Anti-parasitic effects of water-soluble alkaloid fractions from ethanolic extracts of Sophora moorcroftiana seeds in Caenorhabditis elegans

Parasite infections of humans and animals remain a major global health problem, with limited choice of drugs being available to the treatment of parasitosis in the clinic. Sophora moorcroftiana (S. moorcroftiana) is a shrub that grows in Tibet Plateau of China. Decoction of the seeds has been used as a traditional Tibetan medicine to treat parasitosis for years. But the anti-parasitic effects of water-soluble fractions in the seeds need further investigation. In the present study, the water-soluble alkaloid fractions (E2) were obtained from S. moorcroftiana seeds by refluxing extraction with 60% ethanol and low polarity fraction (E2-a) and high polarity fraction (E2-b) were subsequently isolated from E2 using column chromatography. As a parasite model, Caenorhabditis elegans (C. elegans) were treated with different fractions and their survivals were recorded. The results showed that that E2-a induced a lower survival rate in C. elegans than E2-b and E2. The protoscoleces of Echinococcus granulosus (E. granulosus) were cultured in the presence of E2-a. Compared with E2-b and E2, protoscoleces exhibited decreased survival rate following E2-a treatment. Furtherly, the effects of E2-a on the behavior, brood size, and lifespan of the worms were investigated. Body bend frequencies of the worms treated with the high concentration of E2-a were reduced by two-thirds compared with the control group (P < 0.01). Compared with non-E2-a-treated group, exposure of nematodes to E2-a led to a decrease in head thrashes and pharyngeal pumps frequency (P < 0.01). E2-a treatment resulted in a significantly lower brood size (P < 0.01). Additional E2-a treatment induced a significantly shortened lifespan, compared with the control (P < 0.05). These findings indicated that water-soluble fraction E2-a from S. moorcroftiana seeds was a potential helminthic agent.