Zhi-Zhi Du

A cage-monoterpene indole alkaloid from Alstonia scholaris.

An unprecedented cage-like alkaloid, scholarisine A was isolated from the leaves of Alstonia scholaris and its structure determined on the basis of 1D and 2D NMR, FTIR, UV, and high-resolution mass spectroscopic data. This alkaloid might be derived from picrinine via oxygenation, rearrangement, and lactonization.

Monoterpenoid indole alkaloids from the bark of Alstonia scholaris.

Six new monoterpenoid indole alkaloids, scholarisines B-G (1- 6), together with 15 known analogues (7- 21), were isolated from the bark of Alstonia scholaris. Their structures were determined by 1D and 2D NMR spectra and MS analyses. The structure of 1 was further supported by the single-crystal X-ray.

Phomoeuphorbins A-D, azaphilones from the fungus Phomopsis euphorbiae.

Four azaphilones, named phomoeuphorbins A-D (1-4) were isolated from cultures of Phomopsis euphorbiae, an endophytic fungus isolated from Trewia nudiflora. Structures of 1-4 were established on the basis of spectroscopic analyses, including application of 2D NMR spectroscopic techniques. Phomoeuphorbins A and C exhibited very weak inhibitory activities against HIV replication in C8166 cells in vitro.

Antimicrobially active isoquinoline alkaloids from Litsea cubeba.

Bioassay-guided fractionation of the alkaloidal extract of the aerial part of Litsea cubeba led to the isolation of two new isoquinoline alkaloids, (+)- N-(methoxycarbonyl)-N-norboldine (1) and (+)-isoboldine beta-N-oxide (2), together with 11 known analogues (3-13). Their structures were established by extensive spectroscopic techniques and by comparing spectroscopic data with those in the literature. Compounds 1 and 4 showed antimicrobial activities. This is the first report on the presence of compounds 1, 2, 6, 8, 9, 11, and 12 in this plant and on the antimicrobial activities of 1 and 4. The bioactivities of isoquinoline alkaloids are also at least partly responsible for the pharmacological function of the folk medicinal plant Litsea cubeba.

A New Flavone C-Glycoside from Clematis rehderiana

A new flavone C-glycoside, isovitexin 6″-O-E-p-coumarate (1) and two known flavonoid glycosides—quercetin 3-O-β-D-glucuronopyranoside (2) and isoorientin (3)—were isolated from an ethanol extract of aerial parts of Clematis rehderiana. Their structures were determined by spectroscopic methods. The antioxidant effects of the two flavone C-glycosides were evaluated by both the MTT and DPPH assays. Compound 1 showed potent activities against H2O2-induced impairment in PC12 cells within the concentration range tested, whereas compound 3 scavenged DPPH radical strongly, with an IC50 value of 13.5 μM.

Chemical Composition and Antimicrobial Activity of the Essential Oil from the Edible Aromatic Plant Aristolochia delavayi

The essential oil obtained by hydrodistillation from the aerial parts of Aristolochia delavayi Franch. (Aristolochiaceae), a unique edible aromatic plant consumed by the Nakhi (Naxi) people in Yunnan, China, was investigated using GC/MS analysis. In total, 95 components, representing more than 95% of the oil composition, were identified, and the main constituents found were (E)‐dec‐2‐enal (52.0%), (E)‐dodec‐2‐enal (6.8%), dodecanal (3.35%), heptanal (2.88%), and decanal (2.63%). The essential oil showed strong inhibitory activity (96% reduction) of the production of bacterial volatile sulfide compounds (VSC) by Klebsiella pneumoniae, an effect that was comparable with that of the reference compound citral (91% reduction). Moreover, the antimicrobial activity of the essential oil and the isolated major compound against eight bacterial and six fungal strains were evaluated. The essential oil showed significant antibacterial activity against Providencia stuartii and Escherichia coli, with minimal inhibitory concentrations (MIC) ranging from 3.9 to 62.5 μg/ml. The oil also showed strong inhibitory activity against the fungal strains Trichophyton ajelloi, Trichophyton terrestre, Candida glabrata, Candida guilliermondii, and Cryptococcus neoformans, with MIC values ranging from 3.9 to 31.25 μg/ml, while (E)‐dec‐2‐enal presented a lower antifungal activity than the essential oil.

Tarennanosides A-H, Eight New Lignan Glucosides from Tarenna attenuata and Their Protective Effect on H2O2-Induced Impairment in PC12 Cells

Eight new lignan glucosides, tarennanosides A-H (1-8, resp.), were isolated from the whole plant of Tarenna attenuata, together with three known compounds, fernandoside, (-)-lyoniresinol, and (-)-isolariciresinol. The planar structures of new compounds were elucidated mainly by analysis of physical and spectroscopic data, and the absolute configurations were determined by acid hydrolysis as well as CD spectroscopy. Compounds 1 and 2 exhibited potent antioxidant activities against H2O2-induced impairment in PC12 cells. Preliminary mechanism study by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method showed that these two compounds could act as radical scavengers.

Volatiles from leaves and rhizomes of fragrant Acorus spp. (Acoraceae)

Three horticultural selections of Acorus gramineus Soland were investigated to determine the chemical composition of their leaves and rhizomes. The variety ‘liquorice’ was found to contain methylchavicol (49%) which accounts for the unusual anisic odor of this variety, while β‐asarone was the main component of A. christophii (43%) and ‘yodo‐no‐yuki’ (20%). The results are compared with calamus oils, and the possible biosynthetic precursors of the main components methylchavicol and β‐asarone are considered.

C21 Steroidal Saponins from Cynanchum otophyllum

Abstract Objective To study the chemical structures of saponins in the rhizome of Cynanchum otophyllum (Asclepiadaceae), and to find new compounds. Methods The total saponins of the rhizome were separated by silica gel column chromatography. The chemical structures of obtained compounds were determined by NMR and FAB-MS spectra. Results Three C 21 steroidal saponins were separated. Their structures were determined as caudatin 3- O -β- D -glucopyranosyl-(1→4)-β- D -digitoxopyranosyl-(1→40)-β- D -digino-pyranosyl-(1→4)-α-D-oleandropyranoside (1), caudatin 3- O -β- D -oleandropyranosyl-(1→4)-α- D -oleandropyranosyl-(1→4)-α- D -oleandropyranoside (2), and caudatin 3- O -β- D -glucopyranosyl-(1→4)-α- D -oleandropyranosyl-(1→4)-β- D -diginopyranosyl-(1→4)-α-D-oleandropyranoside (3), respectively. Conclusion Saponins 1–3 are new compounds.

A new cyclooxygenase inhibitor from Incarvillea arguta.

A new anti-inflammatory spirovetivane-type sesquiterpenoid, designated as 1,10-didehydrolubimin (1) and thirteen known compounds (2 - 14) were isolated from the whole plants of the ‘Yi’ ethnomedicinal plant Incarvillea arguta. Their structures were established based on spectral methods and by comparison of the spectral data with those reported previously. Compound 1 exhibited significant inhibitory effects on Cox-1 and Cox-2 and a negative effect against 5-Lox at the concentration of 100 μM. Graphical Abstract A New Cyclooxygenase Inhibitor from Incarvillea arguta