Extraction and Hypolipidemic Activity of Low Molecular Weight Polysaccharides Isolated from Rosa Laevigata Fruits

Three novel low molecular weight polysaccharides (RLP-1a, RLP-2a, and RLP-3a) with 9004, 8761, and 7571 Da were first obtained by purifying the crude polysaccharides from the fruits of a traditional Chinese medicinal herb Rosae Laevigatae. The conditions for polysaccharides from the R. Laevigatae fruit (RLP) extraction were optimized by the response surface methodology, and the optimal conditions were as follows: extraction temperature, 93°C; extraction time, 2.8 h; water to raw material ratio, 22; extraction frequency, 3. Structural characterization showed that RLP-1a consisted of rhamnose, arabinose, xylose, glucose, and galactose with the ratio of 3.14 : 8.21 : 1 : 1.37 : 4.90, whereas RLP-2a was composed of rhamnose, mannose, glucose, and galactose with the ratio of 1.70 : 1 : 93.59 : 2.73, and RLP-3a was composed of rhamnose, arabinose, xylose, mannose, glucose, and galactose with the ratio of 6.04 : 26.51 : 2.05 : 1 : 3.17 : 31.77. The NMR analyses revealed that RLP-1a, RLP-2a, and RLP-3a contained 6, 4, and 6 types of glycosidic linkages, respectively. RLP-1a and RLP-3a exhibited distinct antioxidant abilities on the superoxide anions, 1,1-diphenyl-2-picrylhydrazyl (DPPH), and hydroxyl radicals in vitro. RLPs could decrease the serum lipid levels, elevate the serum high-density lipoprotein cholesterol levels, enhance the antioxidant enzymes levels, and upregulate of FADS2, ACOX3, and SCD-1 which involved in the lipid metabolic processes and oxidative stress in the high-fat diet-induced rats. These results suggested that RLPs ameliorated the high-fat diet- (HFD-) induced lipid metabolism disturbance in the rat liver through the peroxisome proliferator-activated receptor (PPAR) signaling pathway. Low molecular weight polysaccharides of RLP could be served as a novel potential functional food for improving hyperlipidemia and liver oxidative stress responses

The complete chloroplast genome of Digitaria sanguinalis (Graminales: Gramineae)

Digitaria sanguinalis (Linnaeus) Scopoli 1722 is an annual herbal plant that has important medicinal and ecological value. The chloroplast genome was 138,079 bp in length. In total, 129 genes were predicted, including 82 protein-coding genes, 39 tRNA genes, and 8 rRNA genes. The overall AT content of the genome was 61.39%. The phylogenetic analysis showed that D. sanguinalis and D. glauca formed a base clade in Panicoideae close to Thyridolepis xerophila. This study will help to understand the genetic diversity of the Digitaria plants

Integrated Analysis of microRNA and RNA-Seq Reveals Phenolic Acid Secretion Metabolism in Continuous Cropping of <i>Polygonatum odoratum</i>

Polygonatum odoratum (Mill.) Druce is an essential Chinese herb, but continuous cropping (CC) often results in a serious root rot disease, reducing the yield and quality. Phenolic acids, released through plant root exudation, are typical autotoxic substances that easily cause root rot in CC. To better understand the phenolic acid biosynthesis of P. odoratum roots in response to CC, this study performed a combined microRNA (miRNA)-seq and RNA-seq analysis. The phenolic acid contents of the first cropping (FC) soil and CC soil were determined by HPLC analysis. The results showed that CC soils contained significantly higher levels of p-coumaric acid, phenylacetate, and caffeic acid than FC soil, except for cinnamic acid and sinapic acid. Transcriptome identification and miRNA sequencing revealed 15,788 differentially expressed genes (DEGs) and 142 differentially expressed miRNAs (DEMs) in roots from FC and CC plants. Among them, 28 DEGs and eight DEMs were involved in phenolic acid biosynthesis. Meanwhile, comparative transcriptome and microRNA-seq analysis demonstrated that eight miRNAs corresponding to five target DEGs related to phenolic acid synthesis were screened. Among them, ath-miR172a, ath-miR172c, novel_130, sbi-miR172f, and tcc-miR172d contributed to phenylalanine synthesis. Osa-miR528-5p and mtr-miR2673a were key miRNAs that regulate syringyl lignin biosynthesis. Nta-miR156f was closely related to the shikimate pathway. These results indicated that the key DEGs and DEMs involved in phenolic acid anabolism might play vital roles in phenolic acid secretion from roots of P. odoratum under the CC system. As a result of the study, we may have a better understanding of phenolic acid biosynthesis during CC of roots of P. odoratum

Characterization of the complete chloroplast genome of Carallia brachiata (Lour.) Merr. (Rhizophoraceae)

Carallia brachiata (Lour.) Merr. (1919) is an important medical resource distributed across subtropical Asia. In this study, the complete chloroplast genome of C. brachiata was sequenced, revealing a total length of 162,460 bp, including four regions – a large single copy (89,814 bp), a small single copy (18,804 bp), and a pair of inverted repeats (26,921 bp each). The overall guanine + cytosine content was 35.76%. In total, 130 genes were annotated within the chloroplast genome, comprising 85 protein-coding, 37 tRNA, and 8 rRNA genes. Subsequent phylogenetic analyses revealed that C. brachiata is closely related to Carallia diplopetala

Optimization of Alkaline Extraction and Bioactivities of Polysaccharides from Rhizome of Polygonatum odoratum

The present study is to explore the optimal extraction parameters, antioxidant activity, and antimicrobial activity of alkaline soluble polysaccharides from rhizome of Polygonatum odoratum. The optimal extraction parameters were determined as the following: NaOH concentration (A) 0.3 M, temperature (B) 80°C, ratio of NaOH to solid (C) 10-fold, and extraction time (D) 4 h, in which ratio of NaOH to solid was a key factor. The order of the factors was ratio of NaOH to solid (fold, C) > extraction temperature (°C, B) > NaOH concentration (M, A) > extraction time (h, D). The monosaccharide compositions of polysaccharides from P. odoratum were rhamnose, mannose, xylose, and arabinose with the molecular ratio of 31.78, 31.89, 11.11, and 1.00, respectively. The reducing power, the 1, 1-diphenyl-2-picryl-hydrazil (DPPH) radical scavenging rate, the hydroxyl radicals scavenging rate, and the inhibition rate to polyunsaturated fatty acid (PUFA) peroxidation of the alkaline soluble polysaccharides from P. odoratum at 1 mg/mL were 9.81%, 52.84%, 19.22%, and 19.42% of ascorbic acid at the same concentration, respectively. They also showed antimicrobial activity against pathogenic bacteria Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, and Escherichia coli

Optimization of Alkaline Extraction and Bioactivities of Polysaccharides from Rhizome of Polygonatum odoratum

The present study is to explore the optimal extraction parameters, antioxidant activity, and antimicrobial activity of alkaline soluble polysaccharides from rhizome of Polygonatum odoratum. The optimal extraction parameters were determined as the following: NaOH concentration (A) 0.3 M, temperature (B) 80 ∘ C, ratio of NaOH to solid (C) 10-fold, and extraction time (D) 4 h, in which ratio of NaOH to solid was a key factor. The order of the factors was ratio of NaOH to solid (fold, C) &gt; extraction temperature ( ∘ C, B) &gt; NaOH concentration (M, A) &gt; extraction time (h, D). The monosaccharide compositions of polysaccharides from P. odoratum were rhamnose, mannose, xylose, and arabinose with the molecular ratio of 31.78, 31.89, 11.11, and 1.00, respectively. The reducing power, the 1, 1-diphenyl-2-picryl-hydrazil (DPPH) radical scavenging rate, the hydroxyl radicals scavenging rate, and the inhibition rate to polyunsaturated fatty acid (PUFA) peroxidation of the alkaline soluble polysaccharides from P. odoratum at 1 mg/mL were 9.81%, 52.84%, 19.22%, and 19.42% of ascorbic acid at the same concentration, respectively. They also showed antimicrobial activity against pathogenic bacteria Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, and Escherichia coli

Metagenomic Sequencing to Analyze Composition and Function of Top-Gray Chalky Grain Microorganisms from Hybrid Rice Seeds

The top-gray chalkiness of hybrid rice (Oryza sativa L.) seeds is a typical phenomenon in hybrid rice seeds. The chalky part of the grain is infected and is the inoculum to infect the normal seeds during storage and soaking. These seed-associated microorganisms were cultivated and sequenced using metagenomics shotgun sequencing to obtain more comprehensive information on the seed-associated microorganisms in this experiment. The results showed that fungi could grow well on the rice flour medium, similar to the ingredients of rice seed endosperms. After the assembly of metagenomic data, a gene catalog was established, comprising 250,918 genes. Function analysis showed that glycoside hydrolases were the dominant enzymes, and the genus Rhizopus accounted for the dominant microorganisms. The fungal species R. microspores, R. delemar, and R. oryzae were likely to be the candidate pathogens in the top-gray chalky grains of hybrid rice seeds. These results will provide a reference for improving hybrid rice processing after harvest