Efficacy and antiparasitic mechanism of 10-gingerol isolated from ginger Zingiber officinale against Ichthyophthirius multifiliis in grass carp

Authors: FU, YAOWU - Jinan University; WANG, BIN - Jinan University; ZHANG, QIZHONG - Jinan University; Xu, Dehai; LIU, YANMENG - Jinan University; HOU, TINGLONG - Jinan University; GUO, SHUQUAN - Jinan University

Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/26/2018
Publication Date: 1/5/2019
Citation: Fu, Y., Wang, B., Zhang, Q., Xu, D., Liu, Y., Hou, T., Guo, S. 2019. Efficacy and antiparasitic mechanism of 10-gingerol isolated from ginger Zingiber officinale against Ichthyophthirius multifiliis in grass carp. Veterinary Parasitology. 265:74-84.
DOI: https://doi.org/10.1016/j.vetpar.2018.11.011

Interpretive Summary: White spot disease caused by Ichthyophthirius multifiliis is one of the most common parasitic diseases, which causes high mortality for many cultured fish and leads to heavy economic losses in aquaculture. There is a lack of therapeutants in aquaculture so there is an urgent need to find effective parasiticides to treat I. multifiliis infections. The present study aimed to investigate the efficacy and antiparasitic mechanism of active compounds isolated from ginger against I. multifiliis. Three compounds were isolated from the ginger extract and identified as 10-gingerol, 6-dehydroshogaol, and 6-dehydro-10-gingerol. In vitro tests, 10-gingerol demonstrated the best antiparasitic efficacy against I. multifiliis and killed young or adult parasite at concentrations of 2 and 16 mg/L, respectively. The 10-gingerol resulted in the increasing of intracellular osmotic pressure and accumulation of free radicals, which damaged the membrane system of I. multifiliis. The study results are important to aquaculture and will help to develop a potential alternative parasiticide to control white spot disease.

Technical Abstract: Ichthyophthirius multifiliis is a ciliate parasite of freshwater fish with a global distribution and results in severe economic losses in aquaculture. The present study aimed to investigate the efficacy and antiparasitic mechanism of active compounds isolated from Zingiber officinale against I. multifiliis. Three compounds were isolated from the Z. officinale extract and identified as 10-gingerol, 6-dehydroshogaol, and 6-dehydro-10-gingerol. In vitro tests, 10-gingerol demonstrated the highest antiparasitic efficacy against I. multifiliis. 10-gingerol resulted in mortalities of theronts, nonencysted tomonts, and encysted tomonts at concentrations of 2, 8, and 16 mg/L, respectively. 10-gingerol significantly reduced theronts infectivity (p<0.05) at 1 mg/L and was effective in treating infected grass carp and protecting naïve fish from I. multifiliis infestation at 4 mg/L. The 96h median lethal concentration (LC50) of 10-gingerol to grass carp was 85.4 mg/L. The antiparasitic mechanism results showed increase of intracellular osmotic pressure, accumulation of free radicals, and membrane damage of I. multifiliis post 10-gingerol treatment. The study demonstrates that 10-gingerol has the potential as a therapeutic agent against I. multifiliis.