Rapid quantification of polysaccharide and the main onosaccharides in Dendrobium huoshanense by near-infrared attenuated total reflectance spectroscopy.

A rapid, green, low cost and nondestructive attenuated total reflection near infrared (ATR NIR) method was developed to quantify the total polysaccharide and the main monosaccharides mannose and glucose in Dendrobium huoshanense. Total 100 D. huoshanense samples from different places were analyzed using ATR NIR method. Potential outlying samples were initially removed from the collected NIR data using the PCA-Mahalanobis distance method. Spectral data preprocessing was studied in the construction of a partial least squares (PLS) model and six different signal pretreatment methods, including multiplicative scattering correction (MSC), standard normal transformation (SNV), first and second derivatives, the combination of MSC with the first derivative, and the combination of SNV with the first derivative, were compared. The results showed that the best signal pretreatment method was the spectral data pretreated by SNV combined with the first derivative due to it showed the lowest root-mean-square error of cross-validation (RMSECV), highest R2 for both the polysaccharide and its main monosaccharides. In order to improve the performance of the model, the pretreated full spectrum was calculated by different wavelength selection method. The results showed that the optional wavelength selection model was the one simultaneously selecting the NIR wavelength ranges 7500-5750 cm-1, 5250-4700 cm-1, 4450-4300 cm-1 and 4200-4100 cm-1 because of the lowest RMSECV and the highest R2 among the ten wavelength selection models. The external validation and the complete external validation confirmed the robustness and reliability of the developed NIR model. The contents of the total polysaccharide and the main monosaccharides are the essential quality assessment criterion for plant medicines while their traditional quantification methods involved sample destruction, tedious sample processing and non-environmentally friendly pretreatment, therefore, our study might provide an efficient technique tool for the rapid, green and nondestructive quantification of the total polysaccharide and the main monosaccharides for D. huoshanense and other rich-in-polysaccharide plant medicines.

Preliminary characterization of proteoglycan from Hyriopsis cumingii.

OBJECTIVE: To study the preliminary characterizations of Hyriopsis cumingii proteoglycan (HCPG). METHODS: The content of carbohydrate and protein were measured by spectrophotometry. FTIR spectrum was used to analyze the functional groups. Relative molecular mass and amino acid composition were detected by HPLC. GC was utilized to determine the monosaccharide composition. The glycopeptide linkage-bond was detected by using the method of beta-elimination reaction. RESULTS: In HCPG,the content of carbohydrate and protein was 80.06% and 9.42%, respectively. FTIR spectrum showed the characteristic absorptions of polysaccharides and protein. Relative molecular mass of HCPG, determined by size-exclusive HPLC, was 503.1 kDa. GC spectra demonstrated that polysaccharide of HCPG was composed of rhamnose, fucose, mannose, glucose and galactose with a molar ratio of 13.80: 4.51: 7.70: 64.92 : 9.07. Fourteen amino acids (13 known and one unknown) have been detected by pre-column derivation HPLC. From beta-elimination reaction, peptide chain was attached to the carbohydrate chain by O-glycosidic bond. CONCLUSION: Basic characterizations of HCPG have been determined preliminarily.

Ultrasonic-assisted extraction and in vitro antioxidant activity of polysaccharides from Agaricus bisporus.

OBJECTIVE: To optimize ultrasonic-assisted extraction parameters of polysaccharides from Agaricus bisporus and evaluate antioxidant activities of A. bisporus polysaccharides. METHODS: Polysaccharides from A. bisporus was extracted by using methods of ultrasonic-assisted hot water lixiviation, ethanol precipitation, Sevag's deproteination and ethanol precipitation again. Extraction temperature, extraction time, ratio of water to raw material and ultrasonic power were selected in single-factor tests. Based on the single-factor tests, parameters combination for the ultrasonic-assisted extraction of A. bisporus polysaccharides was optimized by using four-factor-three-level orthogonal test. Antioxidant activities (reductive potential, superoxide anion scavenging activity and H2O2 scavenging activity) of A. bisporus polysaccharides were evaluated in vitro. RESULTS: Optimum conditions for the extracting of A. bisporus polysaccharides were extracting temperature 65 degrees C, extracting time 40 min, ratio of water to raw material 30 mL/g and ultrasonic power 170 w. Practicing this optimal condition, extraction yield of polysaccharides from A. bisporus was 5.6 014%. In crude polysaccharides of A. bisporus, carbohydrates content, determined by applying the phenol-sulfuric acid method, was 75.48%. Polysaccharides of A. bisporus could reduce ferric ion, scavenge superoxide anion and hydrogen peroxide in a dose-dependent manner. CONCLUSION: Utrasonic-assisted extraction could be used in the extracting of A. bisporus polysaccharides. Polysaccharides of A. bisporus, had direct and potent antioxidant activities, might be developed and utilized as natural antioxidant.