Application of integrative cloud point extraction and concentration for the analysis of polyphenols and alkaloids in mulberry leaves

Analysis of White Mulberry Leaves and Dietary Supplements, ATR-FTIR Combined with Chemometrics for the Rapid Determination of 1-Deoxynojirimycin

Diabetes mellitus is a metabolic disease affecting more people every year. The treatment of diabetes and its complications involve substantial healthcare expenditures. Thus, there is a need to identify natural products that can be used as nutraceuticals to prevent and treat early-stage diabetes. White mulberry (Morus alba L.) is a plant that has been used in traditional Chinese medicine for thousands of years due to its many beneficial biological properties. White mulberry leaves are a source of 1-deoxynojirimycin (DNJ), which, due to its ability to inhibit α-glucosidase, can be used to regulate postprandial glucose concentration. In addition to consuming dried white mulberry leaves as herbal tea, many functional foods also contain this raw material. The development of the dietary supplements market brings many scientific and regulatory challenges to the safety, quality and effectiveness of such products containing concentrated amounts of nutraceuticals. In the present study, the quality of 19 products was assessed by determining the content of DNJ, selected (poly)phenols and antioxidant activity (DPPH^• assay). Nine of these products were herbal teas, and the other samples were dietary supplements. These results indicate the low quality of tested dietary supplements, the use of which (due to the low content of nutraceuticals) cannot bring the expected beneficial effects on health. Moreover, a method for determining the content of DNJ (the essential component for antidiabetic activity) based on ATR-FTIR spectroscopy combined with PLS regression has been proposed. This might be an alternative method to the commonly used chromatographic process requiring extraction and derivatization of the sample. It allows for a quick screening assessment of the quality of products containing white mulberry leaves.

Current development of bioanalytical sample preparation techniques in pharmaceuticals

Sample preparation is considered as the bottleneck step in bioanalysis because each biological matrix has its own unique challenges and complexity. Competent sample preparation to extract the desired analytes and remove redundant components is a crucial step in each bioanalytical approach. The matrix effect is a key hurdle in bioanalytical sample preparation, which has gained extensive consideration. Novel sample preparation techniques have advantages over classical techniques in terms of accuracy, automation, ease of sample preparation, storage, and shipment and have become increasingly popular over the past decade. Our objective is to provide a broad outline of current developments in various bioanalytical sample preparation techniques in chromatographic and spectroscopic examinations. In addition, how these techniques have gained considerable attention over the past decade in bioanalytical research is mentioned with preferred examples. Modern trends in bioanalytical sample preparation techniques, including sorbent-based microextraction techniques, are primarily emphasized.

•

Bioanalytical sampling techniques are described with suitable applications in pharmaceuticals.

•

The pros and cons of each bioanalytical sampling techniques are described.

•

Relevant biological matrices are outlined.

Microcystins can be extracted from Microcystis aeruginosa using amino acid-derived biosurfactants

Microcystin, a cyanotoxin produced by Microcystis aeruginosa growing in eutrophic waters, can promote liver tumors in people ingesting contaminated water. To date, water treatment systems have not been effective in removing or degrading these cyanotoxins. In this work, we investigated the inhibitory activity of surfactants on the growth of M. aeruginosa and their application to extract the intracellular produced cyanotoxins. The experiments involving growth inhibition and extraction of cyanotoxins were carried out using the non-biodegradable surfactant cetyl trimethyl ammonium bromide (CTAB) in addition to other biodegradable surfactants. These were Tween 80 and surfactants derived from amino acids and peptides, respectively, from arginine, SDA, and hydrolyzed peptone, SDP. We demonstrated that the tested surfactants could be used to inhibit the growth of M. aeruginosa. At this point, CTAB and SDA proved to be the most competent surfactants in reducing cyanobacterial growth. Moreover, microcystins have been successfully removed from the water employing a cloud point extraction protocol based on the use of these surfactants and ammonium sulfate.

Evaluation and development of a novel pre-treatment method for mulberry leaves to enhance their bioactivity via enzymatic degradation of GAL-DNJ to DNJ

Mulberry leaves are rich in 1-deoxynojirimycin (DNJ) and 2-O-α-D-galactopyranosyl-deoxynojirimycin (GAL-DNJ). Compared to DNJ, the bioactive potency of GAL-DNJ is low. We proposed that the conversion of GAL-DNJ into DNJ may improve its bioavailability. We evaluated this hypothesis and constructed a novel enzymatic-based method to induce the hydrolysis of GAL-DNJ to DNJ in order to improve the therapeutic potency of mulberry leaves.

Nanomicellar Extraction of Polyphenols-Methodology and Applications Review

The selection of the appropriate extraction method is crucial, especially for the receiving of active substances from plant material. The extraction using supercritical liquids and micellar-mediated extraction (MME) is the most advantageous among the alternative methods to classical solid-liquid extraction. However, the latter seems to be the best solution when the desired actives are polar. The following article presents a comprehensive review of the micellar-mediated extraction method in the last decade. The theoretical principle of the process was also refreshed and the current state of knowledge on the applications for analytical and manufacturing purposes was summarized.

A comprehensive review on the production, pharmacokinetics and health benefits of mulberry leaf iminosugars: Main focus on 1-deoxynojirimycin, d-fagomine, and 2-O-ɑ-d-galactopyranosyl-DNJ

Mulberry leaves are rich in biologically active compounds, including phenolics, polysaccharides, and alkaloids. Mulberry leaf iminosugars (MLIs; a type of polyhydroxylated alkaloids), in particular, have been gaining increasing attention due to their health-promoting effects, including anti-diabetic, anti-obesity, anti-hyperglycemic, anti-hypercholesterolemic, anti-inflammatory, and gut microbiota-modulatory activities. Knowledge regarding the in vivo bioavailability and bioactivity of MLIs are crucial to understand their role and function and human health. Therefore, this review is aimed to comprehensively summarize the existing studies on the oral pharmacokinetics and the physiological significance of selected MLIs (i.e.,1-deoxynojirimycin, d-fagomine, and 2-O-ɑ-d-galactopyranosyl-DNJ). Evidence have suggested that MLIs possess relatively good uptake and safety profiles, which support their prospective use for oral intake; the therapeutic potential of these compounds against metabolic and chronic disorders and the underlying mechanisms behind these effects have also been studied in in vitro and in vivo models. Also discussed are the biosynthetic pathways of MLIs in plants, as well as the agronomic and processing factors that affect their concentration in mulberry leaves-derived products.

Novel bayberry-and-honeycomb-like magnetic surface molecularly imprinted polymers for the selective enrichment of rutin from Sophora japonica

Rutin (RT), a widely distributed natural flavonoid compound, has been generally utilized as an important active ingredient owing to its considerable biomedical and economic value. Inspired by the structure features of densely-packed bayberry and well-orientated honeycomb, a novel type of magnetic molecularly imprinted polymers (HB-TI-MMIPs) with abundant high-affinity and uniformly-distributed binding sites was rationally constructed for the selective enrichment of RT from Sophora japonica. The polymerization conditions, physicochemical properties, and adsorption performance of the imprinted nanomaterials were systematically investigated. The optimized HB-TI-MMIPs display a high adsorption capacity, fast adsorption rate, and satisfactory selectivity towards RT. Meanwhile, the proposed analytical methodology using HPLC, with HB-TI-MMIPs as adsorbents, successfully applied to enrich and detect RT from Sophora japonica with high recoveries (87.2-94.6%) and good RSDs (lower than 4.3%). Therefore, the fabricated HB-TI-MMIPs with a fast magnetic responsivity and desirable adsorption performance would be attractive in plant active ingredients extraction fields.

A Glimpse into the Extraction Methods of Active Compounds from Plants

Naturally active compounds are usually contained inside plants and materials thereof. Thus, the extraction of the active compounds from plants needs appropriate extraction methods. The commonly employed extraction methods are mostly based on solid-liquid extraction. Frequently used conventional extraction methods such as maceration, heat-assisted extraction, Soxhlet extraction, and hydrodistillation are often criticized for large solvent consumption and long extraction times. Therefore, many advanced extraction methods incorporating various technologies such as ultrasound, microwaves, high pressure, high voltage, enzyme hydrolysis, innovative solvent systems, adsorption, and mechanical forces have been studied. These advanced extraction methods are often better than conventional methods in terms of higher yields, higher selectivity, lower solvent consumption, shorter processing time, better energy efficiency, and potential to avoid organic solvents. They are usually designed to be greener, more sustainable, and environment friendly. In this review, we have critically described recently developed extraction methods pertaining to obtaining active compounds from plants and materials thereof. Main factors that affect the extraction performances are tuned, and extraction methods are chosen in line with the properties of targeted active compounds or the objectives of extraction. The review also highlights the advancements in extraction procedures by using combinations of extraction methods to obtain high overall yields or high purity extracts.

Sequential extraction and enrichment of flavonoids from Euonymus alatus by ultrasonic-assisted polyethylene glycol-based extraction coupled to temperature-induced cloud point extraction

A green method for simultaneous extraction and enrichment of flavonoids from Euonymus alatus was developed by ultrasonic-assisted extraction (UAE) and temperature-induced cloud point extraction (TICPE) using PEG-base aqueous solution as the extractant. Based on screening different molecular weights of PEGs, PEG-400/water was used as the extractant, and the effects of key factors on extraction yields of flavonoids were investigated by single-factor experiments and response surface methodology (RSM). The optimum conditions of UAE were as follows: PEG-400 concentration of 16% (w/w), particle size of 80 mesh, solvent-to-material ratio of 60:1, extraction temperature of 90 °C and extraction time of 15 min. The results obtained by validation experiments were consistent with the values predicted by RSM. Temperature-induced formation of the aqueous two-phase system (ATPS) and TICPE process were further investigated by controlling temperature and adding (NH₄)₂SO₄. In the presence of (NH₄)₂SO₄, the ATPS formed at 75 ℃ and pH 3.5 could effectively improve separation and recovery of flavonoids with enrichment factor of above five times. Gallic acid, catechin, dihydromyricetin and ellagic acid in the extract were identified and confirmed by UPLC-Q-TOF-MS and the corresponding standards. The UAE-TICPE coupled to HPLC was successfully applied for extraction and determination of flavonoids in two batches of Euonymus alatus. The extraction yields of catechin, dihydromyricetin and total flavonoids were 0.377-0.684 mg/g, 1.091-1.353 mg/g and 2.612-3.146 mg/g, respectively. Compared to conventional extraction methods, PEG-based UAE integrated with TICPE in one-step procedure exhibited higher extraction efficiency and better extraction selectivity.

Recent advances of green pretreatment techniques for quality control of natural products

A few advancing technologies for natural product analysis have been widely proposed, which focus on decreasing energy consumption and developing an environmentally sustainable manner. These green sample pretreatment and analysis methods following the green Analytical Chemistry (GAC) criteria have the advantage of improving the strategy of chemical analyses, promoting sustainable development to analytical laboratories, and reducing the negative effects of analysis experiments on the environment. A few minimized extraction methodologies have been proposed for replacing the traditional methods in the quality evaluation of natural products, mainly including solid-phase microextraction (SPME) and liquid phase microextraction (LPME). These procedures not only have no need for large numbers of samples and toxic reagent, but also spend a small amount of extraction and analytical time. This overview aims to list out the main green strategies on the application of quality evaluation and control for natural products in the past 3 years.