| Water lily(Nymphaea L.),also known as meridian lotus,is a perennial aquatic herb of the Nymphaeaceae family.Water lily is divided into two ecological types:tropical water lily and hardy water lily.In this study,the Indian red water lily in tropical water lily(Nymphaea rubra Roxb.Ex Andrews),Egyptian White Water Lily(Nympheae lotus),Blue Bird Water Lily(Nymphaea'Blue Bird'),Pink Water Lily as research objects.Through the analysis of the difference in metabolite content in different sampling periods,the best sampling period is selected for further experimental research.The water content,ash,soluble protein,crude fat,soluble sugar,vitamin C,and amino acid types and contents of the petals and stems of four tropical water lilies were measured respectively;the essential oil of red water lily was extracted by ultrasound-assisted subcritical technology,and the essential oil was analyzed by GC-MS Main ingredients;to test the antibacterial and anti-oxidant properties of tropical red water lily essential oils,the strains used in the experiment were two Gram-negative bacteria:Escherichia coli and Pseudomonas aeruginosa,and two Gram-positive bacteria:Staphylococcus aureus and subtilis Bacillus,as well as two fungi:Saccharomyces cerevisiae and Aspergillus niger,the DPPH free radical scavenging rate,ABTS free radical scavenging rate,FRAP iron oxide reducing ion total antioxidant capacity of tropical red water lily essential oil were tested,and compared with the corresponding concentrations of VC and BHT;finally,we developed high-value products of water lily essential oil and prepared essential oil handmade soap.The specific research results are as follows:(1)Through the screening of differential metabolites,the types and contents of phenolic acids,flavonoids,lipids,amino acids and their derivatives in the metabolites during flowering on the second day of flowering were relatively highest.Therefore,our follow-up experimental materials are all plants that bloom on the second day of flowering.(2)The moisture content of the four tropical water lilies was very high,all of which were above 87%,of which the water content of the white water lily stems was95.93%;the highest ash content was the stem of the red water lily,which reached180.61 mg/g;the powder water lily had the highest soluble sugar content,345.97mg/g;the highest fat content was the petals of blue water lily,83.33 mg/g;the highest vitamin C content was the white water lily petal 5.29 mg/100g;among the types and contents of amino acids,water lily petals were significantly better than water lily in the stem section,the flowers of blue water lily and pink water lily contained all 17amino acids.Among them,the total amino acid content of pink water lily petals was the highest,reached 193.86 mg/100g,the essential amino acid content of blue water lily petals was 45.07 mg/100g,the highest specific gravity among all samples.(3)Ultrasonic enhanced subcritical extraction technology was used to extract the essential oils of tropical red water lily.Because it is a new extraction method,it does not require high pressure to achieve a high extraction rate.The main components of tropical water lily essential oil were detected by GC-MS,and the results showed that it contained phenols,alkenals,esters,alcohols,etc.Therefore,the tropical water lily essential oil has antibacterial and antioxidant properties.(4)Tropical water lily essential oil has a strong antibacterial ability against common bacteria:Escherichia coli,Pseudomonas aeruginosa,Bacillus subtilis,Staphylococcus aureus,Aspergillus niger,and Saccharomyces cerevisiae.Through heat stability,ultraviolet stability and acid-base stability experiments,we found that tropical water lily essential oil has antibacterial ability and difference in the range of30?60?,ultraviolet treatment for 10min?60min,p H=4?p H=9 not obvious.Proven that tropical water lily essential oil has strong antibacterial stability.(5)Tropical red water lily essential oil could effectively scavenge DPPH and ABTS free radicals,the scavenging rate increased with the increase of essential oil concentration,and FRAP iron ion reduction ability also conformed to this law.When the essential oil concentration was 2.0 mg/m L,the DPPH free radical scavenging rate of tropical water lily essential oil was 21.38%,the ABTS free radical scavenging rate was 86.61%,and the FRAP value was 65.16%.But its free radical scavenging ability and total antioxidant capacity were lower than the corresponding concentrations of BHT and V_C.(6)Carried out the development of high-value products of tropical water lily essential oil-antibacterial essential oil handmade soap.Tropical water lily essential oil3 m L,mugwort leaf extract 0.5 m L,tea tree essential oil 0.8 m L were evenly mixed,added vitamin E 0.1 m L,coconut oil 1 m L,soap base 84 g,it showed that the resulting compound essential oil has considerable inhibitory ability to common strains and the prepared essential oil soap has certain advantages compared with the commercially available bacteriostatic soap. |
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