Optimization of microwave-assisted extraction of antioxidant compounds from spring onion leaves using Box–Behnken design

Abstract

Many studies have explored the extraction of bioactive compounds from different onion solid wastes, such as bulb, skin, and peel. However, onion leaves have received limited attention despite their potential as a valuable source of nutraceutical compounds. This study aimed to valorise, for the first time, the agricultural waste in the form of spring onion leaves (CN, Cipollotto Nocerino) to obtain antioxidant-rich polyphenolic extracts. A Box–Behnken design (BBD) was used to assess the impact of microwave-assisted extraction (MAE) variables (temperature, time, extraction volume, and ethanol concentration) on total polyphenol content (TPC) measured by Folin–Ciocalteu method and the antioxidant power determined by FRAP assay. Response surface methodology (RSM) was applied, and regression equations, analysis of variance, and 3D response curves were developed. Our results highlighted that the TPC values range from 0.76 to 1.43 mg GAE g−1 dw, while the FRAP values range from 8.25 to 14.80 mmol Fe(II)E g−1 dw. The optimal extraction conditions predicted by the model were 60 °C, 22 min, ethanol concentration 51% (v/v), and solvent volume 11 mL. These conditions resulted in TPC and FRAP values of 1.35 mg GAE g−1 dw and 14.02 mmol Fe(II)E g−1 dw, respectively. Furthermore, the extract obtained under optimized conditions was characterized by UHPLC-ESI-Orbitrap-MS analysis. LC/MS–MS platform allowed us to tentatively identify various compounds belonging to the class of flavonoids, saponins, fatty acids, and lipids. Finally, the ability of CN optimal extract to inhibit the intracellular reactive oxygen species (ROS) release in a hepatocarcinoma cell line using an H2O2-induced oxidative stress model, was evaluated. The results highlighted the potential of CN extract as a valuable source of polyphenols with significant antioxidant properties, suitable for various applications in the food and pharmaceutical industries.

Optimization of Ultrasonic Extraction Parameters for the Recovery of Phenolic Compounds in Brown Seaweed: Comparison with Conventional Techniques

“…With the increasing ultrasonication time, a notable rise in the TPC, TPhC, and DPPH activity was observed in the free phenolic extracts for all brown seaweed samples and bound phenolic extracts in Cytospora sp., D. potatorum, and S. fallax. This observed increase is indicative of the positive effect of the ultrasonication time on the recovery of free and bound phenolics from seaweed, which has been reported before [25,26]. Nonetheless, the TPC, TPhC, and DPPH activity increased from 6 to 8 min ultrasonication time, but decreased when 10 min of ultrasonication was applied in E. radiata and P. comosa bound phenolic extraction.…”

“…Lastly, the quadratic coefficient (C 2 ) was significant for the DPPH model for all free phenolic extracts of brown seaweeds as well as the TPhC model for the free phenolic extract of Cytospora sp. (a The TPC, TPhC, and DPPH activity in the free phenolic extract of all brown seaweed samples show an increasing trend when the solvent:solid ratio increases from 10:1 to 20:1, as a higher amount of solvent enhances the cell wall penetration by increasing the extent of swelling in the cell wall and membrane [25]. This results in a stronger interaction between the solvent and free phenolic compounds that are polar in nature, thus causing the greater solubilization of the free phenolics into the solvent [21].…”

Kinetic modeling of valuable phenolic compounds extraction from strawberry and apple agro‐industrial by‐products

“…Regarding the plant matrices, strawberry by‐products have low concentrations of interfering compounds. Nonetheless, both analytical techniques prove highly valuable in optimizing time and resources during the laboratory‐scale research phase (Aquino et al, 2023) and correlate with more sensitive and precise methods such as HPLC‐DAD. In this study, a strong correlation was determined for RF between TPC and TPC HPLC ( R 2 0.85, p < 0.01) as well as AC ( R 2 0.8, p < 0.01).…”

“…Moreover, GS extracts obtained with W showed a higher phenolic compound content than that reported for red (1.2505 g GAE/kg) and yellow apples (0.9977 g GAE/kg) (Nollet & Gutierrez-Uribe, 2018), even higher than the extracted from other types of agro-industrial waste, like chive leaves. Using a microwave-assisted extraction with 51% ethanol at 60 C, chive leaves showed an optimized TPC content of 1.35 g/kg (Aquino et al, 2023).…”

Antitumor Mechanisms of Lycium barbarum Fruit: An Overview of In Vitro and In Vivo Potential

“…They play a beneficial role in supporting heart health by preserving the structure of cardiac muscle cells and reducing the risk of conditions like atherosclerosis and cardiac hypertrophy as well as neurodegenerative disorders [ 16 , 17 ]. Onions and scallions are increasingly being recognized as potential nutraceuticals due to their rich content of flavonoids and sulfur-containing compounds like thiosulfinates and allyl sulfides, which impart various health-promoting properties stimulating the production of detoxification enzymes, such as glutathione S-transferases (GSTs), contributing to support the liver’s scavenging mechanisms [ 18 , 19 , 20 ].…”