University of Khartoum

Phytochemical Screening and Biological Activity of Eight Medicinal Plants

Phytochemical Screening and Biological Activity of Eight Medicinal Plants

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Title: Phytochemical Screening and Biological Activity of Eight Medicinal Plants
Author: Mohamed, Hiba Elawad
Abstract: The study aimed to investigate the phytoconstituents, antimicrobial and antioxidant activities as well as cytotoxicity of fruits of Allium cepa L. and Citrullus lanatus (Thunb.) Matsum. & Nakai var. lanatus, fruit peel of Cucumis sativus L., seeds of Lepidium sativum L.and Trigonella foenum-graceum L., roots of Daucus carota L., leaves of Ziziphus spina – Christi (L.) Wild and Haplophyllum tuberculatum (Forssk.) A. Juss. whole plant, . Dried powder of plant samples were subjected separately to sequential extraction using petroleum ether and ethanol as solvents and were assessed for their phytochemical constituents using standard methods. Extracts were evaluated for their effectiveness, at different concentrations (two-fold dilution), against four bacterial strains including both Gram negative (Escherichia coli, and Pseudomonas aeruginosa) and Gram positive (Staphylococccus aureus and Bacillus subtilis) bacteria as well as two fungi species (Aspergillus niger and Candida albicans) using the disc diffusion method. The antioxidant potential of extracts was determined on the basis of their scavenging activity of the stable 1, 1-diphenyl-2-picryl hydrazyl (DPPH) free radical. Cytotoxicity was evaluated by brine shrimp (Artemia salina) lethality test. Preliminary phytochmical screening, by thin layer chromatography, of different extracts displayed spots with different colour characteristics and polarities indicative to richness in secondary metabolites. High amount of phenolic content was detected from T. foenum – graecum, Z. spina – Christi, H. tuberculata, A. cepa and L. sativum. Terpenes and sterols were mainly present in Z. spina – Christi and T. foenum–graecum and alkaloids in C. lanatus and L. sativum. All plant samples were devoid of anthraquinones. Moreover, extracts of plants under study were diverse in effectiveness and possessed antimicrobial activity at least against one pathogen. Maximum inhibition zone (IZ) against E. coli was obtained from the ethanolic extracts of iii D. carota roots (20 mm at concentration 100 mg/mL) and T. foenum–graecum seeds (19 mm at concentration 100 mg/mL) whereas, the highest activity against P. aeruginosa was exhibited by the ethanolic extract of L. sativum seeds (IZ 19 mm at concentration 25 mg/mL). The highest antibacterial activity against Gram positive bacteria was obtained from ethanolic extract of C. sativus fruit peel (IZ 11 mm at concentration 100 mg/mL) against B. subtilis and by the ethanolic extracts of L. sativum and T. foenum–graecum seeds (IZ 14 mm at concentration 100 mg/mL) against S. aureus. Ethanolic extract of C. sativus fruit peel was the most active against C. albicans (IZ 14 mm) and A. niger (IZ 19 mm) at concentration 100 mg/mL. DPPH scavenging activity of ethanolic extracts in decreasing order was Z. spina – christi leaves (78% ± 0.03) > L. sativum seeds (57% ± 0.05) > C. sativus fruit peel (49% ± 0.01) > H. tuberculata whole plant (34% ± 0.05) > A. cepa fruit (29% ± 0.04) > D. carota roots (27% ± 0.02) > T. foenum-graecum seeds (24% ± 0.04) > C. lanatus fruits (15% ± 0.03). All extracts were non toxic to brine shrimps as they diaplayed IC50 values ranged from 139.4 and 966.4 μg/mL. In conclusion, the results of the present study provided scientific justification for the use of these plants in traditional medicine and provide some idea about their phytochemical constituents. Further investigations are warranted to identify the active principles
Description: 83page
URI: http://khartoumspace.uofk.edu/123456789/25414


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