Study On The Activity And Mechanism Of Terpinen-4-ol Form Tea Tree Oil Against MRSA

Terpinen-4-ol(terpinen-4-ol)is one of the most biologically active substances in tea tree oil(TTO)extracted from Melaleuca alterniflora.It has been found that terpinen-4-ol has broad-spectrum antimicrobial activity,but there are few studies on its antibacterial and anti-biofilm activity.This research intends to study the activity and mechanism of terpinen-4-olagainst MRSA.This paper is aiming at providing reference for the application of tea tree oil in veterinary clinic,food and cosmetics.1.The anti-MRSA activity of tea tree oil and terpinen-4-ol was evaluated by the multiple dilution method,and It was found that the MIC and MBC of terpinen-4-ol to MRSA were 0.16% and 0.32%,respectively,The mechanism of terpinen-4-ol against MRSA was studied,and it was found that terpinen-4-ol had good anti-MRSA activity which showed a concentration-dependent effect.Terpinen-4-ol can play an anti-MRSA effect by destroying the integrity of MRSA membrane structure and function,and it has a strong synergistic effect with β-lactam antibiotics.2.Study on the actibity of terpinen-4-ol against MRSA biofilm.The effect of different concentrations terpinen-4-ol on MRSA biofilm was determined by crystal violet stain.Terpinen-4-ol as a concentration of 0.16%(v/v)has a significant inhibitory effect on the formation of MRSA biofilm.The damaging effect of different concentrations of terpinen-4-ol on MRSA biofilm was observed by CLSM and crystal violet staining.The release of e DNA,the synthesis of PIAN and the expression of genes related to biofilm formation including agr A,ica A,cid A and sar A in MRSA biofilm formation were also measured and it was found that terpinen-4-ol has a significant inhibitory effect on them.3.Study on the anti-MRSA mechanism of terpinen-4-ol.The changes of MRSA gene expression levels treatment by terpinen-4-ol were measured by transcriptomics.A total of 304 differential genes were found,of which 145 genes were up-regulated and 159 genes were down-regulated.And it was found that the differential genes were mainly concentrated in the branched chain amino acid,nitrogen metabolism,ABC transporter superfamily,2-oxocarboxylic acid metabolism.The content of MRSA small molecule metabolites treatment by terpinen-4-ol was analyzed,and a total of 215 different metabolites were found,of which 125 metabolites increased and 90 metabolites decreased.KEGG enrichment analysis was performed on the differential metabolites,it was found that terpinen-4-ol could affect caffeine metabolism,purine and pyrimidine biosynthesis of MRSA.A joint analysis of the transcriptome and metabolite results revealed that terpinen-4-ol can significantly affect the salvage synthesis pathway of MRSA DNA and RNA,and has a certain impact on its energy metabolism.In summary,terpinen-4-ol has good antibacterial activity and can significantly inhibit the formation of MRSA biofilms.The results of transcriptomics and metabonomics analysis show that terpinen-4-ol could inhibit the growth of MRSA and biofilms by inhibiting the metabolism of purines and pyrimidines.These findings provide new insights into the antibacterial mechanism of terpinen-4-ol,and promote research on the pharmacological activity of tea tree oil as a natural antibacterial product.