Screening of in vitro antitrematodal activities of compounds and secondary metabolites isolated from selected Pteridophytes

Four ferns Blechnum orientale Linn. (BO), Dicranopteris linearis (Burm.f ) Underw. (DL), Marattia fraxinea Sm. (MF), and Microlepia speluncae (L.) Moore (MS) were extracted in varied combination of organic solvents followed by the preparation of eluates and isolation of secondary metabolites using chromatography on a glass column with silica gel as the fixed phase. The chemical components were identified using HPTLC and GC-MS analysis. The in vitro anti-trematodal activities of these eluates and compounds were evaluated against the sheep trematode worm Gastrothylax crumenifer (Plagiorrchiida: Gastrothylacidae) at increasing concentrations (1 to 5 mg/mL), to find the relative motility (RM) values for 0 to 60 min of incubation as reflection of paralysis and death of the worms. Hedon-Fleig salt solution was used as negative control and Oxyclozanide® 1% as standard control. In vitro incubation study showed DL and MS extracts had strong trematodicidal activity. BO extract (5 mg/mL) produced moderate trematodicidal activity and MF (5 mg/mL) showed the least trematodicidal activity. Phytochemicals analysis revealed that the ferns are a potential source of trematodicidal compounds such as phytol isomers fern-8-ene and fern-9(11)-ene (terpenoid derivative), quercetin 7,3 ́,4 ́-trimethoxy (flavonoid derivative), etc., which offer scope for a more elaborate study for exploitation of ferns for human welfare.