New Cyclic Diarylheptanoids from Platycarya strobilacea

Two new diarylheptanoids from the green walnut husks of Juglans mandshurica Maxim

Chemical investigation on the 95% ethanol extract of green walnut husks of Juglans mandshurica Maxim. led to the isolation of two new diarylheptanoid compounds, including Juglanin K (1) and Myricananin I (2), together with ten known compounds (3-13). Their structures were elucidated by extensive analyses of comprehensive spectroscopic methods. The isolated compounds were evaluated for their antibacterial activities against Escherichia coli and Staphylococcus aureus. The results showed that compound 2 had moderate antibacterial activity with the MIC values of 0.313 and 0.156 mg/mL, respectively. compounds 1, 3-7 and 13 showed weakly antibacterial activities against Escherichia coli and Staphylococcus aureus with the MIC values of 0.625-2.5 mg/mL.

rocF affects the production of tetramethylpyrazine in fermented soybeans with Bacillus subtilis BJ3-2

BACKGROUND

Tetramethylpyrazine (TTMP) is a flavoring additive that significantly contributes to the formation of flavor compounds in soybean-based fermented foods. Over recent years, the application of TTMP in the food industry and medicine has been widely investigated. In addition, several methods for the industrial-scale production of TTMP, including chemical and biological synthesis, have been proposed. However, there have been few reports on the synthesis of TTMP through amino acid metabolic flux. In this study, we investigated genetic alterations of arginine metabolic flux in solid-state fermentation (SSF) of soybeans with Bacillus subtilis (B.subtilis) BJ3-2 to enhance the TTMP yield.

RESULTS

SSF of soybeans with BJ3-2 exhibited a strong Chi-flavour (a special flavour of ammonia-containing smelly distinct from natto) at 37 °C and a prominent soy sauce-like aroma at 45 °C. Transcriptome sequencing and RT-qPCR verification showed that the rocF gene was highly expressed at 45 °C but not at 37 °C. Moreover, the fermented soybeans with BJ3-2ΔrocF (a rocF knockout strain in B. subtilis BJ3-2 were obtained by homologous recombination) at 45 °C for 72 h displayed a lighter color and a slightly decreased pH, while exhibiting a higher arginine content (increased by 14%) than that of BJ3-2. However, the ammonia content of fermented soybeans with BJ3-2ΔrocF was 43% lower than that of BJ3-2. Inversely, the NH4+ content in fermented soybeans with BJ3-2ΔrocF was increased by 28% (0.410 mg/kg). Notably, the TTMP content in fermented soybeans with BJ3-2ΔrocF and BJ3-2ΔrocF + Arg (treated with 0.05% arginine) were significantly increased by 8.6% (0.4617 mg/g) and 18.58% (0.504 mg/g) respectively than that of the BJ3-2.

CONCLUSION

The present study provides valuable information for understanding the underlying mechanism during the TTMP formation process through arginine metabolic flux.

Antioxidant effects of diarylheptanoids from two Curcuma species

ABSTRACTSFive linear diarylheptanoids (1-5), including a new one (1), were isolated from the rhizomes of Curcuma kwangsiensis S. G. Lee et C. F. Liang, while four linear diarylheptanoids (6-9) and four cyclic diarylheptanoids (10-13) were isolated from the roots of Curcuma aromatica Salisb. Using the model of H₂O₂-induced PC12 cells, the antioxidant effects of these thirteen diarylheptanoids from these two traditional Chinese medicines from Curcuma genus of Zingiberaceae family were investigated. As result, they produced different efficiency on damaged cell viability, ROS, LDH, SOD, CAT, and GSH-Px, which were the six indexes related to oxidative stress. Further, the correlation between these six bio-indexes and 53 selected molecular descriptors of diarylheptanoids was determined by PLS regression analysis.

Use of cucurbitacins for lung cancer research and therapy

As the main substance in some traditional Chinese medicines, cucurbitacins have been used to treat hepatitis for decades in China. Currently, the use of cucurbitacins against cancer and other diseases has achieved towering popularity among researchers worldwide, as detailed in this review with summarized tables. Numerous studies have reported the potential tumor-killing activities of cucurbitacins in multiple aspects of human malignancies. Continuous research on its anticancer activity mechanisms also brings a glimmer of light to the treatment of patients with lung cancer. In line with the promising roles of cucurbitacins against cancer, through various molecular signaling pathways, it is justifiable to propose the use of cucurbitacins as a potential mainline chemotherapy before the onset and after the diagnosis of lung cancers. Here, this article mainly summarized the findings about the biological functions and underlying mechanisms of cucurbitacins on lung cancer pathogenesis and treatment. In addition, we also discussed the safety and efficacy of their application for further research and even clinical practice.