Antioxidant, cytotoxic and antimicrobial efficacy of potato peels, taro peels, and husk and silk of corn

Development of new therapeutic sources from food waste is a useful and treasured approach as an alternative to their disposal. Vegetable waste can be a ready and low-cost existing source of different bioactive constituents to be recycled in the pharmaceutical industry. The objective of our study is to assay the in vitro antioxidant, cytotoxic, as well as the antimicrobial effects of the total 70% ethanolic extracts of potato peels (Solanum tuberosum), taro peels (Colocasia esculenta), and husk and silk of corn (Zea maiz) along with investigating their phenolic and flavonoid contents spectrophotometrically and by HPLC. Results showed that silk of Z. maiz revealed the maximum antioxidant effect in both DPPH and ABTS assays (29.067 and 81.110, respectively). Cytotoxic outcomes (MTT assay) showed that only S. tuberosum peels revealed a good cytotoxic activity against osteosarcoma cell line (HOS) with IC50: 34.2 ± 0.20 µg/mL. For the antimicrobial activity (agar well diffusion assay), most of the extracts showed moderate activities against the tested pathogens when compared to the standards: Ceftriaxone and Miconazole. These favorable biological properties are commonly related to the high contents of phenolic and flavonoid compounds recognized and quantified in their total extracts spectrophotometrically and by HPLC. Vegetable waste represented in potato peels, taro peels, and husk and silk of corn showed effective antioxidant, cytotoxic, and antimicrobial activities.