# Dynamic Environmental Interactions Shape the Volatile Compounds of Agarwood Oils Extracted from Aquilaria sinensis Using Supercritical Carbon Dioxide

## TL;DR

This study shows how environmental and genetic factors influence the volatile compounds in agarwood oils from Aquilaria sinensis using supercritical CO2 extraction.

## Contribution

The study identifies 2-phenyl-4H-chromen-4-one as a key volatile marker in the 'Qi-Nan' subspecies of Aquilaria sinensis.

## Key findings

- Sesquiterpenes and chromones are the most abundant compounds in agarwood oils.
- 2-phenyl-4H-chromen-4-one is a prominent volatile marker in the 'Qi-Nan' subspecies.
- Genetic and environmental factors significantly affect the composition of agarwood oils.

## Abstract

Aquilaria spp. are a highly valuable plant species found in the Chinese herbal medicine and agarwood fragrance supplement industries for fumigation, combustion and perfume. The phytochemical composition of agarwood oils (extracts) was derived from Aquilaria sinensis and its subspecies ‘Qi-Nan’ using supercritical CO2 extraction technology. Gas chromatography connected with a mass spectrometry apparatus was employed for qualitative and quantitative analyses. Comparing the agarwood oils from six planting areas, 12 common components were obtained, among which sesquiterpenes and chromones had the highest relative content. Genetic and environmental factors had the greatest impact on the three chromones, especially on 2-phenyl-4H-chromen-4-one. According to the PCA and PLS-DA models, the ‘Qi-Nan’ was derived from a variety selected from the native A. sinensis, and the difference in the volatile components was able to indirectly prove that it was genetically heterogeneous with the native A. sinensis. Using the 73 components obtained from GC–MS analysis, the VIP values and S-plots were generated using the OPLS-DA model. Seven components with VIP values > 1.0 were selected from two groups of agarwood oils of the native A. sinensis and ‘Qi-Nan’ subspecies. In addition, by analyzing 12 common components, the differential components with VIP values > 1 were 2-phenyl-4H-chromen-4-one and 2-(4-methoxyphenethyl)-4H-chromen-4-one. Chromones were the main component of agarwood oils extracted by supercritical CO2, and 2-phenyl-4H-chromen-4-one could be used as a volatile marker, especially in the ‘Qi-Nan’ subspecies, where this marker exhibited more prominent characteristics.