New isopimaradiene diterpenoids from kaempulchraol E via Rhizopus oryzae fungal transformation. (August 2020)

• Record Type: Journal Article
• Authors: Elshamy, Abdelsamed I.; Abd El Aty, Abeer A.; Yoneyama, Tatsuro; Hussien, Taha A.; Imagawa, Hiroshi; Suenaga, Midori; Umeyama, Akemi; Hegazy, Mohamed-Elamir F.
• Is Part Of: Phytochemistry letters. Volume 38(2020)
• Page Start: 107
• Page End: 111
• Publication Date: 2020-08
• Subjects: Kaempulchraol E -- Fungal transformation -- Kaempheria galanga -- Isopimaradiene diterpenoids -- Rhizopus oryzae; Botanical chemistry -- Periodicals; Chimie végétale -- Périodiques; 572.205
• DOI: 10.1016/j.phytol.2020.05.006
• Languages: English
• ISSNs: 1874-3900

Abstract

Graphical abstract: Highlights: Fungal transformation of kaempulchraol E (1 ) was performed by Rhizopus oryzae KX685359. Two new diterpenoids 2 and 3 along with roscorane B (4 ) were produced. Compound 2 was confirmed via X-ray diffraction analysis. Compound 4 showed potent toxicity against HSC-2 cell lines. Abstract: Fungal transformation of the diterpenoid kaempulchraol E (1 ) by Rhizopus oryzae KX685359 afforded two trihydroxlated isopimaradienes: 2α, 6β, 14β-trihydroxy-isopimara-8(9), 15-diene (2 ) and 2α, 6β, 14α-trihydroxy-isopimara-8(9), 15-diene (3 ) in addition to the known metabolite roscorane B (4 ). Chemical structures were established by spectroscopic techniques including: HRMS, FT-IR and 1D- & 2D-NMR. The structure of 2 was confirmed by single-crystal, X-ray diffraction analysis. Bio-transformed metabolites as well as the substrate originally isolated from Kaempheria galanga were tested against two cancer cell lines: HSC-2 and B16-BL6. Compounds 4 showed greater toxicity than the original plant derived diterpene (IC50 54.08 ± 0.05 versus 96.05 ± 0.03 μM, respectively) when assayed against the HSC-2 cell line. This study confirms the role of fungal transformations in developing novel natural products with efficacious biological activities.