Characterization of α-Terpineol as an Anti-inflammatory Component of Orange Juice by in Vitro Studies Using Oral Buccal Cells

• Published in: Journal of agricultural and food chemistry Vol. 55; no. 20; pp. 8040 - 8046
• Main Authors: Held, Sandra, Schieberle, Peter, Somoza, Veronika
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 03.10.2007
• Subjects: alpha-terpineol; anti-inflammatory activity; Anti-Inflammatory Agents - pharmacology; Beverages - analysis; bioactive constituent; Biological and medical sciences; Cell Line, Tumor; Cheek; Citrus sinensis - chemistry; Cyclohexenes - administration & dosage; epithelial buccal cells; epithelial cells; Epithelial Cells - drug effects; Epithelial Cells - metabolism; flow cytometry; Food industries; Fruit - chemistry; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; gene expression; gene expression regulation; Humans; immune modulatory effect; in vitro studies; interleukin-6; Interleukin-6 - biosynthesis; Monoterpenes - administration & dosage; mouth; Mouth Neoplasms; oral buccal cells; Orange juice; reaction inhibition; α-terpineol; α-terpineol; flow cytometry; Orange juice; interleukin-6; immune modulatory effect; epithelial buccal cells; Flow cytometry; Antiinflammatory agent; Fruit product; Fruit juice; In vitro; Characterization; Epithelial cell; Chemical composition
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf071691m

Epithelial buccal cells (KB) were exposed to orange juice or orange juice fractions containing either the dry matter (DM), the volatile compounds (aqueous distillate, AD), or individual nonvolatile or volatile components. Intracellular formation of the pro-inflammatory cytokine IL-6 was analyzed by flow cytometry. Exposure to whole orange juice resulted in an increase in IL-6 formation of 23% compared to nontreated control cells, whereas treatment of the cells with either DM or AD resulted in a 22 or 1% increase, respectively. Dose–response experiments revealed that exposure of the cells to a 2- or 4-fold concentrated AD resulted in an increased IL-6 formation, whereas an inhibiting effect was measured after treatment of the cells with an 8-fold concentrated AD. These results indicated the presence of pro- as well as anti-inflammatory compounds in the aqueous distillate. To identify the active principles, volatile compounds present in the AD-treated cells were analyzed by GC-MS. In particular, limonene, linalool, and α-terpineol were shown to be present in significant amounts. Subsequent studies on the IL-6 formation revealed that limonene had a stimulating effect and α-terpineol had an inhibiting effect, whereas linalool had no effect. This anti-inflammatory effect of α-terpineol on IL-6 formation was verified by quantitative real-time reverse transcription Polymerase Chain Reaction experiments in which α-terpineol inhibited the gene expression of the IL-6 receptor.