Abstract
Introduction Synthetic colourants are subject to various allergies. As a result, the use of plant-based additives has proved promising. Objective It is in this perspective that our objective was undertaken to investigate natural colourants from edible cactus.Opuntiaspecies populations were single-sequence repeat (SSR) fingerprinted, the analysis of betalains and phenolic compounds and the evaluation of their biological potentials were also characterised. Results Photometric quantification of betalains and phenols showed an interspecific variation acrossOpuntiaspecies.Opuntia ficus indicafruits showed the highest betalain [betaxanthins; 843.67 and betacyanins; 1400 mg/100 g dry weight (DW)] and polyphenol contents. Reversed-phase high-performance liquid chromatography (RP-HPLC) analysis showed that the variation of individual phenols profile was influenced by interspecific and genetic factors. Isorhamnetin-O-(di-deoxyhexosyl-hexoside) was the major compound and its content varied according toOpuntiaspecies, while catechol was the predominant phenolic compound inO. humifusawith 1.88 mu g/g DW. Concerning cactus species,Opuntiacolourants exhibited a potent antiradical activity [half maximal inhibitory concentration (IC50) up to 1 mu g/mL].Opuntiaspecies were effective against Gram-positive and Gram-negative bacterial strains [inhibition zone (IZ) up to 27 mm]. A high genetic diversity withinOpuntiagenotypes based on SSR markers was revealed. UPGMA (unweighted pair group method with arithmetic mean) dendrogram and PCoA (principal coordinate analysis) based on natural pigments and antimicrobial profiles indicated significant variation. The correlation approach proved the presence of a probably metabolic relationship between genetic markers, pigments and their biological activities. Conclusion A possible association between molecular approach and metabolic profile analysis ofOpuntiaallows tracing the relationship among species for its genetic conservation.