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Direct Research Journals
Direct Research Journal of Biology and Biotechnology: Vol.4 (5), pp. 68-80, August 2018
ISSN 4372-2608

Assessment of Antimicrobial and Antioxidant Properties of Ethanolic Extracts of the Leaves of Dysphania ambrosoides (L.) Tithonia diversifolia (hemsly) A Gray and Laggera alata (D. Don)
Article Number: DRJA2754816092

Original Research Article

Itelima, J.U*., Okoroigwe, J. and Eluma, M.

Department of Plant Science and Biotechnology, Faculty of Natural Sciences, University of Jos, Nigeria.

*Corresponding Author E-mail:

date Received: July 24, 2018     date Accepted: August 21, 2018     date Published: August 31, 2018


This research was designed to assess the antimicrobial and antioxidant properties of ethanolic extracts of the leaves of  Dysphania ambrosoides, Tithonia diversifolia and Laggera alata on some pathogenic organisms. The phytochemical screening of the ethonolic extracts was conducted using standard methods . The antimicrobial activity of the ethanol extracts of the leaves of the plant species was tested against  six pathogens namely; Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus and Candida albicans was determined in vitro using the agar well diffusion method at concentrations ranging from 25 mg/ml to 200 mg/ml. Gentamycin and fluconazole were used as control. The minimum inhibitory concentration (MIC) of the extracts was also determined using standard methods. The extracts were screened for the presence of phytochemicals, and their inhibition of 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical was used to evaluate their free radical scavenging activity. Standard Rutin, Standard Gallic and Vitamin C were used as reference antioxidants. The phytochemical screening of the ethanolic extract of Dysphania ambrosoides revealed the presence of alkaloids, tannins, saponins, flavonoids, carbohydrates, steroids, cardiac glycosides, terpenes while Tithonia diversifolia and Laggera alata revealed all of the above except saponins and  terpenes. The sensitivity test revealed that the zones of inhibition of Dysphania ambrosoides leaf extracts ranged between (6.00-16.00 mm) with the highest zone of inhibition being exhibited on Bacillus subtilis and the least on Pseudomonas aeruginosa, while the leaf extracts of Tithonia diversifolia ranged between (6.00-15 mm) with the highest zone shown on Bacillus subtilis and the least on Pseudomonas aeruginosa. Also, the zones of inhibition exhibited by antimicrobial activity of leaf extracts of laggera alata varied from (6.00-16.00 mm) with the highest zone being shown on Salmonella typhi and the lowest on Pseudomonas aeruginosa. There was no significant difference (p>0.05) between the extracts plant species with regard to their antimicrobial effects on the various test microorganisms. Also, the mean diameter zones of inhibition exhibited by the crude extracts of the plants decreased as the concentrations of the extracts deceased. Overall, the antibiotic drugs used as control exhibited better antimicrobial potential as compared to the plant extracts with zones of inhibition ranging from 13-29 mm for gentamycin and from 14-25 mm for fluconazole. The MIC of the ethanolic extracts of the plant species against the test microorganisms varies between 25-100 mg/ml. The antioxidant activity of the plant extracts were low compared to the control. However, the scavenging effect of L. alata was found to be greater than those of T. diversifolia and D. ambrosoides. Thus, the inhibition concentration at 50% (IC50 ) ) was shown in increasing order 0.397±0.00 μg/ml <10.20±0.50 μg/ml <32.03±3.45 μg/ml <51.00±6.7 μg/ml <57.60±3.87 μg/ml <363.30±8.47 for T. diversifolia, D. ambrosoides, L. alata, Standard Gallic, Standard Rutin and vitamin C respectively. The findings of the present study suggest that the ethanolic extracts of the test plants possess significant antimicrobial and antioxidant activities as well as pharmaceutical potentials which make them potential candidates as natural chemoprophylactic agents. Studies are required to further elucidate antimicrobial and antioxidant potentials using in vivo biochemical and molecular biology techniques.

Keywords: Antimicrobial, Antioxidant, Ethanolic, Leaves Extracts, Dysphania ambrosoides, Tithonia diversifolia, Laggera alata