A Novel Prenylchalcone from Humulus lupulus

s: 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.

Humulus lupulus L. Extract Prevents Ovariectomy-Induced Osteoporosis in Mice and Regulates Activities of Osteoblasts and Osteoclasts

Objective:To systematically evaluate the protective effects of Humulus lupulus L.extract(HLE)on osteoporosis mice.Methods:In vivo experiment,a total of 3512-week-old female ICR mice were equally divided into 5 groups:the sham control group(sham);the ovariectomy with vehicle group(OVX);the OVX with estradiol valerate[EV,0.2 mg/(kg·d)];the OVX with low-or high-dose HLE groups[HLE,1 g/(kg·d)and 3 g/(kg·d)],7 in each group.Treatment began 1 week after the ovariectomized surgery and lasted for 12 weeks.Bone mass and trabecular bone mircoarchitecture were evaluated by micro computed tomography,and bone turnover markers in serum were evaluated using enzyme-linked immunosorbent assay(ELISA)kits.In vitro experiment,osteoblasts and osteoclasts were treated with HLE at doses of 0,4,20 and 100μg/mL.Biomarkers for bone formation in osteoblasts and bone resorption in osteoclasts were analyzed.Results:Compared with the OVX group,HLE exerted bone protective effects by the increase of estradiol(P<0.05),the improvement of cancellous bone structure,bone mineral density(P<0.01)and the reduction of serum alkaline phosphatase(ALP),tartrate resistant acid phosphatase(TRAP),bone gla-protein,c-terminal telopeptides of typeⅠcollagen(CTX-Ⅰ)and deoxypyridinoline levels(P<0.01 for all).In vitro experiment,compared with the control group,HLE at 20μg/mL promoted the cell proliferation(P<0.01),and increased the expression of bone morphogenetic protein-2 and osteopontin levels in osteoblasts(both P<0.05).HLE at 100μg/mL increased the osteoblastic ALP activities,and HLE at all dose enhanced the extracellular matrix mineralization(both P<0.01).Furthermore,compared with the control group,HLE at 20μg/m L and 100μg/m L inhibited osteoclastic TRAP activity(P<0.01),and reduced the expression of matrix metalloproteinase-9 and cathepsin K(both P<0.05).Conclusion:HLE may protect against bone loss,and have potentials in the treatment of osteoporosis.

Effects of Spent Craft Brewers’ Yeast on Fermentation and Methane Production by Rumen Microorganisms

Saccharomyces cerevisiae is a key component of beer brewing and a major by-product. The leftover, spent brewers’ yeast from large breweries has been used as a protein supplement in cattle;however the possible advantages of spent yeast from smaller craft breweries, containing much higher levels of bioactive hop acids, have not been evaluated. Hops secondary metabolites from the hops (Humulus lupulus L.) used to make beer are concentrated in the yeast during brewing, and have antimicrobial activity against Gram-positive bacteria. Uncultivated suspensions of bovine rumen microorganisms produced less methane during fructose fermentation when exposed to inactivated, and freeze-dried spent craft brewers’ yeast than a bakers’ yeast control. The experiment was repeated with caprine rumen microorganisms and ground grass hay as the substrate. Likewise, in the presence of craft brewers’ yeast less methane was produced (2.7% vs. 6.9% CH4). Both experiments also revealed a decrease in acetic acid production, but not propionic acid production, when craft brewers’ yeast was included. These results indicated that spent yeast could represent a co-product for craft breweries, and a feed supplement for ruminants that has a favorable impact on methane production.

Characterization of the Formation of Branched Short-Chain Fatty Acid：CoAs for Bitter Acid Biosynthesis in Hop Glandular Trichomes

Bitter acids, known for their use as beer flavoring and for their diverse biological activities, are predominantly formed in hop （Humulus lupulus） glandular trichomes. Branched short-chain acyI-CoAs （e.g. isobutyryI-CoA, isovaleryl- CoA and 2-methylbutyryI-CoA）, derived from the degradation of branched-chain amino acids （BCAAs）, are essential building blocks for the biosynthesis of bitter acids in hops. However, little is known regarding what components are needed to produce and maintain the pool of branched short-chain acyI-CoAs in hop trichomes. Here, we present several lines of evidence that both CoA ligases and thioesterases are likely involved in bitter acid biosynthesis. Recombinant HICCL2 （carboxyl CoA ligase） protein had high specific activity for isovaleric acid as a substrate （Kcat/Km = 4100 s-~ M-l）, whereas recombinant HICCL4 specifically utilized isobutyric acid （Kcat/Km = 1800 s-1 M-1） and 2-methylbutyric acid （Kcat/ Km = 6900 s-1 M-~） as substrates. Both HICCLs, like hop valerophenone synthase （HIVPS）, were expressed strongly in glandular trichomes and localized to the cytoplasm. Co-expression of HICCL2 and HICCL4 with HIVPS in yeast led to significant production of acylphloroglucinols （the direct precursors for bitter acid biosynthesis）, which further confirmed the biochemical function of these two HICCLs in vivo. Functional identification of a thioesterase that catalyzed the reverse reaction of CCLs in mitochondria, together with the comprehensive analysis of genes involved BCAA catabolism, supported the idea that cytosolic CoA ligases are required for linking BCAA degradation and bitter acid biosynthesis in glandular trichomes. The evolution and other possible physiological roles of branched short-chain fatty acid：CoA ligases in planta are also discussed.