Study On Bioactivity Of Eletherine Americana Extracts And Its Application In Food And Cosmetic

Eleutherine americana Merr.et K.Heyne of Iridaceae is a folk medicinal plant in Southwest China.It had been reported to possess various biological activities such as antibacterial,antioxidant,prevention of cardiovascular diseases,skin whitening,regulating the immune function of organisms ect.The objective of the present experiment was conducted to study on bioactivity of Eletherine americana extracts and its application in food and cosmetic.In this study,the contents of total flavonoid,total anthraquinone,total polyphenol of extracts from Eleutherine americana in different polar solvent fraction were determined.Its antibacterial activity and antioxidant activity were also studied.The optimization of Eleutherine americana red pigments extraction was studied in-depth,meanwhile,the antioxidant activity and stability of red pigments in different pH were investigated.Health drinks was prepared which contained Eleutherine americana water extracts.A whitening emulsion contained Eleutherine americana extracts was also prepared,and its whitening effect was evaluated by human skin test in vitro.The specific research contents and results are as follows:Taking Eleutherine americana as the test material,elementary extract was extracted by solvents of petroleum ether,ethyl acetate,chloroform and n-butanol with the polarity increasing.The contents of total polyphenols,total flavonoids and total anthraquinones from Eleutherine americana extracts were determined by colorimetric method.The results showed that the content of total polyphenols and total anthraquinone were the highest in n-butanol fraction,which were 0.78%,0.78% respectively.The content of total flavonoids in petroleum ether fraction was the highest(3.83%).The results showed that the method had a higher precision,a higher stability,better repetition and higher reclaim rate.The antibacterial effect of ethanol crude extracts of Eleutherine americana on Staphylococcus aureus(ATCC25923),Escherichia coli(ATCC25922),Salmonella typhimurium(ATCC14028),Staphylococcus epidermidis(ATCC11827)were determined by double dilution method,combined with the punching method to detect the antimicrobial diameters of extracts by different polarity solvents.Different polar extracts of Eleutherine americana had different degrees of antibacterial activity.The petroleum ether extraction had the strongest effect on Staphylococcus aureus and Staphylococcus epidermidis,among these samples,the maximum antimicrobial diameters were 31.83±0.50 and 31.15±0.33 mm,respectively,which showed highly sensitive to these test bacteria.The results also showed that the antibacterial activity of petroleum ether extraction was stronger than the positive control drug ethyl 4-hydroxybenzoate.The results of this study showed that different polar fractions of petroleum ether,ethyl acetate,chloroform,n-butanol,ethanol polar from Eleutherine americana extracts all had a certain degree of antioxidant activity.The sequence of total antioxidant activity were ethyl acetate extract,n-butanol extract,chloroform extract,petroleum ether extract,ethanol extract.The scavenging concentration of DPPH· was lower than that of ·OH,the maximum scavenging rate of DPPH· and ·OH of Eleutherine americana ethyl acetate extracts was 88.5% and 86.8% respectively.The free radical scavenging rates of all polar solvents were lower than the positive control drug ascorbic acid.Quadratic regression orthogonal rotation combination design method was used to optimize the ultrasound-assisted extraction conditions of red pigments from Eleutherine americana.The optimal extraction conditions were as follows: Ethanol concentration 31%,sample/solvent ratio 1:54 and ultrasonic time 40 min,the crude extract yield of red pigments from Eleutherine americana was 17.97% with this method.The results showed that Eleutherine americana red pigments had a strong scavenging effect on DPPH· and ·OH,the scavenging rate was direct ratio to the concentration of red pigments in a certain range.The radical scavenging effect of Eleutherine americana red pigments was similar to monascus red pigments which was commercially available.The color stability of Eleutherine americana red pigments was greatly affected by pH value,its color changed markedly in the range of pH2~10,which showed bright yellow to dark red.Eleutherine americana pigments color is stable in the neutral environment of pH5~8,and the color is pure jacinth.A translucent reddish brown drinks was prepared with Eleutherine americana water extracts,with a unique flavor of Eleutherine americana,slightly soda water flavor.In order to investigate the function of Eleutherine americana extracts in cosmetics,extracts was added to prepared Eleutherine americana whitening emulsion.The experimental results showed that the emulsion had good stability and no allergies to human skin.Human skin test in vitro and Lab color analysis system were used to evaluate the whitening effect.It was found that L* and ?E values were increasing with the prolongation of test time,and the whitening effect was higher than the control group.The results indicated that the Eleutherine americana whitening emulsion had a certain degree of whitening effect.The results of this paper provided a theoretical basis and some preliminary product forms of the folk herbs Eleutherine americana in the application of functional food and cosmetics.