Comparison of Ultrasound-Assisted Headspace Solid-Phase Microextraction and Hydrodistillation for the Identification of Major Constituents in Two Species ofHypericum

Abstract

Ultrasound-assisted headspace solid-phase microextraction (UA-HS-SPME) and hydrodistillation (HD) methods, coupled to gas chromatography-mass spectrometry (GC-MS), were used for the extraction and analysis of volatile compounds from Hypericum perforatum and Hypericum scabrum collected from two different sites in Iran. In the UA-HS-SPME method, various experimental parameters such as the type of fiber coating, sonication time, extraction time, extraction temperature and desorption time were investigated. The highest extraction efficiency was achieved by a 100-µm polydimethylsiloxane (PDMS) fiber. Consequently, 36 compounds were identified in H. perforatum and H. scabrum samples, using the UA-HS-SPME-GC-MS method, of which 14 were the same in both species. On the other hand, 57 compounds of these species were identified by the HD-GC-MS method, of which 21 were the same. The predominant constituents identified using the UA-HS-SPME method in H. perforatum included β-caryophyllene, α-pinene, γ-cadinene, α-selinene, germacrene-D, limonene and myrcene, and in H. scabrum were α-pinene, nonane, β-pinene and limonene. The common constituents identified by the HD-GC-MS method for H. perforatum involved germacrene-D, limonene, β-caryophyllene, α-pinene, β-pinene and germacrene-B, and for H. scabrum were α-pinene, β-pinene, germacrene-D, nonane, limonene and γ-cadinene. The results about the main constituents of the examined species correspond to the findings of other researchers. Additionally, comparing UA-HS-SPME-GC-MS and HD-GC-MS methods showed that the UA-HS-SPME-GC-MS method is much faster and simpler, and it requires much less sample size and lower temperature.

Hypericum Essential Oils—Composition and Bioactivities: An Update (2012–2022)

“…It is also estimated that the careful selection of inflorescences and leaves instead of the total aerial part also leads to higher EO yields of up to 13 v/w% using hydro-distillation [22]. Hydro-distillation is by far the most common method used to obtain EOs, which is also proposed by EMA monographs and European Pharmacopoeia; however, to date, other techniques have been introduced in order to improve the extraction efficiency and control the chemical composition of the plant material, including liquid or supercritical extraction, solid-phase microextraction, and ultrasound-assisted headspace [17,23,24]. Moreover, other biotechnological tools have been applied, such as callus culture, which produces biomass on a large scale and could be used as a good experimental system for further research on essential oil production.…”

“…Calli essential oil cultivation enabled the selection of a desired compound or group of compounds with specific aromas or activities as a response to chemical elicitors that stimulate biotic and abiotic stress in vitro [25,26]. Nevertheless, Gas Chromatography (GC) is, by all means, the 'golden standard method' in the chemical analysis of EOs, especially enforced with the aid of GC-MS (Mass Spectrometry) and GC-FID (Flame Ionization Detector) for both the identification and quantification of the content as well as the composition variations, regardless of the extraction protocol [17,[22][23][24].…”

Comparison of the Conventional and Electroenhanced Direct-Immersion Solid-Phase Microextraction for Sampling of Nicotine in Biological Fluids of the Human Body

“…SPME is coupleable with the most commonly-used chromatographic techniques such as gas chromatography (GC), high-performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC) [ 5 ]. It can be applied in three sampling modes including direct-immersion (DI-SPME), headspace (HS-SPME) and membrane-protected SPME (MP-SPME) [ 6 ]. Different variables that affect analyte uptake, in SPME studies, such as sampling mode, the coating’s chemistry, sample matrix complexity and the physicochemical properties of analytes, should be considered [ 7 ].…”