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ARS Home » Southeast Area » Oxford, Mississippi » Natural Products Utilization Research » Research » Publications at this Location » Publication #422986
Research Project: Biobased Pesticide Discovery and Product Optimization and Enhancement from Medicinal and Aromatic Crops

Location: Natural Products Utilization Research

Title: Astracondensatol D: A 6/6/5/6 Cycloartane Triterpenoid from Astragalus condensatus

Author
item AYDOGAN, FADIME - University Of Mississippi
item PANDEY, PANKAJ - University Of Mississippi
item FRONCZEK, FRANK - Louisiana State University
item KHAN, IKHLAS - University Of Mississippi
item ALI, ZULFIQAR - University Of Mississippi
item CHITTIBOYINA, AMAR - University Of Mississippi

Submitted to: Organic Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/10/2025
Publication Date: 3/12/2025
Citation: Aydogan, F., Pandey, P., Fronczek, F.R., Khan, I.A., Ali, Z., Chittiboyina, A.G. 2025. Astracondensatol D: A 6/6/5/6 Cycloartane Triterpenoid from Astragalus condensatus. Organic Letters. 2025(27):2609-2615. https://doi.org/10.1021/acs.orglett.5c00282.
DOI: https://doi.org/10.1021/acs.orglett.5c00282

Interpretive Summary: The roots of Astragalus species are widely used in traditional medicine to treat various ailments, including diabetes, hyper-tension, cirrhosis, nephritis, viral infections, leukemia, and other cancers. Astragalus condensatus is a dwarf, cushion-forming subshrub native to the region from Eastern Ae-gean to Western Armenia. As a part of our ongoing phytochemical investigations of Astragalus spp., we previously re-ported the isolation and structure elucidation of pyrano-type cycloartane triterpenoids with stereochemical revision. In this study, we report the isolation, structural elucidation and pro-posed biogenesis of a novel cycloartane triterpenoid, astracondensatol D. Triterpenoids constitute a vast and structurally diverse class of natural products derived from squalene or related acyclic C30 precursors. Over 200 distinct skeletal structures have been documented possessing various configurational architectures. The resulting structural diversity not only reflects the complex biosynthetic machinery but also underpins their broad-spectrum biological activities and their potential utility in medicine and agriculture.

Technical Abstract: Astracondensatol D (1), a pentacyclic triterpenoid featuring an uncommon 6/6/5/6-fused ring system, along with its precursor 12-hydroxy cycloastragenol (2), and two simplified 20(27)-octanorcycloastragenol derivatives (3, 4) were isolated from Astragalus condensatus for the first time. Classical NMR spectroscopic data, integrated with NMR and DP4+ calculations, unambiguously determined their absolute stereostructures. X-ray crystallography provided independent confirmation of the structure of compound 3. The plausible biosynthetic pathway, encompassing Wagner–Meerwein rearrangement and retro-aldol reaction, was proposed for their formation and supported by computational analysis.