Study on Isolation, Purification, Structural Identification and Antimicrobial Activity of 1′-acetoxychavicol Acetate from Alpina Galanga Willd

Abstract: Alpinia galanga is the rhizomes of Alpinia Galanga(L.)Swartz,widely cultivated in Southeast Asian countries and in Guangdong,Guangxi,Yunnan and Taiwan provinces.In Southeast Asian countries and regions in Guangdong Province, galangal sauce is widely used in folk-style food and cooking,and it is also a kind of Chinese medicine,warm and cold-dispelling stomach,allevation of the pain.ACA is the main active ingredient in the volatile oil of Alpinia galanga,and it has anti-cancer,anti-tumor and anti-HIV,anti-xanthine oxidase,antioxidant,anti-ulcer, anti-bacterial,anti-TB virus,insecticidal and the alike biological activity,In vitro experiments proved that ACA is a broad spectrum of anticancer agents and there was no significant side effects,so it attracted more and more biologists,pathologists, medical scientists,pharmaceutical scientists,nutritionists and chemists free radicals' attention.In this paper,Alpinia galanga from Yangshuo,Guangxi Province for the experimental materials,a series of modern research methods and technolodgy such as integrated food science and application,organic chemistry,natural products chemistry,analytical chemistry,bio-technology and modern equipment analysis were used to be more systematically studied ACA from the perspective of extraction and purification in the Galangal.To the determination of the ACA,the extraction and purification,identification of structure and antibacterial activity had a more in-depth studies.ACA laid the foundation for the functional food as a base for new drug development and research.The main contents and conclusions of the study can be summarized as follows:1.To explore and compare two methods of the ethanol refluxing extraction and supercritical carbon dioxide extraction extraction to produce ACA from Alpinia galanga were studied.On the basis of the single factor,the orthogonal L_9(3~4) experiment of the ethanol refluxing extraction process was optimized reaching the optimum conditions.Under the best conditions:the extract yield was 4.68%,the ACA purity was 27.15%,the content of ACA was 12.71mg / g.On the basis of the single factor,the orthogonal L_9(3~4) experiment of SFE-CO_2 extraction process was optimized reaching the optimum conditions.Under optimal conditions:the essential oil yield was 4.78 percent,the ACA purity was 78.11%,the content of ACA was 37.34mg/g.Comparing the two methods come that the yield and purity of ACA by SFE-CO_2 method were higher than ethanol refluxing method,and extraction time was short,without solvent residue,which was greatly enhanced the efficiency of extraction.In conclusion,SFE-CO_2 extraction is superior to ethanol refluxing method.2.GC-MS and LC-MS analyzed supercritical carbon dioxide extraction of essential oil from Alpinia galanga containing the main ACA,which is the isomer form.And thin-layer chromatography(TLC) and high-performance liquid chromatography(HPLC) technology were applied to the establishment of ACA from the essential oil of Alpinia galanga.TLC results are:Agent for the n-hexane:ethyl acetate=85:15,the R_f value of ACA is 0.39.HPLC results are mobile phase: methanol:water=50:50,detection wavelength was 254nm,found that this method of high precision,reproducibility,stability,and better recovery rate for Alpinia galanga volatile oil detected ACA Determination.3.Supercritical carbon dioxide extraction of essential oil from Alpinia galanga of ACA was separated and identified the structure of the study,using silica gel column purification and recrystallization getting colorless crystals,and finally the purity of 99.6%for the colorless crystals,After UV,IR,MS,~1H and ~(13)CNMR spectral analysis to identify the structure,and finally identified as the ACA.What's more,the determination of the ACA melting point was 67.3℃,which has a thermal instability by TGA.ACA can be seen its crystal form,not amorphous region by the x-diffraction.In conclusion,a process for preparing ACA in this study was simple, with a fast,high output rate,purity,productivity.4.Before and after Supercritical CO_2 extraction,the measuring results of the main components of the big galangal powder show that Alpinia galangal was rich in crude fiber,the physical and chemical composition of materials after supercritical fluid extraction has been no big change,the composition of flavonoids has been greatly enhanced.After the large increase in supercritical fluid extraction,the cost of materials can be turned into treasures for further development and utilization.5.A further study for the antibacterial activity of ACA,filter paper and test-tube method for nine in a row of micro-organisms evaluated the suppression of the ACA in vitro antibacterial activity,the results showed that ACA has significant antimicrobial activities;The anti-bacterial activities were higher than antifungal activities and the antimicrobial activities against Gram-positive were higher than Gram-negative bacterium in the anti-bacterial vitro…
Key words: Alpinia galanga; ACA; supercritical CO_2 extraction; isolation and purification; structure identification; antibacterial activity

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