Phytochemical Screening, Phenolics and Flavonoids Quantification, and Free Radical Scavenging Potential of Emilia praetermissa Milne-Redhead (Asteraceae) Leaf

Abstract

Introduction: Phytochemicals have been linked to the activities exhibited by extracts and fractions from plant in in-vivo and in-vitro experiments. Phenols and flavonoids, two important phytochemicals are implicated in the treatment of different illnesses. They contain at least an aromatic ring and hydroxyl group in their molecules, which are relevant moiety in their in-vitro quantification. Emilia praetermissa, an annual herb, use in traditional medicine for the treatment of varieties of ailments which are oxidative stress related.

Aims: This study aims to evaluate qualitatively phytochemicals in the extract and fractions, limit the quantitative determination of the phytochemicals to total flavonoids and phenolic contents, and evaluate their 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity.

Methods: The methanol extract and fractions obtained from liquid-liquid partitioning of the extract with n-hexane, dichloromethane and ethylacetate were screened for phytochemicals by using preliminary established screening methods. While the level of flavonoids and phenolic compounds were determined spectroscopically using 10 % aluminum chloride and 10 % Folin-Ciocalteu reagents.  Antioxidant potential was evaluated by the ability of the extract and fractions to scavenge for free radicals from DPPH.

Results: Flavonoids and phenolic compounds were identified in the extract and fractions, and quantitatively dichloromethane fraction showed the highest level for phenols 60.94±0.22 mg GAE/g and flavonoids 19.43±0.06 mg QE/g. Radical scavenging potential of the n-hexane fraction compared favorably with the standard, methanol extract and dichloromethane fraction (p < 0.05), and IC50 of 30.00 µg/mL was recorded for dichloromethane fraction.

Conclusion: This study shows that Emilia praetermissa leaf contains varying classes of phytochemicals especially flavonoids and phenols that can scavenge for free radicals.