Improvement of the stabilities and antioxidant activities of polyphenols from the leaves of Chinese star anise (Illicium verum Hook. f.) using β-cyclodextrin-based metal-organic frameworks

Encapsulation of apigenin into β-cyclodextrin metal-organic frameworks with high embedment efficiency and stability

In an effort to improve the application performance of apigenin, β-cyclodextrin metal-organic frameworks (BCDMOFs) known as porous materials were used to encapsulate apigenin via an innovative pH-adjusted method. The embedment efficiency had a significant positive pH dependence, reaching a maximum of 79.2 % ± 1.2 % at pH12. Scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis demonstrated formation of apigenin/BCDMOFs composites, and exposure of BCDMOFs pores facilitated high embedment efficiency. Storage stability experiment and kinetic analysis showed degradation of apigenin/BCDMOFs composites was less than that of apigenin alone. Apigenin stability was increased by approximately 18 % after 7 days. BCDMOFs effectively encapsulated and controlled the release of apigenin, and the composites exhibited improved application performance in vitro.

Pore engineering of micro/mesoporous nanomaterials for encapsulation, controlled release and variegated applications of essential oils

Essential oils have become increasingly popular in fields of medical, food and agriculture, owing to their strongly antimicrobial, anti-inflammation and antioxidant effects, greatly meeting demand from consumers for healthy and safe natural products. However, the easy volatility and/or chemical instability of active ingredients of essential oils (EAIs) can result in the loss of activity before realizing their functions, which have greatly hindered the widely applications of EAIs. As an emerging trend, micro/mesoporous nanomaterials (MNs) have drawn great attention for encapsulation and controlled release of EAIs, owing to their tunable pore structural characteristics. In this review, we briefly discuss the recent advances of MNs that widely used in the controlled release of EAIs, including zeolites, metal-organic frameworks (MOFs), mesoporous silica nanomaterials (MSNs), and provide a comprehensive summary focusing on the pore engineering strategies of MNs that affect their controlled-release or triggered-release for EAIs, including tailorable pore structure properties (e.g., pore size, pore surface area, pore volume, pore geometry, and framework compositions) and surface properties (surface modification and surface functionalization). Finally, the variegated applications and potential challenges are also given for MNs based delivery strategies for EAIs in the fields of healthcare, food and agriculture. These will provide considerable instructions for the rational design of MNs for controlled release of EAIs.

Development and characterization of trans-anethole-containing solid lipid microparticles: antiinflammatory and gastroprotective effects in experimental inflammation

The present study prepared, optimized, and characterized solid lipid microparticles that contained trans-anethole (SLMAN), evaluated their antiinflammatory activity in acute and chronic inflammation models, and investigated their effects on the gastric mucosa in arthritic rats. The microparticles were obtained by a hot homogenization process and characterized by physicochemical analyses. The acute inflammatory response was induced by an intradermal injection of 0.1 ml of carrageenan solution (200 μg) in the hind paw. The rats were treated orally with a single dose of SLMAN 1 h before induction of the inflammatory response. The chronic inflammatory response was induced by the subcutaneous application of 0.1 ml of complete Freund's adjuvant suspension (500 µg) in the hind paw. SLMAN was orally administered, starting on the day of arthritis induction, and continued for 21 days. The results showed that SLMAN was obtained with good encapsulation efficiency. Treatment with SLMAN at doses of 25 and 50 mg/kg was as effective as trans-anethole (AN) at a dose of 250 mg/kg on acute and chronic inflammatory responses. Histological analyses showed that treatment with SLMAN did not aggravate lesions in the gastric mucosa in arthritic rats. These results indicated that treatment with SLMAN at a dose that was 5-10 times lower than non-encapsulated AN exerted an inhibitory effect on acute and chronic inflammatory responses, suggesting the better bioavailability and efficacy of microencapsulated AN without aggravating lesions in the gastric mucosa in arthritic rats.

Synthesis and potential applications of cyclodextrin-based metal-organic frameworks: a review

Metal-organic frameworks are porous polymeric materials formed by linking metal ions with organic bridging ligands. Metal-organic frameworks are used as sensors, catalysts for organic transformations, biomass conversion, photovoltaics, electrochemical applications, gas storage and separation, and photocatalysis. Nonetheless, many actual metal-organic frameworks present limitations such as toxicity of preparation reagents and components, which make frameworks unusable for food and pharmaceutical applications. Here, we review the structure, synthesis and properties of cyclodextrin-based metal-organic frameworks that could be used in bioapplications. Synthetic methods include vapor diffusion, microwave-assisted, hydro/solvothermal, and ultrasound techniques. The vapor diffusion method can produce cyclodextrin-based metal-organic framework crystals with particle sizes ranging from 200 nm to 400 μm. Applications comprise food packaging, drug delivery, sensors, adsorbents, gas separation, and membranes. Cyclodextrin-based metal-organic frameworks showed loading efficacy of the bioactive compounds ranging from 3.29 to 97.80%.

Antioxidant, Anti-Obesity, and Hypolipidemic Effects of Polyphenol Rich Star Anise (Illicium verum) Tea in High-Fat-Sugar Diet-Induced Obesity Rat Model

Star anise (Illicium verum Hook. fil.) is commonly utilized as a culinary and medicinal fruit and is most famous in indigenous systems of medicine. The present research work aims to appraise and validate the potential of polyphenol-rich star anise tea (SAT) on oxidative stress, obesity and related biochemical parameters in high-fat-sugar-diet (HFSD)-induced obesity model in rats. SAT was prepared using the traditional method in warm water. The Reverse Phase High Pressure Liquid Chromatography (RP-HPLC) analysis was performed for the simultaneous determination of phenolic acids and flavonoids in SAT. Two doses (250 and 500 mg/kg body weight) were selected to investigate the anti-obesity potential of SAT using HFSD-induced obese rat model. Major (>5 mg/100 mL) phenolic acids in SAT were p-coumeric acid, gallic aid, cinamic acid, chlorogenic acid and ferulic acid while catechin and rutin were the major flavonoids detected in the SAT. SAT exhibited 51.3% DPPH radical scavenging activity. In vivo study showed that higher doses of SAT (500 mg/kg body weight) significantly reduced the body weight increase (74.82%) and BMI (0.64 g/cm2). Moreover, significant reductions in the levels of serum total cholesterol, triglyceride, LDL and VLDL were recorded in all the treatment groups in comparison to the HFSDC group. Furthermore, SAT reduced the alterations in MDA, SOD and GSH levels of experimental groups thus showing the potential against oxidative stress. The SAT-500 group showed a significant decrease in the elevated kidney and liver weights and atherogenic index in comparison to the HFSDC group. The present study proved that SAT exhibited strong protective effects against obesity and oxidative stress, especially at higher doses.

Cyclodextrin metal-organic frameworks and derivatives: recent developments and applications

While there is a tremendous amount of scientific research on metal organic frameworks (MOFs) for gas storage/separation, catalysis and energy storage, the development and application of biocompatible MOFs still poses major challenges. In general, they can be synthesised from various biocompatible linkers and metal ions but particularly cyclodextrins (CDs) as cyclic oligosaccharides are an astute choice for the former. Although the field of CD-MOF materials is still in the early stages and their design and fabrication comes with many hurdles, the benefits coming from CDs built in a porous framework are exciting. Versatile host-guest complexation abilities, high encapsulation capacity and hydrophilicity are among the valuable properties inherent to CDs and offer extended and novel applications to MOFs. In this review, we provide an overview of the state-of-the-art synthesis, design, properties and applications of these materials. Initially, a rationale for the preparation of CD-based MOFs is provided, based on the chemical and structural properties of CDs and including their advantages and disadvantages. Further on, the review exhaustively surveys CD-MOF based materials by categorising them into three sub-classes, namely (i) CD-MOFs, (ii) CD-MOF hybrids, obtained via combination with external materials, and (iii) CD-MOF-derived materials prepared under pyrolytic conditions. Subsequently, CD-based MOFs in practical applications, such as drug delivery and cancer therapy, sensors, gas storage, (enantiomer) separations, electrical devices, food industry, and agriculture, are discussed. We conclude by summarizing the state of the art in the field and highlighting some promising future developments of CD-MOFs.

An ultrasensitive high-performance baicalin sensor based on C3N4-SWCNTs/reduced graphene oxide/cyclodextrin metal-organic framework nanocomposite

Baicalin (Bn) obtained from natural plants has been found to exhibit significant antiviral activity against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Herein, a novel ultrasensitive Bn electrochemical sensor was proposed based on graphitized carbon-nitride - single-walled carbon nanotube nanocomposites (C₃N₄-SWCNTs), reduced graphene oxide (rGO) and electrodeposited cyclodextrin-metal organic framework (CD-MOF). The sensing nanomaterials were characterized by X-ray diffraction spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. Under optimal conditions, the sensor exhibited sensitive detection of Bn in a wide linear range of 1 × 10^-9-5 × 10^-7 M with an LOD of 4.6 × 10^-10 M and a sensitivity of 220 A/M, and it showed satisfactory stability and accuracy for detecting Bn in real samples (human serum and bear bile scutellaria eye drops). In addition, the electrochemical reaction sites and redox mechanism of Bn were revealed through electrochemical behavior and density functional theory. This work provided an insightful solution for detecting Bn, and extensive potential applications could be further expected.

Two new phenolic glycosides from the fruits of Illicium verum

Two new phenolic glycosides (1-2) and eleven known compounds (3-13) were isolated from the fruits of Illicium verum Hook.f. using silica-gel column and preparative middle pressure liquid chromatography (MPLC). The structures of the compounds were elucidated by NMR spectroscopic data. Among them, compounds 3, 5, and 10 were isolated from the family Magnoliaceae for the first time. Additionally, all the compounds were evaluated for their anti-complementary activities against the classical pathway (CP) and the alternative pathway (AP).

Precision release systems of food bioactive compounds based on metal-organic frameworks: synthesis, mechanisms and recent applications

Controlled release (CR) systems have become a powerful platform for accurate and effective delivery of bioactive compounds (BCs). Metal-organic frameworks (MOFs) are one of the best BCs-loaded carriers for CR systems. In the review, the principles and methods of the design and synthesis of MOFs-CR systems are summarized in detail, the encapsulation of BCs by MOFs and CR mechanisms are explored, and their biological toxicity and biocompatibility are highlighted and applications in the food industry are discussed. In addition, current challenges in this field and possible future development directions are also presented. MOFs have been proven to encapsulate BCs effectively, including gaseous and solid molecules, and control the release of BCs through spontaneous diffusion or stimulus-response. The solubility, stability and biocompatibility of BCs encapsulated by MOFs are greatly improved, which expands their applications in foods. The effective CR of BCs by MOFs-CR systems is beneficial to assist in maintaining or even improving the quality and safety of food, reduce the BCs usage while increasing the bioavailability. Low- or non-biotoxic MOFs, especially bio-MOFs, show greater application prospects in the food industry.

Multistage Extraction of Star Anise and Black Pepper Derivatives for Antibacterial, Antioxidant, and Anticancer Activity

Recently, natural resources have attracted considerable interest for their applications in food security and human health problems. Traditional natural spices, such as star anise and black pepper, played important roles in the pharmaceutical and food industries due to their strong pharmacological activity, antioxidant potential and rare complications. In order to achieve biomasses from the natural product with multiple bioactivities, we developed the multistage extraction method to extract and separate various bioactive compounds from these natural plants. Our work demonstrated that various bioactive-rich extractives were achieved using steam distilled- or oxidative-extraction methods with high extraction yields and purity. Furthermore, the extractives in each step can be used not only as bioactive compounds, but also as a resource to further prepare different derivatives during the next extractive step, providing biomass-saving to a great extent. The extractives obtained with high yields and purities (>82%) were identified by ¹H NMR, ¹³C NMR, FTIR, UV-vis, fluorescence spectroscopy, and high-performance liquid chromatography (HPLC). Moreover, these biomasses display potent antibacterial activities against some types of microorganisms such as S.aureus, S.pyogenes, E.coli, and S.typhi with a lowest MIC of 400 μg/ml for the development of antibacterial agents, significant antioxidant activity as the natural antioxidant for enhancing food shelf-life, and excellent anticancer activity that induces significant cancer cell apoptosis. This work showed the different multistage extracts from natural products, which enable them to be applied in the fields of the pharmaceutical industry and the food industry.