Enhancement of the total phenolic compounds and antioxidant activity of aqueous Citrus limon L. pomace extract using microwave pretreatment on the dry powder

Ultrasound-assisted extraction of bioactive compounds from longan seeds powder: Kinetic modelling and process optimization

Investigating the extraction of bioactive compounds represents a hopeful direction for maximizing the value of longan fruit byproducts. This study explored the influence of ultrasonic-assisted extraction (UAE) parameters-specifically ultrasonic power ratios, temperatures, and exposure times-utilizing water as a green solvent on several properties of the longan seeds extract (LSE). These properties encompassed the energy consumption of the UAE process (EC), extraction yield (EY), total phenolic contents (TPC), total flavonoid contents (TFC), and antioxidant activity (DPPH). Additionally, the study sought to optimize the conditions of UAE process and examine its thermodynamic properties. A three-level, three-factor full factorial design was utilized to assess the effects of different factors on LSE properties. Results indicated that EC, EY, TPC, TFC, and DPPH were significantly influenced by power ratios, temperatures, and exposure time. Moreover, the proposed models effectively characterized the variations in different properties during the extraction process. The optimized extraction conditions, aimed at minimizing EC while maximizing EY, TPC, TFC, and DPPH radical scavenging activity, were demonstrated as an ultrasonic power ratio of 44.4 %, a temperature of 60 °C, and an extraction time of 17.7 min. Optimization led to 563 kJ for EC, 7.85 % for EY, 47.21 mg GAE/mL for TPC, 96.8 mg QE/mL for TFC, and 50.15 % for DPPH radical scavenging activity. The results emphasized that the UAE process exhibited characteristics of endothermicity and spontaneity. The results provide valuable insights that could inform the enhancement of extraction processes, potentially benefiting industrial utilization and pharmaceutical formulations.

Identification of potential phytochemicals from Citrus Limon against main protease of SARS-CoV-2: molecular docking, molecular dynamic simulations and quantum computations

The outbreak of coronavirus disease (COVID-19) caused by a novel RNA virus emerged at the end of 2019. Most of the patient's symptoms are mild to moderate, and influenza, acute respiratory distress syndrome (ARDS) and multi-organ failure are common. The disease is mild to moderate in most patients and is reported in many cases such as pneumonia, ARDS and multi-organ dysfunction. This study's objective is to evaluate 25 natural compounds from Citrus limon (CL) used by comprehensive molecular docking, density functional theory (DFT) and molecular dynamics analysis against SARS-CoV-2 main protease (M^pro). Among all the experimental compounds, diosmetin has shown the best docking values against the M^pro of SARS-CoV-2 compared to the standard antiviral drug. In DFT calculations, the order associated with biochemical reactivity is as follows: eriodictoyl > quercetin > spinacetin > diosmetin > luteolin > apigenin, whereas the regions of oxygen and hydrogen atoms from the selected isolated compounds are appropriate for electrophilic and nucleophilic attacks, respectively. Also, HOMO-LUMO and global descriptors values indicated a promising result of these compounds. Moreover, a molecular dynamics simulation study revealed the stable conformation and binding pattern in a stimulating environment of natural compounds CL. Considering molecular docking, simulation, and DFT analysis of the selected compounds, notably eriodictoyl, quercetin, and diosmetin showed good potential against SARS-CoV-2 M^pro. Our in silico study revealed promising antiviral activity, which may be considered a potential key factor or a therapeutic target for COVID-19.Communicated by Ramaswamy H. Sarma.

The recovery from agro-industrial wastes provides different profiles of anti-inflammatory polyphenols for tailored applications

Food and agro-industrial processing produce a great amount of side-stream and waste materials that are excellent sources of functional bioactive molecules such as phenolic compounds that recover them can be beneficial not only for food sustainability but also to human for many industrial applications such as flavor compounds and therapeutic applications such as antimicrobial and anti-inflammatory. The treatments and extraction techniques have major effects on the recovery of bioactive compounds. Along with the conventional extraction methods, numerous innovative techniques have been evolved and have been optimized to facilitate bioactive extraction more efficiently and sustainably. In this work, we have summarized the state-of-the-art technological approaches concerning novel extraction methods applied for five most produced crops in Italy; Grape Pomace (GP), Tomato Pomace (TP), Olive Pomace (OP), Citrus Pomace (CP), and Spent Coffee Grounds (SCG), presenting the extraction yield and the main class of phenolic classes, with the focus on their biological activity as an anti-inflammatory in vitro and in vivo studies via describing their molecular mechanism of action.

Quality Evaluation of Lemon Cordial Stored at Different Times with Microwave Heating (Pasteurization)

Consumer interest in food quality and safety has shifted over time, as consumers increasingly prefer minimally processed items. As a result, numerous non-thermal approaches have been implemented due to their potential to preserve the nutritional profile of products along with lengthening their storability. Microwaving, a green processing technique, volumetrically heats the product because of the interactions developed between charged ions, polar water molecules of foodstuff and the incoming electromagnetic waves. The study was mapped out to investigate the effect of microwave exposure time (60, 90 and 120 s) at fixed power (1000 W) and frequency (2450 MHz) on physicochemical properties, phytochemical constituents, antioxidant potential and microbial counts of lemon cordial stored at refrigerated temperature (4 ± 2 °C). The mentioned parameters were analyzed after an interval of 30–90 days. Statistical findings illustrated a highly significant (p ≤ 0.01) impact of microwave treatment and storage on titratable acidity, pH, total soluble solids, total phenolic contents, total flavonoids contents, antioxidant potential and total plate count. Sample microwaved for 120 s showed the highest pH values (2.45 ± 0.050), total soluble solids (56.68 ± 2.612 °B) and antioxidant activity (1212.03 ± 716.5 µg—equivalent of ascorbic acid per 100 mL of cordial); meanwhile, it exhibited the lowest total plate counts (1.75 ± 0.144 Log 10 CFU/mL). Therefore, microwaving can be suggested as a suitable alternate to traditional pasteurization techniques as well as to chemical preservatives.

Mutated Shiitake extracts inhibit melanin-producing neural crest-derived cells in zebrafish embryo

The ability of natural extracts to inhibit melanocyte activity is of great interest to researchers. This study evaluates and explores the ability of mutated Shiitake (A37) and wildtype Shiitake (WE) extract to inhibit this activity. Several properties such as total phenolic (TPC) and total flavonoid content (TFC), antioxidant activity, effect on cell and component profiling were conducted. While having no significant differences in total phenolic content, mutation resulted in A37 having a TFC content (1.04 ± 0.7 mg/100 ml) compared to WE (0.86 ± 0.9 mg/100 ml). Despite that, A37 extract has lower antioxidant activity (EC50, A37 = 549.6 ± 2.70 μg/ml) than WE (EC50 = 52.8 ± 1.19 μg/ml). Toxicity tests on zebrafish embryos show that both extracts, stop the embryogenesis process when the concentration used exceeds 900 μg/ml. Although both extracts showed pigmentation reduction in zebrafish embryos, A37 extract showed no effect on embryo heartbeat. Cell cycle studies revealed that WE significantly affect the cell cycle while A37 not. Further tests found that these extracts inhibit the phosphorylation of Glycogen synthase kinase 3 β (pGSK3β) in HS27 cell line, which may explain the activation of apoptosis in melanin-producing cells. It was found that from 19 known compounds, 14 compounds were present in both WE and A37 extracts. Interestingly, the presence of decitabine in A37 extract makes it very potential for use in the medical application such as treatment of melanoma, skin therapy and even cancer.

Non-Extractable Polyphenols from Food By-Products: Current Knowledge on Recovery, Characterisation, and Potential Applications

Non-extractable polyphenols (NEPs), or bound polyphenols, are a significant fraction of polyphenols that are retained in the extraction residues after conventional aqueous organic solvent extraction. They include both high molecular weight polymeric polyphenols and low molecular weight phenolics attached to macromolecules. Current knowledge proved that these bioactive compounds possess high antioxidant, antidiabetic, and other biological activities. Plant-based food by-products, such as peels, pomace, and seeds, possess high amount of NEPs. The recovery of these valuable compounds is considered an effective way to recycle food by-products and mitigate pollution, bad manufacturing practice, and economic loss caused by the residues management. The current challenge to valorise NEPs from plant-based by-products is to increase the extraction efficiency with proper techniques, choose appropriate characterising methods, and explore potential functions to use in some products. Based on this scenario, the present review aims to summarise the extraction procedure and technologies applied to recover NEPs from plant-based by-products. Furthermore, it also describes the main techniques used for the characterisation of NEPs and outlines their potential food, pharmaceutical, nutraceutical, and cosmetic applications.

Natural antioxidants of plant origin

Interest in the content of natural antioxidants in plant-based foods can be from the human health perspective, in terms of how these compounds might help promote one's health and wellness, or from the storage point-of-view, as the endogenous antioxidant constituents aid to extend a foodstuff's shelf-life. This chapter reports essential information about the mechanism of antioxidant action and methods employed for determination of their activity, classes of phenolic compounds (phenolic acids, flavonoids, lignans, stilbenes, tannins), sources of plant antioxidants (oil seeds, cereals, legumes, plants of the Lamiaceae family, tea and coffee, tree nuts, fruits, and berries), extraction strategies of phenolic compounds from plant material, and the influence of processing and storage on the content of natural antioxidants in foods and their antioxidant activity. Thermal processing, if not releasing bound phenolics from the structural matrices of the food, tends to decrease the antioxidant potential or, in the best case scenario, has no significant negative impact. Gentler sterilization processes such as high-pressure processing tend to better retain the antioxidant potential of a foodstuff than thermal treatments such as steaming, boiling, or frying. The impact of processing can be assessed by determining the antioxidant potential of foodstuffs either at the point of formulation or after different periods of storage under specified conditions.

Effect of Freeze-Thaw Pretreatment on Extraction Yield and Antioxidant Bioactivity of Corn Carotenoids (Lutein and Zeaxanthin)

As a green and low-energy pretreatment method, the effect of freeze-thaw (FT) pretreatment on extraction yield and antioxidant bioactivity of carotenoids of the corn gluten meal (CGM) were evaluated in this study. The CGM particles ruptured in FT treatment due to the repeated damage caused by FT to CGM particles. The carotenoid compounds of pretreated CGM were lutein, zeaxanthin, β-carotene, and cryptoxanthin. Among them, the major carotenoids are lutein and zeaxanthin. The optimized FT pretreatment conditions included freezing temperature of −20°C, moisture content of 100%, and 2 cycles. An increase in the yield of lutein and zeaxanthin was observed in the range of 2.23–16.39 µg/g and 4.66–36.3 µg/g as a result of pretreatment as against 1.17 and 2.52 µg/g of the untreated sample, respectively. Moreover, the release of lutein and zeaxanthin from CGM was facilitated by FT pretreatment and increased the antioxidant activity of the carotenoids.

Polypeptide – decorated nanoliposomes as novel delivery systems for lutein

Lutein (LUT) is a bioactive food compound found in various vegetables and plays a critical role in the promotion of health and well-being. However, lutein is an unstable molecule which has a very low bioavailability caused by its poor solubility in aqueous media, and is poorly absorbed when administered orally. To enhance the stability, release and bioactivity of lutein, poly-l-lysine (PLL) decorated nanoliposomes (PLL–LUT-NLP) were developed as novel delivery systems for lutein. The mean particle size of PLL–LUT-NLP was found to be in the range 264–367 nm with a low polydispersity index (PDI < 0.4). The zeta potential changed from −38.6 mV in undecorated nanoliposomes to −27.9 mV in PLL-decorated nanoliposomes. Furthermore, the lutein entrapment efficiency (EE%) of PLL–LUT-NLP was found to be highest in nanoliposomes decorated with 0.06% (w/v) PLL. PLL could protect lutein in nanoliposomes from degradation and promote the lutein release from the nanoliposomes in gastrointestinal fluid conditions. Additionally, the PLL-decorated nanoliposomes maintained the antioxidant activity of the lutein, and the antiproliferative activity was more significant than that of undecorated nanoliposomes in inhibiting the proliferation of human tumor cells. These results suggest that PLL-decorated nanoliposomes have potential to be used for efficient delivery of lutein and further improve its bioavailability.

Polypeptide decorated nanoliposomes were prepared as novel delivery systems to enhance the stability, release and bioactivity of lutein.