Comprehensive analysis of heavy metals and antioxidant properties in various spices and propolis

In this research, various spices, including curry, fenugreek, allspice, ginseng, abaza herb, nutmeg, mahaleb, coriander, cajun spice, propolis, marjoram, star anise, cardamom, poppy, lavender, tarragon, plantago, vitex seed, French lavender, and yarrow were examined for their trace elements and antioxidant contents. Ethanol extractions were used for DPPH, ABTS, reducing power, and total phenolic content tests, revealing that propolis and plantago exhibited the highest antioxidant and phenolic contents, while fenugreek and cardamom showed the lowest. In the heavy metal analysis, samples were dissolved using a microwave, and trace elements were analysed by ICP-OES. Method accuracy was confirmed with NIST-SRM 1515-Apple Leaves certified reference material. Elemental concentrations ranged from 0.013–27 µg/g for Cu, 29–802 µg/g for Fe, 2.13–430 µg/g for Mn, 0.37–5.00 µg/g for Ni, and 3.13–66 µg/g for Zn. These results were compared with existing literature values. This study highlights the balance needed between the beneficial antioxidant properties and potential risks from trace metals in spices and propolis, emphasising the importance of safety in food consumption. © 2024 Informa UK Limited, trading as Taylor & Francis Group.