RESUMO
Flaxseed cake contains cyanogenic glucosides, which can be metabolized into hydrocyanic acid in an animal's body, leading to asphyxia poisoning in cells. Beta-glucosidase is highly efficient in degrading cyanogenic glucosides. The Cattle may have ß-glucosidase-producing strains in the intestinal tract after eating small amounts of flaxseed cake for a long time. This study aimed to isolate of a strain from cow dung that produces ß-glucosidase with high activity and can significantly reduce the amount of cyanogenic glucosides. We used cow dung as the microflora source and an esculin agar as the selective medium. After screening with 0.05% esculin and 0.01% ferric citrate, we isolated 5 strains producing high amounts of ß-glucosidase. In vitro flaxseed cake fermentation was fermented by these 5 strains, in which the strain M-2 exerted the best effect (P < 0.05). The strain M-2 was identified as Lichtheimia ramosa and used as the fermentation strain to optimize the fermentation parameters by a single factor analysis and orthogonal experimental design. The optimum condition was as follows: inoculum size 3%, water content 60%, time 144 h, and temperature 32 °C. Under this condition, the removal rate of cyanogenic glucosides reached 89%, and crude protein increment reached 44%. These results provided a theoretical basis for the removal of cyanogenic glucosides in flaxseed and the comprehensive utilization of flaxseed cake.
RESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Bawei Xileisan (BXS), a traditional Chinese compound medicine, has been historically used in the treatment of ulcers and inflammation. BXS is also used as a topical agent for the treatment of ulcerative colitis in China. The underlying mechanism, however, remains elusive. MATERIALS AND METHODS: Thirty-six female C57BL/6 mice with average weight of 20±2g were used for an in vivo study. The present work was conducted in accordance with the protocols approved by the Ethics Committee of Animal Experiments of Lanzhou University. The mice were induced to develop acute colitis by treating these with 3% dextran sulfate sodium (DSS) solution for 5 days. Subsequently, BXS (200,400mg/kg) was rectally administered daily for one week. All mice were killed at day 12 and their body weight, colon length, and histological changes were all recorded. Serum T helper 17 (Th17) cytokine levels were determined by enzyme-linked immunosorbent assay (ELISA). Th17 and regulatory T cell (Treg) in splenocyte mononuclear cells were isolated and identified via flow cytometry. Stool DNA was extracted and the absolute number of Bacteroides and Lactobacillus were measured by using real-time Q-PCR. RESULTS: Shortened colon and damaged tissue structure were profoundly ameliorated by BXS enema. The expression level of Th17-related cytokines IL-17A/F and IL-22 was significantly and dose-dependently reduced, resulting in the restoration of Th17/Treg balance. Moreover, BXS also improved the feces Lactobacillus levels and manifested beneficial effects on Bacteroides. CONCLUSIONS: The findings of the present study suggest that BXS is curative in a mouse model of ulcerative colitis, and the underlying mechanism might involve disruption of the Th17 pathway and the induction of a Th17/Treg imbalance, as well as an the development of an opsonic effect on specific gut microbiota.
