Study On Screening Of Chinese Herbal Medicine And Compound Herbal Medicine Possessing Selective Bacteriostatic Effect

Animal food safety problems induced by abuse of feeding antibiotics have raised great concerns in China, which leads developing safe, nontoxic substitutions of feeding antibiotics to be imperative. Chinese herbal medicine has many advantages, because of its long history, abundant resources, wide-ranging functions, limited toxic and side effect as well as less residue. Thus, in order to discern the Chinese herbal medicines which can be applied in stead of feeding antibiotics, the present study firstly tested diverse herbal medicines and screened their bacteriostasis functions; then prescriptions were carried out based on the results, and their antibiosis effects were compared with antibiotics; and finally safety of the herbal formula was assessed in vivo. The main methods and results are as follows.1. Study on screening of Chinese herbal medicine possessing selective bacteriostatic effect. 30 kinds of Chinese herbal medicine, such as Prunus mume fruit were utilized as materials to select out those who have function of restraining bacteria growth. The effective components in the crude medicine were separated by water extraction and ultrasonic administration, before they were made into 0.5g/mL aqueous solutions. We conducted bacteriostatic tests in vitro by Oxford-cup method on Escherichia coli, Salmonella enteritidis, Salmonella aertrycke, and Staphylococcus aureus to pick out broad spectrum bacteriostatic herbal medicines, while diameter of inhibition zone was used as the evaluating indicator; on the other hand, Hungate anaerobic technique was employed to single out herbal medicines which do not affect growth of 2 probiotics(Lactobacillus acidophilus and Bifidobacterium), while colony forming units (CFU) and bacteriostasis rate were taken as estimating parameters. The results revealed that Herba Moslae, Wild chrysanthemum, Root of Chinese Thorowax, Forsythia suspense, Rehmannia glutinosa Libosch and Cortex Phellodendri Chinensis had better selective bacteriostatic functions.2. Study on the compound herbal medicine possessing selective bacteriostatic effect. Based on the above data, herbal medicines with different characters were chosen to compose prescriptions considering their synergy and combination effects at random (according to their mass ratio), and multiple compound medicaments at the concentration of 0.5g/mL were manufactured. Also, sensitivity tests were implemented on the mentioned 6 strains, and the optimized recipe was determined by general performance of the inhibition zone size and bacteriostasis rate. The results indicated that formula consists of 30% Prunus mume fruit, 15% Portulaca oleracea L, 10% Folium Isatidis, 15% Wild chrysanthemum, 5%Houttuynia Cordata Thunb, 10% Root of Chinese Thorowax, 5% Cortex Phellodendri Chinensis, 5% Herba Moslae, and 5% Rehmannia glutinosa Libosch had the best selective bacteriostatic effect, for the reason that the pathogenic bacteria growth was bated, while probiotics growth was not disturbed.3.Effect on antibacterial activity of the compound herbal medicine. Moreover, 3 antibiotics (Cefradine, Amoxicillin and Norfloxacin) were utilized as contrasts to compare with the acquired herbal medicament, so as to investigate the feasibility of using it as an alternative of antibiotics. And outcomes evinced that at the concentration of 0.5g/mL, the herbal prescription showed no significant difference in comparison to 35ppm Cefradine when considering inhibition zone of Escherichia coli and Salmonella enteritidis, and Norfloxacin when considering inhibition zone of Salmonella enteritidis and Salmonella aertrycke, which indicated some practicability of applying the prescription replacing antibiotics. The herbal medicament was not sensitive to probiotics , in opposite to antibiotics’suppression effect on probiotic growth; and within the bacterial liquid concentration range of 10-7~10-5, herbal medicament’s negative inhibitory rate of Bifidobacterium was 2 times more than the control group, while there was no repression on strains.4. Acute toxicity test of the compound herbal medicine. Acute toxicity test of the herbal medicament was carried out using maximum tolerable dose (MTD) method; growth situation and weight change of mice were observed for 7 days after gavage. No mice died during the experiment, and they all developed normally with stable weight. The MTD value came out to be 20g/kgbw, and the herbal medicament was hence determined as non-toxic substance, belonging to safe medicine.Conclusion: Chinese herbal prescription consists of 30% Prunus mume fruit, 15% Portulaca oleracea L, 10% Folium Isatidis, 15% Wild chrysanthemum, 5%Houttuynia Cordata Thunb, 10% Root of Chinese Thorowax, 5% Cortex Phellodendri Chinensis, 5% Herba Moslae, and 5% Rehmannia glutinosa Libosch had better selective bacteriostatic effect than antibiotics; and for its safety and non-toxicity, the prescription is capable of being applied as a substitution of antibiotics. The study offered theoretic foundations for further clinical researches.