In Vitro Bacteriostatic Experiment of 12 kinds of Chinese herbal medicines, such as garlic

Garlic is an important condiment in people's daily diet, which has the functions of invigorating the stomach and promoting digestion Its pungent ingredient allicin can inhibit a variety of pathogenic bacteria and deep infection fungi [1,2], and it can play a role in disease prevention, health care and growth promotion in poultry and aquaculture [3,4]; In addition, garlic has a good antioxidant effect, which can be prolonged by adding edible oil [5]; in terms of disease prevention, regular eating garlic can improve the antioxidant performance of plasma and red blood cells [6], effectively reduce blood pressure, prevent atherosclerosis and cardiovascular and cerebrovascular diseases [7, 8]; Garlic can also inhibit the growth of colon cancer cells [9], and prevent the occurrence of gastric cancer by inhibiting the reproduction of nitrate reducing bacteria and the synthesis of nitrite [10]; in addition to allicin, garlic also contains a variety of health care ingredients such as garlic polysaccharide, which can be made into natural health care drink with ginkgo leaves [11, 12] Capsicum is also an important daily condiment, which has the function of improving appetite and maintaining the balance of normal flora in the digestive tract; capsaicin has inhibitory effect on E.coli, yeast and other pathogens [13, 14] Allicin in garlic and capsaicin in Capsicum have bacteriostatic effect, which does not exclude the existence of other bacteriostatic components in garlic and capsicum, nor fully represent their bacteriostatic performance In order to improve the Bacteriostasis of these two kinds of health condiments, the Bacteriostasis of Capsicum Decoction and garlic alcohol were studied Phellodendron amurense, dandelion and other common Chinese herbal medicines are commonly used in the treatment of microbial infectious diseases, and can also be used as disease prevention feed additives, but their antibacterial spectrum and concentration of common pathogens are not clear, which limits their application in traditional Chinese medicine and feed additives In this paper, the antimicrobial spectrum and minimum inhibitory concentration (MIC) of 12 kinds of medicinal plant extracts, such as garlic, capsicum, Phellodendron amurense and so on, against E 1 Materials and instruments 1.1 strains and media E.coli, Salmonella paratyphoid, Staphylococcus aureus and Bacillus subtilis are preserved in our laboratory; E.coli, Salmonella paratyphoid and Bacillus subtilis are nutrient agar No.3; Staphylococcus aureus is Staphylococcus agar 110 and nutrient agar No.3 1.2 vertical flow ultra clean bench, dh3600a electric constant temperature incubator, portable high-pressure sterilizer, 2d-85 constant temperature oscillator, tu-1800 ultraviolet visible spectrophotometer, zd-85 constant temperature shaker, ab204-s basic electronic analytical balance, etc 1.3 garlic and pepper of Chinese herbal medicine are purchased from the farmers' market, and other Chinese herbal medicine are purchased from the Chinese herbal medicine store Method 2.1 preparation of allicin extract: mash 100 g of peeled garlic, extract it with ethanol, evaporate and concentrate it to 200 ml, obtain 50% of garlic extract, and dilute it with ethanol as double series 2.2 the preparation of Chinese herbal medicine extracts such as capsicum, phellodendron, etc is crushed and screened, and the dry matter content (DMC) is determined; 50g of each Chinese herbal medicine powder (calculated by the dry matter quality) is decocted in water and concentrated to 100ml, and the concentration of the extract is 50%, and diluted in twice series with water 2.3 antimicrobial test of drug sensitive paper [15] soak and dry the 6 mm diameter filter paper in each dilution gradient extraction solution of each Chinese herbal medicine, place it in the plate partition coated with a specific amount of bacteria, record the antimicrobial effect of each dilution gradient of each Chinese herbal medicine extract on several pathogens after overnight culture at 37 ℃, record the diameter of the bacteriostatic circle and the minimum bacteriostatic concentration (MIC), and all qualitative and quantitative bacteriostatic tests are heavy Repeat 3 times 2.4 influence of culture medium on bacteriostatic effect of Chinese herbal medicine Staphylococcus aureus was coated on nutrient agar No.3 and Staphylococcus agar 110 respectively The bacteriostatic effect of each Chinese herbal medicine preparation on Staphylococcus aureus on the two culture medium was observed by drug sensitive paper method 2.5 determination of the content of coated bacteria The concentration of coated bacteria solution was calculated by plate coating method Results 3.1 the concentration of coating bacteria was determined by the above method Escherichia coli 2.8 × 108 / ml; Salmonella paratyphoid 1.1 × 108 / ml; Staphylococcus aureus 4.1 × 108 / ml; Bacillus subtilis 1.3 × 106 / ml 3.2 the antibacterial results of garlic extract can be seen from table 1 that garlic ethanol extract has inhibitory effect on Salmonella paratyphi and Staphylococcus aureus growing on Staphylococcus agar 110, with MIC of 6.25% and 12.5% respectively; it has no antibacterial effect on Escherichia coli and Bacillus subtilis within the concentration range of this study Table 1: antibacterial effect of garlic extract on pathogenic bacteria Table 2: antibacterial effect of pepper extract on Salmonella paratyphi and Staphylococcus aureus on Staphylococcus agar 110, MIC 12.5%; no antibacterial effect on Escherichia coli and Bacillus subtilis Table 2 antibacterial effect of capsicum extract on pathogenic bacteria 3.4 antibacterial results of Chinese herbal medicines such as Phellodendron amurense and forsythia (see Table 3) antibacterial spectrum and minimum inhibitory concentration (MIC) of common Chinese herbal medicines such as Phellodendron amurense and Forsythia suspensa Among them, Chinese herbal medicines such as Astragalus, dandelion, Qinpi, Wumei and scutellaria almost have antibacterial effect on four kinds of pathogenic bacteria, and the antibacterial effect is strong, especially Wumei and Qinpi have strong antibacterial effect on all kinds of pathogenic bacteria Among the selected herbs, only indigo naturalis did not inhibit the four pathogens Table 3 the effect of the minimum inhibitory concentration (MIC)% 3.5 medium of Phellodendron amurense and other Chinese herbal medicines on the inhibition of Staphylococcus aureus by Chinese herbal medicines the medium has an effect on the inhibition of Chinese herbal medicines It can be seen from table 4 that the bacteriostatic effect of various Chinese herbal medicine preparations on Staphylococcus aureus on Staphylococcus agar 110 is significantly better than that on nutrient agar No.3, among which garlic, pepper, Qinpi and Yuanzhi preparations have obvious bacteriostatic effect on the former, but no bacteriostatic effect on the latter; The antibacterial effect of rhubarb, mume and scutellaria on the former is better than that on the latter The difference of bacteriostatic effect can be explained by the growth of Staphylococcus aureus on two kinds of culture media The concentration of coated bacteria solution was measured by plate counting method on two kinds of culture media, and the inoculation amount was identical The concentration of bacteria solution was 4.1 × 108 / ml measured by nutrient agar No.3, and 3.1 × 108 / ml measured by Staphylococcus agar 110, which indicated that nutrient agar No.3 was more suitable for the growth of Staphylococcus aureus Due to the growth of Staphylococcus aureus, the bacteriostatic effect of all kinds of Chinese herbal medicines on Staphylococcus aureus is slightly worse, which is consistent with the conclusion of Li Zhongxing et al (2000) [16] On the other hand, it also showed that the medium and the amount of coated bacteria had a great influence on the antibacterial effect of Chinese herbal medicine Table 4 Effect of medium on inhibition of Staphylococcus aureus by Chinese herbal medicine% 4 discussion 4.1 garlic and capsicum have specific antibacterial effects, but their antibacterial components have not been fully determined Guo Li et al [13] have studied the bacteriostatic properties of Capsicum They think that water-soluble capsaicin is its bacteriostatic component In this experiment, capsicum decoction has a good bacteriostatic effect, which further confirms the previous research, but also does not exclude the existence of other water-soluble bacteriostatic components in Capsicum Chen Xiaoyue et al [1] studied the inhibitory effect of allicin on E.coli and Staphylococcus aureus, and proved that allicin in garlic was involved in the antibacterial effect of garlic In this study, allicin ethanol extract had strong antibacterial effect on Staphylococcus aureus and Salmonella paratyphoid, but it had no inhibitory effect on E.coli, which may be related to allicin in garlic ethanol extract The quantity is low 4.2 the influence of medium on the Bacteriostasis of Chinese herbal medicine the medium provides nutrition and suitable environmental conditions for the growth and reproduction of microorganisms The growth performance of microorganisms varies greatly in different medium, and the growth and reproduction is vigorous in the most suitable medium or natural medium The inhibitory effect of Chinese herbal medicine and other antibacterial factors on microorganisms is affected by their growth environment The more suitable the medium is, the better the growth of microorganisms is, and the weaker the antibacterial effect is In order to compare the results of different studies, the type of culture medium and the quantity of coated bacteria should be determined as much as possible; On the other hand, the influence of the medium on the bacteriostatic effect also shows the difference between in vivo and in vitro The antibacterial spectrum and dose results of various antibacterial agents obtained through in vitro experiments must be further verified and confirmed in clinical practice before they can effectively inhibit pathogenic bacteria in vivo Pepper and garlic can inhibit Salmonella paratyphoid and Staphylococcus aureus in vitro, phellodendron, forsythia and other common Chinese herbal medicines have strong inhibitory effect on a variety of pathogenic bacteria, and the culture medium significantly affects the antibacterial effect of Chinese herbal medicine in vitro.