Comparative In vitro Antioxidant Studies and Phytochemical Analysis of Ginger (Zingiber officinale) and Garlic (Allium sativum)

Abstract

Ginger (Zingiber officinale) and garlic (Allium sativum) are globally consumed spices known for their flavor, organoleptic properties, and health benefits. This study evaluates the comparative in-vitro antioxidant and phytochemical profiles of Zingiber officinale and Allium sativum. Fresh samples were washed, chopped, dried, pulverized, and extracted using standard procedures. Phytochemical composition and antioxidant parameters (hydrogen peroxide scavenging and ferric reducing antioxidant property, FRAP) of the methanol extracts were assessed. Phytochemical screening revealed the presence of flavonoids, glycosides, steroids, and carbohydrates in both extracts. Tannins were present in Zingiber officinale but absent in Allium sativum. Conversely, alkaloids and saponins were present in Allium sativum but absent in Zingiber officinale. In the hydrogen peroxide scavenging assay, both extracts showed dose-dependent activity. At 20 µg/ml, Z. officinale and A. sativum exhibited scavenging activities of 34.32 ± 0.10% and 30.16 ± 0.14%, respectively. At 100 µg/ml, activities increased to 73.08 ± 0.16% for Z. officinale and 68.62 ± 0.11% for A. sativum. In the FRAP assay, reducing power also increased with concentration. At 10 µg/ml, Z. officinale and A. sativum recorded values of 36.33 ± 0.16 and 32.23 ± 0.14, respectively, while at 50 µg/ml, values rose to 74.09 ± 0.20 and 71.56 ± 0.20. These results indicate that both extracts possess in-vitro antioxidant activity, with Z. officinale showing slightly higher scavenging and reducing power than A. sativum. The antioxidant potential may be attributed to the phytochemicals present in the plants. Therefore, the methanol extracts of Zingiber officinale and Allium sativum demonstrate notable antioxidant activity against hydrogen peroxide and ferric ions, likely due to their phytochemical constituents.