AIM OF THE STUDY: The present study aimed to characterize the chemical properties of a purified polysaccharide extracted from the aerial part of Tetrastigma hemsleyanum (SYQP) and investigate its antipyretic and antitumor effects in mice models.
MATERIALS AND METHODS: Water-soluble crude polysaccharides from the aerial parts of Tetrastigma hemsleyanum were extracted and fractionated by DEAE and gel permeation chromatography. Homogeneity, molecular weight, monosaccharide composition, and FTIR analysis were performed to characterize the SYQP. Antipyretic effect of SYQP was examined using Brewer's yeast induced hyperthermia test. Antitumor effect was investigated using H22 tumor bearing mice. The serum cytokines were determined to evaluated the biological activities of SYQP.
RESULTS: SYQP was composed of galacturonic acid (GalA), glucose (Glc), mannose (Man), arabinose (Ara), galactose (Gal), and rhamnose (Rha) with a molar ratio of 11.3:7.1:2.5:1.0:0.9:0.5 and it had an average molecular weight of 66.2 kDa. The oral administration of SYQP at 200 and 400 mg/kg could markedly suppress the hyperthermia of mice induced by Brewer's yeast and decrease the production of cytokines especially prostaglandin E2 (PGE2) in the serum of mice. SYQP inhibited the growth of H22 tumor in mice with inhibitory rate of 39.9% at the administration dose of 200 mg/kg and increased the production of cytokines such as tumor necrosis factor-alpha (TNF-a) and interferon γ (IFN-γ). Experimental results showed that the preventive administration of SYQP before lipopolysaccharide (LPS) reduced the high cytokine levels such as IL-6, IL-10 and IFN-γ, indicating that SYQP might act as a competitor with LPS to interact with toll like receptor 4 (TLR4), which further regulated the secretion of cytokines.
CONCLUSION: The anti-inflammatory and antitumor activities of SYQP might be related to its regulation of host immune function by controlling the secretion of cytokines.
RESULTS: We found that none of the monosaccharides that make up the plant cell wall polysaccharides specifically inhibit Salmonella attachment to the bacterial cellulose-based plant cell wall models. Confocal laser scanning microscopy showed that Salmonella cells can penetrate and attach within the tightly arranged bacterial cellulose network. Analysis of images obtained from atomic force microscopy revealed that the bacterial cellulose-pectin-xyloglucan composite with 0.3 % (w/v) xyloglucan, previously shown to have the highest number of Salmonella cells attached to it, had significantly thicker cellulose fibrils compared to other composites. Scanning electron microscopy images also showed that the bacterial cellulose and bacterial cellulose-xyloglucan composites were more porous when compared to the other composites containing pectin.
CONCLUSIONS: Our study found that the attachment of Salmonella cells to cut plant cell walls was not mediated by specific carbohydrate interactions. This suggests that the attachment of Salmonella strains to the plant cell wall models were more dependent on the structural characteristics of the attachment surface. Pectin reduces the porosity and space between cellulose fibrils, which then forms a matrix that is able to retain Salmonella cells within the bacterial cellulose network. When present with pectin, xyloglucan provides a greater surface for Salmonella cells to attach through the thickening of cellulose fibrils.
OBJECTIVES: This work focuses on the development of a simple cultivation strategy for exopolysaccharides (EPS) production using Ganoderma lucidum and submerged cultivation system.
METHODS: At first, the best medium supporting EPS production was chosen experimentally from the current published data. Second, like many EPS production processes, carbon and nitrogen concentrations were optimized to support the highest production of polysaccharides in the shake flask level. Furthermore, the process was scaled up in 16-L stirred tank bioreactor.
RESULTS: The results clearly demonstrated that the best cultivation strategy was cultivation under controlled pH conditions (pH 5.5). Under this condition, the maximal volumetric and specific yield of EPS production were, 5.0 g/L and 0.42 g/g, respectively.
CONCLUSION: The current results clearly demonstrate the high potential use of submerged cultivation system as an alternative to conventional solid-state fermentation for EPS production by G. lucidum. Furthermore, the optimization of both carbon and nitrogen sources concentration and scaling up of the process showed a significant increase in both volumetric and specific EPS production.
METHODS: The parameters of spray-dried 'cempedak' fruit powder under study include inlet air temperature (140-180°C) and maltodextrin (DE 10) concentrations (5-15% w/w). Response surface methodology involving 14 runs was used to assess the effects of inlet temperature and maltodextrin on the powder flow properties and reconstitution properties of the spray-dried 'cempedak' powder.
RESULTS: Out of the tested responses, only bulk density, change in cake height ratio, and water solubility index had a high coefficient of determination value. Inlet air temperature was found to be the main parameter to affect the bulk density, caking and water solubility index, when compared to maltodextrin concentration. By setting minimization of caking and maximization of water solubility index as the main determinants, the optimal parameters of 160°C inlet temperature and 15% (w/w) maltodextrin DE10 were generated, with a desirability of 0.697.
CONCLUSIONS: The powder produced under optimal conditions (160°C and 15% w/w maltodextrin) had a low bulk density (480.01 kg/m3), low caking properties (0.17 change in cake height ratio), and a high solubility index (88.69). This indicates that the powder is stable to be stored (without caking) and will have good reconstitution when added to water.