University of Khartoum

Antimicrobial and Antioxidant Activities of Phytoconstituents from Euclea schimperi

Antimicrobial and Antioxidant Activities of Phytoconstituents from Euclea schimperi

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Title: Antimicrobial and Antioxidant Activities of Phytoconstituents from Euclea schimperi
Author: El Sayed, Amira Mohamed Yousif
Abstract: Euclea schimperi (Ebenaceae) is a plant of Erkowit, eastern Sudan, used as a medicinal plant by native people (Hadandawa) for the treatment of many diseases. This study was performed to determine the phytochemical constituents of this plant and to evaluate the antimicrobial and antioxidant activities of these constituents. The collected plant parts(Leave, Stem, Stem-bark, Root and Root-bark) were subjected to sequential extraction using petroleum ether, chloroform and 80% ethanol as solvents. The major phytochemical components of the leaves, stems, stem-bark, roots and root-bark were qualitatively determined in each extract. Total polyphenols, saponins, alkaloids and flavonoids were quantified in each plant part. Antimicrobial activity was carried out against five standard bacterial trains (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia and Salmonella typhi) and two standard fungal strains (Candida albicans and Aspergillus niger). Antioxidant capacity and IC50 values were estimated for each extract using vitamin C as a standard antioxidant. Colorimetric, gravimetric, spectrophotometeric, thin layer chromatography (TLC) and column chromatography methods were used for analyzing the phytochemical components. Disc diffusion method was used for estimating the antimicrobial activity. Antioxidant activity was evaluated by two in vitro methods; 2, 2-diphenyl-1-pycrilhydrazil hydrate (DPPH) and 2, 2´-Azinobis 3-ethylbenzothiazoline- 6-sulfonic acid (ABTS) methods. The obtained results revealed that the ethanol extract of the leaves produced high yield (23%) as compared with the other extracts while the lowest yield (0.38%) was estimated in the petroleum ether extract of the roots. Preliminary phytochemical screening of various parts of the plant indicated the presence of different classes of secondary metabolites such as phenols, alkaloids, steroids, terpenoids, anthraquinones, saponins and tannins. These secondary constituents vary in type and concentration in different parts of the plant. Thin layer chromatography method confirmed the presence of these compounds. The quantitative analysis revealed that the leaves were rich in total polyphenols, flavonoids and saponins as 10 compared with the other plant parts. In ethanol extract, the amount of total polyphenol in the leaves (0.473 mg/ml) was nearly equal six times the amount of polyphenols in the stems (0.083 mg/ml). These findings indicated that this plant was rich in different chemical constituents, which may be responsible for the many pharmacological actions. Results of antimicrobial assay revealed that the petroleum ether extracts of the leaves and stems exhibited weak inhibitory effect on the tested bacteria. The chloroform extracts of all parts of the plant were almost inactive against all the tested microbes, except the root-bark extract which showed weak activity (< 15 mm). The ethanol extracts of different parts of the plant exhibited broad spectrum activity against the tested strains as compared to petroleum ether and chloroform extracts. The inhibition zone diameters ranged between 15 mm and 28 mm. The ethanol extract of the root-bark exhibited the strongest activity (28 mm) against Staphylococcus aureus and Klebsiella pneumonia. In the DPPH radical-scavenging activities, the chloroform extracts of all the plant parts had the highest antioxidant activity (IC50 = < 0.01 mg/ml) except the root extract had medium activity (IC50 = 0.016 mg/ml). The level of DPPH scavenging activity in chloroform extracts of all parts of the plant was higher than that of vitamin C at all level of concentrations. The ethanol extracts of all plant parts showed extremely high antioxidant activities at all levels of concentrations specially the root--bark extract (93.29 – 96.45%). When using ABTS free radical scavenging assay, the ethanol extracts of the leaves exhibited relatively high ABTS radical scavenging activities (79.67 – 91.16%) with IC50 values less than 0.01 mg/ml. The recorded IC50 value for chloroform extract of the roots (0.05 mg/ml) was less than the standard (0.18 mg/ml) indicating high antioxidant activity of this extract. In conclusion, this study demonstrated that Euclea schimperi was rich in phytochemical constituents and the tested ethanol extracts had moderate to high antimicrobial activity and potent antioxidant activity. These findings could support the traditional use of this plant in the treatment of many diseases
URI: http://khartoumspace.uofk.edu/123456789/16116
Date: 2015-09-15


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