Effect Of Mesona Chinensis Benth Water Extract To Thermal Tolerance Ability Of Fruit Fly And Its Mechanism Study

As an important medicine-food herb,Mesona chinensis Benth contains variety of function compositions,and in the area of Fujian and Taiwan,the Mesona chinensis Benth is often used to make beverage to prevent heatstroke during summer.However,the anti-heatstroke functions and its mechanism of Mesona chinensis Benth still unknown.Therefore,we investigated the chemical compositions of the water extract of Mesona chinensis Benth prepared by the production process of herbal tea.We also studied the change of thermal tolerance ability of fruit fly to evaluate the anti-heatstroke functions of Mesona chinensis Benth and its mechanism.Finally,developed a new product of anti-heatstroke beverage.The research contents were as flowing:(1)Analysis the functional compositions in the Mesona chinensis Benth water extractThe functional compositions of the Mesona chinensis Benth water extract were affected by the processing methods,thus the water extract was prepared by the production process of herbal tea to caster the practical case of drinking.The contents of polysaccharide,polyphenol,flavonoids and triterpenoid in water extract were detected,and the form of polyphenolic compounds were analysed by UPLC-MS.The results showed that the contents of polysaccharide,polyphenol,flavonoids and triterpenoid were 93.33 ug/mL,57.47 ug/mL,66.75 ug/mL,and 75.28 ug/mL,respectively.These contents were significantly lower than those of samples which had been reported.The results of UPLC-MS showed that there were protocatechuate,chlorogenic acid,caffeic acid,rutin,ferulic acid,salicylic acid,kaempferol and baicalein in the water extract,and rutin,ferulic acid,salicylic acid,and baicalein were detected for the first time in Mesona chinensis Benth.The above results provided basis for the further study of the physiological activities of water extract.(2)Effect of the Mesona chinensis Benth water extract on thermal tolerance ability of fruit flyThe best experimental conditions of thermal exposure of fruit fly were investigated in this paper.According to the gender,the fruit fly was divided to cultivate in experimental medium with different concentrations of water extract,and then placed into empty bottles and thermal exposed in manual climatic box with different temperature to investigate the LT50 of fruit fly.The results of the preliminary test indicated that the best temperature was(36±1)℃,the concentration was between 0.2%and 0.6%,and due to the gender of fruit fly was important to the ability of thermal tolerance,the ability of female fruit fly was better than male fruit fly and the data was more security,thus the female fruit fly was the best experimental object.In order to study the effect of water extract on thermal tolerance ability of fruit fly in the experiment of heat resistance,the fruit fly was fed by experimental mediums with different concentrations of water extract(the low dose was 0.2%,the medium dose was 0.4%,the high dose was 0.6%),the culture time was 3 days,and then thermal exposed in manual climatic box to investigate the semi-lethal time(LT50),the average survival time(T),and the maximum survival time(Tmax)of fruit fly.The results indicated that the LT50,T,Tmax increased first and then declined with the increase of concentration,and the best concentration was 0.4%,the LT50,T,Tmax were increased 54.68%,44.68%,51.25%,respectively when compared with control group.The effect of water extract on thermal tolerance ability of fruit fly was studied in the experiment of thermal adaptability.The fruit fly was placed in the temperature of(36±1)℃ to expose 30 min when cultivated by experimental mediums with different concentrations of water extract,after 3 days,the fruit fly exposed in manual climatic box to investigate the LT50,T,Tmax of fruit fly.The results showed that the thermal tolerance ability of fruit fly was increasing after thermal exposure when compared with control group,the addition of water extract could prolong the LT50,T,Tmax,and the LT50,T,Tmax showed a dose dependant manner with the addition of water extract increase,but the significant difference was not existence between the concentration of 0.4%and 0.6%,so the best concentration was 0.4%,and the LT50,T,Tmax were increased 25.78%,23.42%,30.75%,respectively.Finally,the experiments of heat resistance and thermal adaptability all showed that the addition of water extract could enhance the thermal tolerance ability of fruit fly significantly.(3)Mechanism study of the anti-heatstroke activity of the Mesona chinensis Benth water extractThe mechanism of anti-heatstroke activity of water extract was investigated in the experiments of heat resistance and thermal adaptability.The fruit fly was fed by experimental mediums and placed in the temperature of(36±1)℃ to expose 50 min,and then anesthetized by diethyl ether and preserved by liquid nitrogen.The mechanism was evaluated by the antioxidant capacity(TAC,CAT,SOD,anti-superoxide anion,and hydroxyl radical suppression)which tested by antioxidant kit and the gene expression level of heat stress proteins including HSF,HSP70,and SOD which detected by TaqMan probe method.The results showed that the addition of water extract could significantly increase the activities of catalase and superoxide dismutase,anti-superoxide anion and hydroxyl radical suppression in the heat resistance and thermal adaptability assays,it also showed that the water extract could improve antioxidant capacity to protect fruit fly from high temperature damage,and the antioxidant capacity was highest under the concentration of 0.4%.The results also showed that the water extract could increase the expression level of HSF,HSP70,SOD to protect fruit fly without thermal exposure.While the gene expression level increased with thermal exposure with the best concentration of 0.6%.The results indicated that the increasing of thermal tolerance ability will induce the high gene expression of heat stress proteins.(4)The development of Mesona chinensis Benth anti-heatstroke beverage based on the thermal tolerance ability assay on fruit flyThe sugars including glucose,sucrose,high fructose syrup,fructose,and crystal sugar,trace elements including iron,zinc,and copper,various concentration of vitamin C were added into water extract to prepare experimental mediums,and the effect of different ingredients and water extract to the ability of thermal tolerance of fruit fly was studied on the experiment of heat resistance to develop a new product of anti-heatstroke beverage.The results indicated that the addition of sugars could affect the thermal tolerance ability of fruit fly,and the addition of crystal sugar could significantly increase the LT50,T,Tmax to improve the thermal tolerance ability,but the effects of fructose and high fructose syrup were negative.The addition of trace elements also improved the thermal tolerance ability,but there were not significant differences between different concentrations of trace elements.The addition of Vitamin C could also affect the thermal tolerance ability,and with the increase of the concentrations,the thermal tolerance ability increased first and then decreased,and thus they showed the best effect under the concentration of 1.5%.The thermal tolerance ability of water extract after optimizing was better than that of the control group,the LT50,T,Tmax was increased 19.30%,31.60%,8.62%,respectively.All above results indicated that Mesona chinensis Benth water extract could improve the thermal tolerance ability of fruit fly by the increasing of antioxidant capacity and gene expression level of heat stress proteins in vivo,and the interaction between different sugars,trace elements,Vitamin C and water extract could strengthen the function of anti-heatstroke of Mesona chinensis Benth.