A comparison of volatile fractions obtained from Lonicera macranthoides via different extraction processes: ultrasound, microwave, Soxhlet extraction, hydrodistillation, and cold maceration

BACKGROUND Hydrodistillation has been traditionally used to extract volatile fraction in traditional Chinese medicine. However, with the development of Soxhlet extraction (SE), microwave (MW), ultrasound (US), and cold maceration (CM), hydrodistillation (HD) is being replaced to meet some practical requirements. In this study, we investigated the effect of the five methods on the volatile fraction extract of Lonicera macranthoides. METHODS Volatile fraction from the flower buds of Lonicera macranthoides was obtained by using different extraction methods, HD, SE, MW, US, and CM. The compositions of volatile fraction were analyzed by gas chromatography-mass spectrometric and further compared among extraction methods. RESULTS Extracts obtained by the five methods reveal the qualitative and quantitative diversity in their compositions, especially for the low-content compositions. According to the results, SE shows the great value in the research where the high molecular-mass compound is of primary interest, and MW offers a way for the isolation of specific compound like octadecadienoic acid and hexadecanoic acid. HD, US, and CM have the advantage over SE and MW for the integrity of the constituents, whereas the phenomenon of compound degradation seems not so serious in solvent extraction methods such as US or CM as HD. Additionally, US and CM show superiority over time or material saving and diversity of the constituent. CONCLUSION HD is still the best choice for the pure volatile fraction without organic solvent pollution. However, when it comes to some specifically actual demands, it can be replaced by the four methods for the volatile fraction extraction process, especially for production of certain compound groups.