Fourteen naturally occurring compounds and two derivatives of naturally occurring compounds were tested for inhibitory activity with the enzyme alpha-glucosidase. These compounds included anthocyanins, thiol derivatives, and cinnamic acid. Acarbose was used as the standard. Rutin and tannic acid displayed the highest inhibitory effect (almost 90%), whereas thiols had a neglected effect. Compared to acarbose, rutin and tannic inhibitory effects were 1.6% higher. Concerning anthocyanins, pelargodin had a comparable effect as acarbose and the other anthocyanins tested displayed a less effect. More generally, the ortho-diphenolic structures as aglycones or free forms, such as cyanidin, caffeic acid and quercetin, were less active certainly due to their high oxidability in the test solutions. The glycosylation confer a better stability to the polyphenol, found in rutin, and contribute to a better effect.