Chemosystematic study of the tribe Vismieae (Hypericaceae)

Le résumé fourni par la source

While the existence of the Vismieae tribe is well established within the Hypericaceae family, the classification of species within the genera is less clear. Therefore, the aim of this study was to analyze the metabolites found in Vismieae from a chemosystematic aspect, with the goal of understanding metabolic diversity and clarifying the classification of its species. The herbaceousness index, the number of occurrences (NO), the diversity index (DI) and the evolutionary parameters relating to hydroxyl oxidation and protection (AEX), as well as the degree of prenylation, showed the particularities of each genus of Vismieae. The present study considered anthracene derivatives as the tribe’s chemosystematic markers, with Psorospermum exhibiting the highest occurrence of these metabolites. With regard to the identified compound classes, anthraquinones were predominant in Psorospermum, anthrones/anthranols in Vismia, and hydroxyanthrones in Harungana. The most oxygenated anthraquinone derivatives were recorded in Psorospermum, while those less oxygenated were found in Harungana, supporting the basal character of this genus. Despite the high levels of deprotection of phenolic hydroxyls observed in the anthracene derivatives of the three genera, the types of protection (by methylation, prenylation, geranylation, or acetylation) identified refer to a derived characteristic, suggesting a tendency to evolution into the tribe Vismieae. The prevalence of anthraquinone derivatives with isoprenoid residues was observed in all three genera, a characteristic common among derived taxa. The type and degree of prenylation of the anthracene derivatives proved to be useful tools for differentiating Psorospermum from Harungana. Vismia, in turn, is differentiated from these two genera mainly by the high occurrence of sesquiterpenes, which can be considered specific chemosystematic markers for this genus within the tribe.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.