Transmission Electron Microscopy of Schistosoma mansoni Cercariae Treated with Hinokitiol (.BETA.-thujaplicin), a Compound for Potential Skin Application against Cercarial Penetration

Abstract

Since skin is the only route of entry of the parasite in schistosomiasis patients, intervention at the level of skin penetration should control the infection. Several compounds were screened for their ability to protect against cercarial penetration. Hinokitiol (β-thujaplicin) was found to have a significant cercaricidal effect in vitro, although there is no information on its cercaricidal mechanisms. To study the kinetics of morphological changes in Schistosoma mansoni associated with exposure to hinokitiol in vitro, cercariae were incubated in media containing hinokitiol at different concentrations and examined by transmission electron microscopy (TEM). TEM revealed that ultrastructural changes occurred by 15 minutes post exposure, at a concentration of 25 μg/ml. Degenerative changes involving both tegument and deeper parenchymal structures were progressive with duration of exposure at the concentration of 50 μg/ml. These structural changes may account for the inability of hinokitiol-treated cercariae to infect the host.hinokitiol; Schistosoma mansoni; cercariae; transmission electron microscopy

Bioactivity of miltefosine against aquatic stages of Schistosoma mansoni, Schistosoma haematobium and their snail hosts, supported by scanning electron microscopy

“…Gross changes were observed, including loss of tails in about 80% of cercariae. These observations were consistent with the report of [47] and [48] which showed that hinokitiol (β- thujaplicin), a compound for potential skin application against cercarial penetration leads to loss of cercarial tail in about 50% of cercariae thus affecting cercarial movement and swimming activity. SEM also revealed loss of glycocalyx resulting in the thinning of the tegument causing external protrusion or surface blebbing with focal loss of spines.…”

“…SEM also revealed loss of glycocalyx resulting in the thinning of the tegument causing external protrusion or surface blebbing with focal loss of spines. These changes are similar to the changes observed on the cercariae of S.mansoni exposed to hinokitiol by [48]. Those authors suggested that the structural changes may account for the inability of hinokitiol-treated cercariae to infect the host.…”

Plant Troponoids: Chemistry, Biological Activity, and Biosynthesis

“…Thujaplicin has a significant cercaricidal activity in vitro [99]. In schistosomiasis patients, the entry of the parasite Schistosoma mansoni into the body through skin becomes easier.…”

“…In schistosomiasis patients, the entry of the parasite Schistosoma mansoni into the body through skin becomes easier. Transmission electron microscopy study suggests some ultrastructural changes of parasites after 15 min of exposure to -thujaplicin (25-50 g/ml), and such degenerative changes involve both tegument and deeper parenchymal structures [99]. Ke ita et al [100] observed the insecticidal activity of thujaplicinol from Thuja occidentalis on Callosobruchus maculates.…”

In Vitro Inhibitory Effects of Hinokitiol on Proliferation of Chlamydia trachomatis

“…et Zucc and Thuja plicata D. Don. Hinokitiol has antimicrobial activity against several microorganisms (6), such as influenza virus (12), Staphylococcus aureus, Staphylococcus epidermidis (1,7,8,13), and Schistosoma mansoni (5). The objective of this study was to clarify the in vitro inhibitory effects of hinokitiol on C. trachomatis.…”