Hari Jang

Diterpenoids from the Roots of Euphorbia fischeriana with Inhibitory Effects on Nitric Oxide Production

Bioactivity-guided isolation of a methanolic extract of Euphorbia fischeriana led to the isolation of four new abietane-type diterpenoids, fischeriolides A-D (1-4), together with 11 known diterpenoids. Their structures were elucidated based on the interpretation of 1D and 2D NMR spectroscopic and HRESIMS data. The absolute configuration of compound 3 was determined by single-crystal X-ray diffraction analysis and electronic circular dichroism methods. Compounds 5-9 exhibited inhibitory effects on LPS-induced nitric oxide production in RAW 264.7 macrophages with IC50 values in the range 4.9-12.6 μM.

neo-Clerodane Diterpenoids from Scutellaria barbata and Their Inhibitory Effects on LPS-Induced Nitric Oxide Production

Three new neo-clerodane diterpenoids (1-3) along with 12 known compounds (4-15) were isolated from a methanol extract of the aerial parts of Scutellaria barbata. The structures of 1-3 were determined by interpretation of their 1D and 2D NMR spectroscopic data as well as HRESIMS values. All isolated compounds were tested for their inhibitory effects on LPS-induced nitric oxide production in RAW 264.7 macrophages. Compounds 1-4, 7, and 10-12 were found to inhibit nitric oxide production with IC50 values ranging from 20.2 to 35.6 μM.

Sesquiterpenes from Inula japonica with Inhibitory Effects on Nitric Oxide Production in Murine Macrophage RAW 264.7 Cells

Eight new sesquiterpenes (1-8), along with seven known sesquiterpenes (9-15), were isolated from a methanol extract of the flowers of Inula japonica. Their structures were elucidated by a combination of 1D and 2D NMR spectroscopic and HRESIMS data. All of isolates were evaluated for their inhibitory effects on nitric oxide production in LPS-induced RAW 264.7 cells, with their IC50 values ranging from 1.9 to 15.4 μM.

Effect of Korean Red Ginseng extraction conditions on antioxidant activity, extraction yield, and ginsenoside Rg1 and phenolic content: optimization using response surface methodology

Background Extraction conditions greatly affect composition, as well as biological activity. Therefore, optimization is essential for maximum efficacy. Methods Korean Red Ginseng (KRG) was extracted under different conditions and antioxidant activity, extraction yield, and ginsenoside Rg1 and phenolic content evaluated. Optimized extraction conditions were suggested using response surface methodology for maximum antioxidant activity and extraction yield. Results Analysis of KRG extraction conditions using response surface methodology showed a good fit of experimental data as demonstrated by regression analysis. Among extraction factors, such as extraction solvent and extraction time and temperature, ethanol concentration greatly affected antioxidant activity, extraction yield, and ginsenoside Rg1 and phenolic content. The optimal conditions for maximum antioxidant activity and extraction yield were an ethanol concentration of 48.8%, an extraction time 73.3 min, and an extraction temperature of 90°C. The antioxidant activity and extraction yield under optimal conditions were 43.7% and 23.2% of dried KRG, respectively. Conclusion Ethanol concentration is an important extraction factor for KRG antioxidant activity and extraction yield. Optimized extraction conditions provide useful economic advantages in KRG development for functional products.

Jatrophane and ingenane-type diterpenoids from Euphorbia kansui inhibit the LPS-induced NO production in RAW 264.7 cells

Bioactivity-guided fractionation of the MeOH extract from the roots of Euphorbia kansui resulted in the isolation of two new jatrophane-type diterpenoids, kanesulones A (1) and B (2), together with six known jatrophane-type diterpenoids (3-8) and ten known ingenane-type diterpenoids (9-18). Their chemical structures were elucidated on the basis of spectroscopic data interpretation, especially 1D and 2D NMR such as HMQC, HMBC, COSY and NOESY, and HRESIMS data as well as CD analysis. Compounds 1-8 and 11-18 exhibited the inhibitory effects on LPS-induced nitric oxide production with IC50 values ranging from 0.7 to 46.5μM in RAW 264.7 macrophages.

Isolation and Characterization of Dammarane-Type Saponins from Gynostemma pentaphyllum and Their Inhibitory Effects on IL-6-Induced STAT3 Activation.

Five new dammarane-type saponins, gypenosides GD1-GD5 (1-5), along with six known saponins (6-11), were isolated from the aerial parts of Gynostemma pentaphyllum using various chromatographic methods. Their structures were elucidated by a combination of spectroscopic and spectrometric data, including 1D and 2D NMR and HRESIMS. All isolates were tested for their inhibitory effects on IL-6-induced STAT3 promoter activity in Hep3B cells. Compounds 1, 9, and 11 displayed potent inhibitory effects, with IC50 values ranging from 0.27 to 0.59 μM.

Flavonol glycosides from the aerial parts of Gynostemma pentaphyllum and their antioxidant activity

The phytochemical investigation of the aerial parts of Gynostemma pentaphyllum led to the isolation of a new flavonol glycoside, gynopentaphylloside (1), along with seven known compounds (2–8). The structure of the new compound was determined on the basis of 1D, 2D NMR and HRESIMS data as well as acid hydrolysis. The antioxidant activity of the isolates was evaluated by a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay.

Lathyrane-Type Diterpenoids from the Seeds of Euphorbia lathyris L. with Inhibitory Effects on NO Production in RAW 264.7 Cells

Bioactivity‐guided fractionation of the methanolic extract from the seeds of Euphorbia lathyris led to the isolation of 18 lathyrane‐type diterpenoids including a new one, Euphorbia factor L29 (1). Their chemical structures were elucidated by extensive NMR spectroscopic data including 2D‐NMR and HR‐ESI‐MS as well as CD data. All isolates (1 – 18) were found to inhibit the nitric oxide production in LPS‐induced RAW 264.7 macrophages, with their IC50 values in the range of 11.2 – 52.2 μm.

Nitric oxide inhibitory constituents from Siegesbeckia pubescens

Two new sesquiterpenoids (1 and 2) and a new ent-pimarane type diterpenoid (3), together with eighteen known compounds (4-21), were isolated from the whole plants of Siegesbeckia pubescens. The structures of the new compounds were determined on the basis of 1D-, 2D NMR and HRESIMS data. All compounds were evaluated for their inhibitory effects on LPS-induced nitric oxide production in RAW 264.7 macrophages. Of these, highly oxygenated germacrane type sesquiterpenoids (1-2 and 13-14) showed significant inhibitory effects with IC50 values ranging from 3.9 to 16.8 μM.

Chemical Constituents Isolated from Bletilla striata and Their Inhibitory Effects on Nitric Oxide Production in RAW 264.7 Cells.

Bioassay‐guided fractionation of the MeOH extract of the tubers of Bletilla striata led to the isolation of two new C‐methylated flavan‐3‐ols, bletillanols A (1) and B (2), along with ten known compounds (3 – 12). Their structures were determined by using extensive spectroscopic analysis including 1D‐, 2D‐NMR, and circular dichroism data. All of the isolated compounds were tested for their inhibitory potential on the nitric oxide generation in LPS‐stimulated RAW 264.7 cells.