Valorization of Tu Quy mango seed kernel via ultrasound-assisted extraction: Phytochemicals, antioxidant and antibacterial properties

• Ultrasound-assisted extraction significantly increased phenolic recovery • Mango seed kernels are a rich source of natural antioxidants and antimicrobials • UAE extracts showed the lowest IC50 and strongest antibacterial effect • Valorization of mango waste supports circular bioeconomy applications This study explores the valorization potential of Tu Quy mango ( Mangifera indica L.) seed kernel through a comparative evaluation of three extraction techniques: maceration (ME), hot-reflux extraction (HRE), and ultrasound-assisted extraction (UAE). Ethanolic (70%) extracts were examined for total phenolic content (TPC), phytochemical constituents, antioxidant capacity (ABTS and DPPH assays), and antibacterial activity against selected foodborne pathogens. Among the extraction methods, UAE produced the highest extraction yield (47.53 ± 0.38%) and total phenolic content (2779.62 ± 70.30 mg GAE/100 g DW), significantly exceeding ME (2317.72 ± 48.00 mg GAE/100 g DW) and HRE (2517.31 ± 81.70 mg GAE/100 g DW). UAE extracts also demonstrated superior antioxidant activity, exhibiting the lowest IC₅₀ values in both DPPH (121.76 ± 0.89 µg/mL) and ABTS (162.67 ± 0.99 µg/mL) assays. Furthermore, UAE extracts demonstrated superior antibacterial performance in agar diffusion assays, although minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values (0.31–2.50 mg/mL) were comparable among extraction methods under standardized conditions. Taken together, these findings highlight UAE as a promising eco-efficient extraction approach with potential scalability for recovering natural antioxidants and antimicrobials from mango seed kernel, an underutilized agro-industrial by-product. The results provide scientific evidence supporting the incorporation of mango seed kernel extracts into sustainable food biotechnology and the development of natural preservative systems and value-added functional ingredients from mango by-products.