A review of botanical characteristics, phytochemistry, clinical relevance in efficacy and safety of Lycium barbarum fruit (Goji)

Lycium barbarum has been used as a traditional Chinese medicine (TCM) to nourish liver and kidney, and brighten the eye. The fruits are dried or freshly squeezed for their juice and concentrated for beverages. Among various constituents, a group of polysaccharides (LBP) with a Glycan-O-Ser glycopeptide structure has been most researched and considered to be important for the efficacy of L. barbarum. Studies indicate effects of L. barbarum on aging, neuroprotection, general well-being, fatigue/endurance, metabolism/energy expenditure, glucose control in diabetics, glaucoma, anti-oxidant properties, immunomodulation, anti-tumor activity and cytoprotection. In addition to TCM, L. barbarum can be sold as a dietary supplement or classified as a food based upon the long and safe traditional usage. This review is to provide background and updated information of chemical constituents and efficacies with safety including a new direction for research and current regulatory situation of L. barbarum.     

Intramolecular electron transfer in the dihaem cytochrome c peroxidase of Pseudomonas aeruginosa

Mutant forms of the enzyme cytochrome c peroxidase from Pseudomonas aeruginosa, in which the peroxidatic haem ligand (H71) and putative haem-bridging amino acid (W94) have been mutated, were produced in an E. coli expression system as a means of investigating possible mechanisms of intramolecular electron transfer within the enzyme. EPR spectroscopy indicated the presence of a high-spin, presumably five-coordinate, peroxidatic haem site in the H71G and H71G/W94A mutants, whilst the W94A mutant apparently retained the normal six-coordinate haem structures. In turnover experiments, these mutants show 55, 4, and <1% activity, respectively, as compared to the wild-type enzyme. The W94A mutant shows essentially no activity in turnover experiments. Circular dichroism spectroscopy indicates no measurable difference in the secondary structure of the H71G mutant from that of the native enzyme, whilst some small differences are observed for the double mutant. Treatment of the oxidised mutant proteins with hydrogen peroxide, in the absence of preactivation or exogenous reductants, yields products that suggest the formation of a tryptophan radical species in the case of the H71 mutant and the production of a porphyrin radical in the case of the double mutant. These results are discussed in terms of the intramolecular electron transfer in this enzyme.     

可食用动物血液资源的开发利用

可食用动物血液，指屠宰家畜时所能收集到的血液，是一种宝贵的资源，具有很高的营养保健价值，它在人类食品中的开发应用正受到广泛重视。中国每年产生１８０万ｔ的动物血液，工业规模的可食用性利用基本属于空白。本文分析了动物血液的生化组成，论述了血液的营养特性和可食用动物血液对人类营养的价值和意义，介绍了动物血液利用的国内外概况和今后的发展方向，并指出社会经济和科学技术的发展为合理开发畜血资源提供了机遇和条件，可食用动物血液的研究和开发将会取得较大的进展。     

Valorisation of blood protein from livestock to produce haem iron-fortified hydrolysates with antioxidant activity

Blood is the main by-product from slaughterhouses bearing high levels of suspended solids (18% w/w) and BOD₅ (250 000–375 000 mg O₂/L), which makes difficult its handling and disposal. This study proposes the valorisation of blood protein to produce enzymatic hydrolysates rich in haemic iron and antioxidant peptides. Haemic iron presents higher bioavailability compared to its inorganic form, but its incorporation into foodstuffs is restrained by its high tendency to oxidation. Six commercial proteases of animal, plant and bacterial origin were employed to produce the enzymatic hydrolysates. Subtilisin and trypsin treatments were able to recover 70% of haem iron as soluble peptides, in contrast with plant enzymes where the proteolysis was reduced. Moreover, some enzymatic treatments led to hydrolysates with high levels of some in vitro antioxidant activities such as radical scavenging (Protamex, IC₅₀ 3.52 mg/mL) or metal chelating activity (trypsin, IC₅₀ 0.27 mg/mL). We conclude the enzymatic valorisation of blood protein increases haemic iron bioavailability and produces antioxidant peptides. Both properties are of interest for their use as iron fortification supplements.     

Consumption of Red/Processed Meat and Colorectal Carcinoma: Possible Mechanisms Underlying the Significant Association

Epidemiology and experimental studies provide an overwhelming support of the notion that diets high in red or processed meat accompany an elevated risk of developing pre-neoplastic colorectal adenoma and frank colorectal carcinoma (CRC). The underlying mechanisms are disputed; thus several hypotheses have been proposed. A large body of reports converges, however, on haem and nitrosyl haem as major contributors to the CRC development, presumably acting through various mechanisms. Apart from a potentially higher intestinal mutagenic load among consumers on a diet rich in red/processed meat, other mechanisms involving subtle interference with colorectal stem/progenitor cell survival or maturation are likewise at play. From an overarching perspective, suggested candidate mechanisms for red/processed meat-induced CRC appear as three partly overlapping tenets: (i) increased N-nitrosation/oxidative load leading to DNA adducts and lipid peroxidation in the intestinal epithelium, (ii) proliferative stimulation of the epithelium through haem or food-derived metabolites that either act directly or subsequent to conversion, and (iii) higher inflammatory response, which may trigger a wide cascade of pro-malignant processes. In this review, we summarize and discuss major findings of the area in the context of potentially pertinent mechanisms underlying the above-mentioned association between consumption of red/processed meat and increased risk of developing CRC.     

Structure and redox properties of the haem centre in the C357M mutant of cytochrome P450cam

The effects of site-specific mutation of the axial cysteine (C357M) to a methionine residue in cytochrome P450cam on the enzyme's coordination geometry and redox potential have been investigated. The absorption spectra of the haem centre in the C357M mutant of the enzyme showed close similarity to those of cytochrome c both in the oxidised and reduced forms. A well-defined absorption peak at 695 nm, similar to that seen in the case of cytochrome c and characteristic of methionine ligation to the ferric haem, was observed. The results indicated that the haem of C357M cytochrome P450cam is possibly axially coordinated to a methionine and a histidine, analogously to cytochrome c. The circular dichroism spectra in the visible and the far-UV regions suggested that the tertiary structure of the haem cavity in the C357M mutant cytochrome P450cam was distinctly different from that in the wild-type enzyme or in cytochrome c, although the secondary structure of the mutant remained identical to that of the wild-type cytochrome P450cam. Comparison of the natures of the CD spectra in the 400 nm and 695 nm regions of the C357M mutant of cytochrome P450cam with those of horse cytochrome c suggested (R) chirality at the sulfur atom of the iron-bound methionine residue in the mutant. The redox potential of the haem centre, estimated by redox titration of the C357M mutant, was found to be +260 mV, which is much higher than that in the wild-type enzyme and similar to the redox potential of cytochrome c. This supported the concept that axial ligation of the haem plays the major role in tuning the redox potential of the haem centre in haem proteins.