In vitro immunocompetence of two compounds isolated from Polygala tenuifolia and development of resistance against grass carp reovirus (GCRV) and Dactylogyrus intermedius in respective host.

The present study was undertaken to isolate some compounds from methanol extract of Polygala tenuifolia and evaluate their immunostimulatory properties and antiviral activity using grass carp Ctenopharyngodon idella kidney (CIK) cells and GCRV. By applying insecticidal bioassay-guided, chromatography techniques and successive recrystallization, two purified compounds were obtained. The changes of expression of selected immune genes (Mx1, IL-1ß, TNFα, MyD88 and IgM) in C. idella kidney cell lines were evaluated after exposure to these isolated compounds. The results showed that compound 1 and 2 up-regulated to varying degrees of Mx1, IL-1ß, TNFα, and MyD88 in C. idella kidney cells. WST-8 kit assay verified the two compounds has no toxic effects on CIK cell, and furthermore, have in vitro antivirus activity. Especially, that there is keeping 79% cell viability when exposure to compound 2 (100 mg L(-1)). According to in vivo insecticidal assays against Dactylogyrus intermedius, compound 2 exhibited higher efficacy than compound 1, which was found to be 87.2% effective at the concentrations of 5 mg L(-1) and safe to goldfish (Carassius auratus). Besides, the purified compounds were identified by spectral data as: (1) 1,5-Anhydro-D-glucitol and (2) 3,4,5-trimethoxy cinnamic acid. Overall, the results indicate that bath administration of these compounds modulates the immune related genes in C. idella kidney cells and to some extent, eliminate the virus and parasitic infections.

Bioassay-guided isolation and identification of active compounds from Semen pharbitidis against Dactylogyrus intermedius (Monogenea) in goldfish (Carassius auratus).

The present study was undertaken to isolate the active compounds responsible for the anthelmintic activity of methanol extract of Semen pharbitidis against Dactylogyrus intermedius in goldfish (Carassius auratus). The active methanol extract was fractionated on silica gel column chromatography in a bioassay-guided fractionation, eventually yielding two bioactive compounds: palmitic acid and pharnilatin A by comparing spectral data (NMR and ESI-MS) with literature values. According to in vivo anthelmintic assays, they were found to be 50% effective at the concentrations (EC(50)) of 5.3 and 1.4 mg L(-1), respectively. The promising palmitic acid and pharnilatin A from S. pharbitidis were also subjected to acute toxicity tests for the evaluation of their safety to the host (goldfish). After 48h exposure, the mortalities of goldfish were recorded, and the established LC(50) values were 2.45- and 5.29-fold higher than the corresponding EC(50), demonstrating that pharnilatins A may have better application potential than palmitic acid. The present results provide evidence that pharnilatins A might be potential source of new anti-parasitic drug for the control of Dactylogyrus.