Jing-Zhi Yang

Psidials A−C, Three Unusual Meroterpenoids from the Leaves of Psidium guajava L

Three novel sesquiterpenoid-based meroterpenoids of psidials A-C (1-3) have been isolated from the leaves of Psidium guajava L. Their complete structures were elucidated by spectral and chemical methods, and that of 1 was confirmed by single-crystal X-ray diffraction analysis. Psidial B (2) and C (3) represented the new skeleton of the 3,5-diformylbenzyl phloroglucinol-coupled sesquiterpenoid. A possible biosynthetic pathway for 2-3 was postulated. 2-3 showed activity to enzyme PTP1B in 10 microM.

Carbazole alkaloids from the stems of Clausena lansium.

Ten new carbazole alkaloids, claulansines A-J (1-10), and seven known analogues (11-17) were isolated from the stems of Clausena lansium. Their structures were established on the basis of extensive spectroscopic analyses, and their absolute configurations were determined by CD experiments and computational methods. Screening results indicated that compounds 1, 6, 8-10, 13, 14, and 17 showed selective neuroprotective effects at the concentration of 10 μM.

Triterpenoid saponins with neuroprotective effects from the roots of Polygala tenuifolia.

The methanol fraction of an ethanolic extract from the roots of Polygala tenuifolia Willd. showed antagonistic action on neurotoxicity induced by glutamate and serum deficiency in PC12 cells. Bioassay-guided fractionation led to the isolation of six new triterpenoid saponins, onjisaponins V - Z, and Vg ( 1 - 6), together with ten known saponins ( 7 - 16). The structures of 1 - 6 were elucidated by spectroscopic and chemical methods. Screening results indicated that compounds 1 - 16 showed neuroprotective effects against serum deficiency and glutamate at the concentration of 10 (-5) mol/L.

Anti-inflammatory sesquiterpene derivatives from the leaves of Tripterygium wilfordii.

Twelve new dihydroagarofuran sesquiterpene polyol esters, triptersinines A-L (1-12), and eight known sesquiterpene pyridine alkaloids were isolated from the leaves of Tripterygium wilfordii. Their structures were elucidated on the basis of spectroscopic analyses, including UV, IR, and NMR experiments ((1)H-(1)H COSY, NOESY, HSQC, and HMBC). Furthermore, in an in vitro bioassay, compounds 1, 9, 11, 13, 14, and 18 showed moderate inhibitory effects on nitric oxide production in LPS-induced macrophages at 5 μM; all compounds were inactive when tested against five human cancer cell lines (IC(50) values >1 μM).

Hepatoprotective coumarins and secoiridoids from Hydrangea paniculata.

Three new coumarin glucosides (1, 3, 4), and a new secoiridoid glucoside (2), together with one known secoiridoid glucoside (5), were isolated from the stems of Hydrangea paniculata. Their structures were elucidated on the basis of spectroscopic methods, including extensive NMR, MS and CD spectra. At 10 μM, compounds 1-5 showed hepatoprotective activities against DL-galactosamine-induced toxicity in HL-7702 cells.

Bioactive furanocoumarins from stems of Clausena lansium

Clausena lansium Skeels, a member of the Rutaceae, is a shrub or small tree with grapelike fruits. Several parts of this plant have been used in folk medicine. A bioactive constituent investigation of the stems of C. lansium herein resulted in isolation of four furanocoumarins, claucoumarins A-D, and 13 known analogs. Their structures were elucidated on the basis of spectroscopic analyses, including UV, IR, MS, and NMR experiments, and their absolute configurations were determined by CD experiments. Using an in vitro system, several of these compounds showed selective neuroprotective effects at a concentration of 10μM.

A,D-seco-Limonoids from the Stems of Clausena emarginata

Twelve new A,D-seco-limonoids, clauemargines A-L (1-12), and three known analogues were isolated from the stems of Clausena emarginata. The absolute configurations of 1 and 5 were confirmed by X-ray crystallography and ECD spectroscopy, respectively. Compounds 1, 2, 8-10, and 13 showed moderate inhibitory effects on LPS-induced NO production (IC50 values<10 μM).

Coumarin Glycosides and Iridoid Glucosides with Neuroprotective Effects from Hydrangea paniculata

Five new coumarin glycosides, umbelliferone 7-O-sophoroside (1), umbelliferone 7-O-β-D-glucopyranosyl(1 → 3)-β-D-glucopyranoside (2), umbelliferone 7-O-β-D-glucopyranosyl(1 → 3)-[β-D-apiofuranosyl(1 → 6)]-β-D-glucopyranoside (3), umbelliferone 7-O-β-D-glucopyranosyl(1 → 2)-β-D-apiofuranosyl(1 → 6)-β-D-glucopyranoside (4), and umbelliferone 7-O-β-D-glucopyranosyl(1 → 5)-β-D-apiofuranosyl(1 → 6)-β-D-glucopyranoside (5), and two new iridoid glucosides, 7-O-E-isoferuloyl loganic acid (6) and 7-O-β-D-glucopyranosyl loganin (7), together with eight known compounds (8-15) were isolated from the stems of Hydrangea paniculata. Their structures were established by spectroscopic analysis and chemical methods. At 10 µM, compounds 1, 3, 5, 6, 8, 9, and 13 showed neuroprotective effects against serum deprivation-induced PC12 cell damage.

Four new neolignans from the leaves of Tripterygium wilfordii

Four new neolignans, wilfordiols A-D (1-4), together with five known compounds (5-9), were isolated from an aqueous extract of the dried leaves of Tripterygium wilfordii. Their structures were determined by spectroscopic methods, including 1D and 2D NMR, HRESIMS, and CD experiments. The anti-inflammation activities of compounds 1-9 were evaluated by the inhibitory effect on NO production, in vitro.

Skimmin, a Coumarin from Hydrangea paniculata, Slows down the Progression of Membranous Glomerulonephritis by Anti-Inflammatory Effects and Inhibiting Immune Complex Deposition

Skimmin is one of the major pharmacologically active molecules present in Hydrangea paniculata, a medical herb used in the traditional Chinese medicine as an anti-inflammatory agent. In the current study, we attempted to investigate its renoprotective activity and underlying mechanisms in a rat model of membranous glomerulonephritis induced by cationic bovine serum albumin (c-BSA). Sprague-Dawley (SD) rats were divided into five groups, including normal control, model control, Mycophenolate Mofetil-treated group, and two skimming-treated groups (15 mg/kg and 30 mg/kg). Our research showed that treatment with skimmin significantly reduced the levels of blood urea nitrogen (BUN), urinary albumin excretion (UAE), and serum creatinine (Scr) as compared with model control after experimental induction of membranous glomerulonephritis (P < 0.01). Moreover, glomerular hypercellularity, tubulointerstitial injury, and glomerular deposition of IgG were less intense after skimmin treatment. By immunochemistry analysis, we demonstrated that skimmin could significantly inhibit interleukin-1β (IL1β) and IL-6 expression (P < 0.05), reduce the loss of nephrin and podocin, and suppress the infiltration of renal interstitium by CD3-positive T cell and CD20-positive B cell. These results suggest that treatment with skimmin can significantly improve renal function and suppress the IgG deposition as well as the development of glomerular lesions in a rat model of membranous glomerulonephritis.