A comparative study on the antioxidant activity in garlic (Allium sativum) and shallot (Allium cepa)

This study was done in order to determine the presence of antioxidant and the level of antioxidant activity of garlic (Allium sativum) and shallot (Allium cepa). Garlic and shallot have been the most common ingredients in the preparation of Malaysian cuisines and it has been long-held belief that these two Allium species posses many medicinal properties including the antioxidants properties. Samples of A. sativum and A. cepa used in this study were collected from the markets around Kuantan area, Pahang, Malaysia. Total phenolic content (TPC) assay and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay were included as the main methods. The TPC assay was conducted to examine the presence and concentration of phenolics as this compound possesses antioxidant characteristics while the activity of primary antioxidants were determined using the DPPH assay. The TPC results indicated that the concentrations of total phenolics were higher in A. cepa (53.43±1.72 mg/L) as compared to A. sativum (37.60 ± 2.31 mg/L). Furthermore, the DPPH results showed that among the two Allium species, A. sativum expressed higher antioxidant activity than A. cepa. The percentage of scavenging activity for A. sativum reached up to 53.11 ± 3.04% while the highest percentage for A. cepa was 36.05 ± 3.04%. Overall, there was poor correlation between the total phenolics contents and the antioxidant activity by DPPH radical scavenger showing that the antioxidant activity of both Allium species extracts is not solely due to the phenolics compounds. Apart from that, Ferrous ion cgelating activity assay was conducted in order to determine the ion chelating effect of the sample. Derived from the findings of the assay shows that A.cepa shows as higher ion chelating effect compared the to A. sativum, 45.00 ± 1.73% and 43.29 ± 3.89 % respectively. However, in order to strengthen the validity of the current results and to further assess the potential of Allium species as natural antioxidant sources, ferric reducing antioxidant power (FRAP) assay can be conducted for future work