Agarotetrol as an index for evaluating agarwood in crude drug products.

Agarotetrol in agarwood has been detected in water extracts or decoctions from medical use agarwood but the detection of agarotetrol has not been reported from other crude drugs. Agarwood generates the sedative benzylacetone upon heating. In this study, crude drug products containing many kinds of crude drugs in addition to agarwood were analyzed. Agarotetrol was detected and quantified, demonstrating that agarotetrol is useful for the quality evaluation of agarwood in complex prescriptions. High-performance liquid chromatography conditions to clearly separate agarotetrol from crude drug products were established and agarotetrol from Kampo decoctions was detected and quantified. Agarotetrol was also detected even from small crude drug product samples. These results suggest that agarotetrol is a useful component for the quality evaluation of agarwood in crude drug products.

Factors affecting 2-(2-phenylethyl)chromones in artificial agarwood.

Recently, "artificial agarwood" manufactured by the artificial treatment on cultivated agarwood trees is popular in agarwood-producing countries. Although there are various treatment methods, they are not standardized. Moreover, factors that may affect the generated chemical compounds have not been investigated. In this research, the effects of different treatment methods and individual differences on the quantities and types of 2-(2-phenylethyl)chromone in agarwood were investigated to experimentally produce artificial agarwood using Aquilaria sinensis. Each solvent-extracted agarwood sample was analyzed using Liquid Chromatography/Tandem Mass Spectrometry (LC-MS/MS), and peaks were identified by comparing ten types of 2-(2-phenylethyl)chromone with reference standards. The composition and 2-(2-phenylethyl)chromone content of each agarwood sample were observed based on the type of chemical compound, and results indicated that when the treatment method was different, the accumulation pattern of the 2-(2-phenylethyl)chromones differed even when the number of resinification years was the same. Furthermore, the findings of this study showed that additional treatment on a single branch produced more 2-(2-phenylethyl)chromones. Moreover, market products composed of artificial agarwood pieces derived from different tree species and collected from different location were analyzed.

Agarotetrol in agarwood: its use in evaluation of agarwood quality.

Agarwood, which is used as medicine and incense, contains sesquiterpenes and chromones. Agarotetrol is a chromone derivative found in high concentrations in the water-extract fraction of agarwood and thus may be present in pharmaceutical products made from decoctions of agarwood. Agarotetrol has been reported to be present at the early stages of cell death in calli. We therefore examined the presence of agarotetrol in medical- and incense-grade agarwood, in agarwood-source plants lacking resin deposits, and in artificially made agarwood. Agarotetrol appeared as a large peak in the HPLC chromatograms of all samples of medical-grade and artificially made agarwood, and in most incense-grade agarwood samples. In contrast, agarwood samples lacking resin deposits did not contain agarotetrol. These results show that agarotetrol is characteristic of resin formation. Agarotetrol was also detected in decoctions of agarwood. A newly developed TLC method for the detection of agarotetrol in agarwood is described.

Correction to: Agarotetrol: a source compound for low molecular weight aromatic compounds from agarwood heating.

In the original publication of the article, under the paragraphs "Collection of volatile compound" and "Analysis of essential oil and hydrosol" holding time for the end of GC and GC-MS programs at 180 °C was incorrectly published as "10 min". The correct time limit is "30 min".

Agarotetrol: a source compound for low molecular weight aromatic compounds from agarwood heating.

Agarwood is known to generate a distinct fragrance upon heating and is used as both a medicine and a fragrant wood. Low molecular weight aromatic compounds (LACs) such as benzylacetone are emitted from agarwood on heating and have a sedative effect on mice. These are detected exclusively in the headspace vapor of heated agarwood and are absent in the wood itself; hence, some compounds in agarwood are thought to be converted to LACs by the process of heating. In this study, different fractions obtained from agarwood were analyzed to reveal the source compounds of LACs. Some LACs detected in the resinous agarwood were absent from the non-resinous parts and confirmed as characteristic of the resinous parts. The essential oil and hydrosol of agarwood obtained by distillation were analyzed by gas chromatography-mass spectrometry (GC-MS). Sesquiterpenes were detected in the essential oil, and sesquiterpenes and a variety of LACs were detected in the hydrosol. A hot water extract of agarwood remaining in the distillation flask after distillation was analyzed by high-performance liquid chromatography (HPLC), and agarotetrol was found to be the main compound. Purified agarotetrol was heated in a glass vial and its headspace vapor was analyzed by solid-phase microextraction GC-MS. Benzylacetone and other LACs were detected. These results indicate that agarotetrol, a chromone derivative, contributes to the fragrance of agarwood through the generation of LACs upon heating.