Heavy metal content, phytochemical profile, and radical scavenging activity of stingless bee (Heterotrigona itama) propolis cultivated on post-mining land at East Kalimantan, Indonesia

Stingless bees (Heterotrigona itama) propolis is a promising natural product with diverse biomedical uses. However, its safety and bioactivity in disturbed environments, such as post-mining lands, are not well understood. This study evaluated heavy metal content, phytochemical, and antioxidant activity of H. itama propolis from post-mining land in Kalimantan, Indonesia. Heavy metals (As, Pb, Hg, Cd, and Cr) were analysed using ICP-OES. Phytochemical screening identified secondary metabolites. Antioxidant capacity was measured using the DPPH assay, with ascorbic acid as a standard. All heavy metal concentrations were below FAO/WHO limits, indicating safety. Phytochemical tests showed saponins, flavonoids, phenolics, tannins, terpenoids, and triterpenoids. The DPPH assay showed moderate to strong antioxidant activity (IC₅₀ 36.52 ppm vs 2.71 ppm for ascorbic acid). H. itama propolis from post-mining land is chemically safe and active, demonstrating antioxidant potential linked to its phenolic and flavonoid content. These findings support sustainable stingless beekeeping in post-mining areas for environmental rehabilitation and as a source of valuable natural products.