grandiflorus leaves and derived fractions enriched in diterpenes, flavonoids and HCTA, as well as to investigate the correlation between the biological effect and the contents of constituents assayed in the preparations.
The EtOAc layers were combined and evaporated to afford the fraction enriched in HCTA (1.253 g).
Quantification of flavonoids, diterpenes and HCTA derivatives
The total contents of flavonoids, diterpenes and HCTA were determined spectrophotometrically.
HCTA contents were assayed using Arnow reagent (Arnow 1937).