Antibacterial activity of essential oils extracted from the unique Chinese spices cassia bark, bay fruits and cloves.

Spices are widely used in daily life such as diet and have certain activity. Especially in China, spices have been mainly used as condiments for thousands of years in order to improve the sensory quality of food; in addition, they and their derivatives can also be used as preservatives. In this study, three spices with unique Chinese characteristics widely used were selected: cassia bark (bark of Cinnamomum camphora Presl), bay fruits (Laurus nobilis), and cloves (Syzygiumaromaticum). The main components and antibacterial ability of these three spices were analyzed by simulated extraction method. Through headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) analysis, it was determined that the main active compounds in the essential oils of cassia bark, bay fruits and cloves were cinnamaldehyde (78.11%), cinnamaldehyde (61.78%) and eugenol (75.23%), respectively. The agar plate diffusion test and the simulated food culture medium experiment confirmed that the essential oils extracted from the three flavors have antibacterial effects on Listeria monocytogenes, Listeria innocua, Listeria welshimeri, Listeria ivanovii, Listeria grayi and Vibrio parahaemolyticus. The antibacterial activity of different strains has different optimal extraction conditions. Generally speaking, cinnamon essential oil has the strongest antibacterial activity, while laurel fruit has the lowest antibacterial activity. The study proved the antibacterial activity of these three Chinese-specific spices and provided some new ideas and methods for the subsequent research and preparation of natural food additives and food antibacterial agents.

The effect of Chinese wild blueberry fractions on the growth and membrane integrity of various foodborne pathogens.

The objective of this study was to evaluate the antibacterial effect of Chinese wild blueberry extract and its fractions against Listeria monocytogenes, Staphylococcus aureus, Salmonella Enteritidis, and Vibrio parahaemolyticus. Chinese wild blueberry (Vaccinium uliginosum) crude extract (BBE) was obtained using methanol extraction, and sugars plus organic acids (F1), phenolics fraction (F2), and anthocyanins plus proanthocyanidins (F3) fractions were separated using C-18 Sep-Pak columns. The minimal inhibitory concentration and minimal bactericidal concentration of each fractional component were determined using a two-fold-serial dilution method. Nucleic acid leakage (OD260 nm ) and protein release (Bradford protein assay) were determined by spectrophotometry, to evaluate the permeability of the cell membrane. F3 was found to exhibit the greatest antimicrobial activity against the four tested strains, followed by F2, F1, and BBE. V. parahaemolyticus was the most sensitive to the all fractions, followed by S. Enteritidis, L. monocytogenes, and S. aureus. Survival curve analysis showed that the number of bacteria decreased from six log colony-forming units (CFU) to less than 10 CFU after bacteria were treated with fractions for 12 hr, which demonstrated the bactericidal effect of blueberry fractions. Furthermore, when the pathogens were treated with fractions for 2 hr, the OD260 nm and OD595 nm values increased significantly (P < 0.01), which indicated the significant release of nucleic acid and protein. The results from this study indicated that blueberry fractions, especially F3, inhibited the growth of foodborne pathogens by damaging their cell membrane, and may be developed as a natural preservative to prevent and control foodborne pathogens. PRACTICAL APPLICATION: A blueberry crude extract and its sugars plus organic acids, phenolics, and anthocyanins plus proanthocyanidins fractions, inhibited the growth of foodborne pathogens by destroying their cell membrane. Therefore, Chinese wild blueberries have potential as a natural preservative to prevent and control foodborne pathogens.

Immunomodulation of bone marrow macrophages by GLIS, a proteoglycan fraction from Lingzhi or Reishi medicinal mushroom Ganoderma lucidium (W.Curt.:Fr.) P. Karst.

The immunomodulatory effect of GLIS (Lingzhi or Reishi medicinal mushroom Ganoderma lucidum immunomodulating substance) on macrophages has been investigated as part of ongoing research into the anticancer properties of this mushroom. Proliferation of bone marrow macrophages (BMMs) was enhanced by GLIS in a dose-dependent manner. Microscopic examination revealed that numerous GLIS-treated BMMs were enlarged and formed pseudopodia. Exposure of BMMs to GLIS resulted in significant increases in NO production, induction of cellular respiratory burst activity, and increased levels of IL-1ß, IL-6, IL-12p35, IL-12p40, IL-18, and TNF-α gene expression and levels of TNF-α, IL-1ß, and IL-12 secretion. Our data indicate that GLIS activates the immune system by modulating cytokine production.

NMR characterization for polysaccharide moiety of a glycopeptide.

Ganoderma lucidum is a traditional medicinal herb used to treat various diseases in China and Southeast Asia for thousands of years. An aqueous glycopeptide, LZ-B-1, was prepared by successive chromatography and exhibited an immunostimulating potential. To better understand the mechanism of bioactivity for this compound, the polysaccharide moiety of glycopeptide LZ-B-1 was studied by NMR spectroscopy. The results indicated that the polysaccharide moiety had a backbone of 1,6-disubstituted-alpha-galactopyranosyl, 1,2,6-trisubstituted-alpha-galactopyranosyl, 1,3-disubstituted-beta-glucopyranosyl and 1,4,6-trisubstituted-beta-glucopyranosyl residues. The branches were mainly composed of 1-substituted-beta-glucopyranosyl and 1-substituted-alpha-fucopyranosyl residues.

Application of cranberry concentrate (Vaccinium macrocarpon) to control Escherichia coli O157:H7 in ground beef and its antimicrobial mechanism related to the downregulated slp, hdeA and cfa.

The possible use of cranberry concentrate (CC) as a natural food preservative was studied by examining its antimicrobial effect on the growth of Escherichia coli O157:H7 inoculated in ground beef, its organoleptical effect on beef patties, and its antimicrobial mechanism on the gene regulation level. Inoculated ground beef was added with CC and stored at 4 degrees C for 5 days. Bacteria were detected on day 0, 1, 3, and 5. Cranberry concentrate (2.5%, 5%, and 7.5% w/w) reduced total aerobic bacteria 1.5 log, 2.1 log, and 2.7 log CFU/g and E. coli O157:H7 0.4 log, 0.7 log, and 2.4 log CFU/g, respectively, when compared to the control on day 5. Fifty panelists evaluated the burgers supplemented with CC. No differences in appearance, flavor, and taste were found among burgers with 0%, 2.5%, and 5% CC. The expression of E. coli O157:H7 cyclopropane fatty acyl phospholipid synthase (cfa), hypothetical protein (hdeA), outer membrane porin protein C (ompC), hyperosmotically inducible periplasmic protein (osmY), and outer membrane protein induced after carbon starvation (slp) genes with or without CC (2.5% v/v) treatment was investigated by quantitative real-time PCR. Compared to the control, slp, hdeA, and cfa were markedly downregulated, ompC was slightly downregulated, while osmY was slightly affected.

Purification, NMR study and immunostimulating property of a fucogalactan from the fruiting bodies of Ganoderma lucidum.

A water-soluble polysaccharide (LZ-D-1) was isolated from Ganoderma lucidum fruiting bodies by DEAE-Sepharose Fast Flow and Sephacryl S-300 high-resolution chromatography. The polysaccharide had a molecular weight of 2.8 x 10(4) Da and was mainly composed of L-Fuc, D-Glc and D-Gal in a molar ratio of ca.1 : 1 : 5. LZ-D-1 had a sugar content of 98.7 % as measured using the phenol-sulfuric acid method. On the basis of methylation analysis, FT-IR spectrum and NMR experiments, the structure of the repeating unit of the polysaccharide was established. LZ-D-1 had a backbone composed of 1,6-disubstituted alpha-D-galactopyranosyl, 1,2,6-trisubstituted alpha-D-galactopyranosyl and had a branch composed of fucose attached to O-2 of a 1,2,6-trisubstituted alpha-D-galactopyranosyl residue. At the same time, the polysaccharide contained some 1,6-disubstituted glucopyranosyl residues and 1,3-disubstituted glucopyranosyl residues. An immunostimulating experiment in vitro indicated that LZ-D-1 stimulated proliferation of mouse spleen lymphocytes.

Immunomodulation of RAW264.7 macrophages by GLIS, a proteopolysaccharide from Ganoderma lucidum.

The immunomodulatory effect of Ganoderma lucidum immunomodulating substance (GLIS) on macrophages has been investigated as part of on-going research into the anti-cancer properties of Ganoderma lucidum. Proliferation of bone marrow macrophages (BMMs) was enhanced by GLIS in a dose-dependent manner. Microscopic examination revealed that numerous GLIS-treated RAW264.7 macrophages were enlarged and formed pseudopodia. Exposure of RAW264.7 macrophages to GLIS resulted in significant increases in NO production, induction of cellular respiratory burst activity, and increased levels of IL-1beta, IL-12p35 and IL-12p40 gene expression. Our data indicate that GLIS activates the immune system by modulating cytokine production.

[Comparative study on triterpenes in different Ganoderma species].

The triterpene profiles of different Ganoderma products was analysed by HPLC. The results showed that the seven-day fermented mycelia had little triterpene and different growth stages fruiting bodies almost had changeless triterpene. Compared with the fruiting body, the triterpene level of spore was lower. Among different Ganoderma species, Ganoderma atrum had little triterpenes too.