Effects of Colchicine Treatment on Bioactive Compounds and Structural Characteristics of the Epidermis and Cortex of Edible Cactus [Opuntia ficus-indica (L.) Mill.] Cladodes at Different Maturity Stages

This study investigated the effects of colchicine treatment on phenolic and flavonoid profiles, organic acids, antioxidant activities, and structural characteristics of the epidermis and cortex of edible cactus [Opuntia ficus-indica (L.) Mill.] cladodes at different maturity stages (1, 3, and 6 months). Cladodes were treated with 0, 0.5, and 1.0% colchicine for 24 h prior to cultivation. Colchicine significantly influenced metabolite accumulation, with responses varying across tissues and maturity stages. In the epidermis, total phenolic content (TPC) ranged from 942.67 to 1292.72 mg GAE/100 g DW, while total flavonoid content (TFC) ranged from 509.42 to 1322.55 mg QE/100 g DW. HPLC analysis further revealed marked increases in chlorogenic acid (6.25-fold), gentisic acid (3.47-fold), and gallic acid (63.9%), while rutin and apigenin were the predominant flavonoids. In contrast, the cortex accumulated higher levels of organic acids, particularly malic acid. FTIR and XRD analyses indicated that colchicine treatment did not substantially alter the major functional groups or crystalline characteristics of the cladodes. Pearson’s correlation and heatmap analyses further revealed positive associations among phenolic compounds, flavonoids, and antioxidant activities. These findings indicate that colchicine concentration and maturity stage were associated with distinct patterns of metabolite accumulation and antioxidant activity in edible cactus cladodes, supporting their potential application as functional food ingredients.