| Fig leaf is a kind of high-yield plant with activities of detoxification and appetizing deworming.Modern medical research has confirmed that fig leaf has significant pharmacological effects such as antioxidant,antibacterial,anti-insect,hypolipidemic,hypoglycemic,antitumor,anti-osteoporosis and anti-infertility.In this paper,the by-products of figs were used as raw materials,and the major polyphenols and coumarins were efficiently extracted.At the same time,the antioxidant and insect-resistant activities of the crude extracts were also evaluated.The development and efficient use of fig leaf as a medicinal plant resource provides an important theoretical basis and technical support.In this thesis,an efficient,rapid,simple,and accurate method for the determination of six main active ingredients in fig leaves was established,and microwave-assisted extraction of fig leaves was performed using a new natural formulated surfactant.The material was enriched,and the recycling performance of the surfactant was evaluated under multiple cycles.Finally,a crude functional evaluation of the crude extract of the fig leaves obtained by the natural surfactant-assisted extraction was performed.The main research conclusions of this paper are as follows:1.HPLC was established for the simultaneous analysis and detection of six major polyphenols and coumarins in fig leaves,namely chlorogenic acid,caffeomalate,psoralen,rutin,psoralen and bergamot lactone.HPLC conditions:C18 column(5 μm,250 mm × 4.6 mm,i.d.),UV detector,detection wavelength:254 nm,injection volume:5 μL,column temperature:30℃,mobile pahse:acetonitrile:0.15%formic acid aqueous solution(v/v),gradient elution:0 min(13:87)-13 min(16:84)-25 min(17:83)-55 min(65:35),and the flow rate was 1 mL/min.Method verification showed that the six compounds had a good linear relationship within the detection range(R2>0.99),and the method was characterized by good repeatability,precision and stability(R.S.D.<4%),as well as good recovery yield(97.25-99.61%).In this experiment,the contents of six major polyphenols and coumarins in fig leaves were analyzed and determined according to the above detection conditions.The contents of chlorogenic acid,caffeomalate,psoralen,rutin,psoralen and bergamot lactone were 0.49 mg/g,14.32 mg/g,9.20 mg/g,6.81 mg/g,23.66 mg/g and 4.96 mg/g,respectively.2.The experimental design and process optimization of the conditions for the extraction of caffeoyl malate,psoralen,rutin,psoralen and bergamot lactone from fig leaves with microwave-assisted extraction of natural formulated surfactant combined with microwave-assised extraction were carried out.The optimal process parameters were determined:Natural formulated surfactant:Octyl Glucoside(APG):Triton 100(TX100)=3:1,0.015 mg/mLExtraction temperature:40℃Extracted power:400 WExtraction time:10 minLiquid-solid ratio:20:1 mL/gSolution pH:5Under the best optimized extraction conditions,the average extraction yields of caffeoyl malate,psoralen,rutin,psoralen and bergamot lactone were 10.74 mg/g,6.57 mg/g,5.27 mg/g,17.29 mg/g and 3.85 mg/g with the recovery yield of more than 70%.The comparison of different extraction methods showed that natural formulated surfactant combined with microwave-assisted extraction(Surfactant-MAE)was a green and efficient extraction technology with low energy consumption and high extraction efficiency.Compared with ultrasound-assisted extraction and methanol solution extraction,the total amount of the five compounds increased by 1.23 and 1.12 folds,respectively.So Surfactant-MAE was more suitable for the extraction of natural active compounds from plant materials,and had a broad application prospect.In order to recover and reuse the natural formulated surfactant effectively,the cloud point separation technology was used to enrich and recover the surfactant.It was found that the enrichment ratio could reach 9.48 after the equilibrium state was reached at 60℃ for 10 min.Under the optimal enrichment process,the average recovery yields of caffeoyl malate,psoralen,rutin,psoralen and bergamot lactone were 85.27%,88.24%,81.45%,86.65%and 89.27%,respectively.The concentrations also changed from 0.39 mg/mL,0.22 mg/mL,0.18 mg/mL,0.58 mg/mL and 0.13 mg/mL before the enrichment to 2.90 mg/mL,1.83 mg/mL,1.35 mg/mL,4.73 mg/mL and 1.09 mg/mL after enrichment.After five cycles,the recovery yield of natural formulated surfactant was still higher than 80%.3.The preliminary functional evaluation of fig leaves crude extract was completedThe comparison between crude fig extracts obtained by using natural surfactant-assisted extraction and conventional aqueous solution extraction showed that natural formulated surfactant could improve the antioxidant and insect resistance of crude fig extracts.When the crude extract concentration of fig leaves were 1 mg/mL,5 mg/mL and 10 mg/mL,the insect mortality rates were 36.85%,47.24%and 56.39%,respectively,after adding the appropriate concentration of natural surfactant.The IC50 values of fig leaves extract were 0.087 mg/mL and 0.759 mmol/g for DPPH and ABTS radical scavenging activities.Meanwhile,the stability of the active ingresdients in fig leaves extract extracted by surfactant was enhanced,and the stability of the target substances were improved by 3%,20%,20%and 15%in 1-7 days.It provides a valuable reference for the development and utilization of natural products and chemicals such as medical and beauty industries.This paper successfully prepared a kind of natural formulated surfactant,and combined with microwave-assised extraction technology to extract the main polyphenols and coumarins in the fig leaves for the first time.And the enrichment and recovery of the extract were performed by cloud point separation technology,the antioxidant activity,insect resistance and stability of the extract were preliminarily evaluated.The results showed that the formulated surfactant/microwave-assisted extraction method possessed the characteristics of high efficiency,green and environmentally friendly,and can be recycled,as well as good activity of extracts.This study provides favorable data support for the rational development and utilization of fig leaf resources,and has important research value for green extraction and efficient enrichment of plant secondary metabolites. |
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