Necrosis of Microcystis aeruginosa causing tannin derivatives in Rhus chinensis stem.

BACKGROUND: Algal infestation in Korean lakes, rivers, and in agroecosystems is a catastrophic problem resulting in contaminated drinking and agricultural irrigation water. Developing allelochemical-based algicides has previously faced difficulties, including dosage requirements and chemical instability. Despite these challenges, these algicides have enormous potential for eco-friendly use. This study presents the efficient use of tannin derivatives as antialgal chemicals modeled on a tannin-rich stem extract of Rhus chinensis in a thermal processing application. RESULTS: Tannic acids are the key component of algal necrosis in R. chinensis stem extract, and although heat extraction from the stem increased the crude extraction yield 1.8-fold, the procedure induced the conversion of tannic acids to gallic acid, resulting in lower antialgal activity. Gallotannin showed stronger antialgal activity (The 50% lethal dosage (LD50 )= 44.6 mg L-1 ) than gallic acid (LD50  = 99.2 mg L-1 ), and the nonheated extract exhibited 3.7-fold lower LD50 (0.66 g L-1 ) than the heated extract (LD50  = 2.45 g L-1 ), resulting in 2.6-fold higher content of gallotannin. CONCLUSION: These results demonstrate that heat treatment of R. chinensis stems during the extraction process is not beneficial to algal control because of the acceleration of thermal tannin degradation, despite it showing higher crude extract yields. Therefore, it is suggested extraction processes minimizing the loss of tannic acids should be the preferred methods used to develop tannin-based natural algicides for controlling algal infestation. Tannic acids showed higher toxicity into necrosis of M. aeruginosa than gallic acid where heat-processed extraction of R. chinensis stems produces more gallic acid content resulting in thermal degradation of tannic complexes than the extraction of nonthermal treatment. © 2022 Society of Chemical Industry.

Deglycosylation patterns of isoflavones in soybean extracts inoculated with two enzymatically different strains of lactobacillus species.

Microorganism selection is critical to deglycosylation in soybean fermentation for producing beneficial phytochemicals. This study investigated isoflavone bioconversion in soybean extract inoculated with Lactobacillus plantarum K2-12 and Lactobacillus curvatus JD0-31 exhibiting different enzyme activities. L. plantarum showed higher esterase (C4), esterase (C8), ß-galactosidase, α-glucosidase, ß-glucosidase, and N-acetyl-ß-glucosaminase activities. We found that isoflavone bioconversion was distinguished into isoflavone backbone structure types. Malonyl- and acetyl- types of isoflavones except for malonyl daidzin were not significantly differed their contents between lactobacilli. Deglycosylating severity was observed in malonyl genistin in both lactobacilli, resulting mass production of genistein. On the other hand, daidzein glycosides were dependable to lactobacilli, in which L. plantarum efficiently degraded malonyl daidzin and daidzin in fast time. Glycitein was most degradable among the three aglycones by fermentation. These results suggest that efficient control of isoflavone deglycosylation by Lactobacillus species should be controlled to the inoculation period and select target isoflavones.

Kudzu Leaf Extract Suppresses the Production of Inducible Nitric Oxide Synthase, Cyclooxygenase-2, Tumor Necrosis Factor-Alpha, and Interleukin-6 via Inhibition of JNK, TBK1 and STAT1 in Inflammatory Macrophages.

Kudzu (Pueraria montana var. lobata (Willd.) Sanjappa & Pradeep) is a perennial leguminous vine, and its root and flower have been used for herbal medicine in Asia for a long time. Most dietary flavonoids are reported to be concentrated in its root, not in its aerial parts including leaves. In this study, we investigated whether kudzu leaf and its major constituent, robinin (kaempferol-3-O-robinoside-7-O-rhanmoside) possessed anti-inflammatory activity. To test this hypothesis, we used peritoneal macrophages isolated from BALB/c mice and stimulated the cells with lipopolysaccharide (LPS) or LPS plus interferon (IFN)-γ. Compared with kudzu root extract, its leaf extract was more potent in inhibiting the production of inducible nitric oxide synthase (iNOS), cyclooxygenase-2, tumor necrosis factor-α, and interleukin-6. Kudzu leaf extract decreased LPS-induced activation of c-Jun N-terminal kinase (JNK) and TANK-binding kinase 1(TBK1) with no effects on nuclear factor-κB and activator protein 1 transcriptional activity. Also, kudzu leaf extract inhibited LPS/IFN-γ-induced signal transducer and activator of transcription 1 (STAT1) activation partly via an altered level of STAT1 expression. Robinin, being present in 0.46% of dry weight of leaf extract, but almost undetected in the root, decreased iNOS protein involving modulation of JNK and STAT1 activation. However, robinin showed no impact on other inflammatory markers. Our data provide evidence that kudzu leaf is an excellent food source of as yet unknown anti-inflammatory constituents.

Suppressive effects of ginsan on the development of allergic reaction in murine asthmatic model.

BACKGROUND: Asthma is a major health problem worldwide, and the morbidity and mortality caused by asthma are on the rise. Corticosteroid therapies for asthma treatment frequently induce many side effects. Therefore, the development of new medicines that have both high efficacy and fewer side effects has been a scientific challenge. Here we tested the effect of ginsan, a polysaccharide derived from Panax ginseng, against allergic reaction in an ovalbumin (OVA)-induced murine asthmatic model in comparison with dexamethasone, and investigated its underlying mechanism. METHODS: To induce murine asthma, mice were sensitized and challenged with OVA. Ginsan or dexamethasone was administered by injection 3 times a week. Airway hyperresponsiveness, airway inflammation and lung pathology were assessed in order to evaluate the effect of ginsan against asthma. RESULTS: Ginsan treatment reduced airway hyperresponsiveness, remodeling and eosinophilia. These effects of ginsan were equivalent to those of dexamethasone. Ginsan treatment decreased the IL-5 level in the supernatant of cultured splenocytes, while IFN-gamma and serum IgE were not altered. To elucidate the mechanism of ginsan, expression of inflammation-related genes were screened. Interestingly, ginsan treatment upregulated cyclooxygenase (COX)-1 and COX-2 mRNA, and expression of their proteins in the lung were also increased. PGE(2) in the bronchoalveolar lavage fluid was also increased by the ginsan treatment. Lastly, ginsan inhibited the allergic reaction aggravated by COX inhibitor (indomethacin). CONCLUSION: Ginsan has anti-asthmatic effects, which seem to be partially mediated by enhancing the synthesis of COX gene products.