The Bioactive Compounds and Antioxidant Capacity of Nopal Cladodes (Opuntia spp.) as Influenced by Irrigation

The prickly pear is a crop of socioeconomic relevance in arid regions, and its productivity and chemical composition depend on water availability. The effect of irrigation on the crop’s biochemical quality was evaluated. Cladodes of cultivars: ‘Amarilla Olorosa’, ‘Cristalina’, ‘Dalia Roja’, and ‘Roja Lisa’, were subjected to three treatments: no irrigation (NI), supplemental irrigation (SI), equivalent to 50% of the crop’s evapotranspiration, and full irrigation (FI). Subsequently, cladodes were collected, and total polyphenols and flavonoids, polyphenol profile, and antioxidant capacity were determined. Cladodes under NI had the highest concentrations of flavonoids, although the lowest values of total polyphenols. In the cladode extracts, myricetin, rutin, catechin, as well as caffeic, chlorogenic, dihydroxybenzoic, and vanillic acids were identified. Overall, cladodes grown under FI and SI showed higher levels of phenolic acids (caffeic, chlorogenic, and vanillic), while concentrations of catechin, myricetin, and rutin were higher under SI and NI. Antioxidant capacity was higher in NI cladodes assessed by ABTS and DPPH, while the FRAP assay showed higher values under SI. Among the cultivars, ‘Amarilla Olorosa’ stood out for its high content of bioactive compounds, confirming the potential of nopal cladodes as a source of antioxidant metabolites with agro-industrial applications.