Volatile organic sulfur-containing constituents in Poncirus trifoliata (L.) Raf. (Rutaceae).
During our screening of plant materials to find new natural fragrance and flavor ingredients, we discovered two series of 3-sulfanylalkyl alkanoates in a peel extract of fruits of wild-growing Poncirus trifoliata (L.) Raf. (Rutaceae), a species closely related to Citrus. The two series belong to alkanoates of 3-methyl-3-sulfanylbutan-1-ol and 3-sulfanylhexan-1-ol, respectively, and thus are members of a family of natural molecules having in common a 1,3-positioned O,S moiety. The alkanoate residues comprise all even-numbered saturated fatty acids from C2 (acetate) to C18 (octadecanoate). Among the 20 sulfur-containing compounds identified, 14 are described for the first time as naturally occurring in a botanical species. Several cysteine-S-conjugates were synthesized as hypothetical precursors of the new volatile sulfur-containing constituents, where after S-(3-hydroxy-1,1-dimethylpropyl)-L-cysteine, S-[3-(acetyloxy)-1,1-dimethylpropyl]-L-cysteine, and S-[1-(2-hydroxyethyl)butyl]-L-cysteine were identified in the fruit peel. No cysteine-S-conjugates were detected in the fruit juice.
Starkenmann
Christian
C
Firmenich SA, Corporate R&D Division, CH-1211 Geneva 8, Switzerland. christian.starkenmann@firmenich.com
Niclass
Yvan
Y
Escher
Sina
S
D013058:Mass Spectrometry; D019906:Nuclear Magnetic Resonance, Biomolecular; D010936:Plant Extracts / Q000737:chemistry*; D032104:Poncirus / Q000737:chemistry*; D013457:Sulfur Compounds / Q000737:chemistry / Q000302:isolation & purification*
D010936:Plant Extracts; D013457:Sulfur Compounds