Optimization of extraction and lyophilization conditions of Feretia apodanthera (Rubiaceae) leaf powders for galenic formulation

Feretia apodanthera (Rubiaceae) is used in traditional medicine for the treatment of various pathologies. Its leaves are chewed and swallowed to treat stomach aches, sleep disorders, etc. With the aim of improving the extraction method in order to obtain high contents of phytochemical compounds and good antioxidant activity, this study aimed to highlight the extraction and lyophilization conditions of two extracts (aqueous and hydro-ethanolic) leaves of Feretia apodanthera. An aqueous and hydro-ethanolic extraction was carried out from the leaf powder of Feretia apodanthera, after a maceration plan (mass/volume ratio and extraction time). The extracts obtained were freeze-dried (flask size, filling volume and freeze-drying time) in order to determine the optimal extraction conditions. A phytochemical screening of the extracts with extreme yields of different solvents was carried out by TLC, which led to the determination of certains compounds of interest and the evaluation of the antioxidant activity by the DPPH and FRAP method. The optimal maceration conditions were 02 hours and m/V ratio of 1/20 for the aqueous extract and those of the ethanolic extract were 30 min and m/V ratio of 1/20. The optimal freeze-drying conditions were 60h and a 500ml flask 1/3 filled. The presence of flavonoids, tannins, saponosides, coumarins, triterpenes and sterols has been highlighted. The phenolics compounds contents of hydro-ethanolic lyophilisates were higher than those of aqueous lyophilisates. There was no statistical difference between the antioxidant activity of the different extracts. The optimal conditions will serve as a standard for the production of the extract necessary for the formulation. Keywords : Feretia apodanthera, extraction, freeze-drying, phenolics compounds, antioxidant.