Abstract:

Objective: The volatile components, aroma composition, and medicinal active substances in the wood of Populus koreana and Populus ussuriensis were analyzed, in order to improve the added value of poplar wood and provide a theoretical basis for the production of health-care poplar products. Method: Solid-phase microextraction was used to collect volatile substances in samples, and the collected samples were introduced into a gas chromatography-mass spectrometry (GCMS) for component separation and detection. The odor activity value of volatile organic compounds (VOCs) was calculated through the odor threshold and the relative content of the substance. All metabolites in poplar wood obtained from GCMS analysis were used to perform a query in the Traditional Chinese Medicine System Pharmacology (TCMSP) database, and the VOCs with oral bioavailability (OB）≥ 5% and drug-like (DL） ≥ 0.14 were selected as the main active ingredients. Relevant targets and related disease information of the identified metabolites were obtained through the database. Result: P. koreana wood had more VOCs, including aroma compounds and medicinal active ingredients, than P. ussuriensis wood. There were 18 and 16 VOCs that were detected in the wood powders of P. koreana and P. ussuriensis, respectively, including alcohols, alkanes, aldehydes, ketones, and esters. A total of 8 aroma compounds were retrieved from the volatile substances of P. koreana wood, including 7 key aroma compounds with aroma characteristics of butter, fragrance, fat, mushroom, and vanilla, and one potential aroma compound with resin, flower, and fragrance characteristics. However, only five aroma compounds were retrieved from the VOCs of P. ussuriensis wood, all of which were key aroma compounds. Besides the pleasant odor characteristics such as butter odor, grass odor, fat odor, flower odor, and green odor, the key odor compound of 2-hexanone in the wood of P. ussuriensis was more pungent. Further, P. koreana and P. ussuriensis wood shared some volatile metabolites, including 5 medicinal components of acetoin, hexanal, 4,6-dimethyl-dodecane, 3-octanone, and tetradecane. Four medicinal ingredients were found to be unique to P. koreana wood volatiles, which are 2,3-butanediol, 1-octyl-3-ol, 1-hexanol, and β-cedarene, while P. ussuriensis had two medicinal ingredients of pentadecaldehyde and 1-hexadecanol, of which 1-hexadecanol is an effective key component for human health. Conclusion: P. koreana wood volatiles have more aroma compounds and medicinal active ingredients. The key odor compound 2-hexanone in P. ussuriensis wood has a pungent odor and may be potentially harmful to the indoor environment and humans. P. koreana wood has a fresher aroma and contains more medicinal components that are beneficial to human health in volatiles. It can be used as a candidate tree species for health-care wood production. This study result provides a new direction for the selection and breeding of popular varieties.

Key words: Populus koreana, Populus ussuriensis, volatile constituents of wood, odor activity value, medicinal active ingredients