Antisickling properties, thermal and photochemical degradations of anthocyanin extracts from Annona senegalensis (Annonaceae)

Anthocyanin crude extracts and fractions of Annona senegalensis leaves were screened for their antisickling properties using a validated in vitro bioassay model of sickle cell anaemia. Preparative thin layer chromatography of acetylated anthocyanin crude extracts carried out with chloroform as solvent provided two active fractions named Ac1 and Ac2. Fraction Ac2 was  quantitatively isolated and submitted to physicochemical investigations. Thermo-degradation kinetics of the above fraction Ac2 at 80 °C and 100 °C revealed first order reaction with the rate constants k (s-1) of 8.10 10-4 and 11.0 10-4, respectively. Anthocyanin crude extracts and the separated fractions showed in vitro antisickling activity. This activity justifies the use of this plant by congolese traditional healers; thus anthocyanins could be the major active principles. However, these natural pigments are unstable towards UV-vis light irradiations and heat. The conservation of this plant should then be performed in the absence of heat and/or light.Keywords: Sickle cell anemia, Annona senegalensis, anthocyanins, light irradiation, thermodegradatio

Étude de l’activité antifalcemiante et de la thermo- et photo-dégradation des anthocyanes de Centella asiatica, Thomandersia hensii et Maesopsis eminii

Lfactivite antifalcemiante des feuilles de Centella asiatica (L.) Urb. et  Thomandersia hensii De Wild. & T. Durand et des ecorces de la tige de Maesopsis eminii Engl. ; trois plantes utilisees en medicine traditionnelle contre la drepanocytose dans la ville de Kisangani (RD Congo), a ete testee en utilisant le test dfEmmel. Les resultats obtenus ont montre une activite antifalcemiante importante in vitro pour les trois plantes. Cette activite serait due aux anthocyanes. Les concentrations minimales de  normalisation des drepanocytes obtenus sont de lfordre de 8µ/ml pour les anthocyanes de ces trois plantes. Les spectres des anthocyanes ont montre une sensibilite a lumiere UV et a la chaleur indiquant que ces pigments sont instables vis-a-vis de ces deux parametres.c 2013 International Formulae Group. All rights reserved.Mots cles : Drepanocytose, Test dfEmmel, Concentration Minimale de Normalisation, Taux de normalisatio