International Journal of Homoeopathic Sciences

Background: Allium cepa (onion) is not only a widely consumed vegetable but also a plant with well recognized medicinal value. It contains flavonoids, phenolic compounds, quercetin, and sulfur compounds that help in reducing oxidative stress, regulating blood sugar, and promoting overall health. Although the onion bulb is commonly used in traditional and homoeopathic preparations, the dry outer peel usually discarded as waste has been found to contain even higher concentrations of these beneficial compounds.

Aim and objective: The present study was undertaken to evaluate whether the ethanolic extract of onion dry peel demonstrates stronger antioxidant and antidiabetic activities compared to the standard homoeopathic preparation, Allium cepa Ø (mother tincture).

Methodology: Dry onion peels were collected, processed, and subjected to ethanolic extraction. The resulting extract, along with a commercially available Allium cepa Ø (mother tincture), was analyzed at Biogenix Laboratory, Trivandrum. Antioxidant potential was assessed using DPPH and ABTS radical scavenging assays, while antidiabetic activity was evaluated through α-amylase and α-glucosidase inhibition studies.

Results: The ethanolic extract of onion peel exhibited consistently stronger activity than the mother tincture across all assays. In antioxidant tests, the peel extract achieved IC₅₀ values of 19.40 µl/mL (DPPH) and 209.10 µl/mL (ABTS), compared with 140.70 µl/mL and 1058.57 µl/mL for the tincture. Similarly, in enzyme inhibition assays, the peel extract recorded lower IC₅₀ values of 215.40 µl/mL (α-amylase) and 217.09 µl/mL (α-glucosidase), in contrast to 847.60 µl/mL and 700.00 µl/mL for the tincture.

Conclusion: These findings demonstrate that onion dry peel possesses markedly higher antioxidant and antidiabetic activity than the commonly used bulb based mother tincture. As onion peel is generally discarded as agricultural waste, this work highlights its potential as a low-cost, sustainable source of bioactive compounds with promising applications in medicine, nutraceuticals, and functional food industries.