Characterization of the key volatile organic components of different parts of fresh and dried perilla frutescens based on headspace-gas chromatography-ion mobility spectrometry and headspace solid phase microextraction-gas chromatography-mass spectrometry

Perilla frutescens was an annual herb considered as one of the “One Root of Medicine and Food”, and it was used widely for food and medical treatment. Its main active ingredients were volatile organic compounds (VOCs), but it was easily affected during drying and storage. The leaves, seeds and stems had shown differences in therapeutic effects, but the underlying reason remained unclear. In the present work, headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) and headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC–MS) were utilized to effectively and comprehensively analyze VOCs of fresh and dried P. frutescens between the leaves, stems and seeds. Meanwhile, chemometric analysis was applied to compare and identify characteristic volatile markers. As a result, 60 VOCs were identified by HS-GC-IMS and 115 VOCs were identified by HS-SPME-GC–MS from P. frutescen. 25 potential volatile markers were selected based on a combination model of orthogonal partial least squares discriminant analysis (OPLS-DA) and random forest (RF). The models could be used to analyze the variation between fresh and dried P. frutescens and distinguish the differences in different parts effectively and comprehensively. It was the first research regarding the method development of HS-GC-IMS and HS-SPME-GC–MS that comprehensively analyzes the VOCs characterization of fresh and dried P. frutescens in different parts and the findings obtained would evaluate the quality and provide a reference for further exploration of the edible and medicinal effects of P. frutescens.