Therapecutic efficacy of the leaf extract of Croton joufra Roxb. against experimental cestodiasis in rats

Studies on the anthelmintic potentials of the roots of Asparagus racemosus willd. (Asparagaceae)

Background

The Santhal tribe in Assam, India use the roots of Asparagus racemosus (Asparagaceae) as a deworming remedy. The study aimed to investigate the anthelmintic credentials of this plant, using two representative groups of helminth parasites.

Methods

The in vitro testing was conducted against Hymenolepis diminuta (cestode) and Syphacia obvelata (nematode). Parasites were exposed to 10, 20 and 30 mg/ml concentrations of plant extract, and efficacy was adjudged on the basis of parasites paralysis and mortality. In vivo efficacy was examined using H. diminuta-rat and S. obvelata-mice models where animals were administered 125, 250 and 500 mg/kg doses of extract.

Results

In vitro assay, against H. diminuta revealed that at 30 mg/ml concentration the extract showed almost a comparable efficacy with that of reference drug praziquantel (PZQ) (1 mg/ml). The in vitro efficacy of extract against S. obvelata was however lower than H. diminuta. In vivo studies against H. diminuta at 500 mg/kg revealed 53.88 and 24 % reduction in eggs per gram (EPG) and worm counts respectively. Against S. obvelata the extract showed 26.61 and 30.93 % reduction for the same.

Conclusions

The findings of this study present suggest that the roots of A. racemosus are effective against intestinal helminthic infections and justifies its use as an anthelmintic in the traditional medicine of the Santhals.

Evaluation of in vitro and in vivo anthelmintic efficacy of Cyperus compressus Linn., a traditionally used anthelmintic plant in parasite-animal models

Background

The decoction of the roots of Cyperus compressus (Cyperaceae) is used to treat helminth infection by the Santhal tribe of Assam. The study evaluated the anthelmintic efficacy claims of the plant C. compressus through pre-clinical in vitro and in vivo studies employing available parasite-animal models such as Hymenolepis diminuta-Wistar rat (cestode) and Syphacia obvelata-Swiss mice (nematode) models.

Results

Phytochemical analysis revealed the presence of alkaloids, glycosides, reducing sugars, flavonoids, terpenoids, tannins, and steroids. In vitro studies were conducted employing H. diminuta and S. obvelata. In vitro studies against H. diminuta revealed mortality of parasites at 8.3 ± 0.05 h at the highest concentration of C. compressus methanolic root extract (30 mg/ml), whereas reference drug praziquantel (PZQ), showed mortality at 5.84 ± 0.01 h. Against S. obvelata, in the same concentration of the extract, mortality of parasites occurred in a much later time of 24.13 ± 0.03 h, whereas in the reference drug albendazole (ABZ), the parasites showed mortality at 7.24 ± 0.08 h. In vivo studies against H. diminuta revealed 61.74% reduction in the eggs per gram (EPG) counts and 24% reduction in worm counts at the highest dose of 700 mg/kg body weight (b.w.) of plant extract. Against S. obvelata, at 700 mg/kg b.w., 28.92% and 33.85% reduction in EPG and worm counts were recorded respectively.

Conclusion

Although the reference drugs showed better in vitro and in vivo efficacy, the plant extract showed a better in vitro efficacy against cestode parasite compared to its nematode counterpart indicating that it possesses a better cestocidal efficacy. EPG reductions were higher against H. diminuta, whereas worm count reduction was higher against S. obvelata. The findings justify the use of C. compressus as an anthelmintic in the traditional medicine of the Santhals of India.

Structure-activity profiling of alkaloid natural product pharmacophores against a Schistosoma serotonin receptor

Serotonin (5-HT) is an important regulator of numerous aspects of flatworm biology, ranging from neuromuscular function to sexual maturation and egg laying. In the parasitic blood fluke Schistosoma mansoni, 5-HT targets several G-protein coupled receptors (GPCRs), one of which has been demonstrated to couple to cAMP and regulate parasite movement. This receptor, Sm.5HTR_L, has been successfully co-expressed in mammalian cells alongside a luminescent cAMP-biosensor, enabling pharmacological profiling for candidate anti-schistosomal drugs. Here, we have utilized this assay to perform structure-activity investigations of 143 compounds containing previously identified alkaloid natural product pharmacophores (tryptamines, aporphines and protoberberines) shown to regulate Sm.5HTR_L. These experiments mapped regions of the tryptamine pharmacophore amenable and intolerant to substitution, highlighting differences relative to orthologous mammalian 5-HT receptors. Potent Sm.5HTR_L antagonists were identified, and the efficacy of these compounds were evaluated against live adult parasites cultured ex vivo. Such structure-activity profiling, characterizing the effect of various modifications to these core ring systems on Sm.5HTR_L responses, provides greater understanding of pharmacophores selective for this target to aid future drug development efforts.

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Various alkaloids were screened against a schistosome serotonin receptor, Sm.5HTR_L.

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Compounds with a tryptamine core displayed agonist activity at Sm.5HTR_L.

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Aporphine and protoberberine compounds displayed antagonist activity at Sm.5HTR_L.

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Compound activity at Sm.5HTR_L is broadly mirrored by motility effects on adult worms.