Colletotridemin A and Three New Botrydial Sesquiterpenoids From Fungus Colletotrichum dematium

ABSTRACT One new bicyclic sesterterpene, colletotridemin A ( 1 ), and three new botrydial sesquiterpenoids ( 3 – 5 ), along with 11 identified compounds ( 2 , 6 – 15 ) separated from the plant‐associated fungus Colletotrichum dematium . Electronic circular dichroism (ECD) and spectroscopic analyses (NMR and HR–ESI–MS) were conducted to characterize the structures and their absolute configurations. All compounds were assessed for their α‐glucosides and cytotoxic activities. Notably, compound 1 exhibited remarkable inhibitory effects on α‐glucosidase, and the IC 50 value was 16.8 µM, which was 118‐fold greater than that of the positive control acarbose. The mechanisms underlying α‐glucosidase inhibition were investigated through enzyme reaction kinetics and molecular docking. In addition, compound 1 showed potent cytotoxic effects on RKO cells, with an IC 50 value of 33.03 ± 6.13 µM, which induced apoptosis in RKO cells.