Susceptibility of Candida albicans, Staphylococcus aureus and Escherichia coli to Extracts of Mango (Magnifera indica)

Abstract

Aim: This study was carried out to investigate the Susceptibility of Candida albicans, Staphylococcus aureus and Escherichia coli to extracts from young and mature mango (Magnifera indica) leaves and stem-bark of the same plant.                                                                                Study Design: The study employed statistical analysis of the data and interpretation.                                      Place and Duration of Study: Young and mature mango leaves and stem-barks were collected from the Botanical Garden, Kenule Beeson Saro-Wiwa Polytechnic, Bori, Nigeria, and taken to the laboratory for analyses.                            Methodology: The samples were dried in an oven at 80oC for 3 days. Thereafter, 50 g of each ground mango leaves and stem-bark (young and mature of the same plant) were soaked separately in 500 ml of water, ethanol (95% v/v), and acetic acid (99.9% v/v) for another 3 days. The soaked materials were filtered through Whatman No. 1 filter paper into sterile beakers and evaporated to dryness in a water-bath at 80oC. The dried extracts obtained were reconstituted with water at concentrations of 100, 75, 50 and 25 mg/ml. Test organisms, Candida albicans, Staphylococcus aureus and Escherichia coli were obtained after proper laboratory screening of isolates from the diagnostic laboratory of the Rivers State University Teaching Hospital, Port Harcourt, Nigeria, for confirmation of identity and storage in universal bottles in a refrigerator. Sensitivity tests were carried out with the agar well diffusion method against the test organisms, using tetracycline as standard control drug (for bacteria) and fluconazole (for Candida), with cultures incubated accordingly. The measured zones of inhibition were compared with the controls and interpreted as resistant, intermediate, or susceptible to mango extracts in accordance with the interpretive guidelines published by the National Committee for Clinical Laboratory Standards (NCCLS). Assays for minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were also carried out. Results: Results obtained showed that Escherichia coli was completely susceptible to acetic acid young leaf and young bark extracts at 100 mg/ml concentrations. Staphylococcus aureus was susceptible only to Acetic acid young leaf extract at 100 mg/ml. For Candida albicans complete susceptibility was with acetic acid young bark at 100 mg/ml.  mature leaf extract (100 mg/ml ), acetic acid young bark extract (100 to 50 mg/ml ), aqueous young bark extract (100 mg/ml) and acetic acid mature   Candida albicans was susceptible to acetic acid young and mature bark extract at 100 mg/ml concentration. Minimum inhibitory concentration (MIC) values of acetic acid young leaf extract for all three organisms were 12.5 mg/ml. MIC of ethanolic young leaf extract for E. coli was 12.5 mg/ml whereas that for C. albicans was 50 mg/ml.  Minimum bacteriocidal concentration values were same as MIC. Conclusion: E. coli and S.aureus were found to be most susceptible to acetic acid young leaf and stem-bark mango extracts. For C. albicans susceptibility profiles were best with aceti acid young and mature stem-bark extracts. It was also found that mango phytochemicals have broad-spectrum antibacterial activity as well as antifungal properties. The study also reveals that young mango parts contain higher bioactive substances than mature parts. Finally, it was concluded that acetic acid extracts produced the highest antimicrobial effects whereas aqueous extracts produced the least.