New α-glucosidase inhibitors from the resins of Boswellia species. - GreenMedInfo Summary

Phytochemical investigation of the oleo-gum resins from Boswellia papyrifera afforded one new triterpene, named 3α-hydroxyurs-5:19-diene (1) together with twelve known compounds including eight triterpenoids (2-9), two diterpenoids (10 and 11) and two straight chain alkanes (12 and 13). Similarly ten more known compounds were isolated from the resin of Boswellia sacra including one triterpene (20) and nine boswellic acids (14-19 and 21-23). Herein the compound 2 was first time reporting from natural source along with complete NMR assignment, while compounds 3-11 are known, but reported for the first time from the resin of B. papyrifera. The structure elucidation was done by advance spectroscopicD andD NMR techniques viz.,H,C, DEPT, HSQC, HMBC, and COSY, and NEOSY, ESI-MS and compared with the reported literature. All compounds were evaluated for theirα-glucosidase inhibitory activity and as result eight of them 1, 3, 10, 11, 15, and 17-19 were found significantly active against α-glucosidase with an ICvalue ranging from 15.0 ± 0.84 to 80.3 ± 2.33 µM, while 21 exhibited moderate activity with ICof 799.9 ± 4.98 µM. Furthermore, two compounds 24 and 25 were synthesised from 16 and 17 to see the effect of carboxyl group in structural-activity relationship (SAR) study. Compounds 24 and 25 retained good α-glucosidase inhibition as compared to 16 and 17, indicating that carboxylic group play akey role in SAR. In addition, the aforementioned activity of all the active compounds was first time reported for their α-glucosidase inhibition potential. The molecular docking studies showed that all the active compounds well accommodate in the active site of the enzyme. Moreover pharmacokineticproperties of the compounds were predicted in silico, suggesting that the compounds possess drug like properties and excellent ADMET profile.