Kaurane-Type Diterpenoids from Liverworts

Di- and Triterpenoids from the Rhizomes of Isodon amethystoides and Their Anti-inflammatory Activities

Amethystoidesic acid (1), a triterpenoid with an unprecedented 5/6/6/6 tetracyclic skeleton, and six undescribed diterpenoids, amethystoidins A-F (2-7), were isolated from the rhizomes of Isodon amethystoides along with 31 known di- and triterpenoids (8-38). Their structures were fully elucidated via extensive spectroscopic analysis including 1D and 2D NMR, high-resolution electrospray ionization mass spectrometry (HRESIMS), and electronic circular dichroism (ECD) calculations. Compound 1 is the first example of a triterpenoid possessing a rare ring system (5/6/6/6) derived from a contracted A-ring and the 18,19-seco-E-ring of ursolic acid. Compounds 6, 16, 21, 22, 24, and 27 significantly inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 cells, which could be partly mediated by the downregulation of LPS-induced inducible nitric oxide synthase (iNOS) protein expression.

Graphene Modified Molecular Imprinting Electrochemical Sensor for Determining the Content of Dopamine

Background:

The unnatural levels of dopamine (DA) result in serious neurological disorders such as Parkinson’s disease. Electrochemical methods which have the obvious advantages of simple operation and low-cost instrumentation were widely used for determination of DA. In order to improve the measurement performance of the electrochemical sensor, molecular imprinting technique and graphene have always been employed to increase the selectivity and sensitivity.

Methods:

An electrochemical sensor which has specific selectivity to (DA) was proposed based on the combination of a molecular imprinting polymer (MIP) with a graphene (GR) modified gold electrode. The performance and effect of MIP film were investigated by differential pulse voltammetry (DPV) and cyclic voltammetry (CV) in the solution of 5.0 ×10-3 mol/L K3[Fe(CN)6] and K4[Fe(CN)6] with 0.2 mol/L KCl at room temperature.

Results:

This fabricated sensor has well repeatability and stability, and was used to determine the dopamine of urine. Under the optimized experiment conditions, the current response of the imprinted sensor was linear to the concentration of dopamine in the range of 1.0×10-7 ~ 1.0×10-5 mol/L, the linear equation was I (µA) = 7.9824+2.7210lgc (mol/L) with the detection limit of 3.3×10-8 mol/L.

Conclusion:

In this work, a highly efficient sensor for determination of DA was prepared with good sensitivity by GR and great selectivity of high special recognization ability by molecular imprinting membrane. This proposed sensor was used to determine the dopamine in human urine successfully.

Eudesmane-type sesquiterpenoids from the liverwort Lepidoziafauriana

Three new (8, 12, 13) and two revised (7, 9) eudesmane alcohols have been identified from the Taiwanese liverwort Lepidoziafauriana, together with a known macrocyclic bisbibenzyl, isoplagiochin D, and other known sesquiterpenoids. Their structures were determined by NMR and X-ray analyses. Three chemo-types of Lepidoziafauriana may be classified according to the skeleton of the major sesquiterpenoids identified in the species.

Cytotoxic and apoptosis-inducing ent-kaurane-type diterpenoids from the Japanese liverwort Jungermannia truncata NEES

Five new ent-kaurane-type diterpenoids and a new gymnomitrane (=barbatane)-type sesquiterpenoid have been isolated from the Japanese liverwort Jungermannia truncata NEES, together with twelve previously known ent-kaurane-type diterpenoids. The structures of the new compounds were elucidated by two-dimensional (2D) NMR experiments and chemical reaction. Some of the isolated compounds showed cytotoxicity against human leukemia cell lines and induced apoptosis.

seco-Cuparane-type sesquiterpenoid from the Japanese liverwort Jungermannia infusca

A 2,3-seco-cuparane-type sesquiterpenoid and the previously known barbatane-type sesqui- and ent-kaurane-type diterpenoids were isolated from the Japanese liverwort Jungermannia infusca (Mitt.) Steph. The structure of the 2,3-seco-cuparane-type sesquiterpenoid was determined by NMR spectroscopic analyses.

Sesqui- and diterpenoids from two Japanese and three European liverworts

A new peroxy muurolane-type sesquiterpenoid was isolated from the ether extract of the Belgium liverwort Scapania undulata, together with three known ent-muurolanes. A new lepidozane-type sesquiterpenoid was isolated from the Japanese Porella subobtusa together with a known santalane- and two africane-type sesquiterpenoids. All structures were determined by means of NMR spectroscopic techniques. The chemosystematics of each species are discussed.