N Dayie, M Newman, E Ayitey-Smith, F Tayman
ageratum conyzoides, antimicrobial activity, resistant strains, screening, staphylococcus aureus.
N Dayie, M Newman, E Ayitey-Smith, F Tayman. Screening for Antimicrobial Activity of Ageratum conyzoides L.: A Pharmaco-Microbiological Approach. The Internet Journal of Pharmacology. 2007 Volume 5 Number 2.
These crude extracts were screened for antimicrobial activities against typed cultures of
Microbial resistance, a world health hazard, is dramatically increasing 1,2 hence evaluation of natural products to find new, safe and effective active compounds to rotate or substitute with the invalidated ones is one of the scientific strategies to combat drug-resistant pathogens 3 . One of such plants of medicinal value is
The plant is used in Southern Africa for the treatment of fresh wounds and in Central Africa, the leaf is used to aid the healing of burn wounds 6 . In Ghana, it is used for treating chronic sores, sore eyes and dysentery 7 . In East Africa, it is used as a styptic 8 . In Central Africa, it is used to treat pneumonia 9 . In Cameroon and Congo, the traditional use is to treat fever, rheumatism, headache and colic 10 . In Brazil, aqueous extracts of leaves or whole plants have been used to treat spasms, colds and fevers 11,12,13,14,15 .The purpose of this study is to determine the best solvent for the crude extract extraction and to investigate the antimicrobial properties of the plant against resistant and multiple resistant strains of selected microorganisms (
Materials and methods
Fresh whole plants of
For aqueous extraction, 100g of air-dried powder was placed in distilled water and boiled for two hours and furthermore left to soak overnight. The resulting suspensions were filtered and evaporated to dryness at 60 ° C in vacuum.
186g of flowers, 98g of leaves, 300g of flowers, 160g of roots and 200g of whole plant were separately and successively soxhlet extracted with 40 to 60% petroleum ether, dichloromethane and methanol. The vacuum dried extracts were reconstituted in the respective solvents used for the extraction. Water extracts were also prepared. These extracts were kept in dark polythene bags and preserved in the refrigerator until needed.
The microbial strains used for the study were made of two reference strains of
Well diffusion method using Müeller-Hinton agar plates were used to demonstrate the antimicrobial properties of the crude extracts 16 . A suspension of the bacteria compared to 0.5 Macfarland standard was seeded on the Mueller-Hinton agar plates. Wells of 6mm in diameter and 2cm apart were punctured in the culture media using sterile cork borers. Ten percent concentration of the crude extracts was administered to fullness in each well and the plates were incubated overnight at 37° C. Growth was determined by measuring the diameter of the zone of inhibition. The solvents were used as the negative controls whiles 10?g ampicillin disc (Oxoid) was used as the positive control. The control zones of the solvents were deducted from the zones of inhibition created by the crude extracts.
The methanolic extracts showed considerably more activity on all the strains of
The preliminary study using 40-60 % petroleum ether extract, dichloromethane extract and methanol extract of the whole plant indicated that the antibacterial properties were found in the polar region of the plant extracts. The results revealed that the non-polar 40-60 % petroleum ether crude extracts and the water extracts did not show any antibacterial effects on the test microorganisms.
The polar methanol extracts of the whole plant were effective against all the strains of