Headspace solid‐phase microextraction combined with mass spectrometry as a powerful analytical tool for profiling the terpenoid metabolomic pattern of hop‐essential oil derived from Saaz variety

Abstract

Headspace solid-phase microextraction combined with mass spectrometry as a powerful analytical tool for profiling the terpenoid metabolomic pattern of hop-essential oil derived from Saaz variety Hop (Humulus lupulus L., Cannabaceae family) is prized for its essential oil contents, used in beer production and, more recently, in biological and pharmacological applications. In this work, a method involving headspace solid-phase microextraction and gas chromatographymass spectrometry was developed and optimized to establish the terpenoid (monoterpenes and sesquiterpenes) metabolomic pattern of hop-essential oil derived from Saaz variety as a mean to explore this matrix as a powerful biological source for newer, more selective, biodegradable and naturally produced antimicrobial and antioxidant compounds. Different parameters affecting terpenoid metabolites extraction by headspace solid-phase microextraction were considered and optimized: type of fiber coatings, extraction temperature, extraction time, ionic strength, and sample agitation. In the optimized method, analytes were extracted for 30 min at 40ЊC in the sample headspace with a 50/30 m divinylbenzene/carboxen/polydimethylsiloxane coating fiber. The methodology allowed the identification of a total of 27 terpenoid metabolites, representing 92.5% of the total Saaz hop-essential oil volatile terpenoid composition. The headspace composition was dominated by monoterpenes (56.1%, 13 compounds), sesquiterpenes (34.9%, 10), oxygenated monoterpenes (1.41%, 3), and hemiterpenes (0.04%, 1) some of which can probably contribute to the hop of Saaz variety aroma. Mass spectrometry analysis revealed that the main metabolites are the monoterpene ␤-myrcene (53.0 ± 1.1% of the total volatile fraction), and the cyclic sesquiterpenes, ␣-humulene (16.6 ± 0.8%), and ␤-caryophyllene (14.7 ± 0.4%), which together represent about 80% of the total volatile fraction from the hop-essential oil. These findings suggest that this matrix can be explored as a powerful biosource of terpenoid metabolites. Keywords: Essential oil / GC-qMS / HopSaaz variety / HS-SPME / Terpenoid metabolites DOI 10.1002/jssc.201200244 IntroductionIt is well known that plant-derived natural products are extensively used as biologically active compounds. From these, the essential oils, which represent a small fraction of a plant's composition, and some of their constituents are used not only in pharmaceutical products for their therapeutic activities but also in agriculture, as food preservers and additives for human or animal use, in cosmetics and perfumes, and other industrial fields [1,2]. Particular emphasis has been Correspondence: Professor José S. Câmara, Centro de Ciências Exactas e da Engenharia, Universidade da Madeira, Campus Universitário da Penteada, 9000-390 Funchal, Portugal E-mail: jsc@uma.pt Fax: +351-291705149Abbreviations: HS-SPME, headspace solid phase microextraction; RI, retention index placed on their antibacterial, antifungal, and insecticidal activities [3]. In many cases, they serve as (i)...

Methods for verifying the authenticity of hops - an effective tool against falsification

“…The study implied that this variety contains a high concentration of myrcene, alpha-humulene and beta-caryofylene (Goncalves et al, 2012).…”

“…Ze studie vyplývá, že tato odrůda obsahuje charakteristicky vysoké koncentrace myrcenu, alfa-humulenu a beta-caryofylenu (Goncalves et al, 2012).…”

Determination of volatile organic compounds in the dried leaves ofSalviaspecies by solid-phase microextraction coupled to gas chromatography mass spectrometry

“…Furthermore, terpenes are implicated in the attraction of both pollinators and predators of herbivores, in protection against photooxidative stress, and indirect defence against insects (Gonçalves et al 2012). Biological activities and odour description of VOCs in dried leaves derived from the five selected Salvia samples are summarised in Table S2.…”

“…SPME is a pre-concentration technology (Zhang & Pawliszyn 1993) which integrates sampling, extraction, concentration and sample introduction into a single solvent-free step, preventing the production of artefacts compared with conventional solvent extraction procedures. Coupled with gas chromatography (GC)-mass spectrometry (MS) analysis, it has been successfully applied for profiling the metabolomic pattern of environmental, food, forensic, and phamaceutical samples, and also as a powerful technique for extraction of urinary potential biomarkers of several diseases, such as diabetes, cancer and autism syndrome (Gonçalves et al 2012;Cozzolino et al 2014).…”

Partitioning sample collection/solvent extraction cartridge packed with octadecyl-derivatized macroporous silica particles for the analysis of sesquiterpenes in air samples

“…VOCs and SVOCs in air samples have also been extracted using a partition‐based extraction device such as SPME . SPME can be used to extract VOCs and SVOCs in both air and aqueous samples; after the extraction, the extracted analytes can be easily desorbed in a conventional GC injection port.…”