Qin C., Li Y., Niu W., Ding Y., Zhang R., Shang X. (2010): Analysis and characterisation of anthocyanins in mulberry fruit. Czech J. Food Sci., 28: 117-126.The fruit of mulberry (Morus alba L., Moraceae) has been used as medicinal food in China for a long history. The pigment from the fruit extract is a kind of natural colourant for food processing and has potential medical and commercial values. This study focuses on the analysis and characterisation of anthocyanins from mulberry pigment. The fresh mulberry fruits were extracted with the solvent of 95% alcohol/0.1% HC l (1:1, ratio) at room temperature for 4 h in the dark. After the isolation using C-18 column, the pigment was identified with UV-Visible Spectroscopy, HPLC-PAD, LC-MS, and 1 HNMR. The results showed that the abundant anthocyanins in mulberry pigment are cyanidin 3-O-rutinoside (60%) and cyanidin 3-O-glucoside (38%). The minor anthocyanins (totally 2%) are pelargonidin 3-O-glucoside and pelargonidin 3-O-rutinoside.

Cystathionine β-synthase (CBS) is the central enzyme in the trans-sulfuration pathway that converts homocysteine to cysteine. It is also one of the three major enzymes involved in the biogenesis of H 2 S. CBS is a complex protein with a modular three-domain architecture, the central domain of which contains a C 272 XXC 275 motif whose function has yet to be determined. In the present study, we demonstrated that the CXXC motif exists in oxidized and reduced states in the recombinant enzyme by mass spectroscopic analysis and a thiol labeling assay. The activity of reduced CBS is ~2-to 3-fold greater than that of the oxidized enzyme, and substitution of either cysteine in CXXC motif leads to a loss of redox sensitivity. The Cys 272 -Cys 275 disulfide bond in CBS has a midpoint potential of -314 mV at pH 7.4. Additionally, the CXXC motif also exists in oxidized and reduced states in human embryonic kidney 293 (HEK293) cells under oxidative and reductive conditions, and stressing these cells with dithiothreitol (DTT) results in more reduced enzyme and a concomitant increase in H 2 S production in live HEK293 cells as determined using a H 2 S fluorescent probe. By contrast, incubation of cells with aminooxyacetic acid (AOAA), an inhibitor of CBS and cystathionine γ-lyase (CSE), eliminates the increase of H 2 S production after the cells were exposed to DTT. These findings indicate that CBS is post-translationally regulated by a redox-active disulfide bond in the CXXC motif. The results als o demonstrate that CBS-derived H 2 S production is increased in cells under reductive stress conditions.

Gln treatment protects from intestinal injury and regulates the gut flora imbalance in hypoxia environment. These effects may be related to the TLR4/MyD88/NF-κB signaling pathway.

Toll-like receptors (TLRs) recognize microbial pathogens and trigger immune response, but their regulation by neuropeptide-vasoactive intestinal peptide (VIP) in weaned piglets infected by enterotoxigenic Escherichia coli (ETEC) K88 remains unexplored. Therefore, the study was conducted to investigate its role using a model of early weaned piglets infected by ETEC K88. Male Duroc×Landrace×Yorkshire piglets (n = 24) were randomly divided into control, ETEC K88, VIP, and ETEC K88+VIP groups. On the first three days, ETEC K88 and ETEC K88+VIP groups were orally administrated with ETEC K88, other two groups were given sterile medium. Then each piglet from VIP and ETEC K88+VIP group received 10 nmol VIP intraperitoneally (i.p.) once daily, on day four and six. On the seventh day, the piglets were sacrificed. The results indicated that administration of VIP improved the growth performance, reduced diarrhea incidence of ETEC K88 challenged pigs, and mitigated the histopathological changes of intestine. Serum levels of IL-2, IL-6, IL-12p40, IFN-γ and TNF-α in the ETEC K88+ VIP group were significantly reduced compared with those in the ETEC group. VIP significantly increased IL-4, IL-10, TGF-β and S-IgA production compared with the ETEC K88 group. Besides, VIP could inhibit the expression of TLR2, TLR4, MyD88, NF-κB p65 and the phosphorylation of IκB-α, p-ERK, p-JNK, and p-38 induced by ETEC K88. Moreover, VIP could upregulate the expression of occludin in the ileum mucosa compared with the ETEC K88 group. Colon and caecum content bacterial richness and diversity were lower for pigs in the ETEC group than the unchallenged groups. These results demonstrate that VIP is beneficial for the maturation of the intestinal mucosal immune system and elicited local immunomodulatory activities. The TLR2/4-MyD88 mediated NF-κB and MAPK signaling pathway may be critical to the mechanism underlying the modulatory effect of VIP on intestinal mucosal immune function and bacterial community.

A high-throughput assay was developed to identify inhibitors of cystathionine β-synthase (CBS), which is one of three key enzymes involved in HS biosynthesis. Screening of 6491 natural compounds identified several selective CBS inhibitors, which suppressed the proliferation of HT29 cancer cells, with IC values of less than 10 μM.