Porphyra Yezoensis Research Articles

Effects of Porphyra yezoensis polysaccharide on antioxidant and liver health of spotted sea bass, Lateolabrax maculatus

Effects of Porphyra yezoensis polysaccharide on antioxidant and liver health of spotted sea bass, Lateolabrax maculatus

Complete genome sequence of Algimonas porphyrae type strain LMG 26424, a prosthecate bacterium isolated from the red alga Porphyra yezoensis.

Algimonas porphyrae is a dimorphic, prosthecate member of the family Robigintomaculaceae, order Caulobacterales, in the class Alphaproteobacteria, originally isolated from the red alga Porphyra yezoensis. Here we report the complete genome of type strain LMG 26424T (0 C-2-2T) obtained by sequencing with Oxford Nanopore technology.

Unravelling the effects of drying techniques on Porphyra yezoensis: Morphology, rehydration properties, metabolomic profile, and taste formation

This study explored the impact of sun drying (SD), freeze drying (FD), oven drying (OD), and microwave drying (MD) on the morphology, rehydration properties, metabolomic profile, and taste formation of Porphyra yezoensis. FD elicited a brighter colour, smooth surface, porous microstructure, and strong rehydration properties in P. yezoensis, while dramatically maintaining the umami, sweetness, and saltiness. OD and MD decreased structural openness owing to tissue collapse and affected water absorption. Metabolomic analysis revealed 1030 metabolites, among which taste-related compounds, especially free amino acids, nucleotides, organic acids, and their derivatives, were the main biomarkers for distinguishing the different drying methods. Their related metabolic pathways, such as taurine and hypotaurine metabolism; purine metabolism; glyoxylate and dicarboxylate metabolism; and citrate cycle, were the most active. A metabolic pathway network of the main taste compounds was built to provide novel insights into the mechanisms underlying the taste profile changes associated with different drying methods.

Comparative Analysis of XGB, CNN, and ResNet Models for Predicting Moisture Content in Porphyra yezoensis Using Near-Infrared Spectroscopy.

This study explored the performance and reliability of three predictive models-extreme gradient boosting (XGB), convolutional neural network (CNN), and residual neural network (ResNet)-for determining the moisture content in Porphyra yezoensis using near-infrared (NIR) spectroscopy. We meticulously selected 380 samples from various sources to ensure a comprehensive dataset, which was then divided into training (300 samples) and test sets (80 samples). The models were evaluated based on prediction accuracy and stability, employing genetic algorithms (GA) and partial least squares (PLS) for wavelength selection to enhance the interpretability of feature extraction outcomes. The results demonstrated that the XGB model excelled with a determination coefficient (R2) of 0.979, a root mean square error of prediction (RMSEP) of 0.004, and a high ratio of performance to deviation (RPD) of 4.849, outperforming both CNN and ResNet models. A Gaussian process regression (GPR) was employed for uncertainty assessment, reinforcing the reliability of our models. Considering the XGB model's high accuracy and stability, its implementation in industrial settings for quality assurance is recommended, particularly in the food industry where rapid and non-destructive moisture content analysis is essential. This approach facilitates a more efficient process for determining moisture content, thereby enhancing product quality and safety.

Rapid identification of phycobiliproteins in Porphyra yezoensis using near-infrared combined with convolutional neural network

Phycobiliproteins (PBPs) are the main pigment proteins and important indicators for evaluating the quality of Porphyra yezoensis (nori). This study aimed to develop a non-destructive and rapid method for determining PBP content (including total PBPs, phycoerythrin, phycocyanin, and allophycocyanin) in P. yezoensis, using near-infrared spectrum technology combined with a convolutional neural network (CNN), and to explore the influence of spectral preprocessing methods and machine learning algorithms on the predictive ability of the model. First, the spectral data was standardized using a combination of standard normal variable transformation and the first derivative to improve the accuracy and predictive ability of the model. We compared various models and determined that the CNN model performed better than conventional methods. After optimizing the number of convolutional layers, dropout rate, and learning rate, the performance of the CNN model was further improved. This study demonstrates the capability of the CNN model to leverage spectral data and solve regression problems to accurately measure PBPs. Moreover, for the first time, we established a functional equation between PBPs and P. yezoensis grades. This study provides a feasible and rapid method for the quantitative detection of PBPs in P. yezoensis.

Peptidomics- inspired discovery and activity evaluation of antioxidant peptides in multiple strains mixed fermentation of Porphyra yezoensis

This study investigated the production of antioxidant peptides from Porphyra yezoensis through fermentation with three strains of microorganisms: Lactiplantibacillus plantarum L13, Bacillus amyloliquefaciens MMB-02, and Saccharomyces cerevisiae A8. The crude peptides were extracted by aqueous acid precipitation and purified by Sephadex G-25 gel column to produce highly active antioxidant components with molecular weight of <4000 Da. The LC-MS/MS result revealed that the fermentation group contained more hydrophobic amino acids and oligopeptides, which were mainly originated from phycobiliproteins and algal blue proteins. Finally, the antioxidant activity of Porphyra yezoensis was determined with DPPH· and ABTS· scavenging rates of 54.87% and 57.39%, respectively. The ferric ion-reducing power (FRAP) and enzyme activities of SOD and CAT were significantly higher than those of the control group. This study provides a scientific foundation for the deep processing of striped seaweed and contributes to the theoretical understanding of synthetic antioxidant substitutes.

Phycosphere bacterial disturbance of Saccharina japonica caused by white rot disease relates to seawater nutrients.

In mid-November 2021, there were large areas of white rot disease on cultivated Saccharina japonica in Rongcheng City, China, and diseases were undetected on Sargassum horneri and Porphyra yezoensis. The disturbance direction of bacterial community in the phycosphere after disease outbreak and the relationship with seawater nutrients remain unclear. Here, in situ studies of bacterial community in the non-diseased and diseased areas (Shawo and Dongchu islands) and seawater nutrient levels were carried out. 16S rRNA sequencing showed that the bacterial richness of the studied seaweeds increased in the diseased area. Only in S. japonica, Algitalea outcompeted abundant primary bacteria with probiotic relationships to the host of the non-diseased area, and dominated in the diseased area (17.6% of the total abundance). Nitrogen and phosphorus levels in seawater were 57.8% and 19.6% higher in the non-diseased area than those in the diseased area, respectively, and were strongly correlated with the phycosphere bacteria at the family level of S. japonica. There was no difference in potential pathogenicity between the two areas, while positive signal communications decreased, and nitrogen cycle, chemoheterotrophy, and cellulolysis increased in the diseased area compared to the non-diseased area. Overall, white rot disease caused a structural disturbance in phycosphere bacterial community of S. japonica that related to seawater nutrient levels. Enriched degraders and altered bacterial community functions may exacerbate the disease. This evaluation will provide information for white rot disease management to prevent and mitigate the occurrence of S. japonica outbreaks.

Probing the potential of mercury removal by covalently immobilized phycobiliproteins onto the surface of chitosan beads

Mercury emissions represent a significant risk to the environment and human health. Mercury is persistent and can circulate in the environment for thousands of years, which is why treating this toxic metal is important. Chitosan polymer is easily obtainable, and it has good mercury adsorption characteristics. This study aimed to improve its capabilities to absorb mercury by immobilizing phycobiliproteins (PBPs) onto the surface of chitosan beads (chitosan–PBPs). Phycobiliproteins, light-harvesting proteins from algae and cyanobacteria, have several industrially essential applications. These proteins can bind heavy metals with high affinities. Protein extracts obtained from both Arthrospira platensis, with C-phycocyanin (C-PC) as the primary protein, and Porphyra yezoensis, with R-phycocyanin (R-PC) and R-phycoerythrin (R-PE) as the dominant PBPs, were covalently immobilized onto chitosan beads. Beads with immobilized PBPs were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. Binding analysis showed that, on average, each chitosan bead weighed 20 mg and immobilized 63.54 μg of PBPs from Spirulina and 44.12 μg of PBPs from Porphyra. Immobilized proteins were still in their native state, with no visible color change months after immobilization. Chitosan–PBPs and chitosan alone were tested for mercury adsorption at pH 4 and pH 7 by atomic absorption spectroscopy. The tested concentration range of mercury was from 1 to 70 ppm. Affinity, calculated using Henry's binding isotherm, of chitosan–PBPs for mercury was twice as much higher at both pH values than chitosan alone. Furthermore, chitosan-PBP beads were able to absorb more mercury than chitosan alone. These results showed that the covalent immobilization of PBPs onto chitosan improves its mercury adsorption characteristics and creates a more efficient eco-friendly adsorbent to potentially remove mercury ions in the tested concentration range from polluted waters.

Flavour characterization of twelve species of edible algae

Integration of algae as ingredients in food products may contribute to the flavour characteristics, on top of providing nutritional requirements. In this study, characterization of the volatile and non-volatile flavour compounds was performed on 12 species of macroalgae and microalgae representing various groups of algae. Nine macroalgae species from three divisions were selected, namely Phaeophyta (brown alga): Laminaria japonica, Undaria pinnatifida, Sargassum fusiforme and Fucus vesiculosus; Rhodophyta (red alga): Porphyra haitanensis, Porphyra yezoensis, Palmaria palmata and Gelidium amansii, and Chlorophyta (green alga): Ulva lactuca. In addition, three microalgae species include Arthrospira platensis, Chlorella vulgaris and Dunaliella salina. Volatile compounds were analysed by solid-phase microextraction (SPME) and gas chromatography–mass spectrometry-flame ionization detector (GC–MS/FID). Amino acids and nucleotides were analysed using amino acid analyser and high-performance liquid chromatography (HPLC) respectively. Based on the identified volatile and non-volatile compounds, no obvious trend was found within each group of algae. However, some algae variants have been found to contain a unique aroma profile of selected volatile and non-volatile compounds. D. salina was found to be high in volatile aldehydes, ketones, and alcohols, primarily products of carotenoid degradation. U. lactuca contains the highest volatile sulfur content, while F. vesiculosus was found to be high in aldehyde and alcohol compounds, which are potentially fishy odours. C. vulgaris was found to have the highest value of equivalent umami concentration (EUC) followed by roasted P. haitanensis, indicating that both algae have the highest umami potential. Lastly, microalgae species A. platensis and C. vulgaris contained the highest amounts of sulfurous tasting amino acids cysteine and methionine respectively.

Comparative evaluation of amino acid profiles, fatty acid compositions, and nutritional value of two varieties of head water Porphyra yezoensis: “Jianghaida No. 1” and “Sutong No.1”

Comparative nutritional analysis of Porphyra yezoensis strains “Jianghai No. 1” and “Sutong No.1” revealed significant differences in crude protein, crude fat, crude fiber, crude ash, and total sugar. Both strains contained 16 amino acids, with alanine as the highest and histidine the lowest content. Methionine was determined to be the first limiting amino acid for both strains in both amino acid score and chemical score assessment. They also featured 24 fatty acids, differing notably in four saturated fatty acids and five unsaturated fatty acids. All 12 mineral elements were present, notably differing in sodium, magnesium, potassium, calcium, iron, and zinc. The “Jianghai No. 1” strain stands out with its nutrient-rich profile, featuring high protein content, low fat, and abundant minerals, which could potentially command higher market prices and generate greater economic benefits due to its superior nutritional, and set a strong foundation for its future large-scale promotion and cultivation.

Mechanism of Porphyra Yezoensis Polysaccharides in Inhibiting Hyperoxalate-Induced Renal Injury and Crystal Deposition.

Oxidative damage to the kidneys is a primary factor in the occurrence of kidney stones. This study explores the inhibitory effect of Porphyra yezoensis polysaccharides (PYP) on oxalate-induced renal injury by detecting levels of oxidative damage, expression of adhesion molecules, and damage to intracellular organelles and revealed the molecular mechanism by molecular biology methods. Additionally, we validated the role of PYP in vivo using a crystallization model of hyperoxalate-induced rats. PYP effectively scavenged the overproduction of reactive oxygen species (ROS) in HK-2 cells, inhibited the adhesion of calcium oxalate (CaOx) crystals on the cell surface, unblocked the cell cycle, restored the depolarization of the mitochondrial membrane potential, and inhibited cell death. PYP upregulated the expression of antioxidant proteins, including Nrf2, HO-1, SOD, and CAT, while decreasing the expression of Keap-1, thereby activating the Keap1/Nrf2 signaling pathway. PYP inhibited CaOx deposition in renal tubules in the rat crystallization model, significantly reduced high oxalate-induced renal injury, decreased the levels of the cell surface adhesion proteins, improved renal function in rats, and ultimately inhibited the formation of kidney stones. Therefore, PYP, which has crystallization inhibition and antioxidant properties, may be a therapeutic option for the treatment of kidney stones.

Assessing and optimizing the bioactivities of diverse enzyme-derived protein hydrolysates from Porphyra yezoensis: unlocking the health potential.

The interest in algae-derived bioactive compounds has grown due to their potential therapeutic efficacy against a range of diseases. These compounds, derived from proteins, exhibit diverse functions and profound pharmacological effects. Recent research has highlighted the extensive health benefits of algae-derived bioactive compounds, positioning them as potential natural antioxidants in the food, pharmaceutical, and cosmetic industries. This study focuses on extracting proteins from Porphyra yezoensis using innovative physical pre-treatment methods such as stirring, ball milling, and homogenization, under various acidic and alkaline conditions. Enzymatic hydrolysis, employing commercial enzymes at optimal temperature, pH, and enzyme-substrate ratios, produced distinct fractions according to molecular weight. Pepsin demonstrated the highest hydrolysis rate, with the fraction above 10kDa identified as the most bioactive hydrolysate. Antioxidant activity was evaluated through DPPH, ABTS, ferrous ion chelation, and reducing power assays, demonstrating high antioxidant potential and the ability to mitigate oxidative stress. The 10kDa fraction of pepsin hydrolysate exhibited 82.6% DPPH activity, 77.5% ABTS activity, 88.4% ferrous ion chelation activity, and higher reducing power potential (0.84 absorbance at 700nm). Further exploration of mechanisms, amino acid profiles, and potential in vivo benefits is essential to fully exploit the medicinal potential of these algae-derived hydrolysates.

Ultrasound-assisted fermentation of Porphyra yezoensis sauce at different growth stages using Lactiplantibacillus plantarum: Metabolic response and biological activity

This study first employed ultrasonic-assisted fermentation of seaweed foot material with Lactiplantibacillus plantarum to produce Porphyra yezoensis sauce. The aim was to examine L. plantarum's growth and metabolism of nutritional components at different growth stages under low- (133.99 W/L) and high-ultrasonic power densities (169.17 W/L). After 24-h fermentation, L. plantarum exhibited a 21.32 % increase in the sonicated P. yezoensis sauce at 133.99 W/L and the logarithmic growth phase compared to that at 169.17 W/L. In addition, compared to the non-sonicated sauce, total phenolic and flavonoid contents increased by around 58 % and 27 % in sonicated sauce at 133.99 W/L, reaching 92.38 mg GEA/g DW and 111.08 mg RE/g DW, respectively. Principal Component Analysis (PCA) of the evaluation criteria for different fermentation stages under 133.99 W/L power ultrasonication revealed that the P. yezoensis sauce generated more phenolic compounds and exhibited stronger antioxidant capabilities in the sonicated sample at the logarithmic phase of L. plantarum. Compared to the traditional treated P. yezoensis sauce, the content of free amino acids was significantly increased in sonicated sauce, especially for logarithmic phase. Finally, GC-IMS analysis demonstrated that the ultrasonication at logarithmic phase released more volatile compounds compared to the non-sonicated sauce. This led to a reduction in the fishy odour of the Porphyra yezoensis sauce and an improved release of favourable flavour compounds.

The Effects of Porphyra yezoensis Polysaccharides on Intestinal Health of Spotted Sea Bass, Lateolabrax maculatus

Porphyra yezoensis polysaccharides (PPs) have biological activities such as promoting digestion, functioning as antioxidants, and improving intestinal health. The aim of this study was to investigate the effects of PPs on the intestinal health of spotted sea bass (Lateolabrax maculatus). A total of 360 spotted sea bass (10.53 ± 0.02 g) were randomly divided into six groups. Fish in each group were fed with varying PP concentrations (0, 3, 6, 9, 12, 15 g/kg) for 52 days. The results showed that 12 g/kg PPs significantly increased the body weight gain, specific growth rate, and condition factor, while there was no significant change in the feed conversion ratio. A supplementation dosage of 9 g/kg PPs significantly increased intestinal amylase activity, and 12 g/kg PPs supplementation significantly increased intestinal trypsin activity. In addition, compared with the control group, there was no difference in lipase in the experimental groups. When fed 9 g/kg, the intestinal glutathione content was significantly increased, and the malondialdehyde content was significantly decreased; the effect of PPs on the catalase activity was not significant. PPs improved intestinal morphology, specifically by improving the intestinal villus morphology and increasing the intestinal lining surface area. Compared with the control group, PPs increased the abundance of Firmicutes and Bacteroides. At the genus level, Cyanobacteria, Muribaculaceae, and Lachnospiraceae were the main flora in the intestinal tract of spotted sea bass. In addition, PPs increased ACE and Chao1 indices of the intestinal microorganisms, while the Simpson index and Shannon index did not change significantly, indicating that intestinal microbial composition and abundance had increased to a certain extent. The results indicated that different levels of PPs in feed can improve the intestinal physiological and biochemical indexes, intestinal morphology, and microbial composition, and thus improve the intestinal health of spotted sea bass.

In Silico Identification and Characterization of Potential Red Seaweed Allergens

Red seaweeds such as Kappaphycus alvarezii and Porphyra yezoensis have many applications, especially in the food industry, which suggests the need for knowing their potential allergenicity. In silico approaches can be used to determine if a protein is an existing allergen or has the ability to cross-react with one. In this study, 318 sequences for Kappaphycus alvarezii and 641 protein sequences for Porphyra yezoensis were screened for potential allergens using AlgPred 2.0 and AllergenOnline, followed by the FAO allergenicity test using Allermatch. Data from this were used to predict the B-cell epitopes using the IEDP prediction tool and T-cell epitopes using MHC2Pred and were modeled using SWISS-MODEL and PyMOL to highlight specific epitopes. These models were assessed for quality using Global Quality Model Estimate (GQME) scores, ERRAT scores, and VERIFY 3D. Results showed fourteen (14) potential red seaweed allergens, four (4) of which were found in Kappaphycus alvarezii and ten (10) in Porphyra yezoensis. Several proteins of red seaweeds shared structural similarities with species normally associated with food allergies, such as common hazel, Atlantic salmon, and shark catfish, as well as other types of allergens such as those in house-dust mites, that could potentially induce cross-reactivity. Additionally anticipated were specific B-cell and T-cell epitopes and their specific peptide sequences that were incorporated in the 3D models, which were created for further comparison with other molecular structures of recognized allergens. Almost all of the 3D models had a GQME score of above 0.7 and had a high ERRAT score for overall quality but some failed to pass the VERIFY 3D test. This study could serve as a preliminary yet robust approach to identifying allergenic proteins in red seaweed and narrowing down potential existing cross-reactive allergens from various species that could aid in future in vitro and in vivo allergenicity studies.

Photosynthetic Physiological Response of Porphyra yezoensis to Light Change at Different CO2 Concentrations

The effect of different CO2 concentrations and their subsequent light changes on the photosynthetic characteristics of Porphyra yezoensis are not well understood. The relationship between the availability of CO2 and light to physiological traits of the thalli could help understand the response and adaptation mechanisms of P. yezoensis to extreme weather changes. In this study, the photosynthetic response of P. yezoensis to light changes at different CO2 concentrations was determined. Under low light intensity, the high CO2 concentration promoted the relative growth rate (RGR) of P. yezoensis by 22.79% compared to that of ambient CO2 treatment. The net photosynthetic rate and phycoerythrin (PE) content under high CO2 were also significantly greater than those under ambient CO2 treatment at low light therapy. Under high light intensity, high CO2 exacerbated the inhibitory effect of light on the RGR of thalli. The net photosynthetic rate and PE content were significantly reduced by 12.53% and 14.06% at elevated CO2 concentration under a high light intensity, respectively. Furthermore, the net photosynthetic rate was significantly decreased when the light intensity was rapidly reduced, especially under simultaneously elevated CO2 concentrations. These findings indicate that elevated CO2 concentration increased the RGR and PE content at low light intensity of P. yezoensis. In addition, this study provides a theoretical basis for the response and adaptation mechanism of P. yezoensis to extreme weather changes.

Anti-Pollutant Activity of Porphyra yezoensis Water Extract and Its Active Compound, Porphyra 334, against Urban Particulate Matter-Induced Keratinocyte Cell Damage

Urban particulate matter (UPM) causes skin aging and inflammatory reactions by influencing skin cells through the aryl hydrocarbon receptor (AhR) signaling pathway. Porphyra yezoensis (also known as Pyropia yezoensis), a red alga belonging to the Bangiaceae family, is an edible red seaweed. Here, we examined the anti-pollutant effect of P. yezoensis water extract. While UPM treatment induced xenobiotic response element (XRE) promoter luciferase activity, P. yezoensis water extract reduced UPM-induced XRE activity. Next, we isolated an active compound from P. yezoensis and identified it as porphyra 334. Similar to the P. yezoensis water extract, porphyra 334 attenuated UPM-induced XRE activity. Moreover, although UPM augmented AhR nuclear translocation, which led to an increase in cytochrome P450 1A1 (CYP1A1) mRNA levels, these effects were reduced by porphyra 334. Moreover, UPM induced the production of reactive oxygen species (ROS) and reduced cell proliferation. These effects were attenuated in response to porphyra 334 treatment. Furthermore, our results revealed that the increased ROS levels induced by UPM treatment induced transient receptor potential vanilloid 1 (TRPV1) activity, which is related to skin aging and inflammatory responses. However, porphyra 334 treatment reduced this reaction by inhibiting ROS production induced by CYP1A1 activation. This indicates that porphyra 334, an active compound of P. yezoensis, attenuates UP-induced cell damage by inhibiting AhR-induced ROS production, which results in a reduction in TRPV1 activation, leading to cell proliferation. This also suggests that porphyra 334 could protect the epidermis from harmful pollutants.

An ANSYS/LS-DYNA Simulation and Experimental Study of Sectional Hob Type Laver Harvesting Device

To solve the problems of low net harvesting rate, high loss rate, and uneven stubble height during the harvest of laver, the laver (Porphyra yezoensis) was selected as the research object, the analysis of the cultivation mode, biomechanical characteristics, harvesting trajectory and force of laver were carried out. A sectional hob type harvesting device was designed. A rigid-flexible coupling model related to the interaction between the cutting mechanism and the laver was constructed based on ANSYS/LS-DYNA. The Box–Behnken design method was used to simulate the effects of different structural parameters and process parameters on the force of laver cutting, and the bench test of the laver harvesting device was carried out. The simulation results showed that the four factors that significantly affect the force exerted on the laver during cutting in proper order were cutter revolving speed, knife extension length, knife inclination angle and forward velocity. When the combination of the forward velocity, the cutter revolving speed, the knife extension length and inclination angle was 0.77 m/s, 900 r/min, 40 mm, and 110°, respectively, the cutting force on laver was the smallest, which was 4.21 N. The bench test of harvesting performance showed that the cutter revolving speed has a significant impact on the recovery rate, and the forward velocity has a significant impact on the loss rate. When the harvesting speed ratio was λ4 (the cutter revolving speed was 900 r/min and the forward velocity was 0.77 m/s), the net harvesting rate and the loss rate were 97.45% and 3.38%, respectively, and the cutting proportion of laver can reach 77.5%. The results of the study provide a theoretical basis for the development of harvesting for laver.

The increased efficiency of porphyran hydrolysis by constructing a multifunctional enzyme complex from marine microorganisms

Porphyran, a polysaccharide composed of red algae, is a source of a multifunctional oligosaccharide material and raw biomass with various physiological activities. The glycolysis of porphyrans into oligosaccharides through various porphyranases is an approach for obtaining high-quality and promising alternative resources. In this study, porphyran was extracted from Porphyra yezoensis and used as a research substrate. We also established an efficient hydrolysis method using an enzymatic complex obtained through cohesin-dockerin interactions that degrade natural polysaccharides. The cohesion-dockerin interaction is designed to genetically bind the dockerin module to the end of an existing enzyme and then attach the cohesin module to obtain a protein complex. The designed protein complex has been shown to further increase the activity on the substrate, which can be considered a useful method to obtain efficient oligosaccharides or monosaccharides through hydrolysis of red algae for bioresources.

Hypoglycemic Effect of Polysaccharides from Porphyra yezoensis Associated with Reduced Intestinal α-Amylase Activity in Diabetes Mellitus KKAy Mice

ABSTRACT This study investigated the hypoglycaemic activity of Porphyra yezoensis polysaccharides (PPs). Forty eight KKAy mice were randomly assigned to four groups: one control group gavaged once daily with distilled water and three treatment groups gavaged once daily with different doses of PPs (100, 300 and 500 mg/kg) for 6 weeks. PPs administration decreased body weight, serum insulin, glucose, triglycerides, cholesterol, low-density lipoprotein cholesterol and intestinal α-amylase activity, increased high-density lipoprotein cholesterol and oral glucose tolerance. Intestinal α-amylase activities were positively correlated with serum glucose levels. Results indicated that PPs had hypoglycaemic activity and might be used for diabetes mellitus treatment.