Plausible Authentication of Manuka Honey and Related Products by Measuring Leptosperin with Methyl Syringate

• Published in: Journal of agricultural and food chemistry 2014-07, Vol.62 (27), p.6400-6407
• Main Authors: Kato, Yoji, Fujinaka, Rie, Ishisaka, Akari, Nitta, Yoko, Kitamoto, Noritoshi, Takimoto, Yosuke
• Format: Article
• Language: English
• Subjects: Chromatography, High Pressure Liquid; Food Contamination - analysis; Gallic Acid - analogs & derivatives; Gallic Acid - analysis; Honey - analysis; Leptospermum - chemistry; Mass Spectrometry
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf501475h

Manuka honey, obtained from Leptospermum scoparium flowers in New Zealand, has strong antibacterial properties. In this study, plausible authentication of the manuka honey was inspected by measuring leptosperin, methyl syringate 4-O-β-D-gentiobiose, along with methyl syringate. Despite a gradual decrease in methyl syringate content over 30 days at 50 °C, even at moderate 37 °C, leptosperin remained stable. A considerable correlation between nonperoxide antibacterial activity and leptosperin content was observed in 20 certified manuka honey samples. Leptosperin and methyl syringate in manuka honey and related products were analyzed using HPLC connected with mass spectrometry. One noncertified brand displayed significant variations in the leptosperin and methyl syringate contents between two samples obtained from different regions. Therefore, certification is clearly required to protect consumers from disguised and/or low-quality honey. Because leptosperin is stable during storage and specific to manuka honey, its measurement may be applicable for manuka honey authentication.