The Molluscicidal Activity And Physiological Toxicity Of Numb-taste Components From The Peel Of Zanthoxylum Schinifolium Sieb.et Zucc Against Oncomelania Hupensis Snails

Zanthoxylum bungeanum is a commonly used savory seasoning.Its main ingredients are numb-taste components,in addition to food value,there are also avoidance,insecticidal,bacteriostatic,analgesic,hypolipidemic,anti-oxidant,anesthetic,anti-tumor and other physiological functions.Most of the numb-taste components are chain unsaturated aliphatic acid amides,which is the most important active ingredient of Zanthoxylum bungeanum is different from other natural medicines.Synthetic amide chemical molluscicides such as niclosamide has a good molluscicidal activity,but there are hidden dangers such as polluted environment and toxicity to non-target organisms.In order to overcome these problems,this study attempts to extract natural amide compounds from Zanthoxylum bungeanum against Oncomelania hupensis snails and explore its physiological toxicity,in order to find high-efficiency and low-toxic plant-derived molluscicideIn this study,Zanthoxylum schinifolium Sieb.et Zucc was used as the raw material Firstly,ultrasonic extracting organic solvent extraction method was used to extract crude extract of numb-taste components-Zanthoxylum bungeanum oleoresin(aroma and numb-taste ingredient).The Zanthoxylum bungeanum oleoresin A1,B1 and C1 were extracted from the peel of Zanthoxylum schinifolium Sieb.et Zucc(dry powder,100 g)by three organic solvents(hot petroleum ether,anhydrous ether,80%ethanol),respectively,and 21.37 ± 0.64 g and 17.75%0.49 g were obtained respectively 14.26%0.36 g,extraction rates were 21.37%,17.75%,14.26%.The results showed that the extraction of Zanthoxylum bungeanum by ultrasonic-assisted organic solvent had the highest extraction rate of hot petroleum ether,followed by anhydrous ether and 80%ethanol,the difference was extremely significant(P<0.01).Therefore,the Zanthoxylum bungeanum oleoresin A1 and B1 extracted with hot petroleum ether and anhydrous ether were further separatedThe molluscicidal experiments were carried out by using the above three solvent-extracted pepper oleoresins A1,B1 and C1,respectively.The results showed that the half-lethal dose(LC50)at 48 h was 173.784 mg/L,226.45 mg/L,283.304 mg/L,and the lethal dose(LC90)was 331.761 mg/L,461.456 mg/L,547.256 mg/L.72 h LC50 was 84.211 mg/L,100.066 mg/L,123.171 mg/L,LC90 were 167.544 mg/L,221.145 mg/L,282.873 mg/L.Therefore,A1 has the best molluscicidal activity,B1 is the second,and C1 is the weakestAccording to the extraction rate and the molluscicidal effect,the Zanthoxylum bungeanum oleoresin A1 and B1 extracted by hot petroleum ether and anhydrous ether were further separated and purified.The Zanthoxylum bungeanum oleoresins A1 and B1 were further purified by cold petroleum ether removal method and countercurrent dry column chromatography,respectively,and 10 g of A1 and B1 were separately separated to obtain A2(729 ± 30.5 mg)and B2(644 ± 26.1 mg).The extraction rates were 7.29%and 6.44%,respectively.A2 is a white needle crystal,and B2 is a yellow-green needle crystal with a small amount of dark green viscous material attached thereto.The A2 and B2 were detected by ultraviolet spectrophotometry,and the absorbance(254 nm)of A2 was found to be larger than B2.It is presumed that the purity of A2 is higher than that of B2.A2 and B2 were analyzed by LC-TOF/MS with a molecular weight of 263.2 and a molecular formula of C16H25NO2 It was preliminarily determined that A2 and B2 extracted by the two methods were the same type of amide compoundThe purified numb-taste components A2 and B2 were subjected to molluscicidal experiments.The LC50 at 48 h was 15.992 mg/L,26.474 mg/L,LC90 was 30.226 mg/L and 44.348 mg/L,respectively;72 h LC50 was 7.412 mg/L.15.059 mg/L,LC90 was 13.49 mg/L and 29.881 mg/L,respectively.Therefore,A2 is better than B2.It is indicated that the numb-taste components is an important active substance in the dry powder of the Zanthoxylum schinifolium Sieb.et Zucc peel.The higher the purity,the better the molluscicidal effectThe snail liver was treated with different concentrations of succulent substance A2,and the activity of protein,glycogen,acid phosphatase(ACP),alkaline phosphatase(AKP)and glutathione S-transferase(GST)of snail liver was measured.The results showed that protein content and glycogen content gradually decreased with the prolonged treatment time and increased concentration.The changes of acid phosphatase,alkaline phosphatase and glutathione thiotransferase were similar,and the trend of acid phosphatase was the most obvious.All three enzymes showed a trend of increasing first and then decreasing,and the higher the concentration,the higher the inflection point.It indicated that in the early stage of treatment,the enzyme activity increased by the stress effect of the snail,but with the increase of the treatment time,the enzyme concentration decreased gradually with the increase of the treatment concentration.It indicates that the metabolic capacity of the detoxification enzyme of the snail liver is reduced,the energy supply of glycogen is weakened,and the substances and metabolism in the body are disordered,resulting in death of snail poisoning.The above research results show that the numb-taste components has a good molluscicidal activity and is a potential plant-derived molluscicide.In this paper,we study the molluscicidal activity and physiological toxicity of the numb-taste components,in order to lay a certain foundation for the future development of the plant-derived molluscicide or compound-type molluscicides.