Cytotoxic biflavones from Stellera chamaejasme.

Bioassay-guided phytochemical studies on Stellera chamaejasme led to the isolation of two new biflavones, chamaejasmenin E (1) and chamaejasmin D (2), together with ten known compounds. The structures of new compounds were elucidated by extensive spectroscopic analyses and their absolute configurations on 2, 3, 2″ and 3″ were confirmed by TDDFT quantum chemical calculated ECD spectra combined with experimental ECD spectra. All isolated biflavones were evaluated for their cytotoxic activities against Bel-7402 and A549 tumor cell lines, and sikokianin D (3) was found to possess the most potential cytotoxic activities against both the two cell lines with IC50 values of 1.29 ± 0.21 and 0.75 ± 0.25 µM, respectively. Moreover, some structure-function relationships of these bioflavones for cytotoxic activities were explored and summarized.

Lignans from the stems of Clematis armandii ("Chuan-Mu-Tong") and their anti-neuroinflammatory activities.

ETHNOPHARMACOLOGICAL RELEVANCE: The dried stems of Clematis armandii (Caulis clematidis armandii), named "Chuan-Mu-Tong" in Chinese Pharmacopoeia, have been traditionally used as an herbal remedy mainly for inflammation-associated diseases. The Aim of the study is to identify the potential anti-neuroinflammatory components from Clematis armandii. MATERIALS AND METHODS: The ethanol extract of "Chuan-Mu-Tong" was suspended in H2O and exhaustively extracted with CH2Cl2. The CH2Cl2 fraction was successively subjected to column chromatography (CC) over silica gel, Sephadex LH-20, and semi-preparative HPLC. The structures of the isolated compounds were identified by spectroscopic methods and by comparison with those reported in the literature. Their anti-neuroinflammatory activities were evaluated by inhibitory effects on pro-inflammatory mediators [e.g. nitric oxide (NO) and tumor necrosis factor-alpha (TNF-α)] in lipopolysaccharide (LPS)-activated BV-2 cells. RESULTS: One new and sixteen known lignans were isolated and characterized. The absolute configuration of the new lignan, (7R,8S)-9-acetyl-dehydrodiconiferyl alcohol (1), was elucidated by a combination of 1D/2D NMR techniques and the Electronic Circular Dichroism (ECD) spectroscopy based on the empirical helicity rules. The anti-neuroinflammatory bioassay showed that compounds 1, (7R,8S)-dehydrodiconiferyl alcohol (2), erythro-guaiacylglycerol-ß-coniferyl ether (5), and threo-guaiacylglycerol-ß-coniferyl ether (6) displayed significant inhibitory effects on NO production. Among them, neolignans 1 and 2 exhibited more potent activities than the positive control (N(G)-monomethyl-L-arginine, L-NMMA), with an IC50 value of 9.3 and 3.9 µM, respectively. Moreover, both 1 and 2 were also found to concentration-dependently suppress the TNF-α release in LPS-stimulated BV-2 cells. CONCLUSION: The results revealed that lignans are the major components of "Chuan-Mu-Tong", and their anti-neuroinflammatory activities strongly support the traditional application of this herb medicine on inflammation. Moreover, the dihydrobenzo[b]furan neolignans 1 and 2 as well as Caulis clematidis armandii could be further exploited as new therapeutic agents to treat inflammation-mediated neurodegenerative and aging-associated diseases.

Phenolic constituents from the leaves of Cratoxylum formosum ssp. pruniflorum.

One (formosumone A, 1) new and fifteen (2-16) known phenolic compounds were isolated from the leaves of Cratoxylum formosum ssp. pruniflorumm, a substitute for the popular bitter nail tea ("Kuding Tea") generally used in Southeast Asia. Their structures were determined by extensive spectroscopic analysis and by comparison with literature data. Compound 1 possesses a rare scaffold of a flavanone coupled with a phloroglucinol moiety, representing the first example of such a scaffold from the Clusiaceae family. Among the isolates, toxyloxanthone B (11) and vismione D (12) were found to show remarkable anti-neuroinflammatory effects by inhibiting nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated murine BV-2 microglial cells. Additionally, toxyloxanthone B (11) exhibited significant neuroprotective effect against ß-amyloid(25-35) (Aß(25-35))-induced cell viability decrease in SH-SY5Y neuroblastoma cells.