Studies on the Chemical Constituents of Lignum Dalbergiae Odoriferae and Extraction and Isolation Technology of Total Flavonoids
Lignum Dalbergiae Odoriferae is the dry heart wood of trunk and root of Dalbergia odorifera T.Chen which is the endemic plant in Hainan Province and introduced in Guangdong, Guangxi and Fujian recent years. Lignum Dalbergiae Odoriferae mainly contains volatile oil and flavonoids. This paper systematically studied on the total flavonoids in. The methods are as following: (1) flavonoids were separated from acetic ether-soluble fractions extracted from Lignum Dalbergiae Odoriferae and the compound structures were determined by spectrum; (2) self-made naringenin was used as a reference to establish a suitable quantitive method of total flavonoids in Lignum Dalbergiae Odoriferae; (3) the optimum extraction technology of total flavonoids in Lignum Dalbergiae Odoriferae was studied by orthogonal test; (4) the optimum purification technology was studied by comparing the purified ability of various types of resin; (5) the contents of naringenin and isoliquiritigenin in Lignum Dalbergiae Odoriferae of various origins were determined by HPLC. The result and conclusion of this work are as follows:(1) 5 compounds were isolated from acetic ether-soluble extraction by repeated column chromatography and their structures were identified by physico-chemical properties and spectrum as isoliquiritigenin(Ⅰ), sativanone(Ⅱ), naringenin(Ⅲ), alpinetin(Ⅳ) and eriodictyol(Ⅴ). CompoundsⅣandⅤwere found to been isolated in this plant for the first time.(2) Four reported quantitative methods of total flavonoids were compared and was found that none was suitable to quantify total flavonoids in Lignum Dalbergiae Odoriferae. A new suitable quantitative method that self-made naringin was used as a reference, NaOMe as chromogenic reagent and UV absorption was determined at 410nm, was established. This method is simple and good in reproducibility, stability and recovery rate.(3) The optimum extraction technology of total flavonoids in Lignum Dalbergiae Odoriferae was studied by orthogonal test. The result showed that the order of factors influencing extraction quantity was as follows: times of extraction> temperature of extraction> concentration of ethanol> extracting time. The influence of times of extraction and temperature of extraction was significant. The optimum extraction condition was that 70% ethanol was used to extract in 90℃for 1.5h thrice.(4) Nine types of macroporous resin were chosen to purify the total flavonoids in . According to the contrasts of static adsorbing ability and desorbing ability of each resin, HPD-100 macroporous resin had better effect in purifying the total flavonoids. Influence of different concentrations of sample and flow speed on purifying effect were studied. Elution curves of different concentration of elutes were also studied to determine the optimum technology of adsorbing and desorbing condition. The best static adsorbing and desorbing time were both 5h, the best concentration of sample was 3.7mg/mL, the best flow speed was 2mL/min, and upper than 70% of ethanol elute had better eluotropic effect and smaller tailing level. The saturated adsorption quantity of total flavonoids was 24.983mg/g.(5) HPLC quantitative method was established using naringin and isoliquiritigenin as references. The quantities of naringin and isoliquiritigenin in 11 Lignum Dalbergiae Odoriferae samples of various origins were measured, and preliminary assessment of quality of different Lignum Dalbergiae Odoriferae samples from various origins was determined. The contents of naringin and isoliquiritigenin in sample purchased from Guangxi were both higher, and content differences of these two flavonoids in Lignum Dalbergiae Odoriferae of various origins were great.