Alzheimer's disease (AD), a major neurodegenerative disorder, is associated with the enzymatic reaction of β-secretase (BACE1) on the amyloid precursor protein (APP) for the generation of neurotoxic amyloid-β (Aβ). Therefore, Aβ accumulation and oxidative stress-induced neuronal cell death are the pathogenic hallmarks of AD. In this study, we tried to identify BACE1 inhibitors and neuroprotectants from natural products, in particular, from the Korean mushroom Polyozellus multiplex. Four p-terphenyls were identified from the ethanolic extract of P. multiplex; polyozellin (1), thelephoric acid (2), polyozellic acid (3), and kynapcin-12 (4). Compounds 1-4 effectively inhibited BACE1 activity with a half-maximal inhibitory concentration (IC50) of 3.08, 3.50, 4.78, and 15.79 μM, respectively. Compounds 1-3 reduced the production of neurotoxic Aβ1-42 production in APPswe-N2a cells in a concentration-dependent manner. When HT22 cells were stressed with 5 mM glutamate, compounds 2 and 3 significantly recovered cell viability. It was correlated with their inhibitory properties against glutamate-mediated Ca(2+) influx, intracellular reactive oxygen species (ROS) generation, lipid peroxidation, reduction in Bcl-2 and Bid levels, and enhanced phosphorylation of mitogen-activated protein kinase (MAPK). Thus, P. multiplex and the isolated p-terphenyls might be useful in the development of lead compounds for the prevention of neurodegenerative diseases, especially AD.

Mitogen-activated protein (MAP) kinases play an important role in cell growth and differentiation, as well as the modulation of proinflammatory cytokines. The objective of this study was to examine the increase in the anti-inflammatory effect of Gentiana scabra Bunge (GSB), due to bioconversion with the Aspergillus kawachii crude enzyme, via inhibition of the NF-κB signaling and MAP kinase pathways in RAW 264.7 cells. The expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 in RAW 264.7 cells treated with the GSB ethyl acetate fraction bioconverted with A. kawachii crude enzyme (GE-BA), was dramatically suppressed as compared to GSB ethyl acetate fraction non-bioconverted with the A. kawachii crude enzyme (GE-UA). The phosphorylation of p38, extracellular signalregulated kinases, and inhibitory κB in RAW 264.7 cells treated with GE-BA was further suppressed, as compared to exposure to GE-UA. Moreover, the mRNA expression of interleukin 6, interleukin 1-beta, and tumor necrosis factor-α was further suppressed by GE-BA, compared to GE-UA. Similarly, antioxidant activities, such as 2,2-diphenyl-1-picrylhydrazyl hydrate and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging activity, of GE-BA were further increased compared to GE-UA. These observations demonstrate that the anti-oxidant and anti-inflammatory activities of GSB ethyl acetate fraction increases as a result from bioconversion with the A. kawachii crude enzyme.

C h 0, n S. B., 0 x a naG. S a v k a; P.B fez ina, M. Mar 0, u n e k: Acta vet. Bmo, 58, 1989:313'321. The effects o,f tylo,sin o,n productio,n 'o,f end-products o,f carbo,hydrate metabolism, utilizatio,n o,f lactic acid and degradatio,n o,fprotein were investigated in in vitro experiments with rumen inocula;' Tylo,sin no,n-specifically inhibited the rumen fermentatio,n with ino,cula fro,m no,n-adapted cows, but most o,f its effects disappeared when ino,cula wera taken from adapted wethers. Productio,n o,f lactic acid was severely depressed by tylo,sin, no, matter whether inocula o,riginated fro,m no,n-adapted o,r adapted animals. So,me o,ther tylo,sin-induced metabo,lic effects differed from those o,f io,no,pho,re co,mpounds, in spite o,f the fact, that bo,th tylosin and io,no,pho,res are Po,tent gram-positiveantibio,tics. Effect of Tylosin on Rumen Fermentation in vitro. Cattle, wethers, rumenjluid, incubationTylosin is a macro,lide antibio,tic produced by Streptomyces frQdiae that is a potent inhibito,r o,f the pro,teosynthesis in many gram-positive bacteria. Several researchers have demonstrated that co,ntinuo,us lo,w-level feeding o,f tylosin reduced the incidence and severity o,f liver abscesses; increased average daily gains and improved feed conversio,n o,ffeedlo,t cattle (B' r .0, w n et aI. 1973; H e i n e man 'n et al. 1978; P 0, t t e r et al .. 1985). The liver-pro,tecting effect tylosin is based o,n its inhibitory influence o,n Fusobacterium necrophorus (previo,usly recognized as Sphaerophorus necfophorus), a bacterium that was isolated fro,m 9S%o,f the abscess specimens in experiments o,f B r 0, w n et aI. (1973). The co,mbinatio,n o,f mo,nensin and tylosin has. been cleared fo,r co,mmercial use as the feed additive in the cattle industry in the USAnowadays and similar io,no,pho,re Itylosin combinatio,ns are being tested (G i 11 and 0 wen s 1984; S t r a s i a and J 0, r dan 1985).Altho,ughthe additio,n' o,f tylosin to, ruminant diets seems to,. be pro,mising, little info,rmatio,n is currently available o,n its effect· o,n the rumen. fermentatio,n. Pur s.e r et aI. (1965) fo,\lnd that vo,latile fatty acid (VFA) distributio,n was modified towards mo,re butyrate and less pro,Pionate in tylosin-fed wethers. Rumen pro,to,zo,al numbers wereincteased rollo,wing antibio,tic supplementatio,n while no, differences were o,bserved in the to,tal viable. bacteria counts, Similar effects of tylo,sin on the mo,lar compo,sition ofVFA were found by O'C 0, n n o. r et aI. (1970) The purpose o,f this wo,rk was to define better effects of tylosin o,n rumen fermentatio,n in vitro.We aslo, watend to, test the hYPo,thesis o,f R use 1 1 and S t r 0, bel (1988) who, suggested that any gram-positive antibio,tic can produce fermentatio,n shifts similar to, tho,se of monensin. Their experiments.sho,wed that bacitraci~ a polypeptid

The ethyl acetate fraction of Bat Faeces (Ye Ming Sha: natural products used in Chinese Medicine) after fermentation (EFBF-AF) showed enhanced anti-oxidative effects in 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6sulfonic acid) diammonium salt assays. Fermentation of the Bat Faeces by using the crude enzyme extract from Aspergillus kawachii, significantly increased the anti-inflammatory effects. Fermented Bat Faeces markedly inhibited nitric oxide production, inducible nitric oxide synthase, and cyclooxygenase-2 expression in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. The EFBF-AF reduced the nuclear translocation of nuclear factor kappa B (NF-κB) via IKKα and IκBα phosphorylation, and decreased the phosphorylated the extracellular signal-regulated kinases (ERK) and p38 expression in LPS-treated RAW 264.7 macrophages. In addition, the EFBF-AF suppressed the expression of pro-inflammatory genes, such as interleukin-1β, interleukin-6, and tumor necrosis factor-α. These results suggest that fermented Bat Faeces may suppress pro-inflammatory responses in LPSstimulated RAW 264.7 macrophages cells via ERK, p38 mitogenactivated protein kinase and NF-κB signaling pathways.

Brno, 58, 1989: 215-223. In in vitro experiments we studied the effect of monensin on production of volatile fatty acids (VFA) from cellulose, hemicelluloses, pectin and starch in mixed cultures of rumen microorganisms. The following results were obtained:1. Monensin lowered the concentration of VF A in cultures with cellulose. There were only minor differences in total VF A concentration between monensin-free and monensin-treated cultures with hemicelluloses, pectin and starch.2. Monensin decreased the molar ratio acetate to propionate in cultures with hemicelluloses, pectin and starch, but increased this ratio in cultures with cellulose.3. There were no significant differences between monensin from Elanco and its Czechoslovak analogue. Monensin maintained its effect throughout the 3-month experimental period. In vitro, rumen fluid, acetate, propionate, butyrateMonensin, an ionophore antibiotic, is widely used to improve the feed efficiency and stimulate the body mass gains of ruminants. While considerable research has been reported on how rumen fermentation is affected by monensin, information is limited on how this polyether ionophore affects the fermentation of particular components of plant cell material. Some experiments in vivo and in vitro have shown that monensin decreases the digestibility of fibre and fibrous components (Poos et al. 1979;Henderson et al. 1981;Wallace et al. 1981;Whetstone et al. 1981). Also salinomycin, an ionophore similar to monensin, has been shown to depress the digestibility of fibre (Zinn 1986). However, other authors found only minor