3. Results
The microfilaricidal activity of these plants extracts were ex-pressed in relative movability (RM) percentage as shown inTable
1andFigs. 2–4. The negative control cultures showed 100% RM
after 24 h of incubation, showing that the constant environment,
culture process and the DMSO used do not have an effect on the
microfilaricidal activity of the plant extracts. Positive control cul-tures demonstrated by ivermectin simulated a non-linear curve
with 0% RM by 24 h proving that the preparation technique of
the treatment compounds does not have any effects on the micro-filaricidal efficacy of the extracts.
Results showed that all plant extracts successfully demon-strated microfilaricidal activity with the trend of a non-linear curve
over time. There were also dose-dependant microfilaricidal activi-ties observed, with the highest concentration giving the strongest
microfilaricidal activity (reduced RM) with gradual reduced activ-ity with tapering concentration. However, this dose-dependant
activity was only seen in the two highest concentration tested
(10 mg/ml and 1 mg/ml) from in the Z. officinale (ZO) extract
(Fig. 2).
It was also interesting to note that, when observing the ZO and
TC extract, the 100lg/ml concentration has a slightly reduced
microfilaricidal activity than the 10lg/ml and 1lg/ml concentra-tion, but this was proven to be statistically insignificant (p< 0.05).
When these three extracts were compared with one another at
what was observed to be the most effective crude concentration
(10 mg/ml) (Fig. 5), it was found that the ZO extract was superior
at successfully reducing the RM to 0% by the 3rd hour post treat-ment, followed by the AP extract at the RM of 7.48% and TC extract
at 30.15% by the 24th h. These extracts however do not show the
same level of strength in microfilaricidal efficacy as the positive
control (ivermectin), but they do follow a similar trend as the po-sitive control.
Another observation of this experiment was that all the three
extracts effectively reduce the microfilarial motility via a possible
spastic mechanism, with the microfilaria exhibiting reduction in
motility by maintaining a ‘straight pose’ with cessation of any hor-izontal or vertical movement. This ‘pose’ was still observed after
21 h post cessation of movement