Cogent Food & Agriculture (Jan 2020)
Effect of extraction solvent on qualitative and quantitative analysis of major phyto-constituents and in-vitro antioxidant activity evaluation of Cadaba rotundifolia Forssk leaf extracts
Abstract
Leaves of Cadaba rotundifolia Forssk have widely been used by the community of Eastern Ethiopia as traditional phytomedicine against various diseases. The focus of this study was to screen major phytochemical classes and determine their contents, and evaluate in-vitro antioxidant activities of different solvent extracts of C. rotundifolia leaf. The total content of phenolic (TPC), flavonoid (TFC) and tannin (TTC), and in-vitro antioxidant activity (using DPPH and ferric reducing power assays) of four extracts (pure ethanol, pure methanol, 80% methanol and 80% ethanol) were determined using spectrophotometric method. The obtained data revealed that 80% ethanol extract scored the highest extraction yield (16.22%) followed by 80% aqueous methanol (12.90%), methanol (12.87%) and ethanol (12.86%); whereas the lowest crude extract percentage yield was recorded by petroleum ether (1.11%) followed by ethyl acetate (1.42%) and dichloromethane (1.65%). Flavonoids, phenols, alkaloids, saponins, carbohydrates and tannins were positively screened especially in the alcoholic and their corresponding aqueous extracts. The present finding also showed the presence of appreciable amounts of total phenolic (8.04 ± 1.04–10.46 ± 1.25) mgGAE/gDCE (gallic acid equivalents per gram of dried crude extracts), flavonoid (0.38 ± 0.05–0.51 ± 0.03) and tannin (0.75 ± 0.03–1.05 ± 0.03) mgCE/gDCE (catechin equivalent per gram of dried crude extracts). The 80% methanol extract exhibited the highest phenolic (10.46 ± 1.25 mgGA/gDCE) and flavonoid (0.51 ± 0.03 mgCE/gDCE) contents; whereas the highest total tannin content (0.92 ± 0.03 mgCE/gDCE) was recorded in aqueous (80%) ethanol extract. The aqueous ethanol and methanol extracts showed the highest scavenging activity against DPPH-free radical and ferric reducing antioxidant power (FRAP) than the non-aqueous parts; which is also correlated with the obtained total contents of phenolic, flavonoid and tannin expected to have antioxidant potency. In the immediate future, it is therefore very important to note that the hydro-alcoholic solvents should be prioritized while conducting any phyto-pharmacological studies on the C. rotundifolia leaves.
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