Municipal solid waste compost application improves productivity, polyphenol content, and antioxidant capacity of Mesembryanthemum edule

► We used municipal waste compost 40 t ha−1 to improve plant antioxidant activities. ► Slow-release fertilizer effect of compost enhanced growth of Mesembryanthemum edule. ► Compost amendment positively affect polyphenol contents and antioxidant capacities. ► The levels of heavy metals (Pb, Cd, Cu, and Zn) were under allowed limits.