Characterization of reduced iso‐α‐acids derived from hops (Humulus lupulus) by NMR

Reduced forms of iso‐α‐acids (isohumulones), used in modern beer brewing were separated and characterized by ¹H and ¹³C NMR spectroscopy. Components from mixtures of rho‐iso‐α‐acids, tetrahydro‐iso‐α‐acids, and hexahydro‐iso‐α‐acids were isolated using high‐performance liquid chromatography (HPLC) and analyzed by use of one‐ and two‐dimensional NMR experiments. The data presented assign the identities of the main peaks in the HPLC traces for the reduced iso‐α‐acids. Previous tentative assignments regarding the cis and trans configurations and the structures of the acyl residues of the reduced iso‐α‐acids were confirmed and extensive NMR assignments were made. Furthermore, the previously unknown stereochemistry in the C‐4 side‐chain of the rho‐ and hexahydro‐iso‐α‐acids was assigned. Copyright © 2003 John Wiley & Sons, Ltd.     

超声波法提取啤酒花中总多糖的工艺

采用超声波法提取啤酒花中总多糖.采用正交试验设计,以总多糖含量为评价指标进行实验.最佳提取工艺为:超声提取2次,加12倍量的水,每次40min,超声功率为160W.本提取工艺合理,啤酒花中总多糖提取率较高.     

插条粗度、节数与NAA对啤酒花脱毒苗绿枝扦插生根的影响

采用啤酒花脱毒苗一年生枝条作插条,研究了插条粗度、节数与NAA对啤酒花脱毒苗绿枝扦插生根的影响。结果表明:插条粗度、NAA处理以及二者交互作用可极显著影响啤酒花脱毒苗的生根率,其作用大小依次为:NAA>插条粗度>NAA×插条粗度,而节数对啤酒花脱毒苗生根率的影响不显著;愈伤组织诱导率与插条粗度有很大的关系。     

啤酒花浸膏液态CO_2萃取试验研究

阐述了开发生产国产液态ＣＯ２酒花浸膏的重要性和必要性,测定了酒花浸膏在超临界及液态ＣＯ２中的溶解度,研究了原料类型、原料含水率及ＣＯ２流量等因素对液态ＣＯ２萃取酒花浸膏效果的影响     

新疆野生啤酒花DNA提取及RAPD反应体系的建立

采用2种方法提取啤酒花的基因组DNA,并分析了样品的不同状况和是否纯化对所提DNA质量及其RAPD扩增效果的影响。结果表明：采用改进的高盐低pH法优于CTAB法。以此法所提DNA为模板进行随机扩增多态DNA(RAPD)试验,分别测试了Mg2 ,dNTP、Taq酶、模板DNA浓度和退火温度对反应结果的影响,最终确定了野生啤酒花RAPD反应的最佳体系。     

流动注射动力学光度法测定啤酒花中的单宁

提出了啤酒花中单宁的流动注射分析法。本法将单宁注入Ｆｅ（Ⅲ）载流中,然后与１,１０－二氮菲的０．０３ｍｏｌ／ＬＨ２ＳＯ４溶液混合,混合物经１００ｃｍ反应盘管,生成的１,１０二氮ｅ（Ⅲ）络合物在５０６ｎｍ波长处检测。方法快速、准确,测样频率为７１样／ｈ,相对标准偏差为１．１％,测定单 纯性范围为０．００－３００ｍｇ／Ｌ,检测限０．８４ｍｇ／Ｌ,成功地用于啤酒花中单宁的测定。     

A Novel Prenylchalcone from Humulus lupulus

From hops of Humulus lupulus, a novel prenylchalcone was isolated, which showed inhibition against BGC-823 cells. The structure was elucidated as 5“-(2“‘-hydroxyisopropyl-)-dihydrofurano-[2“, 3“-B]-4, 4‘-dihydroxy-6‘-methoxychalcone, by HRFABMS and NMR spectra.     

A new formylated chalcone from Humulus lupulus with protective effect on HUVECs injury by angiotensin II

One new formylated chalcone, 3′- formyl xanthohumol (1) was isolated from the EtOAc-soluble partition of the cones of Humulus lupulus, along with two other known chalcones, namely dehydrocycloxanthohumol (2) and xanthohumol (3). The structure of compound 1 was elucidated on the basis of its 1D, 2D NMR and MS data. The structures of the known compounds were identified by comparison of their spectroscopic data with those reported by the literatures. The isolates were tested for their protective effects on human umbilical vein endothelial cells (HUVECs) injured by angiotensin II (Ang II), all the three compounds protected against the cell injury at the concentration of 20 μΜ, and compound 3 showed the most potent activity by improving cell viability from 53.9 to 74.9%.     

Determination of xanthohumol in hops (Humulus lupulus L.) by nonaqueous CE

Xanthohumol (XN) is a prenylated chalcone with antimutagenic and anticancer activity from hops. A nonaqueous reverse polarity capillary electrophoretic method for the determination of XN in hop extract was developed and validated. The optimal parameters were a 64.5 cm long fused-silica capillary with 50 microm id at 25 degrees C; 30 kV negative voltage (anode at detector side of the capillary); nonaqueous buffer with 75 mM NaOH and 50 mM boric acid in methanol; hydrodynamical injection with 10 mbar for 40 s; and detection at 440 nm. XN, isoxanthohumol (IX), colupulone, adlupulone, and n-lupulone were well resolved on the electropherogram. The LOD for XN was 0.05 mg/L and RSD for peak area was below 3%. The amount of XN in different samples of hop pellets varied from 0.14 to 0.42%.     

Use of hop cone extract obtained under supercritical CO2 conditions for producing antibacterial all-purpose cleaners

This paper attempts to demonstrate empirically the possibility of using a hydrophobic extract of hop cone obtained under the conditions of supercritical carbon dioxide to produce all-purpose cleaner with antimicrobial activity and low irritant potential. A series of prototypes of products varied by the extract concentration was developed. The formulations were assessed for physicochemical properties: particle size, turbidity, and color. The results indicate that the hydrophobic extracts of hop cone can be a valuable component of chemical products intended for washing, having a broad spectrum of action and contributing to improvement of the product’s safety.