Changes in polyphenols content and biological activities on Tetrapleura tetraptera and Aframomum citratum fruits extracts using different extraction methods in an acid/alkaline medium

Abstract

Listen

Translate article

Description. Tetrapleura tetraptera and Aframomum citratum fruits are ingredients in traditional medicines in some sub-Saharan countries. For medicinal purposes, the fruit extracts are obtained using different extraction methods and by adding lime juice or baking soda powder. Objectives. Evaluate the influence of the solid-liquid ratio, the pH and the extraction procedures on the total polyphenols content and the biological activities (antioxidant, anti-inflammatory) of their extracts. Method. Fresh fruits were harvested, crushed and various extracts were obtained using three extraction methods (infusion, 100 °C/30 min; decoction, 100 °C/30 min; ethanol maceration, 30 min at room temperature); four solid-liquid ratios (1/4, 1/6, 1/8, 1/10: mass of the sample in gram/volume of the solvent in ml) and two extraction mediums (alkaline and acidic). Polyphenol compounds of the aqueous extracts were identified and quantified using HPLC-DAD. The total polyphenols content, the total antioxidant capacity and the anti-inflammatory activities of both extracts were evaluated by spectrophotometric methods. Principal Component Analysis providing a transparent view of information was performed. Results. Aframomum citratum extracts revealed the presence of major compounds like: gallic, protocatechuic, caffeic and syringic acids, epicatechin, catechin while T. tetraptera extracts revealed the presence of major compounds like protocatechuic, chlorogenic, kojik and sinapic acids, and catechin. The solid-liquid ratio, the pH and the extraction method significantly (p < 0.05) affect the total polyphenols content and the biological activities. The best results were obtained with T. tetraptera extracts using decoction in alkaline medium at a solid-liquid ratio of 1/4. Aframomum citratum best results were obtained by alcohol maceration in an alkaline medium at the same solid-liquid ratio. Conclusions. All these extraction factors are important to optimize the use of the plant extracts. They should be controlled carefully during the various processes due to their significant effects on the biological activities.