Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: 2/4/2007
Publication Date: 2/6/2007
Citation: Harrison Jr, H.F., Mitchell, T.R., Peterson, J.K., Snook, M.E., Wechter, W.P. 2007. Content and potential biological activity of dicaffeoylquinic acids in sweetpotato storage roots. HortScience. National Sweetpotato Collaborators Progress Report. Page 7.
Technical Abstract: Three dicaffeoylquinic acid isomers (3,4-, 3,5-, and 4,5-DCQA) were identified in sweetpotato (USPI 399163) storage root cortex by methanol extraction followed by preparative-reversed phase and silicic acid column chromatography. Structures were confirmed by HPLC-MS. DCQAs were quantified in the storage root periderm, cortex and stele of 17 sweetpotato genotypes. The 3,5-DCQA isomer comprised >70% of the total DCQAs in most instances. Levels of 3,5-DCQA averaged 490, 2570, and 670 ug/g in periderm, cortex and stele, respectively. Contents of 3,5 DCQA in individual clones ranged from 0-1700 ug/g, 800-7400 ug/g, and 200-1600 ug/g in periderm, cortex and stele, respectively. I. pandurata cortex and stele were very high in DCQAs and contained almost equal amounts of all three isomers. I. pandurata cortex contained 22,000 ug/g (2.2% dry wgt.) and stele contained 24,000 ug/g (2.4% dry wgt.) DCQAs. I. pandurata periderm contained only 0.04% dry weight DCQA. All three isomers of DCQA were isolated from PI 399163 cortex, and tested for biological activity. The 3,5 DCQA isomer was inhibitory in Fusarium solani and proso millet bioassays which suggests it may contribute to the allelopathic potential and disease resistance in sweetpotato. The 3,4- and 4,5-DCQA isomers were not as inhibitory as 4,5-DCQA in the bioassays.