The antidiabetic effect of cinnamon has generated broad interest during the past decade. We investigated the hypoglycemic activity and pancreas-protective effect of leaf essential oil from indigenous cinnamon (CO) in diabetic rats induced with streptozotocin (STZ, iv, 65 mg/(kg bw)) and found linalool to be the major component representing 40.24% of the CO composition. In diabetics, all tested doses of CO significantly lowered fasting blood glucose and fructosamine and are concomitant with elevated plasma and pancreatic insulin levels under a fasting condition. However, during the oral glucose tolerance test (OGTT) period the effect of 25 and 50 mg/(kg bw) of CO was shown to be less effective than that of 12.5 mg/(kg bw) in ameliorating the accumulation of plasma insulin. In addition, at 12.5 mg/(kg bw), CO significantly ameliorated pancreatic values of thiobarbituric acid reactive substances and activities of superoxide dismutase and glutathione reductase in diabetics to an extent greater than that of higher CO doses. At doses 12.5 and 25 but not 50 mg/(kg bw), CO significantly ameliorated pancreatic levels of interleukin-1β and nitric oxide. In conclusion, appropriate doses of CO of the linalool chemotype exhibited therapeutic potential in glycemic control in diabetes that was at least partially resulted from improved insulin secretion. The ameliorated oxidative stress and proinflammatory environment in the pancreas by CO may provide a protective effect on pancreatic β cells and warrant further investigation.

Cinnamomum osmophloeum Kanehira is a Taiwan native plant that belongs to genus Cinnamomum and is also known as pseudocinnamomum or indigenous cinnamon. Its leaf is traditionally used by local people in cooking and as folk therapy. We previously demonstrated the chemical composition and anti-inflammatory effect of leaf essential oil of Cinnamomum osmophloeum Kanehira of linalool chemotype in streptozotocin-induced diabetic rats and on endotoxin-injected mice. The aim of the present study is to evaluate whether cinnamaldehyde and linalool the active anti-inflammatory compounds in leaf essential oil of Cinnamomum osmophloeum Kanehira. Before the injection of endotoxin, C57BL/6 mice of the experimental groups were administered cinnamaldehyde (0.45 or 0.9 mg/kg body weight) or linalool (2.6 or 5.2 mg/kg body weight), mice of the positive control group were administered the leaf essential oil (13 mg/kg body weight), and mice of the negative group were administered vehicle (corn oil, 4 mL/kg body weight) by gavage every other day for two weeks. All mice received endotoxin (i.p. 10 mg/mL/kg body weight) the next day after the final administration and were killed 12 h after the injection. Normal control mice were pretreated with vehicle followed by the injection with saline. None of the treatment found to affect body weight or food or water intake of mice before the injection of endotoxin. Cinnamaldehyde and linalool were found significantly reversed endotoxin-induced body weight loss and lymphoid organ enlargement compared with vehicle (P < 0.05). Both compounds also significantly lowered endotoxin-induced levels of peripheral nitrate/nitrite, interleukin (IL)-1β, IL-18, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, and High-mobility group box 1 protein (HMGB-1), and levels of nitrate/nitrite, IL-1β, TNF-α, and IFN-γ in spleen and mesenteric lymph nodes (MLNs) (P < 0.05). Endotoxin-induced expression of toll-like receptor 4 (TLR4), Myeloid differentiation primary response gene 88 (MyD88), myeloid differentiation protein 2 (MD2), Nod-like receptor family, pyrin domain containing 3 (NLRP3), apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC), and caspase-1 in spleen and mesenteric lymph nodes (MLNs) were inhibited by all tested doses of cinnamaldehyde and linalool (P < 0.05). Subsequently, the activation of nuclear factor (NF)-κB and the activity of caspase-1 in spleen and MLNs were also suppressed by these two compounds (P < 0.05). In addition, cinnamaldehyde and linalool at the dose equivalent to their corresponding content in the tested dose of the leaf essential oil, which was 0.9 mg/kg and 5.2 mg/kg, respectively, showed similar or slightly less inhibitory activity for most of these inflammatory parameters compared with that of the leaf essential oil. Our data confirmed the potential use of leaf essential oil of Cinnamomum osmophloeum Kanehira as an anti-inflammatory natural product and provide evidence for cinnamaldehyde and linalool as two potent agents for prophylactic use in ...

Two nucleotide sequences for genes that encode alpha-amylase inhibitor 4 (alphaAI-4) from white kidney bean (WKB) cv. 858, designated gene alphaAI-4 (Accession No. ), and alpha-amylase inhibitor 5 (alphaAI-5) from black bean (BB), designated gene alphaAI-5 (Accession No. ), were determined. Genes alphaAI-4 and alphaAI-5 encode 244 amino acid prepro-alphaAI-4 and prepro-alphaAI-5 polypeptides that are 93 and 95% identical with alpha-amylase inhibitor l (alphaAI-l; Hoffman, L. M.; Ma, Y.; Barker, R. F. Nucleic Acids Res. 1982, 10, 7819-7828), 40 and 43% identical with red kidney bean lectin, and 52 and 55% identical with arcelin l of wild-type bean. The high degree of sequence similarity indicates the evolutionary relationship among these genes. PCR analysis of genomic DNA purified from six genotypes of Phaseolus vulgaris showed very similar band patterns in 2% agarose gel, another indication of the conserved size homology among these genes. Proteolytic processing sites were located between Asn77 and Ser78 for pro-alphaAI-4 and pro-alphaAI-5. A bend next to Asn77 in three-dimensional model structures of alphaAI-4 and alphaAI-5 proinhibitors indicates that the proteolytic cleavage is necessary to remove the conformational constraint for activation to the mature protein. Mature WKB alphaAI-4 was composed of four subunits (2alpha2beta) and had a molecular weight of 50000 determined by multiangle laser light scattering and 56714 determined by laser-assisted time-of-flight mass spectrometry.

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The major aim of made tea identification is to identify the variety and provenance of the tea plant. The present experiment used 113 tea plants [Camellia sinensis (L.) O. Kuntze] housed at the Tea Research and Extension Substation, from which 113 internal transcribed spacer 2 (ITS2) fragments, 104 trnL intron, and 98 trnL-trnF intergenic sequence region DNA sequences were successfully sequenced. The similarity of the ITS2 nucleotide sequences between tea plants housed at the Tea Research and Extension Substation was 0.379-0.994. In this polymerase chain reaction-amplified noncoding region, no varieties possessed identical sequences. Compared with the trnL intron and trnL-trnF intergenic sequence fragments of chloroplast cpDNA, the proportion of ITS2 nucleotide sequence variation was large and is more suitable for establishing a DNA barcode database to identify tea plant varieties. After establishing the database, 30 imported teas and 35 domestic made teas were used in this model system to explore the feasibility of using ITS2 sequences to identify the varieties and provenances of made teas. A phylogenetic tree was constructed using ITS2 sequences with the unweighted pair group method with arithmetic mean, which indicated that the same variety of tea plant is likely to be successfully categorized into one cluster, but contamination from other tea plants was also detected. This result provides molecular evidence that the similarity between important tea varieties in Taiwan remains high. We suggest a direct, wide collection of made tea and original samples of tea plants to establish an ITS2 sequence molecular barcode identification database to identify the varieties and provenances of tea plants. The DNA barcode comparison method can satisfy the need for a rapid, low-cost, frontline differentiation of the large amount of made teas from Taiwan and abroad, and can provide molecular evidence of their varieties and provenances.