From the labs. Onion peel gives gold

A low-cost gold nano biocomposite material from onion peel with anti-inflammatory and antioxidant properties has been developed, paving the way for an effective herbal drug.

The secondary product of metabolism of plants, such as flavonoids, demonstrates high degrees of antioxidant, anti-inflammatory, and anti-cancer activities. Among flavonoids, quercetin — which is found in many fruits, vegetables, and red onions — plays an important role in decreasing inflammation by lowering the level of various cytokines.

Scientists from the Institute of Advanced Study in Science and Technology (IASST), an autonomous institute of the governmental Department of Science and Technology (DST), utilised onion ( Allium cepa ) peel for the synthesis of the gold nano bio-conjugate. The team led by Devasish Chowdhury, Associate Professor, extracted crude onion peel and subjected it to fractional distillation with ethyl acetate, butanol, methanol, and water. These fractionates were tested for various antioxidant activities.

The ethyl acetate fractionates showed high antioxidant activities in all the assays. The component in onion peel identified as quercetin was found in high quantities. The team then prepared bio-conjugates or stable compounds with gold nanoparticles with the help of these fractionates. The nano bio-conjugates were not found to be toxic to cells and did not show toxic effects on skeletal muscle tissues. The finding, recently published in the journal ACS Omega , could be a step towards effective, low-cost medicines from biocomposites of natural substances.