Quercetin Fatty Acid Monoesters (C2:0-C18:0): Enzymatic Preparation and Antioxidant Activity

Herbal bioactive-loaded biopolymeric formulations for wound healing applications

Recent advancements in wound healing technologies focus on incorporating herbal bioactives into biopolymeric formulations. A biocompatible matrix that promotes healing is provided by biopolymeric wound dressings. These dressings use components such as ulvan, hyaluronic acid, starch, cellulose, chitosan, alginate, gelatin, and pectin. These natural polymers assist in three crucial processes, namely, cell adhesion, proliferation, and moisture retention, all of which are necessary for effective wound repair. Curcumin, quercetin, Aloe vera, Vinca alkaloids, and Centella asiatica are some of the herbal bioactives that are included in biopolymeric formulations. They have powerful anti-inflammatory, antibacterial, and antioxidant activities. Chitosan, cellulose, collagen, alginate, and hyaluronic acid are some of the biopolymers that have shown promise in clinical trials for wound healing. These trials have also confirmed the safety and functional performance of these materials. Their recent advancements in wound care can be understood by the increasing number of patents linked to these formulations. These innovative dressings improve healing outcomes in acute and chronic wounds while minimizing adverse effects by incorporating biopolymers with herbal bioactives in an efficient manner. This review emphasizes that the development of next-generation wound care products can be facilitated via the integration of natural materials and bioactive substances.

Self-assembled metal-coordinated nanoparticles for synergistic energy metabolism inhibition and low-temperature photothermal therapy

Photothermal therapy has been observed to upregulate the heat shock protein 70 (HSP 70) expression in tumor cells, consequently diminishing the anti-tumor efficacy of the treatment. The expression of HSP 70 is intricately linked to the adenosine triphosphate (ATP) levels within tumors, suggesting that modulating energy metabolism could potentially enhance the effectiveness of photothermal therapy. To address these challenges, ATO-QUE-Fe2+-PVP K30 nanoparticles (AQFP NPs) were synthesized through the coordinated self-assembly of the oxidative phosphorylation (OXPHOS) inhibitor atovaquone (ATO) and the glycolysis inhibitor quercetin (QUE) with ferrous ions (Fe2+) for synergetic energy depletion and low-temperature photothermal therapy (LTPTT). The synthesized AQFP NPs exhibited a small particle size and demonstrated high encapsulation efficiency of ATO and QUE. AQFP NPs could effectively downregulate the expression of HSP 70 by inhibiting the activity of mitochondrial complex Ⅲ and hexokinase Ⅱ (HK Ⅱ) to inhibiting suppress mitochondrial OXPHOS and glycolytic pathways in 4T1 cells, respectively. This inhibition resulted in a reduction of ATP levels within tumor cells, subsequently leading to decreased expression of HSP 70 and enhancing the therapeutic efficacy of LTPTT. Furthermore, AQFP NPs can remarkably inhibit the growth of tumors when subjected to laser irradiation. Furthermore, the analysis of blood biochemical indices and hematoxylin and eosin (H&E) staining of major organs suggested that AQFP NPs exhibit a preferable in vivo safety profile. In conclusion, the anti-tumor efficacy of LTPTT could be substantially enhanced by concurrently inhibiting OXPHOS and glycolysis, thereby offering an innovative therapeutic for the clinical treatment of tumors.

Comprehensive Overview of Interface Strategies in Implant Osseointegration

With the improvement of implant design and the expansion of application scenarios, orthopedic implants have become a common surgical option for treating fractures and end‐stage osteoarthritis. Their common goal is rapidly forming and long‐term stable osseointegration. However, this fixation effect is limited by implant surface characteristics and peri‐implant bone tissue activity. Therefore, this review summarizes the strategies of interface engineering (osteogenic peptides, growth factors, and metal ions) and treatment methods (porous nanotubes, hydrogel embedding, and other load‐release systems) through research on its biological mechanism, paving the way to achieve the adaptation of both and coordination between different strategies. With the transition of the osseointegration stage, interface engineering strategies have demonstrated varying therapeutic effects. Especially, the activity of osteoblasts runs almost through the entire process of osseointegration, and their physiological activities play a dominant role in bone formation. Furthermore, diseases impacting bone metabolism exacerbate the difficulty of achieving osseointegration. This review aims to assist future research on osseointegration engineering strategies to improve implant‐bone fixation, promote fracture healing, and enhance post‐implantation recovery.

Metabolic, toxicological, chemical, and commercial perspectives on esterification of dietary polyphenols: a review

Molecular modifications have been practiced for more than a century and nowadays they are widely applied in food, pharmaceutical, or other industries to manipulate the physicochemical, bioactivity, metabolic/catabolic, and pharmacokinetic properties. Among various structural modifications, the esterification/O-acylation has been well-established in altering lipophilicity and bioactivity of parent bioactive compounds, especially natural polyphenolics, while maintaining their high biocompatibility. Meanwhile, various classic chemical and enzymatic protocols and other recently emerged cell factory technology are being employed as viable esterification strategies. In this contribution, the main motivations of phenolic esterification, including the tendency to replace synthetic alkyl phenolics with safer alternatives in the food industry to improve the bioavailability of phenolics as dietary supplements/pharmaceuticals, are discussed. In addition, the toxicity, metabolism, and commercial application of synthetic and natural phenolics are briefly introduced. Under these contexts, the mechanisms and reaction features of several most prevalent chemical and enzymatic esterification pathways are demonstrated. In addition, insights into the studies of esterification modification of natural phenolic compounds and specific pros/cons of various reaction systems with regard to their practical application are provided.

The antioxidant and anticancer activity of Quercus coccifera plant leaves extracts

Quercus species are one of the medicinal plants that commonly used in the treatment of different diseases. Quercus coccifera (Q. coccifera) is part of the Quercus species which grow in Jordan and used in traditional folklore medicine. The aim of this study is to confirm the ability of (Q. coccifera) leaves extracts to exert anticancer activity. In this study, an extraction method of the dried-leaves using different polarity solvents was used. Extracts were pre-evaluated for antioxidant and anticancer activities while active extracts were used to measure half maximal effective concentration (EC50) against 2,2-Diphenyl-1-picrylhydrazyl (DPPH), and Half-maximal inhibitory concentration (IC50) against cancer cells. Methanol, boiled and microwaved water extracts had greater than 80 % antioxidant activity, and the strongest activity, of more than 99 %, was boiled water extract. Similarly, the pre-evaluation treatments of cancer cell lines indicated a strong biological activity of more than 70 % from the previously mentioned extracts, and the highest activity, of greater than 90 %, was from boiled water extracts against all cancer cell lines. The highest EC50 against DPPH was obtained by using 0.009 mg/ml boiled water extracts, which was lower than positive control quercetin. In the same manner, lung, breast, and prostate cancer cell lines were highly affected by boiled water extracts with IC50 of 14.1, 7.2, and 25.1 µg/ml, respectively, and a selectivity index (SI) of greater than 4.71. Q. coccifera leaves extracts show promising ability to be a source of a new anticancer therapeutics.

Overview of alkyl quercetin lipophenol synthesis and its protective effect against carbonyl stress involved in neurodegeneration

Oxidative stress and carbonyl stress resulting from the toxicity of small aldehydes are part of the detrimental mechanisms leading to neuronal cell loss involved in the progression of neurodegenerative diseases such as Alzheimer's disease. Polyunsaturated alkylated lipophenols represent a new class of hybrid molecules that combine the health benefits of anti-inflammatory omega-3 fatty acids with the anti-carbonyl and oxidative stress (anti-COS) properties of (poly)phenols in a single pharmacological entity. To investigate the therapeutic potential of quercetin-3-docosahexaenoic acid-7-isopropyl lipophenol in neurodegenerative diseases, three synthetic pathways using chemical or chemo-enzymatic strategies were developed to access milligram or gram scale quantities of this alkyl lipophenol. The protective effect of quercetin-3-DHA-7-iPr against cytotoxic concentrations of acrolein (a carbonyl stressor) was assessed in human SHSY-5Y neuroblastoma cells to underscore its ability to alleviate harmful mechanisms associated with carbonyl stress in the context of neurodegenerative diseases.

Strategy for the Enzymatic Acylation of the Apple Flavonoid Phloretin Based on Prior α-Glucosylation

The acylation of flavonoids serves as a means to alter their physicochemical properties, enhance their stability, and improve their bioactivity. Compared with natural flavonoid glycosides, the acylation of nonglycosylated flavonoids presents greater challenges since they contain fewer reactive sites. In this work, we propose an efficient strategy to solve this problem based on a first α-glucosylation step catalyzed by a sucrose phosphorylase, followed by acylation using a lipase. The method was applied to phloretin, a bioactive dihydrochalcone mainly present in apples. Phloretin underwent initial glucosylation at the 4'-OH position, followed by subsequent (and quantitative) acylation with C8, C12, and C16 acyl chains employing an immobilized lipase from Thermomyces lanuginosus. Electrospray ionization-mass spectrometry (ESI-MS) and two-dimensional nuclear magnetic resonance spectroscopy (2D-NMR) confirmed that the acylation took place at 6-OH of glucose. The water solubility of C8 acyl glucoside closely resembled that of aglycone, but for C12 and C16 derivatives, it was approximately 3 times lower. Compared with phloretin, the radical scavenging capacity of the new derivatives slightly decreased with 2,2-diphenyl-1-picrylhydrazyl (DPPH) and was similar to 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+). Interestingly, C12 acyl-α-glucoside displayed an enhanced (3-fold) transdermal absorption (using pig skin biopsies) compared to phloretin and its α-glucoside.

Mechanism of melanogenesis inhibition by Keggin-type polyoxometalates

Abnormal melanin overproduction can result in hyperpigmentation syndrome in human skin diseases and enzymatic browning of fruits and vegetables. Recently, our group found that Keggin-type polyoxometalates (POMs) can efficiently inhibit tyrosinase activity. However, it remains unclear whether Keggin-type POMs exhibit optimal effects in vivo. Additionally, the inhibitory effect and mechanism of action of POMs on cellular tyrosinase activity and melanogenesis have been rarely reported. Here we demonstrate that our screened and synthesised PMo11Zn and GaMo12 show superior inhibitory effects on melanin formation as well as inhibition of cellular tyrosinase activity compared to other Keggin-type POMs. Intriguingly, we reveal that Keggin-type POMs competitively bind to tyrosinase mainly through more interactions with Cu2+ ions and the amino acid residue is capable of forming van der Waals, cation-π and hydrogen bonds, resulting in a reversible non-covalent complex formation. Our findings provide valuable insights into the design, synthesis and screening of polyoxometalates as multifunctional metallodrugs and food preservatives against hyperpigmentation.