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OBJECTIVE:To study the chemical constituents in ethanol extract from the stem of Miao medicine Rubus multibracteatus. METHODS:The ethanol extract from the stem of Miao medicine R. multibracteatus was isolated and purified by silica gel column,preparative liquid chromatography and Sephadex LH-20 gel column,etc. The structure of compounds were analyzed and identified according to physicochemical properties and spectrum data(MS,hydrogen spectrum and carbon spectrum). RESULTS:Ten compounds were isolated from the ethanol extract of R. multibracteatus stem,i.e. 5,4′-dihydroxy-8-(3,3-dimethylally)-2″, 2″-dimethylpyrano [5,6∶6,7] isoflavone(1),3-hydroxy-1-(4′-hydroxy-3′-methoxyphenyl)propan-1-one(2),3β-hydroxysitost-5-en-7-one (3),Lupeol(4),Coniferaldehyde(5),E-p-hydroxy-coumaric acid(6),Genistein(7),1-O-p-coumaroylglycerol(8),Scopoletin(9), and Kaempferol(10). CONCLUSIONS:Compound 1-9 are isolated from the plants of R. multibracteatus for the first time,and Compound 2,5,8 are isolated from the plants of Rubus L. for the first time. The study lays the foundation for further development and utilization of R. multibracteatus.
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OBJECTIVE:To investigate in vitro antibacterial effect of extracts from Miao medicine Rubus multibracteatus leaves. METHODS:The aqueous extract and 80% ethanol extracts from R. multibracteatus leaves were used to prepare solution with mass concentration of 200 mg/mL. Using ampicillin and fluconazol as positive control (50 mg/mL),cup plate method was used to determine antibacterial effects of the extracts from R. multibracteatus leaves to Staphylococcus aureus,Staphylococcus epi-dermidis,Escherichia coli,Shigella dysenteriae,Proteus vulgaris,Candida albicans and Cryptococcus neoformans. The petroleum ether,acetic ether and n-butyl alcohol were used to extract 80% ethanol extracts in turns. After obtaining relevant extracts (50 mg/mL),cup plate method was used to investigate antibacterial effects of them to above 7 bacterial strains. The parts with antibacte-rial effects and bacterial strains sensitive to drug were screened. Micro-broth dilution method and agar culture medium plate method were used to determine minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC). RESULTS:The aqueous extract of R. multibracteatus leaves almost had no inhibitory effect while 80% ethanol extract showed different degrees of antibacterial effect to tested bacterial strains,and it also had higher activity against 5 bacterial stains than 2 fungus. The ethyl ace-tate and n-butyl alcohol fractions of 80% ethanol extracts showed good effect while the petroleum ether and water layer fractions had no antibacterial effect,and all the fractions of 80% ethanol extracts showed no inhibitory effect on fungus. To 5 bacterial stains,MIC and MBC of 80% ethanol extract were 6.25-12.5,12.5-25 mg/mL,those of ethyl acetate fractions were 3.13,6.25 mg/mL and those of n-butyl alcohol fraction were 3.13-6.25,6.25-12.5 mg/mL,respectively. CONCLUSIONS:80% ethanol ex-tract of Miao medicine R. multibracteatus leaves and its ethyl acetate and n-butyl alcohol fractions have obvious in vitro antibacteri-al effect to bacteria.
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Objective To supply scientific basis for the reasonable development and utilization of Rubus multibracteatus Levl.et Vant.resources.Method The total flavonoids was extracted from Rubus multibracteatus Levl.et Vant.with 60% methanol and its content was determined by spectrophotometry.The reliability and repeatability of the method were tested through stability,repeatability,accuracy and recovery experiments.Result Both standard and tested solutions had the maximum absorbance at 510 nm.The RSD values of repeatability,accuracy and recovery experiments were 2.11%,0.97% and 2.4% respectively.The results of content determination showed that the total flavonoids in Rubus multibracteatus Levl.et Vant.was 3.8%.Conclusion Extracted with 60% methanol,colored with aluminiumnitrate and determined by spectrophotometry at 510 nm were suitable for the determination of total flavonoids in Rubus multibracteatus Levl.et Vant..