Unlocking the Power of Onion Peel Extracts: Antimicrobial and Anti-Inflammatory Effects Improve Wound Healing through Repressing Notch-1/NLRP3/Caspase-1 Signaling

Abstract

Onion peels are often discarded, representing an unlimited amount of food by-products; however, they are a valuable source of bioactive phenolics. Thus, we utilized UPLC-MS/MS to analyze the metabolomic profiles of red (RO) and yellow (YO) onion peel extracts. The cytotoxic (SRB assay), anti-inflammatory (Griess assay), and antimicrobial (sensitivity test, MIC, antibiofilm, and SP-SDS tests) properties were assessed in vitro. Additionally, histological analysis, immunohistochemistry, and ELISA tests were conducted to investigate the healing potential in excisional skin wound injury and Candida albicans infection in vivo. RO extract demonstrated antibacterial activity, limited skin infection with C. albicans, and improved the skin’s appearance due to the abundance of quercetin and anthocyanin derivatives. Both extracts reduced lipopolysaccharide-induced nitric oxide release in vitro and showed a negligible cytotoxic effect on MCF-7 and HT29 cells. When extracts were tested in vivo for their ability to promote tissue regeneration, it was found that YO peel extract had the greatest impact. Further biochemical analysis revealed that YO extract suppressed NLRP3/caspase-1 signaling and decreased inflammatory cytokines. Furthermore, YO extract decreased Notch-1 levels and boosted VEGF-mediated angiogenesis. Our findings imply that onion peel extract can effectively treat wounds by reducing microbial infection, reducing inflammation, and promoting tissue regeneration.

Onion Peel as a Potential Source of Antioxidants and Antimicrobial Agents

“…Similar MIC values were obtained in a study by Mounir et al (2023), which showed that yellow onion peel extract can limit skin infection with Candida albicans in vivo. [60].…”

“…Candida albicans was sensitive to the action of all extracts, with MIC values ranging from 1.56 to 12.05 mg/mL. Similar MIC values were obtained in a study by Mounir et al (2023), which showed that yellow onion peel extract can limit skin infection with Candida albicans in vivo. [60].…”

“…Protocatechuic acid is otherwise regarded as a degradation product of quercetin, which is formed during the decomposition of quercetin through the action of peroxidase [57]. The extracts contained smaller amounts of quinic acid, caffeic acid, vanillic acid, and taxifolin, which were all previously detected in onion peels [58][59][60].…”

Wound Healing Efficacy of Cucurbitaceae Seed Oils in Rats: Comprehensive Phytochemical, Pharmacological, and Histological Studies Tackling AGE/RAGE and Nrf2/Ho-1 Cue

“…Once the rats were sedated, their back hair was shaved, and their skin was purified using an alcohol solution and cleaned with sterile water. A circular wound with an approximate diameter of 10 mm was made using a skin biopsy tool and surgical scissors [ 43 ].…”

Agro-Food Waste: Harnessing the Potential Significance of Natural Biofilm Inhibitors

“…It displayed an effective biofilm inhibitory activity on the initial biofilm adherence and formation in addition to a little destructive effect on mature biofilm masses. 29 Pomegranate peel Pomegranate (Punica granatum L., Punicaceae) is one of the oldest cultivated fruits across the world. Its fruit juice processing industry generates a considerable quantity of waste fraction composed of the fruit residuals including the seed and the external peel.…”