The Mosquito Larvicidal Activity of Lignans from Branches of Cinnamomum camphora chvar. Borneol.

The chemical investigation of branches of Cinnamomum camphora chvar. Borneol guided by mosquito larvicidal activity led to the isolation of fourteen known lignans (1-14). Their structures were elucidated unambiguously based on comprehensive spectroscopic analysis and comparison with the literature data. This is the first report of these compounds being isolated from branches of Cinnamomum camphora chvar. Borneol. Compounds 3-5 and 8-14 were isolated from this plant for the first time. All compounds isolated were subjected to anti-inflammatory, mosquito larvicidal activity and cytotoxic activity evaluation. Compounds (1-14) showed significant mosquito larvicidal activity against Culex pipiens quinquefasciatus with lethal mortality in 50% (LC50), with values ranging from 0.009 to 0.24 µg/mL. Among them, furofuran lignans(1-8) exhibited potent mosquito larvicidal activity against Cx. p. quinquefasciatus, with LC50 values of 0.009-0.021 µg/mL. From the perspective of a structure-activity relationship, compounds with a dioxolane group showed high mosquito larvicidal activity and have potential to be developed into a mosquitocide.

Acute Oral Toxicity and Genotoxicity Test and Evaluation of Cinnamomum camphora Seed Kernel Oil.

Cinnamomum camphora seed kernel oil (CCSKO) is one of the important natural medium chain triglycerides (MCT) resources, with more than 95.00% of medium chain fatty acids found in the world, and has various physiological effects. However, CCSKO has not been generally recognized as a safe oil or new food resource yet. The acute oral toxicity test and a standard battery of genotoxicity tests (mammalian erythrocyte micronucleus test, Ames test, and in vitro mammalian cell TK gene mutation test) of CCSKO as a new edible plant oil were used in the study. The results of the acute oral toxicity test showed that CCSKO was preliminary non-toxic, with an LD50 value higher than 21.5 g/kg body weight. In the mammalian erythrocyte micronucleus test, there was no concentration-response relationship between the dose of CCSKO and micronucleus value in polychromatic erythrocytes compared to the negative control group. No genotoxicity was observed in the Ames test in the presence or absence of S9 at 5000 µg/mL. In vitro mammalian cell TK gene mutation test showed that CCSKO did not induce in vitro mammalian cell TK gene mutation in the presence or absence of S9 at 5000 µg/mL. These results indicated that CCSKO is a non-toxic natural medium-chain oil.

Dietary Linolenic Acid Increases Sensitizing and Eliciting Capacities of Cow's Milk Whey Proteins in BALB/c Mice.

α-Lactalbumin (BLA) and ß-lactoglobulin (BLG) are the major whey proteins causing allergic reactions. Polyunsaturated fatty acids (PUFAs) stand among the extrinsic factors of the food matrix that can bind BLA and BLG and change their bioactivities, but their contribution to change the allergenic properties of these proteins has not been investigated. Here, we aimed to determine how PUFAs influence BLA and BLG to sensitize and trigger allergic responses in BALB/c mice. First, tricine-SDS-PAGE and spectroscopic assays identified that α-linolenic acid (ALA, as a proof-of-concept model) can induce BLA and BLG to form cross-linked complexes and substantially modify their conformation. Then, BALB/c mice (n = 10/group) were orally sensitized and challenged with BLA and BLG or ALA-interacted BLA and BLG, respectively. Allergic reactions upon oral challenge were determined by measuring clinical allergic signs, specific antibodies, levels of type-1/2 cytokines, the status of mast cell activation, and percentage of cell populations (B and T cells) in different tissues (PP, MLN, and spleen). Overall, systemic allergic reaction was promoted in mice gavage with ALA-interacted BLA and BLG by disrupting the Th1/Th2 balance toward a Th2 immune response with the decreased number of Tregs. Enhanced induction of Th2-related cytokines, as well as serum-specific antibodies and mast cell activation, was also observed. In this study, we validated that ALA in the food matrix promoted both the sensitization and elicitation of allergic reactions in BALB/c mice.

In Vitro Antibacterial Activity and Mechanism of Monocaprylin against Escherichia coli and Staphylococcus aureus.

In the present study, the antibacterial activity of monocaprylin in comparison with sodium benzoate and potassium sorbate against Staphylococcus aureus and Escherichia coli was assessed by measuring MIC, MBC, effect of pH on MIC, and incubation temperature on bactericidal efficacy. Results showed that monocaprylin exhibited an excellent antibacterial activity against both strains, with the lowest MIC and MBC of 1.28 mg/mL. A MIC of monocaprylin remained unchanged despite the pH values of culture medium, ranging from 5 to 9, unlike that of potassium sorbate or sodium benzoate. Furthermore, monocaprylin at MBC effectively reduced the population of E. coli and S. aureus by >5.5 log CFU/mL at 25°C within 6 h and decreased E. coli by approximately 5.0 log CFU/mL and S. aureus by 2.9 log CFU/mL at 12 h. The underlying mechanism of monocaprylin was then investigated by measuring ß-galactosidase activity, membrane potential, release of cellular contents, scanning electron microscopy, and transmission electron microscopy observations. Results indicated that monocaprylin killed E. coli by the rapid change in permeability and integrity of cell membrane, leading to decline of membrane potential, leakage of nucleic acids and proteins, and ultimately cell membrane disintegration and lysis. On the other hand, monocaprylin might exert its antibacterial activity against S. aureus mainly by diffusing across the cell wall, collapsing the cell membrane, and disturbing the order of intracellular contents. These findings indicated that monocaprylin had better antibacterial ability compared with traditional synthetic preservatives and might be a potential antibacterial additive independent of pH.

Medium and Long Chain Fatty Acids Differentially Modulate Apoptosis and Release of Inflammatory Cytokines in Human Liver Cells.

Medium chain fatty acids (MCFA) can be more easily absorbed and supply energy more rapidly than long chain fatty acids (LCFA). However, little is known about the inflammatory response by the treatment of MCFA in human liver cells. Thus this study used human liver cells (LO2) to evaluate the effects of MCFA on apoptosis and inflammatory response. Tetrazolim-based colorimetric assay and lactate dehydrogenase assay were used to measure the viability of LO2 cells, isolated spleens and liver cells from BALB/C mice. Inverted fluorescence microscopy and flow cytometry were used to assess the cell apoptosis. Activity of superoxide dismutase and malondialdehyde level were measured to determine the oxidative damage. mRNA or protein levels of classical pro-inflammatory cytokines were analyzed by quantitative real-time polymerase chain reaction (qPCR), enzyme-linked immunosorbent assay and western blotting. The results showed that the liver cells treated with the fatty acids at 200 µM for 24 h exhibited good viability. Fatty acids induced inflammatory cytokines at transcriptional and translational levels to a lesser extent than lipopolysaccharide. LCFA (oleic acid) up-regulated tumor necrosis fator-α, monocyte chemoattractant-1 and interleukin-1ß while down-regulated IL-6 and IL-8 secretion to a higher extent than MCFA in mRNA and protein levels. These findings suggested that MCFA may induce apoptosis to a less extent and exert more gentle inflammation than LCFA in human liver cells.

Cinnamomum camphora Seed Kernel Oil Improves Lipid Metabolism and Enhances ß3-Adrenergic Receptor Expression in Diet-Induced Obese Rats.

The effects of dietary Cinnamomum camphora seed kernel oil (CCSKO) containing medium-chain triacylglycerols on lipid metabolism and mRNA and protein expression of ß-3 adrenergic receptor in adipose tissue were studied in diet-induced obese rats. High fat food-induced obese rats were randomly divided into CCSKO group, Lard group, Soybean oil (SOY) group and naturally restoring group (n = 10). Rats fed with low fat food were used as a normal control group. Significant decreases in body mass and abdominal fat mass/body mass after 12 weeks were found in CCSKO group as compared with Lard and SOY groups (p < 0.05). Levels of blood total cholesterol (TC), triglyceride, free fatty acid, fasting insulin and insulin resistance in the CCSKO group were decreased significantly, and noradrenaline level and insulin sensitivity index in the CCSKO group were significantly higher than other groups. Meanwhile liver TC and triglyceride levels in the CCSKO group were also decreased markedly. Expression levels of ß3-adrenergic receptor mRNA and protein were higher in CCSKO group than in Lard and SOY groups. These results suggest that CCSKO may contribute to reduction of the body fat mass, promote lipid metabolism and up-regulate ß3-adrenergic receptor expression in high fat diet-induced obese rats.

Medium-chain fatty acid reduces lipid accumulation by regulating expression of lipid-sensing genes in human liver cells with steatosis.

Accumulation of lipids in the liver can lead to cell dysfunction and steatosis, an important factor in pathogenesis causing non-alcoholic fatty liver disease. The mechanisms related to lipid deposition in the liver, however, remain poorly understood. This study was aimed to investigate the effects of medium-chain fatty acid (MCFA) on the lipolysis and expression of lipid-sensing genes in human liver cells with steatosis. A cellular steatosis model, which is suitable to experimentally investigate the impact of fat accumulation in the liver, was established in human normal liver cells (LO2 cells) with a mixture of free fatty acids (oleate/palmitate, 2:1) at 200 µm for 24 h incubation. MCFA was found to down-regulate expression of liver X receptor-α, sterol regulatory element binding protein-1, acetyl-CoA carboxylase, fatty acid synthase, CD 36 and lipoprotein lipase in this cellular model, and have positive effects on adipose triglyceride lipase and hormone-sensitive lipase. These results suggest that MCFA may reduce lipid accumulation by regulating key lipid-sensing genes in human liver cells with steatosis.

Antiallodynic action of 1-(3-(9H-Carbazol-9-yl)-1-propyl)-4-(2-methyoxyphenyl)-4-piperidinol (NNC05-2090), a betaine/GABA transporter inhibitor.

The GABAergic system in the spinal cord has been shown to participate in neuropathic pain in various animal models. GABA transporters (GATs) play a role in controlling the synaptic clearance of GABA; however, their role in neuropathic pain remains unclear. In the present study, we compared the betaine/GABA transporter (BGT-1) with other GAT subtypes to determine its participation in neuropathic pain using a mouse model of sciatic nerve ligation. 1-(3-(9H-Carbazol-9-yl)-1-propyl)-4-(2-methyoxyphenyl)-4-piperidinol (NNC05-2090), an inhibitor that displays moderate selectivity for BGT-1, had an antiallodynic action on model mice treated through both intrathecally and intravenous administration routes. On the other hand, SKF89976A, a selective GAT-1 inhibitor, had a weak antiallodynic action, and (S)-SNAP5114, an inhibitor that displays selectivity for GAT-3, had no antiallodynic action. Systemic analysis of these compounds on GABA uptake in CHO cells stably expressing BGT-1 revealed that NNC05-2090 not only inhibited BGT-1, but also serotonin, noradrenaline, and dopamine transporters, using a substrate uptake assay in CHO cells stably expressing each transporter, with IC50: 5.29, 7.91, and 4.08 µM, respectively. These values were similar to the IC50 value at BGT-1 (10.6 µM). These results suggest that the antiallodynic action of NNC05-2090 is due to the inhibition of both BGT-1 and monoamine transporters.