Analytical Sciences

Analysis of Fresh Sap Collected from Ryukyu Lacquer Tree

Rong LU,* Takayuki HONDA,* Meesook SUNG,** Jaekook JUNG,*** and Tetsuo MIYAKOSHI*

*Department of Applied Chemistry, School of Science and Technology, Meiji University, 1-1-1 Higashi-Mita, Tama, Kawasaki 214-8571, Japan
**Department of Biochemistry, Institute for Clinical and Translational Research, College of Medicine, Catholic Kwandong University, Beomil-ro 579 Beon-gil 24, Gangneung 25601, Korea
***Department of Architecture, College of Engineering, Catholic Kwandong University, Beomil-ro 579 Beon-gil 24, Gangneung 25601, Korea

The chemical structure of fresh lacquer sap collected from a lacquer tree growing in Nago City of Okinawa, Japan, was analyzed by gas chromatography/mass-spectrometry (GC/MS) and nuclear magnetic resonance (NMR). The results showed that Nago lacquer is laccol lacquer and its major components are 3-(heptadeca-10Z,13E,15E-trienyl)catechol, 3-(heptadeca-10Z,13E-dienyl)catechol, 3-(heptadeca-14Z-enyl)catechol, and 3-(heptadeca-12Z-enyl)catechol, which are similar to the components of Vietnamese lacquer. It showed higher laccase activity at pH 5 – 8 and better low temperature adaptability than Vietnamese lacquer. The Nago lacquer reached a dust free dry (DF) condition after 6 h, but Vietnamese lacquer did not. However, both were able to achieve harden dry (HD) in 24 h at 25°C, 80% relative humidity. In order to identify the lacquer provenance, the strontium isotope ratio was analyzed. The strontium isotope ratio (⁸⁷Sr/⁸⁶Sr) of Nago lacquer was 0.7110, which is different from the 0.7450 of Vietnamese lacquer.

J-STAGE: View this article in J-STAGE