| Staphylococcus aureus(S.aureus)is an adaptable and ubiquitous pathogen that can survive in a variety of extreme environments and cause a wide range of infections in humans and animals.Pyogenic inflammation,pneumonia and bacteremia caused by S.aureus are serious threats to public health,especially during hospital operations.According to the world health organization,more than 15 million people worldwide are infected with S.aureus every year.Once infected,the main treatment for S.aureus is antibiotics.Unfortunately,the bacteria have become resistant,and methicillin-resistant S.aureus(MRSA)has become one of the most difficult problems in clinical treatment.Currently,there is no approved vaccine against S.aureus,and the design of bacterial vaccine is also faced with great challenges due to the complexity of bacterial toxicity factors.Therefore,there is an urgent need to develop new methicillin-resistant S.aureus drugs.Herpes simplex virus type II(HSV-2),which is an enveloped double-stranded DNA virus that is a major cause of genital Herpes,cervical cancer and human immunodeficiency disease,is recurrent and difficult to get effective treatment.However,There is currently no vaccine for HSV-2 infection,and the routine use of synthetic nucleoside analogues has led to the emergence of drug resistance.Therefore,the development of new anti-HSV-2 drugs is urgently needed.In recent years,the application of natural products has become a hot spot because of its wide distribution,easy access,low price.Natural products,as traditional Chinese medicines with antibacterial efficacy,have been used for thousands of years in east Asia,while Chinese herbal medicines are also widely used in the treatment of viral infections with remarkable effects.Therefore,natural products are rich resources for the search of antibacterial and antiviral drugs.Rumex patientia L.,Which belongs to Polygonaceae that is a dicotyledonous plant belonging to the order polygonales,is perennial herbs and is mainly produced from north temperate zone.In recent years,R.patientia L.has attracted extensive attention because of its remarkable therapeutic effects such as anti-tumor,anti-bacterial and anti-virus.So far,there have been few reports on the chemical constituents of actinomum,and only a few compounds,such as anthraquinone,flavone,naphthalene and styrene,have been isolated.In this study,we took R.patientia L.as the research object to study its bacteriostatic effect on Staphylococcus aureus and antiviral effect on HSV-2 virus.This study is divided into the following parts:(1)The screening of antibacterial and antiviral activities of Rumex patientia L.Determining the best extraction method of the extract of R.patientia L.was ethanol extraction.Screening the strain with the best antibacterial effect and the virus strain with the best anti-virus effect was S.aureus and HSV-2 virus.Crude separation of the alcohol extract Rumex patientia L.of was conducted by liquid-liquid extraction method,and petroleum ether,chloroform,ethyl acetate and n-butanol layer samples were successfully obtained.(2)The study on inhibition of S.aureus by Rumex patientia L.The minimum inhibitory concentration(MIC)of crude extract of Rumex patientia L.against S.aureus was determined to be 10 mg/m L,and the bactericidal effect was significant in vitro.The n-butanol layer in the crude isolates had the best inhibitory effect on S.aureus.The MIC value was 2.5mg /m L,and the bactericidal effect was significant in vitro.We had carried on the preliminary exploration of its antibacterial mechanism and found that the main reason was the extract of Rumex patientia L.destroyed the cell wall and cell membrane structure of S.aureus,inhibited S.aureus mucus secretion and Hla hemolysis effect,promoted cell aggregation,and may participate in DNA groove,disrupted the normal physiology function,which leads to the death.(3)The study on the anti-HSV-2 virus of Rumex patientia L.At the cell level,it was proved that the crude extract of chlorophyll at low concentration showed antiviral activity against HSV-2 virus,which was mainly the direct inactivation of HSV-2.Through the establishment of animal models,it was found that the survival rate could be significantly improved at the animal level.The survival rate of the experimental mucosa group was 28.57% higher than that of the PBS group,and the clinical symptoms were significantly improved.Similarly,the n-butanol layer sample after crude separation had the best anti-HSV-2 effect with the inhibition rate of 0.25 mg /m L crude separation sample reaching 95%.Through the establishment of animal models,it was found that the survival rate of the 2 mg/kg mucosa group was 50% higher thanthat of the PBS group,and the clinical symptoms were also significantly improved.The mechanism of its anti-HSV-2 virus was preliminarily studied and it was found that the nucleic acid and VP5 protein of HSV-2 virus were mainly destroyed by the Rumex patientia L.(4)The toxicity evaluation of Rumex patientia L.The cytotoxicity was determined by MTT assay.When the concentration of crude extract was lower than1.25 mg/m L,the cytotoxicity was less than 50%.0.5mg /m L n-butanol layer sample was less toxic to VERO cells and the cytotoxicity was less than 50%.Acute toxicology experiments showed that the concentration of crude extract lower than 25mg/kg had no effect on the normal physiological activities of mice,which was considered as the safe concentration for drug administration,and lower than 50 mg/kg was considered as the safe concentration for n-butanol layer samples.Through the research in this paper,it was successfully found that Rumex patientia L.could be used as a source of antibacterial and antiviral drugs,which laid a certain foundation for the future research on new drugs against drug-resistant bacteria and viruses. |
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