Headspace, volatile and semi-volatile organic compounds diversity and radical scavenging activity of ultrasonic solvent extracts from Amorpha fruticosa honey samples

Abstract

Volatile organic compounds of Amorpha fruticosa honey samples were isolated by headspace solid-phase microextraction (HS-SPME) and ultrasonic solvent extraction (USE), followed by gas chromatography and mass spectrometry analyses (GC, GC-MS), in order to obtain complementary data for overall characterization of the honey aroma. The headspace of the honey was dominated by 2-phenylethanol (38.3-58.4%), while other major compounds were trans- and cis-linalool oxides, benzaldehyde and benzyl alcohol. 2-Phenylethanol (10.5-16.8%) and methyl syringate (5.8-8.2%) were the major compounds of ultrasonic solvent extracts, with an array of small percentages of linalool, benzene and benzoic acid derivatives, aliphatic hydrocarbons and alcohols, furan derivatives and others. The scavenging ability of the series of concentrations of the honey ultrasonic solvent extracts and the corresponding honey samples was tested by a DPPH (1,1-diphenyl-2-picrylhydrazyl) assay. Approximately 25 times lower concentration ranges (up to 2 g/L) of the extracts exhibited significantly higher free radical scavenging potential with respect to the honey samples.

Figure 1

Representative TIC chromatogram of A. fruticosa honey headspace VOCs isolated by HS-SPME. Numbers refer to the compounds listed in Table 1.

Figure 2

Representative TIC chromatogram of A. fruticosa honey VOCs isolated by USE. Numbers refer to the compounds listed in Table 2.

Figure 3

DPPH reduction percentage against increasing concentration of A. fruticosa USE extracts (a) and the honey samples (b) Results are expressed as mean values ± SD.