Enhanced yield of bioactivities from onion (Allium cepa L.) skin and their antioxidant and anti-α-amylase activities

Gois Ruivo da Silva, Mariana (author), Skrt, Mihaela (author), Komes, Draženka (author), Poklar Ulrih, Nataša (author), Pogačnik da Silva, Lea (author)

There is increasing concern for reduction of the ecological impacts of industrial waste caused by fruits and vegetables. To reduce costs of onion waste disposal while obtaining value-added products, onion skin can be used to extract quercetin, a natural flavonoid with antioxidant, anti-inflammatory and anti-cancer effects. The aim was to optimize quercetin extraction from brown onion (Allium cepa L.) skin through investigation of the effects of different parameters on quercetin yield. Operational parameters for conventional maceration extraction and for ultrasound-assisted extraction were compared: solvent type, mass-to-liquid ratio, extraction time and temperature. Antioxidant capacity was determined using DPPH· radical scavenging assays and quercetin yield using HPLC/DAD. Anti-α-amylase activity of onion skin extracts was investigated using α-amylase inhibition assays. Optimal extraction conditions of quercetin from onion skin were obtained with maceration extraction, 50% ethanol, 1:100 mass-to-liquid ratio, 25 °C, for 15 min. Under these conditions, the antioxidant capacity (expressed as quercetin equivalents) was 18.7 mg/g and the mass fraction of quercetin was 7.96 mg/g. The onion skin extracts showed a dose-dependent relationship between dry extract concentration and α-amylase inhibition, which confirms that this onion skin extract can be considered as an anti-diabetes agent.

• Language: English
• Keywords: Allium cepa L., anti-α-amylase activity, antioxidant capacity, extraction optimization, quercetin
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Year: 2020
• Number of pages: 15 str.
• Numbering: Vol. 21, iss. 8, art. 2909
• PID: 20.500.12556/RUL-128259
• UDC: 66.061:635.25:547.56
• ISSN on article: 1422-0067
• DOI: 10.3390/ijms21082909
• COBISS.SI-ID: 13140483
• Publication date in RUL: 07.07.2021

Record is a part of a journal

• Title: International journal of molecular sciences
• Shortened title: Int. j. mol. sci.
• Publisher: MDPI
• ISSN: 1422-0067
• COBISS.SI-ID: 2779162

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 21.04.2020

Secondary language

• Language: Slovenian
• Keywords: čebula, Allium cepa L., antioksidanti, antioksidativna učinkovitost, ekstrakcija, kvercetin, bioaktivne snovi

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P4-0121
• Name: Biokemijska in biofizikalno-kemijska karakterizacija naravnih snovi

• Funder: ARRS - Slovenian Research Agency
• Project number: BI-HR/18-19-040