Termitomenins F and G,Two New Lignan Glucosides from Terminalia chebula var.tomentella(Kurz)C.B.Clarke

The extensive chemical investigation on the branches and leaves of Terminalia chebula var.tomentella(Combretaceae)led to the isolation of two new lignan glucosides with a furofuran skeleton,termitomenins F(1)and G(2).In addition,19 known compounds including five lignan glucosides(3-7),six hydrolyzable tannins(8-13)and eight simple phenolics(14-21)were also identified.Their structures were determined by comprehensive spectroscopic analyses.It is noted that 8 and 9 were C-glycosidic hydrolyzable tannins with one hexahydroxydiphenoyl and one gallagyl group linked to an open-chain glucosyl C-1/O-2/O-3 and O-4/O-6,respectively,which were rarely found in plants.Nine known compounds,6-9,13,and 18-21,were procured from the titled plant for the first time,while 3-5,10-12 and 14-17 were also found in the fruits.Notably,the known hydrolyzable tannins 8-13 exhibited strongerα-glucosidase inhibitory activities with IC_(50) values ranging from 0.10 to 3.12μM,than the positive control,quercetin(IC_(50)=9.38±0.33μM).

Lignans with NO inhibitory activity from Tinospora sinensis

Two new lignan glucosides,tinsinlignans A and B(1 and 2),two new oxyneolignans,tinsinlignans C and D(3 and 4),along with one known analogue(5),were isolated from the stems of Tinospora sinensis.The structures of the new compounds were elucidated based on analysis of spectroscopic data,and the absolute configuration of 1 was determined through electronic circular dichroism(ECD)calculation based on the time-dependent density functional theory(TD-DFT).Compounds 1−4 were evaluated for their inhibitory effects on nitric oxide(NO)production induced by lipopolysaccharide(LPS)in murine RAW264.7 macrophage cells and compounds 1 and 2 exhibited moderate inhibitory activities with IC50 values of 18.5±2.0 and 28.8±1.2μmol·L^(−1),respectively.

A new lignan glycoside from Forsythia suspensa

Phytochemical investigation on Forsythia suspensa(Thunb.) Vahl afforded ten compounds, including five lignan glycosides and five phenylethanoid glycosides. The compounds were isolated by using HP-20 macroporous resin, silica gel, octadecyl silica gel(ODS), size exclusion chromatography resin HW-40 chromatography, and preparative HPLC. The structures were established through application of extensive spectroscopic methods, including ESI-MS, 1D- and 2D-NMR spectroscopy. They were identified as forsythialanside E(1), 8′-hydroxypinoresinol-4′-O-β-D-glucoside(2), 8′-hydroxypinoresinol(3), lariciresinol-4′-O-β- D-glucoside(4), lariciresinol-4-O-β-D-glucoside(5), forsythoside H(6), forsythoside I(7), forsythoside F(8), plantainoside B(9), and plantainoside A(10). Compound 1 was a new lignan glycoside.

A lignin glycoside and a nortriterpenoid from Kadsura coccinea

AIM: To study the chemical constituents of the roots and stem bark of Kadsura coccinea. METHOD: Compounds were isolated by column chromatography on silica gel and Sephadex LH-20, and finally purified by prep-HPLC. Their structures were elucidated by extensive spectroscopic methods, including 1D- and 2D-NMR, and HR-ESI-MS. RESULTS: Two compounds were determined as(7′S,8′S,8R)-(8β,8′α)- dimethyl-4,4′-dihydroxy-5,3′-dimethoxy-5′-cyclolignan glucoside(1) and micrandiactone H(2), respectively. CONCLUSION: Compunds 1 and 2 are new and neither showed inhibitory effects on nitric oxide(NO) production in lipopolysaccharide-induced RAW264.7 macrophages.