Submitted to: Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/18/2008
Publication Date: 3/4/2009
Citation: Lee, J., Scagel, C.F. 2009. Chicoric acid found in basil (Ocimum basilicum L.) leaves. Food Chemistry. 115:650-656.
Interpretive Summary: We were the first to identify and report that chicoric acid can be found within basil leaves, a widely used culinary herb. Chicoric acid is the main phenolic compound in Echinacea purpurea extracts sold as dietary supplements in the United States. In basil leaves, we found chicoric acid to be the second most abundant phenolic after rosmarinic acid. Basil is a more commonly available and inexpensive source for chicoric acid than E. purpurea. The impact of arbuscular mycorrhizal fungi on basil phenolics was also explored.
Technical Abstract: This is the first report to identify the presence of chicoric acid (cichoric acid; also known as dicaffeoyltartaric acid) in basil leaves. Rosmarinic acid, chicoric acid, and caftaric acid (in the order of most abundant to least; all derivatives of caffeic acid) were identified in fresh basil leaves. Rosmarinic acid was the main phenolic found in both leaves and stems. Chicoric acid was not present in sweet basil stems, although a low concentration was present in Thai basil stems. Other caffeic acid monomers, dimers, and trimers were also found in minor quantities in both stems and leaves. Blanched methanol extraction procedure was used on basil samples, which stopped enzymatic degradation of the phenolic compounds by the native enzymes and retained more phenolics. This extraction and HPLC method was used on ‘Genovese Italian’ and ‘Purple Petra’ basil samples obtained from a study examining the influence of inoculation with an arbuscular mycorrhizal fungus (AMF), Glomus intraradices, on plant phenolic composition. Inoculation with AMF increased total anthocyanin concentration of ‘Purple Petra’ but did not alter polyphenolic content or profile of leaves and stems of either cultivar, compared to non-inoculated plants. This is the first report identifying caffeic acid derivatized with tartaric acid (caftaric and chicoric acids) in basil leaves. In the U.S. diet, basil presents a more accessible source for chicoric acid, the major phenolic compound of Echinacea purpurea.