Development and validation evaluation of a technique for the spectrophotometric determination of the amount of aromatic compounds in fruits and essential oil of fennel

Introduction. Fennel fruits have pronounced carminative and antispasmodic activities due to the composition of the essential oil. The major component of the fennel fruits essential oil is phenylpropanoid trans-anethole. Its content in essential oil varies over a wide range. However, the Russian Pharmacopoeia XV does not provide for a standardization of anethole content for fennel fruits.

Aim. The aim is to develop and validate a spectrophotometric method for determining the amount of aromatic compounds in terms of anethole in the fennel fruits essential oil.

Material and methods. The fruits of common fennel (Foeniculum vulgare Mill.) produced by LLC Firma "Zdorovye" in 2024 were used as the object of the study. A UNICO-2802 spectrophotometer (Russia), ADV-200M analytical scales (Russia), GCMS-QP2010 Ultra gas chromatograph (Shimadzu, Japan) combined with a mass-selective detector were used in the work. An essential oil and a standard anethole samples were dissolved in 95 % ethanol during the spectrophotometric determination. The optical densities of the test solutions at 259 nm were determined in cuvettes with a layer thickness of 10 mm. The results of the spectrophotometric method were confirmed by gas chromatography.

Results and discussion. Validation of the presented method in accordance with the requirements of OFC.1.1.0012 "Validation of analytical methods" of the State Pharmacopeia XV edition was carried out. Its specificity, linearity, precision and correctness were showed. Results are not subject to systematic error. The relative standard deviation (RSD) does not exceed 2.0 %. The results of spectrophotometric determination of the amount of aromatic compounds in terms of anethole (46.5 ± 0.7 %) correlate with the results of GC analysis (48.6 ± 1.1 %).

Conclusion. The developed method for quantifying the amount of aromatic compounds in terms of anethole can be used to standardize both the fennel fruits themselves and the essential oil obtained from them.

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