A comparative study of antibacterial properties of Elephantorrhiza elephantine (Muzezapasi) and Zanthoxylum chalybeum (Mukundanyoka) against those of commercial drug Azithromycin on Escherich

Abstract

A study was carried out at the Midlands State University during the month of September

2016, to compare the antibacterial properties of Elephantorrhiza elephantine (Muzezapasi)

and Zanthoxylum chalybeum (Mukundanyoka), against those of the commercial drug

Azithromycin on Escherichia coli. Plant extracts were purchased, sun dried and ground into

fine powders. Azithromycin tablets were also purchased. Escherichia coli bacteria were

isolated from the University toilets. Confirmatory tests were used to verify Escherichia coli.

The three treatment drugs were then prepared into percentage solutions of 1%, 5%, 10%,

25% and 40% for E. elephantine and Z. chalybeum alone. A control was also prepared with

sterile distilled water. Filter paper discs of a diameter of 6mm were prepared and embedded

with the treatment drug percentage solution. Mueller hinton agar was inoculated with E.coli

and the treated filter paper discs were placed on the media and incubated for 18 hours at

37°C. Zones of inhibition (ZOI) were measured in millimetres. Comparisons on the

effectiveness of the drugs were then done and the results showed that the standard drug

Azithromycin was the most effective. Azithromycin had the lowest inhibitory effect of 12mm

at 1% concentration and a highest inhibitory effect of 27mm at 25%. Its general inhibitory

effect increased by an average of 15mm from 1% to 25%. Azithromycin’s most significant

increase was 10mm between 1% and 5%. Elephantorrhiza elephantine was more effective

than Zanthoxylum chalybeum at lower percentage concentrations as it showed some

inhibitory effect at 1% and 5% of 7mm and 8mm respectively and Zanthoxylum chalybeum

showed no inhibitory effect at all at the two lowest concentrations. Elephantorrhiza

elephantine had an average total inhibitory effect of 15mm. Its most significant inhibitory

effect occurred between 25% and 40% at 7mm zone of inhibition diameter. Zanthoxylum

chalybeum inhibition effect started at 10% concentration and its most significant increase was

between 25% and 40% at 8mm zone of inhibition diameter, which was similar to that of

Elephantorrhiza elephantine. Elephantorrhiza elephantine and Zanthoxylum chalybeum had

the same average effectiveness of 8mm at 25% concentration. The results concluded that the

commercial drug is greatly more effective than the unstandardized plant treatments, meaning

that its dosage must be less than that of the plant drugs. Azithromycin therefore can have

different dosages starting from below 1% because its 1% concentration has significant

antibacterial effectiveness. The two plants Elephantorrhiza elephantine and Zanthoxylum

chalybeum have an insignificant difference in effectiveness maybe due to differences in

active ingredients and mode of action on bacteria, and so their dosages may be the same and

should be in concentrations higher than 25% as their effectiveness is significant from that

point going to higher concentrations.