The optimization of antioxidant and anti-inflammatory activities of carotenoids, total polyphenols, and indole alkaloids from coral Astroides calycularis and their interactions using simplex-centroid designs

This research aimed to examine the interplay among carotenoids, total polyphenols, and indole alkaloids for the discovery of new bioactive compounds using “simplex-centroid” designs and response surface methodology (RSM). The antioxidant (AOA) and anti-inflammatory (AIA) activities of mixtures containing different proportions of each compound were evaluated by measuring the percentage inhibition of oxidation and spontaneous inflammation. The results showed that the highest AOAs were obtained with different mixtures of polyphenols, indole alkaloids, and carotenoids. The DPPH test revealed that a mixture of 16.94% polyphenols and 83.05% indole alkaloids produced the best results, whereas, for the ABTS test, 100% polyphenols gave the best results. The FRAP assay showed that the best-performing mixture was composed of 85.96% carotenoids and 14.03% polyphenols, with an IC₅₀ of 8.85 ± 1.17 μg/mL. In contrast, the most potent AIA was obtained with 100% carotenoids. Model validation tests were performed and showed that the experimentally observed values for AOA and AIA were not significantly different from the values estimated by the fitted models. The results also showed that the RSM model can be used to estimate the behavior of mixed compounds in the development of new functional ingredients or the discovery of new bioactive compounds with pharmacological properties. Finally, the results also suggested that there is a good correlation between several AOA and AIA assays, which makes natural substances combining these biological activities particularly interesting.

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