Structural elucidation of two intricate polycyclic polyprenylated acylphloroglucinols using quantum chemical calculations and their hypoglycemic activities

Compounds 1-2, the rare examples of polycyclic polyprenylated acylphloroglucinols (PPAPs) with unique 6/5/7 and 6/6 ring systems possessing unprecedented 2, 3, 12-trioxatricyclo-[5.3.1.15,11] dodecane and bicyclo-[4.4.0] decane, respectively, were isolated from the fruits of Gar-cinia bracteata and Garcinia multiflora, respectively. Their structures and absolute configurations were elucidated by the combination of gauge-independent atomic orbital (GIAO) NMR calcula-tions and electronic circular dichroism (ECD) calculations. Furthermore, the hypoglycemic activity of 1 was assayed by the insulin resistance (IR)-HepG2 cell model. The results showed that com-pound 1 at the concentrations of 2, 4, and 6 lM could significantly promote glucose uptake dose-dependently and improve glucose metabolism disorder. Taken together, these findings sug-gested 1 could be a promising candidate for the treatment of diabetes mellitus. (c) 2022 The Author(s). Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

The article presents the isolation and characterization of two rare compounds from fruits of two plants, which have unique ring systems and show potential for treating diabetes mellitus.