Structural characterization of polysaccharides from Geranium sanguineum L. and their immunomodulatory effects in response to inflammatory agents

Analyzing the structure-activity relationship of raspberry polysaccharides using interpretable artificial neural network model

The structure-activity relationship has been a hot topic in the field of polysaccharide research. Six polysaccharides and three polysaccharide fragments were obtained from raspberry pulp. Based on their structural information and immune-enhancing activity data, an artificial neural network (ANN) model was used for prediction, and Gradient-weighted class activation mapping (Grad-CAM) algorithm was exploited for explanation structure-activity relationship of these raspberry polysaccharides in the present study. The structural information and immune activity data of raspberry polysaccharides were respectively used as input and output in the ANN model. The training and testing losses of ANN model was no longer decreased after trained for 200 epochs. The mean-square error (MSE) of training set and test set stabilized around 0.003 and 0.013, and the mean absolute percentage error (MAPE) of training set and test set were 0.21 % and 0.98 %, indicating the trained ANN model converged well and exhibited strong robustness. The interpretability analysis showed that molecular weight, content of arabinose, galactose or galacturonic acid, and glycosyl linkage patterns of →3)-Arap-(1→, Araf-(1→, →4)-Galp-(1 → were the main structural factors greatly affecting the immune-enhancing activity of raspberry polysaccharides. This work may provide a new perspective for the study of structure-activity relationship of polysaccharides.

Emerging Therapeutic Potential of Polyphenols from Geranium sanguineum L. in Viral Infections, Including SARS-CoV-2

The existing literature supports the anti-inflammatory, antioxidant, and antiviral capacities of the polyphenol extracts derived from Geranium sanguineum L. These extracts exhibit potential in hindering viral replication by inhibiting enzymes like DNA polymerase and reverse transcriptase. The antiviral properties of G. sanguineum L. seem to complement its immunomodulatory effects, contributing to infection resolution. While preclinical studies on G. sanguineum L. suggest its potential effectiveness against COVID-19, there is still a lack of clinical evidence. Therefore, the polyphenols extracted from this herb warrant further investigation as a potential alternative for preventing and treating COVID-19 infections.

Postbiotics Production of Candidate-Probiotic Lactiplantibacillus plantarum AC131 with Renewable Bio Resources

Lactiplantibacillus plantarum is a versatile specie, well known as a producer of lactic acid (LA) and other metabolites with biotechnological significance. The present work characterizes growth and lactic acid production of the candidate-probiotic strain L. plantarum AC131, from Bulgarian white brined cheeses. Different nutritional media with ingredients from renewable resources-reduced sugars from dried distillers' grains with soluble (DDGS) and waste waters from the water-vapor distillation of Bulgarian Rosa alba L. and Rosa damascena Mill. essential oil-were assessed. The results obtained showed significant LA production (up to 95% conversion) in modified MRS broth with reducing sugars from DDGS hydrolysates. The addition of R. alba L. and R. damascena Mill. distillation effluents stimulated the growth and biological activity of postbiotics produced by L. plantarum AC131. In both experimental approaches, a statistically significant inhibition (from 20 to 60%) of E. coli HB 101 growth was found during 24 h exposure and a variable effect on the biofilm formed. In conclusion, reducing sugars from DDGS hydrolysates can be successfully used as a carbon source for lactic acid production. In the case of fermentation without pH control, the process is product inhibited, while with pH control, nearly full conversion was achieved. Postbiotics produced during the process of fermentation showed a variety of biological activity and inhibitory effects on the growth of Escherichia coli HB 101.

Study on the structure, antioxidant activity and degradation pattern of polysaccharides isolated from lotus seedpod

The lotus (Nelumbo nucifera Gaertn.) is the largest aquatic vegetable in Asia. The lotus seedpod (LS) is an inedible part of the mature flower receptacle of the lotus plant. However, the polysaccharide isolated from the receptacle has been less studied. The purification of LS resulted in two polysaccharides (LSP-1 and LSP-2). Both polysaccharides were found to be medium-sized HG pectin, with a Mw of 74 kDa. Their structures were elucidated via GC-MS and NMR spectrum and proposed as the repeating sugar units of GalA connected via α-1,4-glycosidic linkage, with LSP-1 having a higher degree of esterification. They have certain content of antioxidant and immunomodulatory activities. The esterification of HG pectin would have an adverse effect on these activities. Furthermore, the degradation pattern and kinetics of LSPs by pectinase conformed to the Michaelis-Menten model. There is a large amount of LS, resulting from the by-product of locus seed production, and thus a promising source for the isolation of the polysaccharide. The findings of the structure, bioactivities, and degradation property provide the chemical basis for their applications in the food and pharmaceutical industries.