedical sciences and engineering.

Extending the Bioavailability of Hydrophilic Antioxidants for Metal Ion Detoxification via Crystallization with Polysaccharide Dopamine

Although metal ions, such as silver and gold, have been shown to have strong antimicrobial properties, their potential to have toxic effects on human and environmental health has gained interest with an improved understanding of their mechanisms to promote oxidative stress. Redox control is a major focus of many drug delivery systems and often incorporates an antioxidant as the active pharmaceutical ingredient (API) to neutralize overproduced reactive oxygen species (ROS). Nevertheless, there are still limitations with bioavailability and extended redox control with regard to antioxidant drug delivery. Herein, this study develops a colloidal antioxidant crystal system that dissolves sustainably through polymer stabilization using sodium hyaluronate conjugated with dopamine (HA-dopa). We explore the role of dopamine incorporation into crystal-stabilizing polymers and quantify the balance between drug-polymer interactions and competing polymer-polymer interactions. We propose that this type of analysis is useful in the engineering of and provides insight into the release behavior of polymer-crystal complexes. In developing our crystal complex, N-acetylcysteine (NAC) was used as the model antioxidant to protect against silver ion toxicity. We found that our optimized HA-dopa-stabilized NAC crystals prolong the release time of NAC 5-fold compared to a polymer-free NAC crystal. Therefore, following sublethal exposure to AgNO₃, the extended lifetime of NAC was able to maintain normal intracellular ROS levels, modulate metabolic function, mitigate fluctuations in ATP levels and ATP synthase activity, and preserve contraction frequency in engineered cardiac muscle tissue. Furthermore, the protective effects of the HA-dopa-stabilized NAC crystals were extended to a Daphnia magna model where silver-ion-induced change to both cell-level biochemistry and organ function was alleviated. As such, we propose that the packaging of hydrophilic antioxidants as colloidal crystals drastically extends the lifetime of the API, better maintains ROS homeostasis post metal ion exposure, and therefore preserves both intracellular biochemistry and tissue functionality.

Nanoantioxidants: Pioneer Types, Advantages, Limitations, and Future Insights

Free radicals are generated as byproducts of normal metabolic processes as well as due to exposure to several environmental pollutants. They are highly reactive species, causing cellular damage and are associated with a plethora of oxidative stress-related diseases and disorders. Antioxidants can control autoxidation by interfering with free radical propagation or inhibiting free radical formation, reducing oxidative stress, improving immune function, and increasing health longevity. Antioxidant functionalized metal nanoparticles, transition metal oxides, and nanocomposites have been identified as potent nanoantioxidants. They can be formulated in monometallic, bimetallic, and multi-metallic combinations via chemical and green synthesis techniques. The intrinsic antioxidant properties of nanomaterials are dependent on their tunable configuration, physico-chemical properties, crystallinity, surface charge, particle size, surface-to-volume ratio, and surface coating. Nanoantioxidants have several advantages over conventional antioxidants, involving increased bioavailability, controlled release, and targeted delivery to the site of action. This review emphasizes the most pioneering types of nanoantioxidants such as nanoceria, silica nanoparticles, polydopamine nanoparticles, and nanocomposite-, polysaccharide-, and protein-based nanoantioxidants. This review overviews the antioxidant potential of biologically synthesized nanomaterials, which have emerged as significant alternatives due to their biocompatibility and high stability. The promising nanoencapsulation nanosystems such as solid lipid nanoparticles, nanostructured lipid carriers, and liposome nanoparticles are highlighted. The advantages, limitations, and future insights of nanoantioxidant applications are discussed.

In vitro effects of nutraceutical treatment on human osteoarthritic chondrocytes of females of different age and weight groups

The in vitro effects of four nutraceuticals, catechin hydrate, gallic acid, α-tocopherol and ascorbic acid, on the ability of human osteoarthritic chondrocytes of two female obese groups to form articular cartilage (AC) tissues and to reduce inflammation were investigated. Group 1 represented thirteen females in the 50-69 years old range, an average weight of 100 kg and an average body mass index (BMI) of 34⋅06 kg/m2. Group 2 was constituted of three females in the 70-80 years old range, an average weight of 75 kg and an average BMI of 31⋅43 kg/m2. The efficacy of nutraceuticals was assessed in monolayer cultures using histological, colorimetric and mRNA gene expression analyses. AC engineered tissues of group 1 produced less total collagen and COL2A1 (38-fold), and higher COL10A1 (2⋅7-fold), MMP13 (50-fold) and NOS2 (15-fold) mRNA levels than those of group 2. In comparison, engineered tissues of group 1 had a significant decrease in NO levels from day 1 to day 21 (2⋅6-fold), as well as higher mRNA levels of FOXO1 (2-fold) and TNFAIP6 (16-fold) compared to group 2. Catechin hydrate decreased NO levels significantly in group 1 (1⋅5-fold) while increasing NO levels significantly in group 2 (3⋅8-fold). No differences from the negative control were observed in the presence of other nutraceuticals for either group. In conclusion, engineered tissues of the younger but heavier patients responded better to nutraceuticals than those from the older but leaner study participants. Finally, cells of group 2 formed better AC tissues with less inflammation and better extracellular matrix than cells of group 1.

Evaluating the Anticarcinogenic Activity of Surface Modified/Functionalized Nanochitosan: The Emerging Trends and Endeavors

Chitosan begins its humble journey from marine food shell wastes and ends up as a versatile nutraceutical. This review focuses on briefly discussing the antioxidant activity of chitosan and retrospecting the accomplishments of chitosan nanoparticles as an anticarcinogen. The various modified/functionalized/encapsulated chitosan nanoparticles and nanoforms have been listed and their biomedical deliverables presented. The anticancer accomplishments of chitosan and its modified composites have been reviewed and presented. The future of surface modified chitosan and the lacunae in the current research focus have been discussed as future perspective. This review puts forth the urge to expand the scientific curiosity towards attempting a variety of functionalization and surface modifications to chitosan. There are few well known modifications and functionalization that benefit biomedical applications that have been proven for other systems. Being a biodegradable, biocompatible polymer, chitosan-based nanomaterials are an attractive option for medical applications. Therefore, maximizing expansion of its bioactive properties are explored. The need for applying the ideal functionalization that will significantly promote the anticancer contributions of chitosan nanomaterials has also been stressed.

Strategies of confining green tea catechin compounds in nano-biopolymeric matrices: A review

Catechins are polyphenolic compounds which abundantly occur in the plants, especially tea leaves. They are widely used in nutraceutical and pharmaceutical formulations due to their capability of lowering the risk of developing various diseases. Nevertheless, low stability, loss of antioxidant and antimicrobial activities hinder the direct application of catechins in food formulations. To surmount this pervasive challenge, bioactive ingredients should be entrapped in a biopolymeric matrix. Thus, nanoencapsulation technology would be an appropriate strategy to improve the stability of these bioactive compounds and to protect them against degradation. Among different types of nanocarriers, biopolymer-based nanovehicles has captured a lot of attention in both industry and academia due to their safety and biocompatibility. This revision enlarges upon the various types of biopolymeric nanostructures used for accommodation of catechins, namely nanogels, nanotubes, nanofibers, nanoemulsions and nanoparticles. Last but not least, the applications of the entrapped catechins in the food industry are highlighted.

Formulation and characterization of catechin-loaded proniosomes for food fortification

BACKGROUND

To overcome the problems associated with niosomes, proniosomes - a dry powder - was prepared to nanoencapsulate catechins using Span 60 as surfactant, cholesterol as stabilizer and maltodextrin, lactose monohydrate and pullulan as wall materials. The proniosomes were made by the thin-film hydration technique, and were characterized for fortification in milk beverages. Scanning and atomic force microscopic images showed the varying morphology and ultrastructure of the proniosomes. The mean hydrodynamic diameter of 193.57-262.52 nm, polydispersity index of 0.24-0.25 and zeta potential of -15.8 to -24.73 were suggestive of the size, homogeneity and stability of the catechin-loaded proniosomes. X-ray powder diffractograms and Fourier transform infrared (FTIR) spectra provided insight about the interaction between catechins and wall materials. Entrapment efficiency and in vitro release were calculated to determine the extent of nanoencapsulation of catechins and their bioavailability, respectively. The nanoencapsulates were fortified in milk and yogurt to find their organoleptic acceptability.

RESULTS

Moisture content was found to be 20-30 g kg^-1 , indicating longer stability of the proniosomes. Scanning electron microscopic and atomic force microscopic images revealed the ultrastructure and spherical-shaped morphology of proniosomes. Entrapment efficiency of catechins using pullulan as wall material was as high as 83.43%. In vitro release studies revealed the sustained release of catechins from the proniosomes. FTIR and X-ray diffraction spectra revealed the absence of chemical interactions between catechins and encapsulants.

CONCLUSION

Food-grade proniosomes are a good vehicle for fortification of milk and yogurt without noticeable adverse changes in their organoleptic and physicochemical properties, thus increasing the potential for bioavailability of catechins in the gastrointestinal tract. © 2020 Society of Chemical Industry.

Polyphenol-rich leaf of Aphanamixis polystachya averts liver inflammation, fibrogenesis and oxidative stress in ovariectomized Long-Evans rats

Aphanamixis polystachya (Wall.) R.Parker, locally known as Pithraj, is a medicinal herb having enormous traditional applications. However, the scientific rationale underlying the ethnomedicinal claims was not well-founded. The current investigation aimed to explore the mechanistic insights of protective effects of ethanol extract of A. polystachya leaf (PT), given orally, on the chemical-intoxicated hepatic inflammation and fibrosis in Long-Evans female overiectomized rats. The GC-MS and HPLC-DAD analysis of PT revealed the presence of several bioactive metabolites, including polyphenolic compounds. Catechin hydrate, caffeic acid, syringic acid, epicatechin and p-coumaric acid have been identified and quantified in the ethanol extract of PT leaf. Intoxication with CCl₄ developed the oxidative stress, fibrosis and inflammation in liver of rats. Moreover, thiobarbituric acid reactive substances (TBARS), nitric oxide (NO), advanced protein oxidation product (APOP) level were found increased; whereas superoxide dismutase (SOD) and catalase activities in the plasma and liver were decreased in CCl₄ administered rats. Treatment with PT prominently mitigated the oxidative stress (TBARS, NO, APOP), and inflammatory (MPO) markers and improved the endogenous antioxidant enzymes (catalase and SOD) activities in CCl₄-intoxicated rats. Additionally, histological assessment confirmed the clear manifestation of inflammation and fibrosis in the liver of CCl₄-intoxicated rats, which was prevented by PT and silymarin treatment. In conclusion, PT treatment may protect the liver in CCl₄-administered rats, probably by mitigating oxidative stress, inflammation and fibrosis, and also augmenting the function of the antioxidant enzymes.

Catechins within the Biopolymer Matrix-Design Concepts and Bioactivity Prospects

Epidemiological studies and clinical investigations proposed that catechins extracts alone may not provide a sufficient level of bioactivities and promising therapeutic effects to achieve health benefits due to a number of constraints related to poor oral absorption, limited bioavailability, sensitivity to oxidation, etc. Modern scientific studies have reported numerous techniques for the design of micro- and nano-bio-delivery systems as novel and promising strategies to overcome these obstacles and to enhance catechins' therapeutic activity. The objective assessment of their benefits, however, requires a critical comparative estimation of the advantages and disadvantages of the designed catechins-biocarrier systems, their biological activities and safety administration aspects. In this respect, the present review objectively outlines, compares and assesses the recent advances related to newly developed design concepts of catechins' encapsulation into various biopolymer carriers and their release behaviour, with a special emphasis on the specific physiological biofunctionalities of the innovative bioflavonoid/biopolymer delivery systems.

Nanoantioxidants: Recent Trends in Antioxidant Delivery Applications

Antioxidants interact with free radicals, terminating the adverse chain reactions and converting them to harmless products. Antioxidants thus minimize the oxidative stress and play a crucial role in the treatment of free radicals-induced diseases. However, the effectiveness of natural and/or synthetic antioxidants is limited due to their poor absorption, difficulties to cross the cell membranes, and degradation during delivery, hence contributing to their limited bioavailability. To address these issues, antioxidants covalently linked with nanoparticles, entrapped in nanogel, hollow particles, or encapsulated into nanoparticles of diverse origin have been used to provide better stability, gradual and sustained release, biocompatibility, and targeted delivery of the antioxidants with superior antioxidant profiles. This review aims to critically evaluate the recent scientific evaluations of nanoparticles as the antioxidant delivery vehicles, as well as their contribution in efficient and enhanced antioxidant activities.

Bio Pharmaceutics Classification System (BCS) Class IV Drug Nanoparticles: Quantum Leap to Improve Their Therapeutic Index

Purpose: Biopharmaceutics classification system (BCS) class IV compounds, exhibits least oral bioavailability, low solubility and intestinal permeability among all pharmaceutical classes of drugs. Thus, these drugs need more compatible and efficient delivery system. Since, their solubility in various medium, remains a limitation so, polymeric nano coacervates based drug loading with modified approach for them may prove to be a solution ahead. Therefore, in present study Chitosan is opted for encapsulating the BCS class IV drug (Hydrochlorothiazide) to attain better stability, enhanced permeability and lower toxicity.

Methods: For this study, Hydrochlorothiazide (HCTZ) was opted for formulating chitosan based nano-coacervate system.

Results: Optimized HCTZ nanocoacervates exhibited the average particle size of 91.39 ± 0.75 nm with Poly-dispersity index score of 0.159 ± 0.01, indicating homogeneity of colloidal solution. Zeta potential and encapsulation efficiency of HCTZ nanocoacervates were recorded as -18.9 ± 0.8 mV and 76.69 ± 0.82 % respectively. Further, from TEM and SEM evaluation the average particle size for the same were found in conformity (35-50 nm), with almost spherical morphology. Also, the EDX (Electron Dispersive X-ray) spectrometry and FT – IR analysis of optimized formulation indicated the balanced chemical composition and interaction between the polymeric molecules. The HCTZ nano coacervates showed the linear diffusion profile through the dialysis membrane.

Conclusion: We can conclude from the present study that the optimized HCTZ nano coacervates may prove to be a suitable potential option for effective delivery of BCS class IV drugs.