HPLC-DAD Profiling of Phenolic Components and Comparative Assessment of Antioxidant Potency in Opuntia robusta, Opuntia dillenii, and Opuntia ficus-indica Cladodes at Diverse Stages of Ripening.

Global distribution of prickly pear spans worldwide, with limited cladode exploitation, particularly in Mediterranean regions, excluding American continent nations. Our research reports on three species found in eastern Morocco, including Opuntia ficus indica and the two newly introduced species Opuntia robusta and Opuntia dillenii. The study aims to evaluate the total phenolic content, the amounts of various phenolic compounds classes, and the antioxidant activity across a spectrum of biochemical measurements including the 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant potential (FRAP), 2,2'-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and total antioxidant capacity assay (TAC). The results showed that O. robusta exhibited the highest total phenolic content (5061.70 mg GAE/100 g) which enhances the significance of this species in terms of nutrition. Differences were also observed in different stage of cladodes maturity, demonstrating that the age factor affects the polyphenol contents. Moreover, O. robusta displays the highest amount of total phenolic compounds (11430.35 μg/g) either for flavonoids or phenolic acids. Furthermore, the oldest cladodes show more higher phenolic compounds (22998.62 μg/g) compared to the youngest one's (20438.54 μg/g). Ten phenolic compounds were identified, in which isorhamnetin represent the most abundant flavonoid (6747.85 μg/g), while the chlorogenic acid was determined as the major phenolic acid (2771.69 μg/g) followed by sinapic acid (2047.64 μg/g). The DPPH assay indicates that O. ficus-indica possessed the higher hydrophilic antioxidants able to reduction the 2,2-diphenyl-1-picrylhydrazylradical free radical. While O. robusta exhibited a greater quantity of antioxidants, which effectively reduced the Fe complex of ferric ions (TPTZ) . In contrast, old cladodes of O. robusta and O. dillenii demonstrate the higher ability to scavenge the 2,20-azinobis (3-ethylbenzthiazolin-6-sulfonic acid) or ABTS .