As for the cessation of movement with maintenance of ‘straight poses’ one possible explanation as to why the microfilaria maintain this rigid ‘pose’ in the experiment was that the most possible
mode of inhibiting their motility is via spastic paralysis, when
compared to ivermectin which causes flaccid paralysis. This comparison will be further discussed in theA. paniculatapart of the discussion.
For the Z. officinale observation, direct comparison of this
study’s results to previous reports regarding the extract’s efficacy against filarial species could not be performed due to the lack of in vitroreports ofZ. officinale’s activity against D. immitis.However,in vivo studies done by Datta and Sukul (1987)which involved administering 100 mg/kg alcohol extract of Z. officinale subcutaneously in three phases of four daily injections (with seven day gaps)
over eight weeks into microfilaremic dogs, proved that it was effective in reducing the microfilaria burden by 83% at 55 days post treatment. This finding can be further supported by the results of this experiment as a concentration of 1 mg/ml was sufficient enough to exert microfilaricidal effects by reducing the RM to
30.98% after 24 h. There is a strong possibility that the active compounds responsible for the microfilaricidal activity inZ. officinale are heatstable and able to withstand the different types of preparation (methanol or aqueous extraction).
The mode of action forZ. officinaleon the microfilaria is unknown, although two speculations exist;Chrubasik et al. (2005)
suggested that the active compounds may cause destruction of the Anisakis larvae’s cuticle in which in a similar manner may ap-ply to theD. immitismicrofilaria. Another mechanism would be through the extract’s cholinergic effects; whereby there is excessive stimulation of the acetylcholine excitatory receptors especially at the presynapses and neuromuscular junction, thereby resulting in spastic muscular spasms and eventual paralysis. It is
not known whether this is a reversible or irreversible process
whether or not, these two possible modes of microfilaricidal action may have act synergistically with one another.
As for A. paniculata, the only in vitrostudy done on filarids using this extract was using the adult B. malayi, whereby Zaridah et al.
(2001), reported that with 10 mg/ml, a RM of 0% could be achieved