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Pelargonium graveolens L. is a medicinal and aromatic plant known to possess phenolic compounds with significant antioxidant potential. The extraction efficiency of these bioactive compounds depends on several experimental parameters such as the type of extraction, the solvent used for extraction, the characteristics of the plant material and the solvent-solid ratio.1,2 The aim of this study was a preliminary assessment of the influence of different extraction conditions on the total phenolic content (TPC) of extracts from Pelargonium graveolens L. leaves.
Fresh and dried leaves were extracted using two polar solvents, absolute methanol and ethanol. Three extraction techniques were investigated: maceration, ultrasound-assisted extraction and Soxhlet extraction. The influence of different solid-solvent ratios was analyzed to determine their effect on the extraction efficiency of phenolic compounds. TPC was determined spectrophotometrically using the Folin-Ciocalteu method and expressed as gallic acid equivalents (GAE) based on a calibration curve prepared with gallic acid as a reference standard.2
From the previous studies, it is evident that Soxhlet extraction method (using ethanol as a solvent) represents an efficient system to recover a high content of phenolic compounds.3 The largest amount of TPC (4.40±0.06 mgGAE/g dw) was obtained with the Soxhlet extraction using the ethanol as a polar solvent. These results may be attributed to prolonged exposure of the Pelargonium graveolens L. leaves to heated solvent and repeated solvent cycling, which can enhance the release of phenolic compounds.
The information obtained will help in optimizing the extraction of phenolic constituents from Pelargonium graveolens L. and will help in selecting extraction conditions to obtain extracts with increased phenolic content and antioxidant potential.