Antifungal activities and antioxidant potential of aframomum aulacocarpos essential oil against isolated cocoa bean fungi

Tonye E. L*, Kenfack N.S.B, Chouela S,Talla A, Talla C, Ekwala R, Mounbain F, Ambata T, Manz E, Kamsu P, Moussango Davy, Nguikwie* K.S, Jazet D.P.M
Laboratory of Biochemistry, Department of Biochemistry, Faculty of Sciences, University of Douala, Cameroon,
P. O. Box 24 157 Douala, Cameroon.
*Correspondent: nguikwie_sylvie@yahoo.fr
Introduction
Cocoa beans are highly valued for their aroma, nutritional potential and therapeutic effects. The quality of the beans is affected by contamination due to pathogenic fungi inducing oxidative stress in consumers causing cardiovascular diseases. The present work was to evaluate in vitro the antifungal and antioxidant activity of the essential oil of A. aulacocarpos seeds.
Methodology
The material used in this study was the seeds of A. aulacocarpos (short mbongo) and the cocoa beans used to isolate the fungi. The antifungal activity of our essential oil was evaluated by the agar incorporation technique or nutrient packing method as described by Lalhou, (2004) and the antioxidant activity was evaluated by three methods namely: DPPH, ABTS and FRAP.
Results
The isolation of fungi carried out on the fragments of cocoa beans incubated on the culture medium led to 4 pure isolates: Fusarium solani; Curvularia lunata; Aspergillus niger and Aspergillus flavus. Concerning the antifungal activity at MIC= 1000 ppm the difference in antifungal activity of the essential oil has the same effect on both fungi (C lunata and F solani) as A. Regardless of the method used, the essential oil of A. aulacocarpos showed good antiradical activity. These different values of 〖SC〗_50 DPPH and ABTS are respectively 200×〖10〗^(-3) g/L and 18×〖10〗^(-3) g/L higher than the values of BHT. The essential oil presented a strong iron reducing activity higher than that of BHT (referent) which gives it the properties of powerful electron donor.
The impact of the results
The essential oil of A. aulacocarpos could be used as an alternative for the control of fungi in stored beans.
Key words: Aframomum aulacocarpos, essential oil, antifungal activity, antioxidant activity.