title: Inhibition of dioscin on Saprolegnia in vitro.
abstract: As one of the most serious pathogens in the freshwater aquatic environment, Saprolegnia can induce a high mortality rate during the fish egg incubation period. This study investigated the anti-Saprolegnia activity of a total of 108 plants on Saprolegnia parasitica in vitro and Dioscorea collettii was selected for further studies. By loading on an open silica gel column and eluting with petroleum ether-ethyl acetate-methanol, dioscin (C45H72O16) was isolated from D. collettii. Saprolegnia parasitica growth was inhibited significantly when dioscin concentration was more than 2.0 mg L(-1). When compared with formalin and hydrogen peroxide, dioscin showed a higher inhibitory effect. As potential inhibition mechanisms, dioscin could cause the S. parasitica mycelium morphologic damage, dense folds, or disheveled protuberances observed by field emission scanning electron microscopy and the influx of Propidium iodide. The structural changes in the treated mycelium were indicative of an efficient anti-Saprolegnia activity of dioscin. The oxidative stress results showed that dioscin also accumulated reactive oxygen species excessively and increased total antioxidant and superoxide dismutase activity. These situations could render S. parasitica more vulnerable to oxidative damage. Additionally, when dioscin concentration was less than 2.0 mg L(-1), the survival rate of embryos was more than 70%. Therefore, the use of dioscin could be a viable way of preventing and controlling saprolegniasis.
authors.affiliation: College of Animal Science and Technology, Northwest A&F University, Xinong Road 22nd, Yangling, Shaanxi 712100, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.affiliation: College of Animal Science and Technology, Northwest A&F University, Xinong Road 22nd, Yangling, Shaanxi 712100, China.
authors.forename: Yu-Feng
authors.initials: YF
authors.lastname: Shen
authors.affiliation: College of Science, Northwest A&F University, Xinong Road 22nd, Yangling, Shaanxi 712100, China.
authors.forename: Guang-Lu
authors.initials: GL
authors.lastname: Liu
authors.affiliation: College of Animal Science and Technology, Northwest A&F University, Xinong Road 22nd, Yangling, Shaanxi 712100, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Ling
authors.affiliation: College of Animal Science and Technology, Northwest A&F University, Xinong Road 22nd, Yangling, Shaanxi 712100, China.
authors.forename: Xin-Yang
authors.initials: XY
authors.lastname: Liu
authors.affiliation: National Pathogen Collection Center for Aquatic Animals, College of Fisheries and Life Science, Shanghai Ocean University, 999 Hucheng Huan Road, Shanghai 201306, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Hu
authors.affiliation: National Pathogen Collection Center for Aquatic Animals, College of Fisheries and Life Science, Shanghai Ocean University, 999 Hucheng Huan Road, Shanghai 201306, China.
authors.forename: Xian-Le
authors.initials: XL
authors.lastname: Yang
authors.affiliation: College of Animal Science and Technology, Northwest A&F University, Xinong Road 22nd, Yangling, Shaanxi 712100, China wanggaoxue@126.com.
authors.forename: Gao-Xue
authors.initials: GX
authors.lastname: Wang
mesh_terms: D000818:Animals; D002463:Cell Membrane Permeability / Q000187:drug effects; D004144:Diosgenin / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000494:pharmacology; D005399:Fishes / Q000469:parasitology; D005557:Formaldehyde / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D025282:Mycelium / Q000187:drug effects / Q000254:growth & development / Q000648:ultrastructure; D017382:Reactive Oxygen Species / Q000378:metabolism; D044762:Saprolegnia / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D005557:Formaldehyde; C019357:dioscin; D006861:Hydrogen Peroxide; D004144:Diosgenin
keywords: aquatic disease; dioscin; membrane damage; natural plant agent