Comparative phytochemical analysis and antioxidant capacity of leaves from five species of miconia and one of clidemia

The flowering plant family Melastomataceae is one of the most diverse in neotropical ecosystems and represents an interesting field of research in chemistry, particularly for the isolation of secondary metabolites due to their medicinal value and application in pharmaceuticals. Among the main constituents of this family are terpenoids, phenolics, lignans, polyphenols, some flavonoids, and anthocyanins. The objective of this study was to perform a phytochemical characterization and a comparative evaluation of the antioxidant capacity and the content of key secondary metabolites in the leaf extracts of five species of the genus Miconia (M. aeruginosa, M. minutiflora, M. sp, M. sp1, M. sp2) and one species of the genus Clidemia (C. tococoidea).

Methanolic extracts were prepared from the dried leaf material, and the quantification of total phenols, flavonols, and catechins was carried out using standardized spectrophotometric methods. The antioxidant activity was determined using three complementary assays that evaluate different mechanisms of action: free radical scavenging capacity (DPPH and ABTS) and ferric reducing antioxidant power (FRAP).

The highest total phenol content was found in M. sp and M. aeruginosa, suggesting a high concentration of polyphenolic compounds. On the other hand, the species C. tococoidea presented the highest concentration of catechins and flavonols, indicating a particular phytochemical profile. The species M. sp exhibited the most potent antioxidant capacity in the three methods evaluated, which correlates with its high phenolic content. These findings underscore the potential of these species, especially M. sp, as a valuable source for the isolation of antioxidant compounds and the development of future nutraceutical or phytotherapeutic products.