ABSTRACT
Two new sempervirol type diterpenes, inumakiols A, B, and six new totarol type diterpenes, inumakiols C-H, were isolated from a methanolic extract of bark of Podocarpus macrophyllus (Podocarpaceae), along with one known abietane, two known totarol type diterpenes, and one known totarol type diterpene dimer. The structures of the new compounds were elucidated by the spectroscopic methods. Some of them possessed antibacterial activity against oral pathogenic microorganisms with minimum inhibitory concentration (MIC) values ranging from 3.1 to 25 ppm.
Subject(s)
Anti-Bacterial Agents/isolation & purification , Anti-Bacterial Agents/pharmacology , Diterpenes/isolation & purification , Diterpenes/pharmacology , Plants/chemistry , Bacteria/drug effects , Chromatography, High Pressure Liquid , Crystallography, X-Ray , Magnetic Resonance Spectroscopy , Microbial Sensitivity Tests , Models, Molecular , Mouth/microbiology , Plant Bark/chemistry , Plant Extracts/chemistry , Plant Extracts/isolation & purification , Spectrometry, Mass, Electrospray Ionization , Spectrophotometry, Infrared , Spectrophotometry, UltravioletABSTRACT
For one-step enzymatic synthesis of eugenyl alpha-glucoside as a promising pro-drug for a hair restorer and a derivative of spices, selective alpha-glucosylation of eugenol was carried out using the alpha-glucosyl transfer enzyme of Xanthomonas campestris WU-9701. When 130 micromol eugenol and crude enzyme showing 1.0 unit of alpha-glucosyl transfer activity were shaken in 2 ml of 10 mM H3BO3-NaOH-KCl buffer (pH 8.0) containing 1.2 M maltose as a glucosyl donor at 40 degrees C, only one form of eugenyl glucoside was selectively obtained as a product and identified as eugenyl alpha-D-glucopyranoside (alpha-EG) by 13C-NMR, 1H-NMR, and two-dimensional heteronuclear multiple-bond coherence analyses. In the reaction, no other glucosylated products such as maltotriose or eugenyl maltoside were detected in the reaction mixture. The reaction at 40 degrees C for 48 h under the above conditions yielded 68 mumol alpha-EG in 2 ml suspension, and the maximum molar conversion yield based on the amount of eugenol supplied reached 52%.
ABSTRACT
Alpha-arbutin, a useful cosmetic ingredient, was selectively synthesized by alpha-anomer-selective glucosylation of hydroquinone with maltose as a glucosyl donor using lyophilized cells of Xanthomonas campestris WU-9701 as a biocatalyst. When 45 mM hydroquinone and 120 mg of lyophilized cells showing 11 nkat of alpha-glucosyl transfer activity were shaken in 2 ml of 10 mM H3BO3NaOHKCl buffer (pH 7.5) containing 1.2 M maltose at 40 degrees C, only one form of hydroquinone glucoside was selectively obtained as a product and identified as hydroquinone 1-O-alpha-D-glucopyranoside (alpha-arbutin) by 13C-NMR, 1H-NMR and two-dimensional HMBC analysis. Although hydroquinone has two phenolic -OH groups at the para position in its structure, only one -OH group, but not both -OHs, was glucosylated and no other glucosylated products such as maltotriose were detected in the reaction mixture. The reaction at 40 degrees C for 36 h under optimum conditions yielded 42 mM alpha-arbutin, and the maximum molar conversion yield based on the amount of hydroquinone supplied reached 93%.
