Two new antidiabetic xanthones from the twigs of Garcinia oblongifolia

Abstract

Two new xanthones, oblongixanthones I (1) and J (2), and seven known compounds (3–9), were isolated from an EtOAc extract of the twigs of Garcinia oblongifolia. Their structures were elucidated using spectroscopic methods, mainly 1 D and 2 D NMR. The antidiabetic effects of the two new compounds were evaluated using α-glucosidase and PTP1B inhibition assays. Both compounds displayed strong inhibition towards α-glucosidase with IC₅₀ values of 258.7 ± 49.3 and 187.1 ± 27.5 μM, respectively (compared with acarbose, IC₅₀ = 900.0 ± 3.0 μM) and moderate effects against PTP1B with IC₅₀ values of 93.9 ± 12.3 and 64.1 ± 5.8 μM, respectively (compared with RK682, IC₅₀ = 4.4 ± 0.3 l μM).

Graphical Abstract

Keywords:

• Type 2 diabetes
• α-glucosidase
• PTP1B
• Garcinia oblongifolia
• xanthones

Disclosure statement

The authors declare no conflict of interest.

Supplementary material

Supplementary material associated with this article can be found in the online version at: TO BE INSERTED.

Additional information

Funding

This research work is funded by Vietnam National University Ho Chi Minh City (VNU-HCM) under the grant number C2018-18-16.