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Onion leaves you'd toss could fight skin aging

Food Forest

The green tops you cut off and compost when harvesting onions contain more antioxidant punch than most people realize, and this study shows a simple heat-and-solvent trick pulls it out efficiently.

Researchers took the leafy green tops of onion plants, the part usually thrown away as waste, and used microwaves to quickly pull out beneficial plant compounds like quercetin. In lab and cell tests, the extract calmed oxidative stress, blocked enzymes linked to wrinkles and dark spots, and didn't harm skin cells even at fairly high doses. It suggests a common kitchen scrap could become a useful ingredient in natural skincare products.

Key Findings

1

Microwave-assisted extraction boosted total flavonoid content 1.34-fold compared to conventional maceration, using optimized conditions of 50% ethanol, 50°C, 15 minutes, and a 1:20 solid-to-solvent ratio.

2

LC-QTOF-MS profiling identified 56 bioactive compounds in the extract, including flavonoids, phenolic acids, and sulfur-containing compounds, with quercetin quantified at 2.51 mg/g.

3

The extract showed measurable antioxidant activity (DPPH IC50 = 97.1 µg/mL), tyrosinase inhibition (IC50 = 50.66 µg/mL), and anti-collagenase activity (IC50 = 2.84 mg/mL), while remaining non-cytotoxic to human keratinocytes up to 100 µg/mL.

chevron_right Technical Summary

Scientists turned discarded onion leaves into a skin-protecting extract using microwave heating, pulling out quercetin and dozens of other compounds that fought oxidative stress and skin-aging enzymes in lab tests without harming skin cells.

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Abstract Preview

Original paper

Microwave-Assisted Extraction of a Quercetin-Containing Onion Leaf Extract for Potential Anti-Aging Cosmetic Applications

Onion (Allium cepa L.) is one of the most widely cultivated vegetables worldwide, while its leaves are discarded as agricultural waste despite being a valuable source of bioactive compounds. This s...

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Abstract copyright held by the original publisher.

hub This connects to 10 other discoveries — Onion food-forest, composting, medicinal-plants +1 more 5 related articles

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