Clinostomum complanatum: Anthelmintic potential of curcumin on the infective progenetic metacercarial stage.

The emerging resistance against commonly used antiparasitic drugs has driven investigators to explore alternative approaches using plant-derived active ingredients. These compounds have been tested for antiviral, antibacterial, and anthelmintic properties, particularly against adult worms. However, their effects on larval forms have been neglected. Curcumin is a polyphenol that is a significant constituent of the rhizome of Curcuma longa and possesses various biological activities, including antioxidant, anti-inflammatory, anti-infectious, and anti-carcinogenic. In the present study, the anthelmintic potential of curcumin was tested in vitro for its efficacy against the zoonotically important larval form, the progenetic metacercariae of Clinostomum complanatum, which were procured from the forage fish, Trichogaster fasciatus. Curcumin produced time and concentration-dependent inhibition in the motility of treated metacercarial worms, with the maximum inhibition of motility reported at 60 µM along with a significant increase of (36-92%) in ROS and (57-112%) in GSH levels at the end of a period of 6 h. In contrast, curcumin at the highest concentration significantly inhibited the activities of the antioxidant and detoxification enzymes SOD (36%) and GST (16%), respectively, in addition to altering the polypeptide profile and inhibiting cysteine proteases. The tegumental surface appeared to be highly disrupted in curcumin-treated worms, exhibiting severe blebbing, shearing of the tegument, and spine erosion. Such changes would affect the tegumental functions and survival of worms in the hostile microenvironment. This would render worms more susceptible to host-mediated rejection responses. Based on the results of the present study, it is inferred that C. complanatum could serve as an excellent model for screening novel anthelmintic drugs against larval trematodes of great economic significance. Furthermore, we conclude that curcumin could be exploited as an excellent phytotherapeutic agent against the virulent larval form under investigation.

Antihelminthic effect of thymoquinone against biliary amphistome, Gigantocotyleexplanatum.

Recent research on the emergence of parasitic resistance to commonly prescribed anthelmintics has sparked a greater interest in finding novel therapeutic molecules, including those derived from plants. The use of medicinal plants and their derivatives has been viewed as an alternative source of anti-parasitic compounds and as being safe in comparison to synthetic medications due to the absence of adverse effects, ease of accessibility, and little to no expense. Consequently, in the current study, thymoquinone (TQ), an active component of Nigella sativa (Black cumin), has been tested to see their effect on the activity of some important parameters of Gigantocotyle explanatum worms, including Gamma-glutamyl Transpeptidase (GGT), glutathione (GSH), Glutathione-S-Transferase (GST), Superoxide dismutase (NO). Additionally, various other survival indicators are also used, such as assays for motility, tegument damage, and DNA fragmentation. G. explanatum adult flukes were in vitro treated to thymoquinone at various concentrations for 3 h at 37 °C. Even though all of the worms were still alive after 3 h of exposure, there was a substantial (p < 0.05) reduction in worm motility at a concentration of 90 M. There were pronounced tegumental disturbances, a loss of surface annulations, and erosion in the papillae posterior region and around the acetabulum. A significant (p < 0.05) decrease in glutathione-S-transferase and superoxide dismutase activity and reduced glutathione (GSH) level was observed. A significant inhibition of Gamma-glutamyl Transpeptidase (GGT) in thymoquinone treated worms was also evident. Thymoquinone and GGT also displayed a high interaction during in silico molecular docking, suggesting that this combination may be more effective at inhibiting the antioxidant enzymes of G. explanatum. The present findings suggest that thymoquinone would reduce the worm capacity for detoxification, while GGT inhibition would have a major impact on their ability to transport amino acids across the tegument. Thymoquinone thus seemed to be a promising anthelmintic compound for future investigations.

Generation of oxidative stress and induction of apoptotic like events in curcumin and thymoquinone treated adult Fasciola gigantica worms.

Fasciolosis is a neglected tropical disease caused by the liver fluke Fasciola gigantica. The absence of successful vaccine and emerging resistance in flukes against the drug of choice, triclabendazole, has necessitated the search for alternatives including phyto-therapeutic approaches. Curcumin and thymoquinone, the active ingredients of Curcuma longa and Nigella sativa plants respectively, were first screened for their binding affinity with Glutathione-S-transferase (GST) molecule through in silico molecular docking followed by in vitro treatment of worms with varying concentrations of the test compounds. The in silico molecular docking of curcumin and thymoquinone with sigma GST revealed strong hydrogen bonding as well as hydrophobic interactions with high fitness scores but showing inter-specific differences. The in vitro treatment of F. gigantica worms with both curcumin and thymoquinone resulted in a significant increase in the generation of reactive oxygen species (ROS) whereas the level of reduced glutathione, a primary redox regulator, was found to be significantly decreased (p < 0.05). The two compounds not only inhibited the GST activity, which is an important detoxification enzyme and also a key drug/vaccine target for the control of fasciolosis but also significantly inhibited the activity of antioxidant enzymes glutathione peroxidase and glutathione reductase that are vital in maintenance of redox homeostasis. The immunohistochemistry performed using anti sigma GST polyclonal antibodies revealed that both the compounds used in the present study significantly reduced immunofluorescence in the vitellaria, developing eggs present in the ovary and the intestinal caecae indicating inhibition of GST enzyme in these regions of the worms. Further, following treatment with curcumin and thymoquinone, chromatin condensation and DNA fragmentation was also observed in F. gigantica worms. In conclusion, both curcumin and thymoquinone generated oxidative stress in the worms by production of ROS and significantly inhibiting their antioxidant and detoxification ability. The oxidative stress along with induction of apoptotic like events would compromise the survival ability of worms within the host. However, further studies are required to establish their anthelmintic potential alone and in combination with the commonly used anthelmintic drugs under in vivo conditions.

Observations on in vitro and in vivo antimicrofilarial effects of Bishop's weed (Trachispermum ammi).

The antimicrofilarial efficacy of Trachispermum ammi extacts in vitro and in vivo using Setaria cervi as a model, was investigated. T. ammi seed extracts were prepared using different solvents (with increasing order of polarity of the solvent) including petroleum ether, diethyl ether, chloroform, ethyl acetate, acetone, ethanol, and methanol. The extracts were tested for in vitro antimicrofilarial activity. The ethanolic and the methanolic extracts showed maximum activity in causing flaccidity in the microfilariae. The extracts were potent even at concentrations as low as 5 µl/ml. When orally administered to experimentally infected rats, the extracts eliminated circulating microfilariae within 2 weeks. It is inferred that the antimicrofilarial molecule(s), are polar in nature. They induce flaccidity in the microfilariae, by possibly inhibiting monoamine oxidase. This communication supplements the ethnopharmacological information for the use of T. ammi as an antihelminthic, and indicates that T. ammi could be used as a potential source of antimicrofilarial drugs.