Antimicrobial, free radical scavenging and cytotoxic activities of Khaya grandifoliola C.DC extracts

Abstract

Aims: Khaya grandifoliola C.DC is a plant used locally in Nigeria ethno medicine for remedy of various disease conditions. However, there is little scientific evidence to support the therapeutic claims of the plant. Therefore, these investigations were conducted to determine the antimicrobial activity, antioxidant and cytotoxic potentials of the plant extracts. Methodology and results: In vitro antimicrobial activity of the leaf and stem bark extracts of K. grandifoliola against some human pathogens was done using agar diffusion method. The free radical scavenging activity and cytotoxic property of the plant materials were evaluated using 2, 2-diphenyl-1-pieryhydrazyl radical (DPPH) and brine shrimp lethality bioassay methods respectively. The yields of the plant material extracts ranged from 3.57±0.06 to 6.49±0.01% and 4.76±0.02 to 9.17±0.06% for the leaf and stem bark extracts respectively. The minimum inhibitory concentration (MIC) of KG-A and KG-E ranged from 2.5 to 200 mg/mL and recorded remarkable activity against the growth of Staphylococcus aureus, Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa, Trichophyton rubrum and Aspergillus flavus. However, Strepcoccus pneumoniae, Staphylococcus epidermidis, Klebsiella pneumoniae, and T. rubrum were resistant to the KG-W. The plant extracts demonstrated high DPPH free radical scavenging activity when compared with ascorbic acid used as control in the assay and, also exhibited lethality against brine shrimp larvae with LC50 values ranging from: leaf extracts (0.67 to 1502 ppm) and stem bark extracts (0.91 to 1431 ppm). Conclusion, significance and impact of study: The results show that the KG-A and KG-E have great potentials as antimicrobial agent and may be used in the treatment of infectious diseases caused by the susceptible organisms.

Chemical composition, antimicrobial and free- radical scavenging activity of essential oils from Khaya senegalensis (Desr) A. Juss

“…The inhibitory effect obtained on these microorganisms is significant for the plant materials as the previous epidemiological study by [22] on these microorganisms indicated that they are highly resistant to ampicillin, chloramphenicol and augmentin. The values obtained in the present study were in agreement with those reported by [23,24] who assessed the antimicrobial potential of the essential oils obtained from some members of the family Meliaceae. The results revealed that K. senegalensis may be a good source of antimicrobial agent with interesting activity on multi resistant strains and may therefore be exploited for the development of new therapeutic agents.…”

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“…This may be attributed to the differences in the concentrations and the types of phytocompounds of various secondary metabolites present in the extracts as well as the extracting ability of the solvents. The results also corroborated the observations of Bharet and Vidyasagar [21], Kashariet al, [22], Guerra-Boone et al, [23] and Opawale et al, [24]. The study suggests that the stem bark extracts of L. trichiliodes and T. heudeulotii have a broad spectrum of antibacterial activity, although the degree of susceptibility differed between microorganisms.…”