Study On The Synthesis And Antibacterial Activity Of Rosmarinic Acid Precious Metal Compound Preparation

Rosmarinic acid is a water-soluble plant secondary metabolite acid containing polyphenolic hydroxyl groups isolated from rosemary.It is widely distributed in rosemary and perilla.Rosmarinic acid is a natural reducing agent,and it has many properties and applications.This thesis studies the extraction of rosmarinic acid,the exploration of the synthesis conditions for preparing gold,silver,and gold-silver alloy nanoparticles with rosmarinic acid,and the exploration of the antibacterial properties of functionalized precious metal nanoparticles.1.The optimal preparation conditions of rosmarinic acid gold nanoparticles are:50 mL of RA(1.28 mM)solution and 0.6 mL of HAuCI(2%)solution are mixed,the pH of the solution is adjusted to 3,and the reaction is carried out at 160? for 4 hours.The rosmarinic acid gold nanoparticles prepared under the optimal preparation conditions are spherical,and the UV-Vis spectrum of the rosmarinic acid nano gold colloidal solution has a good characteristic absorption peak of gold nanoparticles.The TEM resuLts showed that the nano-gold colloidal particles were uniformLy sized small balls with an average diameter of 48nm.XRD proved that the prepared gold nanoparticles were good gold crystals.Rosmarinic acid gold nano colloidal particles have a certain inhibitory effect on bacteria and fungi.The rosmarinic acid gold nanocolloidal particles have very good stability,because gold is non-toxic and can be used in medical and other fields.2.Research on the conditions and antibacterial properties of rosmarinic acid to synthesize silver nanoparticles.The optimal reaction conditions for the synthesis of rosmarinic acid silver nanoparticles are RA(1.28 mM)solution 50 mL and AgNO3(5%)solution Mix 0.5 mL,adjust the pH of the solution to 11,and react at 140? for 4 hours.The product was characterized,and the UV-Vis spectrum of the rosmarinic acid nano-silver colloidal solution had a good absorption peak.The TEM resuLts showed that the nano-silver colloidal particles were very uniform in size,showing spherical crystals with an average diameter of 24nm.Infrared spectroscopy resuLts showed that rosmarinic acid and silver nitrate had a good oxidation-reduction reaction,and the hydroxyl groups of rosmarinic acid had a strong interaction with silver particles.The photoelectron spectroscopy resuLts showed that good silver nanoparticles were formed.Studies have shown that silver rosmarinic acid nano colloidal particles have a very strong inhibitory effect on bacteria and fungi.It has attracted much attention because of its strong antibacterial properties.3.The optimal reaction conditions for the synthesis of rosmarinic acid gold-silver alloy nanoparticles are:50 mL of RA(0.3 mM)solution and 0.5 mL of AgNO3(1%)solution are mixed,and the pH of the solution is adjusted to 5 at 130? Reaction for 3h.The product under this condition was characterized.The UV-Vis spectrum of the rosmarinic acid alloy nanocolloidal solution has a good characteristic absorption peak.The TEM resuLt shows that the alloy nanocolloidal particles are spherical crystals and there are aggregation phenomena.The average diameter of the small spheres is 31 nm..The thermogravimetric resuLts show that the rosmarinic acid alloy nano colloidal particles are very stable.The rosmarinic acid alloy nano colloidal particles have both the stability of gold and the antibacterial properties of silver,and have better application value.