Lactobacillus reuteri is a commensal-derived anaerobic probiotic that resides in the human gastrointestinal tract. L. reuteri converts glycerol into a potent broad-spectrum antimicrobial compound, reuterin, which inhibits the growth of gram-positive and gram-negative bacteria. In this study, we compared four human-derived L. reuteri isolates (ATCC 55730, ATCC PTA 6475, ATCC PTA 4659 and ATCC PTA 5289) in their ability to produce reuterin and to inhibit the growth of different enteric pathogens in vitro. Reuterin was produced by each of the four L. reuteri strains and assessed for biological activity. The minimum inhibitory concentration (MIC) of reuterin derived from each strain was determined for the following enteric pathogens: enterohemorrhagic Escherichia coli, enterotoxigenic E. coli, Salmonella enterica, Shigella sonnei and Vibrio cholerae. We also analyzed the relative abilities of L. reuteri to inhibit enteric pathogens in a pathogen overlay assay. The magnitude of reuterin production did not directly correlate with the relative ability of L. reuteri to suppress the proliferation of enteric pathogens. Additional antimicrobial factors may be produced by L. reuteri, and multiple factors may act synergistically with reuterin to inhibit enteric pathogens.

No abstract

The chemical constituents and biological activities of Corydalis crispa (Fumariaceae) were investigated for the first time. The phytochemical study resulted in the isolation of nine known isoquinoline alkaloids: protopine (1), 13-oxoprotopine (2), 13-oxocryptopine (3), stylopine (4), coreximine (5), rheagenine (6), ochrobirine (7), sibiricine (8) and bicuculline (9), with complete NMR data for 2 and 3 provided here for the first time. Crude extracts exhibited significant anti-inflammatory (p<0.01) activity against TNF-α production in LPS activated THP-1 cells. The acetylcholinesterase inhibitory activity of compounds 2, 4 and 7 and the antiplasmodial activity of compound 5 against P. falciparum strains TM4/8.2 and K1CB1 (multidrug resistant strain) are reported here for the first time. Stylopine (4) did not show antimalarial activity against the K1CB1 strain in contrast to a previous report. This study generated a scientific basis for the use of this plant in Bhutanese traditional medicine, either individually or in combination with other medicinal ingredients to treat a broad range of disorders. This study also identified compound 5 as potential new antimalarial lead compound.

Human-derived lactobacilli were isolated from fecal samples of healthy volunteers. Forty-six isolates from different volunteers were selected and investigated for their immunomodulatory properties. Conditioned medium from each isolate was assessed for its effect on tumor necrosis factor (TNF) production in lipopolysaccharide (LPS) - activated THP-1 monocytes. Of 46 Lactobacillus isolates, 12 significantly inhibited TNF production in varying magnitude. Lactobacillus strain TH58 displayed the most potent TNF - inhibitory activity (70% inhibition). In contrast, Lactobacillus strain TH14 exhibited immunostimulatory property by activating TNF production in THP-1 monocytes. Lactobacillus TH14 induced NF-κB activation in the absence of LPS stimulation, whereas Lactobacillus TH58 had no effect on NF-κB signaling, irrespective of LPS stimulation. Strain TH58 was identified as Lactobacillus saerimneri and strain TH14 as Lactobacillus ruminis by sequence analysis of the16S rRNA gene. This is the first report of a human isolate of L. saerimneri with TNF inhibitory activity and L. ruminis, an indigenous species to humans, with TNF stimulatory activity. Our data suggest the potential use of these two strains as immunoprobiotic candidates.

With the objective of determining safety and verifying the traditional uses of the Bhutanese medicinal plant, Pleurospermum amabile Craib & W. W. Smith, we investigated its crude extracts and the isolated phytochemicals for their biological activities. Four phenylpropanoids [(E)-isomyristicin (1), (E)-isoapiol (2), methyl eugenol (3) and (E)-isoelemicin (4)] and six furanocoumarins [psoralen (5), bergapten (6), isoimperatorin (7), isopimpinellin (8), oxypeucedanin hydrate (9) and oxypeucedanin methanolate (10)] were isolated from this plant. Among the test samples, compound 10 showed weak antibacterial activity against Bacillus subtilis and best antimalarial activity against the Plasmodium falciparum strains, TM4/8.2 (chloroquine and antifolate sensitive) and K1CB1 (multidrug resistant). None of the test samples showed cytotoxicity. This study generated scientific data that support the traditional medical uses of the plant.

No abstract

An investigation of the essential oil (EO) and the crude MeOH extract of a Bhutanese variety of Ajania nubigena using GC/GC-MS and NMR found the following: a) one kg of the dried plant material contained 0.7% w/w EO; b) 44 of the 53 GC-FID peaks of the EO were identified with (3 R,6 R)-linalool oxide acetate (75.8 %) as the major constituent (chemotype II) and chamazulene as a new sub-chemotype; c) purification of the EO furnished ( 3R, 6R)-linalool oxide acetate (1), chamazulene (2), ( E)-2-(2,4-hexadiynylidene)-1,6-dioxaspiro[4,4]non-3-ene (3), and ( Z)-2-(2,4-hexadinylidene)-1,6-dioxaspiro[4,4]non-3-ene (4); d) from the crude MeOH extract, four flavonoid compounds: 1-(4-hydroxyphenyl)propan-1-one (5), oxyanin B (6), luteolin (7) (major) and the luteolin-7- O-β-D-glucoside (8) were isolated; e) among the EO and pure compounds tested for biological activities, compound 7 exhibited a broad range of moderate antiplasmodial, cytoxicity and antimicrobial activities; c) compound 8 showed significant in vitro antiplasmodial activity against P. falciparum strains TM4/8.2 and K1CB1 (multidrug resistant strain) and was identified as a potential antimalarial scaffold; and f) the in vitro antimicrobial and cytotoxicity activities were in alignment with the traditional medical uses of this plant and thus substantiate its use in Bhutanese traditional medicine.

A new geranylated xanthone derivative, fuscaxanthone I (1), along with nine xanthones (2-9 and 11), a biphenyl (10) and three biflavonoids (12-14) were isolated from the roots of Garcinia fusca Pierre. Compounds 8, 10 and 11-14 were reported from this plant species for the first time. Their structures were elucidated by spectroscopic analyses, including 1D- and 2D-NMR and MS. The isolated compounds were evaluated for antibacterial activity against Helicobacter pylori. Cowaxanthone (5) and fukugiside (14) exhibited stronger inhibitory activity against H. pylori DMST reference strain at MICs 4.6 and 10.8 μM, respectively, than that of the control metronidazole. Isojacareubin (8) displayed the most potent activity against H. pylori HP40 clinical isolate with MIC 23.9 μM, which was approximately two times greater than that of the standard drug amoxicillin.