Studies On Preparation Of Broussonetia Papyrifera Leaves Alcohol Extract Gel And Its Anti-inflammatory Effect

Objective:The content of two flavonoids were studied in the alcohol extract of Broussonetia papyrifera leaves,Broussonetia papyrifera leaves alcohol extract gel was prepared and its anti-dermatitis effect was studied.Methods:(1)1kg of fresh Broussonetia papyrifera leaves were collected from Nanhu Lake in Wuhan,the active constituents from leaves were extracted by alcohol extraction and ultrasonic-assisted extraction,and the contents of quercetin and isoliquiritigenin in the alcohol extract of leaves were measured by HPLC.(2)Fresh Broussonetia papyrifera leaves were collected in the April,June,August,October,and December,and the content of quercetin and isoliquiritigenin contained in the leaves was measured vary with seasons.(3)Carbomer-940 was used as gel matrix,and propylene glycol and glycerin were used as moisturizer,laurinone as skin penetration enhancer,and Hibiscus leaf alcohol extract was used as a main drug to prepare Broussonetia papyrifera leaves alcohol extract gel.(4)The mouse were divided into complete skin and damaged skin groups,the single-applied skin irritation and multi-applied skin irritation of the leaf ethanol extract gel were investigated by self-controlled study.(5)Swollen auricle acute inflammation mouse model caused by xylene was established,hydrocortisone was used as a positive control,the anti-inflammatory effects of 2.5%and 3%Broussonetia papyrifera leaves alcohol extract gel was investigated..Results:(1)15.5g extract was recevied from 1kg leaves alcohol extract,the standard curve of isoliquiritigenin was y=2.7616x-0.8247,R~2=0.9994,there was a good linear relationship in the concentration range of 5~17.5ug/mL,The standard curve of quercetin was y=2.1559x+0.2884,R~2=0.9992,the linearity was well within the concentration range of 7.5~27.5ug/mL,the content of quercetin in the leaves was more than 157.06mg/kg,the content of isoliquiritigenin was more than 104mg/kg.(2)The content of quercetin and isoliquiritigenin in Broussonetia papyrifera leaves collected in August was the highest.(3)The optimal formulation of gel was:Broussonetia papyrifera leavesalcoholextract/Carbomer-940/laurusnitrogenAnthrone/propylene glycol/glycerin=3%:1.2%:3.5%:15%:8.0%,the resulting gel was homogeneously stable.(4)The single application group was not irritating to intact skin and had slight irritation to damaged skin.The multiple application group was not irritating to intact skin and had slight irritation to damaged skin.(5)The inhibition rate to xylene-induced mouse ear swelling by 2.5%and 3%of Broussonetia papyrifera leaves alcohol extract gel were 25.3%and 36.8%respectively.Conclusion:The quantitative analysis of quercetin and isoliquiritigenin by HPLC is sensitive and rapid.The results can be used for the content analysis of quercetin and isoliquiritigenin in the alcohol extract of Broussonetia papyrifera leaves.Broussonetia papyrifera leaves should be collected in August.The gel was safe for transdermal delivery through preliminary mouse skin safety test.It should not be contacted with broken skin.Through anti-inflammation experiments,it was found that the 3%Broussonetia papyrifera leaves alcohol extract gel has obvious anti-inflammatory effects and can be used as a natural medicine gel for the treatment of dermatitis.