Studies on bioactive potentials of stem bark extract of dracaenacinnabari balf on some bacteria and fungal isolates.
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Date
2015
Authors
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Publisher
Obafemi Awolowo University
Abstract
This study assessed the bioactive potentials of the stem bark extract of Dracaena cinnabari on some bacterial and fungal isolates that were associated with human diseases. This was with the view to determining the mechanisms of action of potent fractions on the test isolates and the phytochemical compounds that were responsible for the bioactive action of the extract.
Fresh stem bark of D. cinnabari was collected from Ile-Ife, Nigeria. The sample was dried in hot air oven at 40oC and then ground into fine powder. The powdered stem bark was cold extracted using methanol and distilled water in the ratio 3 to 2. The crude extract obtained was concentrated in vacuo and lyophilized. The methanolic crude extract was screened for phytochemicals and tested for antimicrobial activity against all the bacterial isolates. The extract was partitioned into n-hexane, chloroform, ethyl acetate and butanol. The antimicrobial potentials, minimum inhibitory concentrations (MIC) and the minimum bacteriocidal concentration (MBC) of the extract and those of fractions were determined. Finally the rate of killing, potassium ions and nucleotides leakages from the test cells were determined using different fractions.
The crude extract of the plant and the two active fractions (n-hexane and chloroform) at a concentration of 30 mg/mL and 10 mg/mL respectively, exhibited antibacterial activities against the test isolates. The MIC of the crude extract ranged between 0.94 and 15 mg/mL while that of n-hexane and chloroform fractions ranged between 0.16 and 5 mg/mL. All the fungal isolates tested against the crude extract were resistant to it. The MBC ranged between 1.88 to 15 mg/mL and 0.31 to 5 mg/mL for the extract and the fractions respectively. The results of the antibacterial activities of the stem bark extracts compared favourably with the activity of standard antibiotics, streptomycin and ampicillin. The phytochemical screening of the extract showed the presence of tannins, flavonoids, saponins, steroids, reducing sugars, cardiac glycosides and terpenoids. The time kill assay reveals that the percentage of the cells killed increases with increase in the concentrations of the fractions as well as contact time intervals. The time-kill assay reveals a minimum of 8.4% killed at 1 x MIC after 15 min contact with the fractions and minimum of 61.1% killed after 120 mins. Varying amount of potassium ions as well as nucleotides were leaked from the test cells by n-hexane and chloroform fractions.
In conclusion, this study established the possibility of developing antimicrobial agents of natural origin to combat the effect of probable multiple resistance to antimicrobial compounds by some pathogens currently being experienced in health care industries.
Description
xvi,114
Keywords
Stem Bark, Bacterial Isolates, Fungal Isolates, Bioactive Potentials, Dracaena Cinnabari, Baterials, Fungal, Human diseases, Phytochemical
Citation
Raji, B.H. (2015). Studies on bioactive potentials of stem bark extract of dracaenacinnabari balf on some bacteria and fungal isolate