Unusual D:B-friedobaccharane and oxygenated friedelane-type triterpenoids from Salvadorean Celastraceae species

Montecrinanes A–C: Triterpenes with an Unprecedented Rearranged Tetracyclic Skeleton from Celastrus vulcanicola. Insights into Triterpenoid Biosynthesis Based on DFT Calculations

“…The hexanes/Et 2 O extract of the root bark of C. vulcanicola , a Salvadorian Celastraceae species, was subjected to multiple chromatographic steps, involving vacuum liquid chromatography (VLC), medium‐pressure liquid chromatography (MPLC), and preparative TLC to yield three new triterpenoids, 1 – 3 , along with the known related compounds, 4 , leonatriol ( 5 ), and leonatriolone ( 6 ) . Moreover, six known pentacyclic lupane triterpenes (Figure ) were isolated and identified as nepeticin ( 7 ), 2α,3β‐dihydroxy‐lup‐20(29)‐ene ( 8 ), 3β,6β‐dihydroxy‐lup‐20(29)‐ene ( 9 ), betulin ( 10 ), 6β,28‐dihydroxy‐3‐oxolup‐20(29)‐ene ( 11 ), and 6β‐hydroxy‐3‐oxolup‐20(29)‐en‐28‐oic acid ( 12 ) by comparison of their spectral data with values reported in the literature.…”

“…However, Cassine xylocarpa , a Salvadorian plant species, mainly biosynthesizes a small group of triterpenoids with an olean‐18‐ene backbone . Moreover, species of this family are the first reported sources of D : B ‐friedobaccharanes, the biosynthetic origin of which has been postulated from the D : B ‐friedobaccharenyl cation; an intermediate between baccharane and shionane series . Thus, the characterization of chemically novel triterpenoids from Celastraceae species could shed light on their biosynthetic biodiversity.…”

“…Previously,b ioactive dihydro-b-agarofuran sesquiterpenes [30][31][32][33] and friedelane, [34,35] glutinane, olean-12-ene, [36] and D:B-friedobaccharane triterpenoids [29] from Celastrus vulcanicola were reported. Herein, we report the isolation and stereostructure of three triterpenoidsw ith an unprecedented tetracyclic 6/6/6/6 backbone, namedm ontecrinanes A-C (1-3), along with three knownb iosynthetic related D:B-friedobaccharanes (4-6), and six known lupane-typet riterpenes (7)(8)(9)(10)(11)(12).…”

Triterpenoids

“…293 Cassinolide 644, from Cassine xylocarpa, is a 2,3secofriedelan-3,24-olide derivative. 294 Maytenus robusta is the source of the 3,4-secofriedelan-3,11b-olide 645 (ref. 295) and friedelane-3b,11b-diol 646.…”

“…346 The D:B-friedobaccharane derivatives leonatriol 751 and the corresponding ketone leonatriolone 752 have been isolated from Cassine xylocarpa and Celastrus vulcanicola, respectively. 294 Globostelletins J 753-S 761, from the marine sponge Rhabdastrella globostellata, are isomalabaricanes with cyclopentane side chains. 347…”