n-Octyl .ALPHA.-L-Rhamnopyranosyl-(1.RAR.2)-.BETA.-D-glucopyranoside Derivatives from the Glandular Trichome Exudate of Geranium carolinianum

Abstract

Chemical investigation of the glandular trichome exudate from Geranium carolinianum L. (Geraniaceae) led to the characterization of unique disaccharide derivatives, n-octyl, named caroliniasides A-C, respectively. These structures were determined by spectral means. n-Alkyl glycoside derivatives have been isolated from the glandular trichome exudates for the first time. This rare type of secondary metabolites could be applicable to chemotaxonomic perspective because they are found in glandular trichome exudates of plants belonging to the genus Geranium, according to our studies.

Dodecyl α‐L‐Rhamnopyranosyl‐(1→2)‐β‐D‐fucopyranoside Derivatives from the Glandular Trichome Exudate of Erodium pelargoniflorum

“…We recently reported the isolation of three octyl a-l-rhamnopyranosyl-(1 ! 2)-b-d-glucopyranoside derivatives from the glandular trichome exudate of Geranium carolinianum [8]. This was the first isolation of n-alkyl saccharides from glandular trichome exudates.…”

“…However, it is worthy of note that, as long as Geranium species are concerned, they all have a common skeleton of octyl a-l-rhamnopyranosyl-(1 ! 2)-b-d-glucopyranoside [8] [11], and this particular type of n-alkyl disaccharides have been characterized neither from any other family, nor from any other genera of the Geraniaceae family. Thus further investigations of glandular trichome exudates from plants belonging to Erodium and other genera of the Geraniaceae family are justified.…”

“…These MS data, taken together with the finding that the 1 H-and 13 C-NMR spectra of Fr. B and compound 2 were essentially identical, and that there was no indication for the presence of branched alkyl chains permitted us to characterize the three minor constituents as undecyl 3, (8). Compounds 6 -8 were named pelargosides B2, B3, and B4, respectively.…”

“…2)-fucose vs. rhamnosyl-(1 ! 2)-glucose) in the disaccharide moiety [8]. Recently, octyl 4-O-isovaleroyl-a-l-rhamnopyranosyl-(1 !…”

“…Tetradecyl 4-O-Acetyl-6-deoxy-2-O-(3,4-di-O-acetyl-6-deoxy-a-l-mannopyranosyl)-b-d-galactopyranoside (8 4 Cl (2.5 mg) was added to the mixture, and the solvent was removed by flushing with N 2 . The concentrated soln.…”