Antioxidant and antimicrobial potential of essential oil blendings against microorganisms isolated from aqueous extracts of Hibiscus sabdariffa

Kenfack B.*, Tonye E., Nguikwie S., Kabeyene M., Chouela S., Kamsu P, Talla A., Ekwala R, Mounbain F., Ambata T., Tchientcheu R.., Davy M., Jazet P.
Laboratory of Biochemistry, Department of Biochemistry, Faculty of Sciences, University of Douala, Cameroon,
P. O. Box 24 157 Douala, Cameroon.
Corresponding author : nguikwie_sylvie@yahoo.fr
Introduction
The aqueous extract of Hibiscus sabdariffa (Foléré) is rich in essential nutrients for humans but is generally the site of many microorganisms despite current alternatives (Agassounon et al., 2011). This work focused on the evaluation of the antioxidant and antimicrobial potential of the five essential oil blends (Cymbpogon citratus, Syzygium aromaticum and Lippia multiflora) against microorganisms isolated from aqueous extracts of H. sabdariffa.
Methodology
The essential oils were obtained by hydrodistillation. The antioxidant potential has been demonstrated by three methods, namely: the scavenging of the DPPH° and ABTS• + radicals and the reducing power of iron (FRAP). The evaluation of antimicrobial activity was carried out by the method of incorporation into agar (Goby et al., 2015).
Results
Isolation and identification yielded Staphylococcus sp, Escherichia coli, Aspergillus niger, Penicillium sp., Geotrichum sp. and Candidas sp .. The extraction yield obtained is 8.4%, 0.36% and 0.1% respectively for the EO of S. aromaticum, C. citratus and L. multiflora. Five blendings (C1, C2, C3, C4, and C5) were formulated from these EOs. The blendings C1 and C2 showed better anti-free radical activity than the antioxidant benchmark BHT (p˂0,05%) for the methods used. The growth of bacteria and yeast was inhibited at 750 ppm (MIC) by all five blendings. A. niger and Penicillium sp. were sensitive to 600 ppm. Hibiscus sabdariffa extracts supplemented with mixtures (C1, C2, and C3) were microbiologically stable for 27 days at room temperature.
Conclusion
These mixtures could be used to preserve the microbiological quality of foléré drinks.
Keywords: Antioxidant activity, Antimicrobial activity, Essential oil, Biopreservatives.