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Mesona chinensis Benth (MCB) is an important medicinal and edible plant in Southern China and Southeast Asian countries. Chloroplast (cp) genome is usually used for plant phylogeny, species identification, and chloroplast genetic engineering. To characterize the cp genome and determine the evolutionary position and perform the genetic diversity analysis of MCB, we sequence and characterize the MCB cp genome. The results show that the cp genome of MCB is a single circular molecule with a length of 152,635 bp. It is a typical quadripartite structure, comprising a large single-copy region (LSC, 83,514 bp) and a small single-copy region (SSC, 17,751 bp) separated by two inverted repeat regions (IRs, 51,370 bp). It encodes 129 unique genes, including 84 protein-coding genes (PCGs), 37 transfer RNAs (tRNAs), and 8 ribosomal RNAs (rRNAs). Altogether 127 simple sequence repeats (SSRs) are identified in the MCB cp genome with 86.61% of mononucleotide repeats. Phylogenetic analysis reveals that MCB is most closely related to Ocimum basilicum based on the whole cp genomes. Several highly divergent regions are found, such as trnH_psbA, rps16_trnQ, trnS_trnG, trnE_trnT, psaA_ycf3, rpl32_trnL, ccsA_ndhD, ndhG_ndhI, and rps15_ycf1, which can be proposed for use as DNA barcode regions. Genetic diversity analysis unveils a relatively narrow genetic basis of MCB germplasm resources. Therefore, the innovative breeding of MCB is very urgent and necessary in future research., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The homeostasis of oxidative stress is vital to the physiological behavior of normal human or animal cells, and its underlying molecular mechanism is contributed to the exploitation of functional food used in chronic diseases. Thus, the mechanism of protective effect of Mesona chinensis Benth polysaccharides (MP) in H 2 O 2 -induced oxidative damage was investigated thoroughly. Results showed that MP significantly recovered cell viability and elevated activity of antioxidant enzymes. Based on RNA-seq analysis, we found that MP mainly exhibited protection effect thought regulation mitochondrial function and affect PI3K and MAPK signaling pathways. Furthermore, we found that MP affected mitochondrial function via improved mitochondrial membrane potential (MMP), thereby elevating ATP biosynthesis. Moreover, western blot analysis verified that MP mitigated H 2 O 2 -induced oxidative damage via PI3K/Akt, MAPK, and mitochondrial-mediated apoptosis signaling pathway. These findings provided a possible mechanism for MP on preventing and treating chronic diseases involved in oxidative stress, which was a benefit for development of functional food., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

In this study, the antioxidant and hypolipidemic effects of Mesona Chinensis Benth (MCB) extracts were evaluated. Seven fractions (F0, F10, F20, F30, F40, F50 and MTF) were obtained from the MCB ethanol extracts. Compared to the commercial antioxidants (vitamin C), MTF and F30 exhibited higher antioxidant activities in the antiradical activity test and the FRAP assay. The half-inhibition concentration (IC50) for MTF and F30 were 5.323 µg/mL and 5.278 µg/mL, respectively. MTF at 200 µg/mL significantly decreased the accumulation of TG in oleic acid (OA)-induced HepG2 cells and reversed the inhibitory effect of Compound C on AMPK (MTF and F30 significantly increased the glucose utilization of insulin-induced HepG2 cells). In addition, the components of MTF were identified by HPLC-MS, which were caffeic acid, quercetin 3-O-galactoside, isoquercetin, astragalin, rosmarinic acid, aromadendrin-3-O-rutinoside, rosmarinic acid-3-O-glucoside and kaempferol-7-O-glucoside. Through statistical correlations by Simca P software, it was found that the main antioxidant and hypolipidemic components of MCB might be caffeic acid, kaempferol-7-O-glucoside, rosmarinic acid-3-O-glucoside and aromadendrin-3-O-rutinoside, which may play important roles in the AMPK pathway. MTF and F30 in MCB could be potential health products for the treatment of hyperlipidemia.

Mesona chinensis Benth (MCB) is one of the main economic crops in tropical and subtropical areas. To understand the codon usage bias (CUB) in M. chinensis Benth, chloroplast genome is essential to study its genetic law, molecular phylogenetic relationships, and exogenous gene expression. Results showed that the GC content of 53 CDS sequences was 37.95%, and GC1, GC2, and GC3 content were 46.02%, 38.26%, and 29.85%, respectively. The general GC content order was GC1>GC2>GC3. Moreover, the majority of genes had an effective number of codon (ENC) value greater than 40, except ndhE, rps8, and rps18. Correlation analysis results revealed that the GC content was significantly correlated with GC1, GC2, GC3, and ENC. Neutrality plot analysis, ENC-plot analysis, and PR2-plot analysis presented that the CUB of M. chinensis Benth chloroplast genome was mainly affected by mutation and selection. In addition, GGG, GCA, and TCC were found to be the optimal codons. Furthermore, results of cluster analysis and evolutionary tree showed that M. chinensis Benth was closely related to Ocimum basilicum, indicating that there was a certain correlation between the CUB of the chloroplast gene and the genetic relationship of plant species. Overall, the study on the CUB of chloroplast genome laid a basis for genetic modification and phylogenetic research of M. chinensis Benth chloroplast genome.

In this study, the immune responses of Mesona chinensis Benth polysaccharides (MP) in vitro and in vivo were investigated. Results showed that MP presented immunomodulatory activities on macrophages and T lymphocytes in vitro. Compared with the cyclophosphamide (Cy)-induced immunosuppressive mice, the body weights, spleen indexes (3.45 to 4.91) and thymus indexes (0.78 to 1.04) of the mice treated with MP were increased, and the peripheral blood levels were recovered. MP treatment also increased superoxide dismutase, glutathione peroxidase and catalase activities, and reduced malondialdehyde levels to enhance the total antioxidant capacity of Cy-treated mice. In addition, MP significantly elevated IL-2, NO, and IFN-γ secretions of splenic lymphocytes and spleen, while MP mainly exerts an immune effect by regulating T lymphocytes. Furthermore, MP possessed the immunomodulatory activity by up-regulating the phosphorylation levels of proteins factors (c-Jun N-terminal kinase, extracellular regulated protein kinase and p38 kinase) in mitogen activated protein kinases signaling pathways. This study suggested that MP may be explored as a natural immune stimulant for functional food and nutraceutical industries., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Dynamic high-pressure appears to be an alternative approach to physical modification of polysaccharides aimed to improve their functional characteristics. The objective of our study was to evaluate the effect of dynamic high-pressure microfluidization (DHPM) treatment on the physicochemical properties and antioxidant activities of Mesona chinensis Benth polysaccharide (MP). The results indicated that the contents of total sugar and uronic acid in DHPM-treated polysaccharide samples (DMP) were increased, and protein content in DMP was significantly decreased after DHPM treatment. The molecular weights of MP and DMP were 1.58 × 10 5 Da and 1.64 × 10 5 Da. MP and DMP were composed of Gal, Xyl, and GalA in a molar ratio of 2.8: 5.5: 2.4 and 3.8: 7.4: 3.0, respectively. The antioxidant activities of MP were slightly promoted after DHPM treatment. Moreover, DHPM treatment leads to changes in the morphology of polysaccharide. The surface appearances of DHPM-treated polysaccharide samples showed a slightly curly surface compared to original polysaccharide by SEM analysis. No considerable changes were observed in the structure between the MP and DMP by FT-IR. The results provide useful information for future application of MP, and show DHPM treatment can improve the antioxidant activity of polysaccharides., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Polysaccharides MP-A, MP-U and MP-C were extracted from Mesona chinensis Benth by hot-alkali extraction (HAE), ultrasonic-assisted extraction (UAE) and cellulose-enzyme assisted extraction (CAE), respectively. The yields, physicochemical properties and antioxidant of polysaccharides were investigated. Results showed that the yields of MP-A (11.14%), MP-U (10.62%) and MP-C (9.70%) were similar, and they were all heteropolysaccharides with average molecular weights of 1.9×10 5 Da, 1.5×10 5 Da, 1.4×10 5 Da. Glucose, galactose, and galacturonic acid were the main monosaccharides in MP-A, MP-U and MP-C with molar ratios of 1.00:1.34:0.25, 1.00:2.49:0.19 and 1.00:2.95:0.84, respectively. MP-C extracted by CAE exhibited higher antioxidant activities in FRAP, DPPH, hydroxyl radical assays and the H 2 O 2 -induced injury cell model. The three extraction methods had only slight effects on chemical composition, while MP-C extracted by CAE exhibited the highest antioxidant activity, which could potentially be used for an addition ingredient as it was previously shown to have good gelling property in food products., (Copyright © 2017 Elsevier Ltd. All rights reserved.)