ent-Clerodane diterpenoids from the stems of Croton krabas

September 27, 2021

Title

ent-Clerodane diterpenoids from the stems of Croton krabas

Author

Oue-artorn Rajachan

Year

2021

Journal

Fitoterapia

Abstract

The first phytochemical investigation from the stems of Croton krabas resulted in the isolation of three new ent-clerodane diterpenoids, crotonkrabases A–C (1–3), along with two known compounds, 12-oxohardwickiic acid (4) and crotonpyrone B (5). Their structures were elucidated using extensive spectroscopic methods. The structure of 3 was unambiguously proven by X-ray crystallography. Furthermore, the absolute configurations of compounds 1–3 were identified by NOESY and the comparison of their experimental ECD spectra with those of calculated ECD spectra reported in the literature. Compounds 1, 2, and 5 showed antibacterial activities against two Gram-positive bacteria (Bacillus cereus and Bacillus subtilis); whereas compound 4 exhibited weak antibacterial against B. cereus. In addition, compound 4 showed potent α-glucosidase inhibitory activity, which was lower than the reference standard acarbose.

Instrument

P-1020, J-810

Keywords

Croton krabas, structure