Comparative Studies on Antioxidant and Antifungal Potentials of Some Tropical Spices

Abstract

Spices have lots of health benefits due to their antioxidative properties. However, the antioxidative efficacy of these spices differs from one another and depends on the extracting solvents. This study, therefore aimed at determining the antioxidant properties and antifungal activities of eight tropical spices (Aframomum danielli, Allium sativum, Piper guineense, Curcuma longa, Syzygium aromaticum, Tetrapleura tetraptera, Monodora myristica, and Xylopia aethiopica) using two extracting solvents (water and ethanol). The extracts obtained were analysed for antioxidant and antifungal activities. The antioxidant activities of the extracts were determined using DPPH, FRAP, nitric oxide, metal ion chelating activity. The values were calculated to identify the extract with the best antioxidant activity.  Antifungal activities of the extracts were determined using the mycelia inhibition method. Spice ethanol extracts showed good antifungal properties with higher mycelial inhibition percentages. M. myristica, X. aethiopica, S. aromaticum, and M. myristica showed the highest mycelial inhibition percentage against A. niger (83.75%), A. fumigatus (93%), A. flavus (87.5%), Candida albican (89.6%) and Fusarium solani (88.6%) respectively. Syzygium aromaticum and Tetrapleura tetraptera showed the best DPPH radical scavenging activity in water and ethanol extracts with values of 0.67 and 0.64, respectively. M. myristica and X. aethiopica showed the best Ferric reducing antioxidant power for water and ethanol extracts with values of 0.40 and 0.69, respectively. The water extracts showed better metal ion chelating activity than the ethanol extracts. Overall observation showed that the selected food spices are good source of antioxidants, could protect against oxidative stress related diseases and toxicogenic fungi.