In vitro effect of Myrrh extracts on the viability of Schistosoma mansoni larvae
Schistosomiasis, a parasitic disease caused by trematode flatworms of the genus Schistosoma, represents a growing concern in the Sub-Saharan Africa, where up to 80% of the population is infected. Mirazid®, a commercial drug obtained by combination of two solvent extracts of Myrrh, the oleo-gum-resin from the stem of Commiphora molmol Engl. ex Tschirch (Burseraceae), is marketed in Egypt since 2001 as an alternative treatment for schistosomiasis . However, recent independent studies question its efficacy. All experiments conducted with Myrrh so far are either in vivo tests or clinical trials, but no in vitro data is available. In order to shed light into controversy around Myrrh, two commercial Myrrh samples (from S. Africa and M. East) were extracted and/or combined as described a) for Mirazid®; first with petroleum ether (A), subsequently with MeOH (B) b) hydrodistillation to yield volatile oil c) for myrrh (8.5 parts of resin + 3.5 parts of volatile oil) [2–4]. They were also extracted with MeOH and then partitioned between hexane, CHCl3 and aqueous MeOH. As the combination ratios of the extracts A+B in Mirazid® are unclear, extracts A/B were combined in simple ratios. In the medium throughput visual S. mansoni larval assay, all lipophilic extracts, the combinations, and the essential oils showed moderate, but differenzial activity (IC50s 7.18–32.69µg/ml). The extracts and the essential oils were also different phytochemically (by TLC, 1H NMR, GC-MS). This study shows that Myrrh has antischistosomal potential, but the origin of the plant material and extraction method is of importance.
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