Valorization of orange (Citrus sinensis) peel waste: Isolation and structural elucidation of polymethoxylated flavones

Abstract

This study explores the valorization of orange (Citrus sinensis) peel waste as a source of bioactive polymethoxylated flavones (PMFs) with nutraceutical potential. A dichloromethane extract from fresh orange
peel (including both albedo and flavedo) was subjected to sequential chromatographic separation, yielding three known compounds: 3,5,6,7,8,3′,4′-heptamethoxyflavone (1), nobiletin (2), and sinensetin (3). Structural elucidation was achieved through 1D and 2D NMR techniques, supported by high-resolution mass spectrometry. Although these compounds are already known, their recovery from citrus waste underscores the potential of agri-food by-products as valuable sources of health-promoting natural products. The findings contribute to sustainable waste valorization and support the development of high-value ingredients for pharmaceutical and nutraceutical
applications