ARS | Publication request: HPLC-MS ANALYSIS OF PHENOLS IN LONGAN (DIMOCARPUS LONGAN LOUR.) PEEL

Submitted to: Florida State Horticultural Society Meeting
Publication Type: Abstract Only
Publication Acceptance Date: March 1, 2006
Publication Date: June 4, 2006
Citation: Jaitrong, S., Manthey, J.A., Baldwin, E.A. 2006. Hplc-ms analysis of phenols in longan (dimocarpus longan lour.) peel. Florida State Horticultural Society Meeting. Paper No. 51.

Technical Abstract: Longan fruit are susceptible to chilling injury, where the peel exhibits discoloration (water-soaking and/or browning area on the peel). Two varieties of longan (Daw and Biew Kiew) were subjected to abusive cold storage to evaluate the changes in the phenolic compounds that occurred in peel exhibiting chilling injury. The peel of the stored fruit was freeze-dried and subsequently extracted with 80% aqueous methanol. HPLC-PDA analysis of the peel extracts showed a very large number of phenolic compounds. Fractionation of the phenols by size-exclusion P2 (Biogel) chromatography effectively separated several main classes of phenols, including ellagic acid conjugates, flavone glycosides, and a collection of putatively similar phenols based on their common UV and MS properties. Analysis of phenolic extracts following hydrolysis showed that the majority of flavones constituted glycosides of quercetin and kaempferol. A number of other unusual flavone conjugates were also detected by HPLC-ESI-MS analysis. Similar analyses also showed evidence of 2 ellagic acid-pentose conjugates. The spectral properties of these compounds are reported.