Untargeted metabolomics, optimization of microwave-assisted extraction using Box-Behnken design and evaluation of antioxidant, and antidiabetic activities of sugarcane bagasse.

INTRODUCTION: The fruit wastes, in particular agricultural wastes, are considered potential and inexpensive sources of bioactive compounds. OBJECTIVE: The current study was aimed at the preparation of an optimized extract of sugarcane bagasse using microwave-assisted extraction (MAE) technology and comparative evaluation of chemical composition, antioxidant, and antidiabetic activities with extract prepared through maceration technique. METHODOLOGY: Box-Behnken Design (BDD) with response surface methodology was applied to observe interactions of three independent variables (ethanol concentrations [%], microwave power [W], and extraction time [min]) on the dependent variables (total phenolic content [TPC] and antioxidant status via 2,2-diphenyl-1-picrylhydrazyl [DPPH] to establish optimal extraction conditions. The ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) analysis was applied for untargeted metabolite profiling, and in vitro assays were used for evaluation of the antidiabetic and antioxidant potential of the extract. Moreover, an in silico study was used to predict the interaction of five dominant compounds from the UHPLC-Q-TOF-MS profile against the dipeptidyl peptidase-IV (DPP-IV) enzyme. RESULTS: The optimal conditions for the extraction were established at 60% (v/v) ethanol, 500 W microwave power, and 5 min time with TPC 12.83 ± 0.66 mg GAE/g d.w. and DPPH 45.09 ± 0.07%. The UHPLC-Q-TOF-MS analysis revealed the presence of a total of 106 compounds in the extract. Moreover, the extract prepared through MAE technology presented higher TPC and DPPH findings than the extract prepared through maceration. Similarly, the extract was also found with good antidiabetic activity by inhibiting the DPP-IV enzyme which was also rectified theoretically by a molecular docking study. CONCLUSION: The current study presents a sustainable and an optimized approach for the preparation of sugarcane bagasse extract with functional phytoconstituents and higher antidiabetic and antioxidant activities.

Enhancing protein trapping efficiency of graphene oxide-polybutylene succinate nanofiber membrane via molecular imprinting.

Filtration of biological liquids has been widely employed in biological, medical, and environmental investigations due to its convenience; many could be performed without energy and on-site, particularly protein separation. However, most available membranes are universal protein absorption or sub-fractionation due to molecule sizes or properties. SPMA, or syringe-push membrane absorption, is a quick and easy way to prepare biofluids for protein evaluation. The idea of initiating SPMA was to filter proteins from human urine for subsequent proteomic analysis. In our previous study, we developed nanofiber membranes made from polybutylene succinate (PBS) composed of graphene oxide (GO) for SPMA. In this study, we combined molecular imprinting with our developed PBS fiber membranes mixed with graphene oxide to improve protein capture selectivity in a lock-and-key fashion and thereby increase the efficacy of protein capture. As a model, we selected albumin from human serum (ABH), a clinically significant urine biomarker, for proteomic application. The nanofibrous membrane was generated utilizing the electrospinning technique with PBS/GO composite. The PBS/GO solution mixed with ABH was injected from a syringe and transformed into nanofibers by an electric voltage, which led the fibers to a rotating collector spinning for fiber collection. The imprinting process was carried out by removing the albumin protein template from the membrane through immersion of the membrane in a 60% acetonitrile solution for 4 h to generate a molecular imprint on the membrane. Protein trapping ability, high surface area, the potential for producing affinity with proteins, and molecular-level memory were all evaluated using the fabricated membrane morphology, protein binding capacity, and quantitative protein measurement. This study revealed that GO is a controlling factor, increasing electrical conductivity and reducing fiber sizes and membrane pore areas in PBS-GO-composites. On the other hand, the molecular imprinting did not influence membrane shape, nanofiber size, or density. Human albumin imprinted membrane could increase the PBS-GO membrane's ABH binding capacity from 50 to 83%. It can be indicated that applying the imprinting technique in combination with the graphene oxide composite technique resulted in enhanced ABH binding capabilities than using either technique individually in membrane fabrication. The suitable protein elution solution is at 60% acetonitrile with an immersion time of 4 h. Our approach has resulted in the possibility of improving filter membranes for protein enrichment and storage in a variety of biological fluids.

Recognition properties and competitive assays of a dual dopamine/serotonin selective molecularly imprinted polymer.

A molecularly imprinted polymer (MIP) with dual dopamine/serotonin-like binding sites (DS-MIP) was synthesized for use as a receptor model of study the drug-interaction of biological mixed receptors at a molecular level. The polymer material was produced using methacrylic acid (MAA) and acrylamide (ACM) as functional monomers, N,N'-methylene bisacrylamide (MBAA) as cross-linker, methanol/water mixture (4:1, v/v) as porogen and a mixture of dopamine (D) and serotonin (S) as templates. The prepared DS-MIP exhibited the greatest rebinding of the template(s) in aqueous methanol solution with decreased recognition in acetonitrile, water and methanol solvent. The binding affinity and binding capacity of DS-MIP with S were found to be higher than those of DS-MIP with D. The selectivity profiles of DS-MIP suggest that the D binding site of DS-MIP has sufficient integrity to discriminate between species of non-optimal functional group orientation, whilst the S binding site of DS-MIP is less selective toward species having structural features and functional group orientations different from S. The ligand binding activities of a series of ergot derivatives (ergocryptine, ergocornine, ergocristine, ergonovine, agroclavine, pergolide and terguride) have been studied with the DS-MIP using a competitive ligand binding assay protocol. The binding affinities of DS-MIP were demonstrated in the micro- or submicro-molar range for a series of ergot derivatives, whereas the binding affinities were considerably greater to natural receptors derived from the rat hypothalamus. The DS-MIP afforded the same pattern of differentiation as the natural receptors, i.e. affinity for the clavines > lysergic acid derivatives > ergopeptines. The results suggest that the discrimination for the ergot derivatives by the dopamine and serotonin sites of DS-MIP is due to the structural features and functional orientation of the phenylethylamine and indolylethylamine entities at the binding sites, and the fidelity of the dopamine and serotonin imprinted cavities.