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Abnormal skin pigmentation commonly occurs during the wound healing process due to the overproduction of melanin. Chicken egg white (CEW) has long been used to improve skin health. Previous published works had found CEW proteins house bioactive peptides that inhibit tyrosinase, the key enzyme of melanogenesis. The current study aimed to evaluate the anti-pigmentation potential and mechanism of the CEW-derived peptide (GYSLGNWVCAAK) and hydrolysates (CEWHmono and CEWHdi), using a cell-based model. All of these peptide and hydrolysates inhibited intracellular tyrosinase activity and melanin level up to 45.39 ± 1.31 and 70.01 ± 1.00%, respectively. GYSLGNWVCAAK and CEWHdi reduced intracellular cAMP levels by 13.38 ± 3.65 and 14.55 ± 2.82%, respectively; however, CEWHmono did not affect cAMP level. Moreover, the hydrolysates downregulated the mRNA expression of melanogenesis-related genes, such as Mitf, Tyr, Trp-1 and Trp-2, but GYSLGNWVCAAK only suppressed Tyr gene expression. Downregulation of the genes may lower the catalytic activities and/or affect the structural stability of TYR, TRP-1 and TRP-2; thus, impeding melanogenesis to cause an anti-pigmentation effect in the cell. Outcomes from the current study could serve as the starting point to understand the underlying complex, multifaceted melanogenesis regulatory mechanism at the cellular level. [ABSTRACT FROM AUTHOR]

Due to the inherent multiple response characteristics in many biological and separation processes, parameter optimization and modelling is usually a daunting task. The integration of Deng's grey incidence model (GRA) and Taguchi optimization (TM) therefore helps in transforming multiple quality characteristics into a single response presented as the grey relational grade (GRG). This was applied to optimize the multiple quality response characteristics in the maceration‐assisted extraction of African cucumber leaves. Two responses and five design factors were selected with L16(25) layout using signal‐to‐noise ratio as a point prediction feature. Under the optimized conditions, the optimum total phenolic content and antioxidant capacity of 0.8569 mg/ml gallic acid equivalence and 0.9259 mg/ml were achieved, respectively. The mass ratio was the highest contributor (38.2%), whereas the maceration time presented the least contribution (9.8%) to the cumulative response grade (GRG). In the neural network analysis, three models were deployed: Levenberg Marquardt backpropagation neural network (LMNN), gradient descent with adaptive learning rate neural network (GDALRNN), and the resilient back‐propagation neural network (RPNN). A better prediction of hold‐out data was achieved with the GDALRNN model, generating lesser absolute deviation error (MADGDALRNN = 0.099), root mean square error (RMSEGDALRNN = 0.1033), relative mean bias error (rMBEGDALRNN = − 0.24), and highest computational time (CTGDALRNN = 8.8), which is expected of an effective model. Based on the GRG and the signal‐to‐noise ratio, the optimum conditions and the neural network model succinctly provided a benchmark for future assessment of complex relationship among extraction variables, which could form the basis for a potential future scale‐up applications. [ABSTRACT FROM AUTHOR]

Introduction: The quality characteristics and stability of phenolic by‐products from Cola nitida wastes are critical factors for drug formulation and food nutraceutical applications. Objectives: In this study, the effect of electromagnetic‐based microwave‐reflux extraction on the total phenolic content, antioxidant capacity, morphological characteristics, physisorption and chromatographic phenolic profiles were successfully investigated. These physicochemical analyses are often employed in the standardisation of dried herbal and food nutraceutical products. Material and methods: In this study, the electromagnetic‐based extraction process was optimised using the Box–Behnken design. The oleoresin bio‐products were subsequently characterised to determine the total phenolic content, morphological and microstructural degradation. These analyses were conducted to elucidate the effect of the microwave heating on the C. nitida pod powder. Results: From the predicted response, the optimal percentage yield was achieved at 26.20% under 5.39 min of irradiation time, 440 W microwave power and oven temperature of 55°C. Moreover, the rapid estimation of the phenolic content and antioxidant capacity were recorded at 124.84 ± 0.064 mg gallic acid equivalent (GAE)/g dry weight (d.w.) and 6.93 ± 0.34 μg/mL, respectively. The physicochemical characterisation results from the Fourier‐transform infrared spectroscopy, field emission scanning electron microscopy and physisorption analyses showed remarkable changes in the micro‐surface area (13.66%) characteristics. Conclusion: The recorded optimal conditions established a basis for future scale‐up of microwave extraction parameters with a potential for maximum yield. The physiochemical characterisation revealed the functional characteristics of C. nitida and their tolerance to microwave heating. The preservation of these heat‐sensitive polyphenolic constituents and their microchemical identities are largely dependent on the appropriate choice of extraction method. In this study, the effect of microwave‐processing on the phenolic constituents, antioxidant activity, physicochemical characteristics were succinctly investigated. Moreover, the recorded optimal conditions established a basis for future standardization and eventual scale‐up with maximum yield. The result from this investigation could be used as blueprints for post‐harvest processing, storage, and valorisation of C. nitida pod into useful bioproducts. [ABSTRACT FROM AUTHOR]

This study succinctly investigated the impacts of energy-based functions on the total phenolic and physicochemical characteristics of Euphorbia hirta. The results of the orthogonal experimental array gave an optimum microwave condition at 2 min of irradiation time, 400 W of microwave power, 12 mL/g of solvent loading, 40°C of the temperature level, and 50% of ethanol concentration. The results from the thermal stability curves revealed initial 89.96% weight retention (< 100°C) from moisture loss and the potential formation of sixty-six phenolic constituents from the disorientated microstructure (<170°C). The above results established the satisfactory performance of the microwave-reflux extraction method. [ABSTRACT FROM AUTHOR]

[Display omitted] • Deep eutectic solvents were prepared using citric acid monohydrate and glycerol. • The properties of DES were affected by the molar ratio of citric acid monohydrate and glycerol. • The molar ratio of DES influences the pH and affected the extraction efficiency. • DES has a potential as an extraction medium for polysaccharide. Organic acids are often used as an extraction media to separate bioactive compounds in animal or plant sources. However, organic acids have a big drawback on extraction efficiency such as low yields and harmful to environment. In this study, different molar ratios of citric acid monohydrate (CAM)–glycerol (GLY) based deep eutectic solvents (DESs) were successfully produced as a new extraction media with different physicochemical characteristics. All the synthesized DESs were observed as a clear, homogenous liquid and remained stable as liquids at room temperature throughout the time. FTIR analysis confirmed the hydrogen bond and electrostatic interactions within the produced DESs as the wavenumbers of OH stretching and C = O bond in DESs were shifted. CAM-GLY 1:1 meet the lowest eutectic point compared to other ratios. The increases in molar ratio of citric acid monohydrate had produced DES with higher density and viscosity. The result showed that CAM-GLY 1:1 exhibited the lowest water absorption rate among others. The synthesized DESs also considered hydrophilic and highly soluble in a highly polar solvent as well as semi-polar solvents. To compare the extraction capacity of the extracted DES and conventional citric acid, extraction of polysaccharide from Micromelum minutum leaves was performed. Result showed that the extraction yield using the DES were in the range of 5.85 – 10.39% (w/w, dry basis). On the other hand, the yield obtained using conventional citric acid was 5.49 % (w/w, dry basis). Therefore, the DES at selected ratio has the potential in extracting natural polar and hydrophilic bioactive components, such as polysaccharides. [ABSTRACT FROM AUTHOR]