Potential Cercaricidal Properties of Topical VCO and VCO-Based Celery (Apium graveolens) and Onion (Allium cepa) Extract Preparations Against Schistosoma japonicum

Abstract

Schistosomiasis in the Philippines is a disease acquired through dermal penetration of Schistosoma japonicum cercariae. Because the disease remains to be prevalent despite mass treatment, cheaper and more accessible alternatives have been proposed in the form of extracts of endemic plants. Hence, this study tested the potential cercaricidal properties of topically applied VCO and VCO-based celery stalk (Apium graveolens) and onion stalk (Allium cepa) extracts to localize the treatment to the site of infection. Hexane and chloroform extracts were tested m vitro through observation of cercarial mortality and in vivo through mice infection. Analysis using the Kaplan-Meier survival estimate (a=0.0001) implied significant differences in the treatments in vitro. Post hoc Logrank test and Fisher’s exact test (a=0.0001) showed that only the celery- hexane (CH) extract exhibited significant cercaricidal property. The VCO, celery- chloroform and onion-chloforom extracts exhibited slight cercaricidal activity. Analysis using ANOVA (a=0.05) in the COPT results in vivo showed a significant difference in the results. The post hoc Tukey-Kramer test showed that only CH was able to exhibit significant cercaricidal property in vivo. This is attributed to the potential cercaricidal compounds like 3-n-butyl-tetrahydrophthalide and 5-allyl-methoxyphenol present in the CH extract. These compounds were found to be structurally similar to the cercaricidal components of cedarwood oil, a known cercaricide. This experiment showed that only CH was able to exhibit potential cercaricidal properties, and the researchers recommend the identification and confirmation of the active cercaricidal components of this extract.