Quercetin 3-(6″-caffeoylsophoroside) is an orally active α-amylase inhibitor, with an IC 50 of 73.66 μg/mL. Quercetin 3-(6″-caffeoylsophoroside) presents in thehydro-methanolic extract of Cardamine hirsuta Linn. Quercetin 3-(6″-caffeoylsophoroside) shows the antidiabetic activities by oxidative stress reduction and α-amylase inhibition. Quercetin 3-(6″-caffeoylsophoroside) can be used for diabetes mellitus research.