ULTRASTRUCTURAL CHANGES IN Schistosoma mansoni MALE WORMS AFTER in vitro INCUBATION WITH THE ESSENTIAL OIL OF Mentha x villosa Huds

Abstract

Introduction:The essential oil Mentha x villosa (MVEO) has a wide range of actions, including antibacterial, antifungal, antiprotozoal and schistosomicidal actions. The present study aimed to investigate the ultrastructural changes of MVEO on the tegument of adult Schistosoma mansoni. Materials and Methods:Different concentrations of MVEO were tested on S. mansoni adult worms in vitro. Ultrastructural changes on the tegument of these adult worms were evaluated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results:The MVEO caused the death of all worms at 500 μg mL-1 after 24 h. After 24h of 500 μg mL-1 MVEO treatment, bubble lesions were observed over the entire body of worms and they presented loss of tubercles in some regions of the ventral portion. In the evaluation by TEM, S. mansoni adult worms treated with MVEO, 500 μg mL-1, presented changes in the tegument and vacuoles in the syncytial matrix region. Glycogen granules close to the muscle fibers were visible. Conclusion:The ability of MVEO to cause extensive ultrastructural damage to S. mansoni adult worms correlates with its schistosomicidal effects and confirms earlier findings with S. mansoni.

Ultrastructural study of morphological changes in Schistosoma mansoni after in vitro exposure to the monoterpene rotundifolone

“…Recently, in vitro studies for new active compounds against S. mansoni [14][15][16] showed that ROT, a monoterpene found in Mentha species, showed promising antischistosomal properties against adult schistosomes 17,27 .…”

“…As a positive control, worms were incubated in 0.5μg/ mL -1 PZQ. The worms were monitored every 24h until 120h and changes in motor activity were assessed and the mortality rate was determined 27 . The evaluation of the viability of adult worms was based on the standard procedures for screening schistosomicidal compounds established by the World Health Organization (WHO) Special Program for Research and Training in Tropical Diseases.…”

“…In this evaluation system, (+ + +) indicates normal activity, (+ +) slight loss of movement, with active tail, suckers, and gynecophoral canal membrane, (+) indicates movement of tails and suckers alone, and (−) indicates no movement. The worms were considered to be dead when no movement was identified after 3 min of observation using an inverted microscope 27 .…”

“…The samples were dehydrated through an ethanol series, dried in a critical point dryer, and then mounted on stubs and coated with gold using a sputter coater. The specimens were examined using a JEOL-5600LV microscope 27 .…”

“…It has the chemical formula C 10 H 14 O 2 ( Figure 1) 21 . It has been reported to have hypotensive and bradycardic 22 , antimicrobial 23 , spasmolytic 24 , larvicidal 25 , antitumour effects 26 and schistosomicidal activity on adult S. mansoni 27 .…”