Multi-instrumental approach to unravel molecular mechanisms of natural bioactive compounds: Case studies for flavonoids

Deep eutectic solvent extraction of polyphenol from plant materials: Current status and future prospects in food applications

The increasing environmental concerns related to biomass waste have led to the exploration of sustainable methods for extracting bioactive compounds from plant materials, especially polyphenols, which are valued for their health benefits and use in functional foods and natural additives. These bioactive compounds are abundant in fruits, vegetables, tea, and herbs, and encompass flavonoids, phenolic acids, tannins, stilbenes, and lignans. Traditional extraction methods often rely on harmful petrochemical solvents, which pose significant environmental and health risks. In contrast, Deep Eutectic Solvents (DESs) have emerged as an eco-friendly alternative, offering advantages such as low toxicity, cost-efficiency, and a wide range of solubility. This review focused recent advancements in DES-based polyphenol extraction, emphasizing their applications in the food industry. It highlights the potential of DES to efficiently extract polyphenols, improving their bioavailability and stability, and exploring future prospect for enhancing food quality, safety, and functionality through functional foods and natural preservatives.

Comprehensive experimental and computational analysis of endemic Allium tuncelianum: Phytochemical profiling, antimicrobial activity, and In silico studies for potential therapeutic applications

Allium tuncelianum (TG), an endemic garlic species from Tunceli, Turkey, was investigated using a multidisciplinary approach combining experimental and computational methods. Density Functional Theory (DFT) calculations with B3LYP/def2-SVP/def2-TZVP basis sets were employed to analyze electronic properties, reactivity, and stability under gas and ethanol conditions. Headspace/GC-MS identified 10 major components, with diallyl disulfide (48.03 %) and 1-propene (20.72 %) as predominant. Antimicrobial assays revealed potent activity against MRSA, Salmonella paratyphi A, and E. coli, with MIC values as low as 0.063 mg/mL. Antioxidant capacity, evaluated via DPPH, metal chelating, and FRAP assays, showed promising results, with the water extract exhibiting the highest activity (1.74 mg BHT equivalent/mL). DFT and molecular docking studies highlighted key compounds as potential inhibitors of E. coli Gyrase B, with binding energies of -5.68 and -6.07 kcal/mol. ADME predictions indicated favorable drug-like properties, though some compounds showed potential CYP450 interactions and toxicity. This study provides a comprehensive understanding of TG's biochemical profile and therapeutic potential, offering insights for future research and optimization.

Green Extraction of Antioxidant-Rich Flavonoids from Fagonia cretica Using Deep Eutectic Solvents

This study optimized the extraction of flavonoids from Fagonia cretica using deep eutectic solvents (DESs), focusing on key factors such as the type of DES used, molar ratio, water content, solid/liquid ratio, extraction temperature, and time. Among six DESs tested, the betaine-acetic acid combination exhibited the highest extraction efficiency, attributed to its low viscosity (4.98 mPa·s). Optimal extraction conditions were determined to be a 1:4 molar ratio of betaine to acetic acid, a 25% water content, a solid/liquid ratio of 1:60 g/mL, an extraction temperature of 50 °C, and an extraction time of 30 min. Under these conditions, the flavonoid yield was maximized while preserving bioactivity. Antioxidant assays revealed that flavonoids extracted with DESs exhibited superior scavenging activity against DPPH and hydroxyl radical compared to ethanol-extracted flavonoids, highlighting DESs' potential to enhance antioxidant properties. The recyclability of DESs was demonstrated using ultracapacitor porous activated carbon, achieving an 89.78% recovery efficiency. The reused DES maintained a high flavonoid extraction yield, retaining 92% efficiency after six cycles, emphasizing its sustainability and cost-effectiveness. This study establishes DES-based extraction as an environmentally friendly and efficient approach for isolating flavonoids with strong antioxidant properties, offering significant advantages in green chemistry and bioactive compound recovery.

Ultrasonic Enhancement of Aqueous Two-Phase Extraction and Acid Hydrolysis of Flavonoids from Malvaviscus arboreus Cav. Flower for Evaluation of Antioxidant Activity

The ultrasonic-assisted aqueous two-phase extraction (UAATPE) of flavonoid glycosides from Malvaviscus arboreous Cav. flower (MACF) was developed using ethanol/ammonia sulfate systems, followed by the ultrasonic-assisted acid hydrolysis (UAAH) of the top extract with HCl solution. The optimization of UAATPE and UAAH processes was accomplished by single-factor experiments and response surface methodology. As a result, the flavonoid glycosides enriched in the top phase could achieve a maximum yield of 35.9 ± 1.1 mg/g by UAATPE and were completely hydrolyzed by UAAH deglycosylation. The flavonoid glycosides and their hydrolyzates were separated and characterized by high-performance liquid chromatography and ultra-high-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry. Ultrasonic enhancement of the extraction and hydrolysis was explored by comparative study. Furthermore, the in vitro activity of the flavonoid glycosides and the aglycones were comprehensively evaluated by antioxidant activity assays, including ferric-reducing antioxidant power and scavenging DPPH, hydroxyl, and superoxide radicals. All of the IC₅₀ values suggest that the antioxidant activity of flavonoid aglycones was stronger than that of their glucosides and even vitamin C, revealing that the deglycosylated flavonoids from MACF were the more powerful antioxidants. This study provided an effective and eco-friendly strategy for the extraction, separation, and purification of flavonoids from MACF, as well as for the development of the potential flavonoid antioxidants.

Silver@quercetin Nanoparticles with Aggregation-Induced Emission for Bioimaging In Vitro and In Vivo

Fluorescent materials based on aggregation-induced emission luminogens (AIEgens) have unique advantages for in situ and real-time monitoring of biomolecules and biological processes because of their high luminescence intensity and resistance to photobleaching. Unfortunately, many AIEgens require time-consuming and expensive syntheses, and the presence of residual toxic reagents reduces their biocompatibility. Herein, silver@quercetin nanoparticles (Ag@QCNPs), which have a clear core–shell structure, were prepared by redox reaction of quercetin (QC), a polyphenolic compound widely obtained from plants, including those used as foods, and silver ions. Ag@QCNPs show both aggregation-induced luminescence and the distinct plasma scattering of silver nanoparticles, as well as good resistance to photobleaching and biocompatibility. The Ag@QCNPs were successfully used for cytoplasmic labeling of living cells and for computerized tomography imaging in tumor-bearing mice, demonstrating their potential for clinical applications.

Modern Methods of Pre-Treatment of Plant Material for the Extraction of Bioactive Compounds

In this review, recent advances in the methods of pre-treatment of plant material for the extraction of secondary metabolites with high biological activity are presented. The correct preparation of the material for extraction is as important as the selection of the extraction method. This step should prevent the degradation of bioactive compounds as well as the development of fungi and bacteria. Currently, the methods of preparation are expected to modify the particles of the plant material in such a way that will contribute to the release of bioactive compounds loosely bonded to cell wall polymers. This review presents a wide range of methods of preparing plant material, including drying, freeze-drying, convection drying, microwave vacuum drying, enzymatic processes, and fermentation. The influence of the particular methods on the structure of plant material particles, the level of preserved bioactive compounds, and the possibility of their release during the extraction were highlighted. The plant material pre-treatment techniques used were discussed with respect to the amount of compounds released during extraction as well their application in various industries interested in products with a high content of biologically active compounds, such as the pharmaceutical, cosmetics, and food industries.