ISSN 2995-9246
International Journal of Chemistry | Vol. 1, No. 4, April 2010 | pp. 26–34
DOI: 10.46882/2010/IJC/000004
Article Type: Original Research Paper
Title: Phytochemical Screening, Total Phenolic Content, and In Vitro Antioxidant Activities of Methanolic Extracts from Zingiber officinale Varieties
Names of Authors: Fatima B. Ibrahim¹, Suresh K. Patel²
Authors’ Affiliations:
¹Department of Biochemistry, Ahmadu Bello University, Zaria, Nigeria
²Department of Natural Products Chemistry, Indian Institute of Science, Bangalore, India
Abstract: Zingiber officinale (Ginger) is widely utilized globally as both a spice and a traditional medicine. This study evaluates and compares the quantitative phytochemical composition, total phenolic content (TPC), total flavonoid content (TFC), and in vitro antioxidant properties of methanolic extracts from two distinct ginger varieties: yellow ginger and white ginger. Quantitative screening revealed high concentrations of alkaloids, saponins, and terpenoids in both cultivars. TPC was determined using the Folin-Ciocalteu reagent and expressed as gallic acid equivalents (GAE). The TPC of yellow ginger (84.32 ± 1.45 mg GAE/g extract) was significantly higher than that of white ginger (62.15 ± 2.10 mg GAE/g extract). Similarly, the TFC was higher in the yellow variety (34.18 ± 0.85 mg quercetin equivalents [QE]/g) compared to the white variety (21.40 ± 1.12 mg QE/g). The antioxidant capacity was measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and Ferric Reducing Antioxidant Power (FRAP) assays. Yellow ginger displayed a superior DPPH radical scavenging activity with a lower IC50 value of 42.15 micro-g/mL, compared to white ginger which exhibited an IC50 of 65.80 micro-g/mL. A strong positive correlation (R² = 0.945) was observed between the total phenolic content and the antioxidant performance, validating that phenolic compounds are the primary drivers of antioxidant potential in these ginger varieties.
Keywords: Zingiber officinale, Phytochemicals, Phenolic content, Flavonoids, DPPH assay, Antioxidant activity
Manuscript Timeline: Received: January 10, 2010; Revised: February 18, 2010; Accepted: March 11, 2010; Published: April 02, 2010