Bactericidal and antibiofilm properties of Rumex japonicus Houtt. on multidrug-resistant Staphylococcus aureus isolated from milk.

Multidrug-resistant (MDR) Staphylococcus aureus and its biofilm formation have been challenging to control in milk and dairy industries. Biofilms formed by Staph. aureus may result in the failure of antibacterial agents and disinfectants to penetrate the biofilm in an attempt to control contamination. Novel natural antibacterial agents are required to combat MDR bacteria and biofilms. In this study, we evaluated the bactericidal, antibiofilm, and antimotility effects of Rumex japonicus Houtt. (RJH) extract on MDR Staph. aureus isolated from milk. The RJH extract exhibited good antibacterial activity against MDR strains with minimum inhibitory concentrations (MIC) ranging from 0.78 to 6.25 mg/mL and minimum bactericidal concentrations ranging from 3.125 to 12.5 mg/mL. The extract showed strong inhibition of biofilm formation (81.9%) at sub-MIC value and eradication of biofilm at higher concentrations. The motility of Staph. aureus was effectively blocked by the extract. Major compounds emodin, chrysophanol, and physcion were identified in RJH extract using HPLC-linear trap quadrupole (LTQ)/Orbitrap-mass spectrometry. The extract was nontoxic to human epithelial cell lines such as Caco-2 and HT-29 cell lines at concentrations ranging from 0.1 to 0.5 mg/mL, and from 0.1 to 0.75 mg/mL, respectively. These findings suggest that RJH extract could be an alternative to synthetic preservatives in milk and dairy products.

The complete plastome sequence of Rumex japonicus Houtt.: a medicinal plant.

Rumex japonicus is a medicinal plant distributed in East Asia. Here, we report and characterize the complete plastid genome sequence of R. japonicus and size is 159,292 bp in length and contains the typical structure and gene content of other angiosperm plastomes, including two inverted repeat regions of 30,629 bp, a large single-copy region of 85,028 bp and a small single-copy region of 13,006 bp. There are 112 unique genes, including 78 protein-coding, 30 tRNAs and 4 rRNAs. We constructed a phylogenetic tree with 14 species and the phylogenetic topologies showed that R. japonicus was closely related to Rheum wittrockii.

Inhibition of Jurkat T Cell Proliferation by Active Components of Rumex japonicus Roots Via Induced Mitochondrial Damage and Apoptosis Promotion.

Rumex japonicus Houtt (RJH) is a valuable plant used in traditional medicine to treat several diseases, such as scabies and jaundice. In this study, Jurkat cell growth inhibitory extracts of R. japonicus roots were subjected to bioassay-guided fractionation, resulting in the isolation of three naphthalene derivatives (3-5) along with one anthraquinone (6) and two phenolic compounds (1 and 2). Among these compounds, 2-methoxystypandrone (5) exhibited potent anti-proliferative effects on Jurkat cells. Analysis by flow cytometry confirmed that 2-methoxystypandrone (5) could significantly reduce mitochondrial membrane potential and promote increased levels of mitochondrial reactive oxygen species (ROS), suggesting a strong mitochondrial depolarization effect. Real-time quantitative polymerase chain reaction (qPCR) analysis was also performed, and the results revealed that the accumulation of ROS was caused by reduced mRNA expression levels of heme oxygenase (HO-1), catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD). In addition, 2-methoxystypandrone (5) triggered strong apoptosis that was mediated by the arrest of the G0/G1 phase of the cell cycle. Furthermore, 2-methoxystypandrone (5) downregulated p-IκB-α, p-NF-κB p65, Bcl2, and Bcl-xl and upregulated BAX proteins. Taken together, these findings revealed that 2-methoxystypandrone (5) isolated from RJH could potentially serve as an early lead compound for leukemia treatment involving intracellular signaling by increasing mitochondrial ROS and exerting anti-proliferative effects.

Rumex japonicus Houtt.: A phytochemical, pharmacological, and pharmacokinetic review.

Rumex japonicus Houtt. (RJH-Yang Ti) RJH has been used as a folk medicine in East Asian countries for thousands of years. It has a wide range of therapeutic effects in terms of anti-microorganic, anti-oxidant, anti-inflammatory, and antitumor effects. Therefore, it is urgent to thoroughly review the existing knowledge for this herb from phytochemical, pharmacological, and pharmacokinetic perspectives. "Yang Ti" and its English, botanical and pharmaceutical names used as keywords to perform database search which included the Encyclopaedia of traditional Chinese Medicines, PubMed, EMBASE, AMED, CINAHL, Cochrane Library, MEDLINE, Science Direct, Scopus, Web of Science, and China Network Knowledge Infrastructure. Forty-five compounds identified from RJH. Besides, the therapeutic effects of RJH have been summarized as well. The root of RJH contains derivatives of anthraquinones, phytosterols, nepodin, oxanthrone c-glycosides, phenolic acid, cinnamic acid, flavonoid, epoxynaphthoquinol, triterpenoids, methoxynaphthalene, trihydroxybenzene, anthracene-9,10-dione, and other compounds. The extract of RJH and its chemical compounds showed the potentials as a complementary agent to exert antioxidant, antimicrobial, antisepsis, anticancer, anti-haematological disease, anti-dermatological disease, and antidiabetic activities. For the record, there is no study conducted on RJH regarding its pharmacokinetic aspect. Notably, Emodin may require additional attention due to its multiple organ toxicity concerns.

Therapeutic Effect of Rumex japonicus Houtt. on DNCB-Induced Atopic Dermatitis-Like Skin Lesions in Balb/c Mice and Human Keratinocyte HaCaT Cells.

Rumex japonicus Houtt. (RJ) is traditionally used in folk medicines to treat patients suffering from skin disease in Korea and other parts of East Asia. However, the beneficial effect of RJ extract on atopic dermatitis (AD) has not been thoroughly examined. Therefore, this study aimed to investigate the anti-inflammatory effects of RJ on AD in vitro and in vivo. Treatment with RJ inhibited the phosphorylation of mitogen-activated protein kinase (MAPK) as well as the activation of nuclear factor-kappa B (NF-κB) in tumor necrosis factor-α (TNF-α) stimulated in HaCaT cells. The five-week-old Balb/c mice were used as an AD-like mouse model by treating them with 1-chloro-2, 4-dinitrobenzene (DNCB). Topical administration of RJ to DNCB-treated mice significantly reduced clinical dermatitis severity, epidermal thickness, and decreased mast cell and eosinophil infiltration into skin and ear tissue. These results suggest that RJ inhibits the development of AD-like skin lesions by regulating the skin inflammation responses in HaCaT cells and Balb/c mice. Thus, RJ may be a potential therapeutic agent for AD.

Evaluation of raw nepodin extraction from Rumex japonicus and R. obtusifolius and their DNA polymorphisms.

Nepodin, found in the roots of Rumex japonicus Houtt. (Polygonaceae), inhibits osteoclast differentiation and has an antidiabetic effect. We propose nepodin as an ingredient of new functional foods or as a drug candidate for reducing the risk of reduced locomotion resulting from diseases such as osteoporosis. Although there are no previous reports of R. obtusifolius L., which is found throughout Japan, having roots containing nepodin, we found nepodin in the roots of this species. Therefore, R. obtusifolius as well as R. japonicus was considered a candidate raw material for nepodin extraction. We also discuss the suitability of R. japonicus and R. obtusifolius as sources of raw nepodin for cultivation on the Ryukyu Islands. In this study, all specimens on the Ryukyu Islands were identified as R. japonicus. Conversely, all specimens on mainland Japan were R. obtusifolius. The DNA sequence of the chloroplast trnL-trnF intergenic spacer region and partial nuclear internal transcribed spacer was consistent with the identification of R. japonicus and R. obtusifolius by morphological characteristics of the perianth segments. Therefore, to avoid erroneous identification and misuse of the plant species used for extraction of raw materials, it is preferable to develop DNA markers for these two regions. The content of nepodin varied from undetectable to 0.34% of the fresh weight (%FW) in R. japonicus and from undetectable to 0.21%FW in R. obtusifolius. From a pharmacological perspective, as plants that might be suitable as raw materials for nepodin extraction, it became clear that both R. japonicus and R. obtusifolius can be used with the same expected extraction efficiency. Based on our findings, R. obtusifolius could not be confirmed as inhabiting the Ryukyu Islands. For this reason, to conserve the endemic genetic characteristics of the Ryukyu Islands and to prevent genetic pollution by R. obtusifolius, only R. japonicus should be cultivated on the Ryukyu Islands.