Optimizing preparation of the fenell (foeniculum vulgare L.) extracts by using ultrassound - methodology in accordance with the principles of green chemistry

Abstract

Fennel (foeniculun vulgare L.) is a vegetal species that presents bioactive monoterpenes. These compounds are lipophilic substances almost insoluble in water. The best conditions to extract these substances, employs organic solvents or heating process. With the aim to developing new extractive methods in which the green chemical principles cam be applied, this work was performed. The effect of the use of ultrasound during the preparation of fennel extracts by water infusion and by ethyl acetate maceration methods was verified. The ethyl acetate extracts, and the organic portion of the aqueous extracts were analyzed by gas chromatography coupled to mass spectrometry. The ethyl acetate extraction, without the use of ultrasound leads only to the extraction of two metabolites (fenchone and anethole), the maceration performed by using ultrasound by 5 and 10 minutes, promoted the extraction of seven metabolites (a-pinene, L-fenchone, estragole, anethole, β-caryophyllene, a-cadenol, and geranylgeraniol), while the use of ultrasound in times upper than 10 minutes leas to extracts with 4 metabolites (a-pinene, L-fenchone, estragole and limonene). The aqueous extracts submitted or not to the use of ultrasound led to the extraction of the same and five metabolites (D-limonene, L-fenchone, estragole, and anethole).