Efficacy of albendazole and thymol combination against Echinococcus multilocularis protoscoleces and metacestodes

ALBANI C, ; ELISSONDO MC

ACTA TROPICA

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2014 vol. 140 p. 61 - 67

0001-706X

The larval (metacestode) stage of the tapeworm Echinococcus multilocularis causes alveolar echinococ-cosis (AE), a mainly hepatic disease characterized by continuous asexual proliferation of metacestodesby exogenous budding, resulting in the tumor-like, infiltrative growth of the parasite lesion. Currentchemotherapeutical treatment of AE relies on the use of benzimidazoles, albendazole (ABZ) and meben-dazole, but these drugs act parasitostatic rather than parasitocidal, and due to their low success ratethey imply a lifelong application causing severe side effects. Thymol is one of the major components ofthe essential oils of Thymus and is a widely known anti-microbial agent. The aim of the present workwas to compare the efficacy of albendazole (ABZ) and thymol separately or combined on E. multilocularisprotoscoleces and metacestodes. For this purpose, microscopical examinations at different time pointswere carried out. Moreover the tegumentary enzyme gamma glutamyl transferase (GGT) was measuredto quantify the damage in metacestodes. Even though treatments of in vitro cultured E. multilocularisprotoscoleces or metacestodes with ABZ or/and thymol showed that the drugs have an adverse effect onparasite viability, the combination of the two compounds at the concentration of 10 ug/ml showed the maximum anti-parasitic effect. Three days postincubation the first effects of the treatment were detectedon protoscoleces and a marked reduction in viability (33%) was registered at day 18. Incubation of E. mul-tilocularis metacestodes in the presence of ABZ 10 ug/ml + thymol 10 ug/ml during 10 days resulted indramatic alterations such as strongly irregular and fissured surface and markedly disrupted vesicles.Scanning electron microscopy showed that protoscoleces as well as the germinal layer of E. multilocularismetacestodes were dramatically damaged following ABZ or/and thymol treatment. Also an importantincrease of tegumentary enzyme GGT was registered after 72 h postincubation with both drugs. Thedata reported in this article demonstrate a clear in vitro effect of ABZ + thymol against E. multilocularisprotoscoleces and metacestodes.