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-[5.3.1.1 (5,11)] dodecane and bicyclo-[4.4.0] decane, respectively, were isolated from the fruits of Garcinia bracteata and Garcinia multiflora, respectively. Their structures and absolute configurations were elucidated by the combination of gauge-independent atomic orbital (GIAO) NMR calculations 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 compound 1 at the concentrations of 2, 4, and 6 mu M could significantly promote glucose uptake dose-dependently and improve glucose metabolism disorder. Taken together, these findings suggested 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.

Automated summary

In this study, rare polycyclic polyprenylated acylphloroglucinols compounds 1-2 were isolated from the fruits of Garcinia bracteata and Garcinia multiflora. The structures and activities of these compounds were investigated, and compound 1 showed hypoglycemic activity, making it a potential candidate for the treatment of diabetes.