Two new triterpene glycoside, Arjunoglycoside VI (1) and Arjunursglycoside I (2) alone with five previously known analogues (3-7) were isolated from methanolic extract of the fruits of Terminalia arjuna. The structures were elucidated by extensive spectroscopic studies (1 D and 2 D NMR and mass). Compound 1 and 2 showed moderate activity on α-chymotrypsin enzyme inhibition with IC50 values 53.8 ± 1.39 and 64.27 ± 1.27 µg/mL respectively. Molecular docking was performed for compound 1 and 2 with the 1CGI co crystals of α-chymotrypsin enzyme protein of Bovine from protein data bank showed -7.7 and -7.6 kcal/mol binding energy, respectively.
Keywords: Terminalia arjuna; arjunoglycoside VI; arjunursglycoside I; combretaceae; molecular docking; triterpenoid glycoside; α-chymotrypsin.