Nitric oxide inhibitors with a spiro diterpenoid skeleton from Scutellaria formosana: Structures, NO inhibitory effects, and interactions with iNOS.

A phytochemical investigation to obtain new NO inhibitors resulted in the isolation of five new spiro diterpenoids (1 -5) from the aerial parts of Scutellaria formosana. The structures were elucidated on the basis of extensive 1D and 2D NMR spectroscopic data analysis, and the absolute configurations of these compounds were established via comparison of experimental and calculated electronic circular dichroism (ECD) spectra. The nitric oxide (NO) inhibitory effects were evaluated and all of the compounds showed inhibitory effects on lipopolysaccharide-induced NO production in murine microglial BV-2 cells. The possible mechanism of NO inhibition of bioactive compounds was also investigated using molecular docking, which revealed the interactions of bioactive compounds with the iNOS protein.

Natural NO inhibitors from the leaves of Callicarpa kwangtungensis: Structures, activities, and interactions with iNOS.

A phytochemical investigation to obtain new NO inhibitors resulted in the isolation of a new diterpenoid with a rare 9,10-seco-abietane skeleton (1) and twelve known terpenoids (2-13) from Callicarpa kwangtungensis. Their structures were elucidated on the basis of extensive 1D and 2D NMR spectroscopic data analyses, and the absolute configuration of compound 1 was established by comparison of the calculated and experimental electronic circular dichroism (ECD) spectra. The inhibitory activities on lipopolysaccharide-induced NO production in murine microglial BV-2 cells of these terpenoids were evaluated, and all of the compounds showed inhibitory effects. The following molecular docking studies showed interactions of the bioactive compounds with the iNOS protein.

Phytochemicals with NO inhibitory effects and interactions with iNOS protein from Trigonostemon howii.

A phytochemical investigation to obtain new NO inhibitors led to the isolation of nine compounds including one new guaiane-type sesquiterpenoid (1) and two new cleistanthane diterpenoids (2 and 3) from the stems of Trigonostemon howii. Their structures were elucidated on the basis of extensive 1D and 2D NMR spectroscopic data analysis, and the absolute configurations of new compounds 1-3 were established via comparison of experimental and calculated electronic circular dichroism (ECD) spectra. Compounds 2 and 3 possess a rare 3,4-seco-cleistanthane diterpenoid skeleton. All of the compounds showed inhibitory effects on lipopolysaccharide-induced NO production in murine microglial BV-2 cells. The further molecular docking studies indicated the strong interactions between some bioactive compounds with the iNOS protein, which revealed the possible and potential mechanism of NO inhibition of bioactive compounds.

Bioactive diterpenoids from Trigonostemon chinensis: Structures, NO inhibitory activities, and interactions with iNOS.

A phytochemical investigation to obtain new NO inhibitors led to the isolation of two new (1 and 2) and four known (3-6) diterpenoids from Trigonostemon chinensis. Their structures were elucidated on the basis of extensive 1D and 2D NMR spectroscopic data analyses, and the absolute configurations of new compounds were established by experimental and calculated ECD spectra. The inhibitory activities on lipopolysaccharide-induced NO production in murine microglial BV-2 cells of these diterpenoids were evaluated, and all of the compounds showed inhibitory effects. The interactions of bioactive compounds with iNOS protein were also studied by molecular docking.

Bioactive Terpenoids from Salvia plebeia: Structures, NO Inhibitory Activities, and Interactions with iNOS.

A phytochemical investigation to obtain new NO inhibitors resulted in the identification of six new (1-6) and four known (7-10) terpenoids from Salvia plebeia. Compounds 1 and 2 are new diterpenoids, 3-5 are new meroditerpenoids, 6-9 are sesquiterpenoids, and 10 is a known meroditerpenoid. The structures of these isolates were determined by routine NMR experiments and X-ray diffraction, as well as the electronic circular dichroism spectra. Compounds 1-4 are diterpenoids carrying an oxygen bridge, and 6 is a rare copane-type sesquiterpenoid with a bridged tricyclic framework. The isolates inhibited NO generation induced by lipopolysaccharide in BV-2 cells. The possible mechanism of NO inhibition of some bioactive compounds was also investigated using molecular docking, which revealed interactions of bioactive compounds with the iNOS protein.

Daphnane diterpenoids with nitric oxide inhibitory activities and interactions with iNOS from the leaves of Trigonostemon thyrsoideus.

A phytochemical investigation to search for new nitric oxide (NO) inhibitors resulted in the isolation of seven previously undescribed daphnane diterpenoids, thyrsoidpenes A-G, from the leaves of Trigonostemon thyrsoideus. Their structures including absolute configurations were elucidated on the basis of extensive NMR spectroscopic data analysis and the time-dependent density functional theory (TDDFT) electronic circular dichroism (ECD) calculations. Thyrsoidpenes B-G feature rare polycyclic caged structures of daphnane diterpenoid orthoester. The NO inhibitory effects were examined and all of the compounds showed inhibitory activities toward LPS-induced NO production in murine microglial BV-2 cells. The possible mechanism of NO inhibition of some bioactive compounds was also investigated using molecular docking, which revealed the interactions of bioactive compounds with the iNOS protein.

Clerodane diterpenoids from Scutellaria formosana with inhibitory effects on NO production and interactions with iNOS protein.

A phytochemical study on Scutellaria formosana afforded five previously undescribed spiro-diterpenoids, scutellapenes A-E. The structures were elucidated on the basis of extensive 1D and 2D NMR spectroscopic data analysis, and the absolute configurations of these compounds were established by the time-dependent density functional theory (TDDFT) electronic circular dichroism (ECD) calculations. Scutellapenes B-E possess a spiro-diterpenoid skeleton. All of the compounds showed inhibitory effects on LPS-induced nitric oxide (NO) production in murine microglial BV-2 cells. The further molecular docking studies revealed that these bioactive compounds had strong interactions with the iNOS protein.

Characterization of diterpenoids from Caesalpinia decapetala and their anti-TMV activities.

Caesalpinia decapetala is a versatile medicinal plant belonging to the Fabaceae plant family. In our survey on plant secondary metabolites to obtain bioactive substances for the development of new agricultural anti-TMV agents, the chemical constituents of C. decapetala were investigated. This investigation led to the isolation of three new and ten known diterpenoids. Their structures including absolute configurations were elucidated based on the extensive NMR spectroscopic data analyses and the time-dependent density functional theory calculations. The following biological screenings revealed that most of these diterpenoids possessed anti-TMV activities.

Alkaloids from the South China Sea Black Coral Antipathes dichotoma.

A new carbazole alkaloid, antipathine A (1), together with three known zoanthoxanthin alkaloids (2--4) was isolated from the EtOH/CH2Cl2 extracts of the South China Sea black coral Antipathes dichotoma. The structure of 1 was determined on the bases of extensive spectroscopic analysis, including 1D and 2D NMR data. Compounds 1 and 2 showed moderate cytotoxicity against human stomach carcinoma SGC-7901 cell line with IC50 of 67.38 and 86.40 microg/ml, respectively, and 1 and 2 also showed weak cytotoxicity toward human liver carcinoma Hep_G2 cell line.