Please login first
Chemometrical analysis of structure-structure and structure-activity trends of cycloartane-based saponins in Astragalus genus
1 , * 2
1  University of Tunis El Manar, Faculté des Sciences de Tunis, Campus Universitaire, 2092 Tunis , Tunisia
2  University of Tunis El Manar. Pasteur Institute of Tunis. Laboratory of BioInformatics, bioMathematics and bioStatistics (BIMS), 1002, Tunis, Tunisia


Astragalus genus represents the widest terrestrial plant taxon with more than 2500 species of herbs or shrubs. Under phytochemical aspect, this genus was characterized by a high structural diversity of saponins essentially based on cycloartane. The high number and diversity of saponins offers a strong basis for analysis of structural properties and metabolic trends governing molecular synthesis. Such trends can be highlighted by significant correlations between chemical substitution types/positions and aglycone forms. Beyond general biosynthetic machinery, structure-activity trends represent more specific aspects which are essential to be analyzed for highlighting structural factors influencing activity. These two complementary aims were considered in this paper by statistically analyzing structure-structure (SS) and structure-activity (SA) trends in saponins based on different cycloartane forms of Astragalus genus. For that, 193 saponin structures were statistically analyzed by ordination method to highlight positive and negative trends between different chemical substitutions and aglycone forms. In ordination analysis, the most published pharmacological activities of Astragalus saponins (immunomodulatory, cytotoxic) were considered to identify SA trends which were statistically evaluated by Fisher’s exact test. Results revealed significant contributions of cycloartane forms, glucosylation and/or hydroxylation positions on different studied pharmacological activities. Finally, using the significantly influent structural variables, SAR models were developed by logistic regressions. Statistical analysis of cumulated bibliographic data provides interesting integrative way for understanding biosynthetic rules governing structural diversity and influencing pharmacological activities within a wide metabolites’ family.