Phytochemical enrichment and DPPH-guided evaluation of flavonoid-rich fractions from catharanthus roseus roots as potential natural antioxidants for hypertension-associated oxidative stress
- Author
- Tawasika, Perpetua A.
- Title
- Phytochemical enrichment and DPPH-guided evaluation of flavonoid-rich fractions from catharanthus roseus roots as potential natural antioxidants for hypertension-associated oxidative stress
- Abstract
- This study investigated the antioxidant potential of flavonoid-rich fractions from Catharanthus roseus root extracts in the context of hypertension-associated oxidative stress. Roots of C. roseus were collected from Mashonaland Central, Zimbabwe, and extracted using 90% ethanol. The crude extract was subjected to sequential solvent–solvent fractionation using n-hexane, ethyl acetate, n-butanol, and water to obtain fractions enriched in phytochemicals of varying polarity. Preliminary phytochemical screening and Thin Layer Chromatography (TLC) confirmed the presence and enrichment of flavonoids, especially in the ethyl acetate and n-butanol fractions. Total flavonoid content (TFC) was quantified using the aluminum chloride colorimetric assay, with the ethyl acetate fraction showing the highest TFC (185.7 ± 6.5 mg RE/g), followed by n-butanol (130.2 ± 4.8 mg RE/g), both significantly higher than the crude extract (55.3 ± 2.1 mg RE/g). Antioxidant activity was evaluated using the DPPH radical scavenging assay, and the IC₅₀ values indicated potent activity in the ethyl acetate (28.3 ± 1.5 µg/mL) and n-butanol (45.8 ± 2.1 µg/mL) fractions compared to the crude extract (95.5 ± 4.2 µg/mL). A strong negative correlation (r = −0.965, p < 0.01) was observed between TFC and IC₅₀, suggesting that flavonoids were the main contributors to antioxidant activity. These findings validate the traditional use of C. roseus roots and highlight their potential as a source of natural antioxidants for managing oxidative stress in hypertension. The ethyl acetate fraction, in particular, demonstrated promising activity and warrants further study for isolation of specific bioactive compounds and in vivo testing.
- Date
- June 2025
- Publisher
- BUSE
- Keywords
- Phytochemical Enrichment
- DPPH-Guided Evaluation
- Flavonoid-Rich Fractions
- Catharanthus roseus Root
- Natural Antioxidants
- Supervisor
- Dr. L Gwatidzo
- Item sets
- Faculty of Science
- Media
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Tawasika, P.pdf