Records of Natural Products

A new ent-atisane diterpenoid, named euphrosanoid A (1), along with five known analogues (2-6) were isolated from the stems of Euphorbia royleana. The structure of new compound 1 was determined by extensive spectroscopic data, especially 1D and 2D NMR experiments, and the absolute configuration of 1 was determined by comparison of experimental and calculated electronic circular dichroism (ECD) data. All isolated compounds were evaluated for their cytotoxic activities, and compounds 1 and 5 showed weak cytotoxicities against HCT-15 cancer cells with IC50 values of 62.98 ± 6.27 and 44.35 ± 3.66 uM, respectively.

Prunus mahaleb seeds  were selected for phytochemical study directed by ex-vivo bronchodilator effect based on the traditional use for the treatment of respiratory problems. From the active chloroform fraction, five known phenylpropanoid glycosides: cis-melilotoside sodium salt (1), cis-methoxy-melilotoside (2), 3-(2-O-b-D-glucopyranosyl-4-methoxyphenyl) propanoic acid (3), trans-methoxy-melilotoside (4) and trans-melilotoside (5) were identified for the first time from genus Prunus. Chemical structure of the compounds elucidated by spectroscopic techniques such as 1D, 2D NMR and HR-ESI/MS. Compounds 1, 2, 4, 5 showed promising bronchodilator effects against carbamylcholine (CCh) induced bronchospasm in isolated Guinea-pig trachea while 2 was found completely inactive. The mechanism(s) of action was studied using both CCh, low K+ (25 mM) and high K+ (80 mM)-mediated contractions and compound 2 was found distinctly more potent and efficacious against CCh compared to both types of K+-mediated contractions where partial efficacy was observed, hence showed dual inhibition of cholinergic receptors followed by Ca2+ channels. The anticholinergic and Ca2+ inhibitory activities of compound 2 were further confirmed when it deflected CCh concentration response curves (CRCs) without suppression, whereas its higher doses shifted Ca2+ CRCs similar to verapamil. The bronchodilator effect proved to be mediated via dual anticholinergic and Ca2+ channels blocking effects.

The herbs, Dehaasia cuneata (Blume) Blume and Caryodaphnopsis tonkinensis (Lecomte) Airy-Shaw (Lauraceae) were used ethnomedically for the treatment of malaria, inflammation and amelioration of microbial infections. We report herein the chemical constituents and antimicrobial activity of the leaf essential oils of D. cuneata and C. tonkinensis from Vietnam. The technique of gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC/MS) was used to analyze the oil samples while the microdilution assay was employed to determine the antimicrobial efficacy. The main constituents of D. cuneata were α-pinene (49.0%), camphene (19.5%), β-pinene (15.6%) and limonene (7.5%), while α-pinene (26.8%), β-pinene (23.0%) and bicyclogermacrene (8.5%). The leaf oil of D. cuneata displayed potent antimicrobial activity against Gram-negative bacteria, Pseudomonas aeruginosa ATCC27853 with minimum inhibitory concentration (MIC) value of 5.37 µg/mL; and Gram-positive microorganisms of Staphylococcus aureus ATCC25923 (MIC, 21.56 µg/mL and Bacillus cereus ATCC14579 (MIC, 23.45 µg/mL). The leaf oil of C. tonkinensis exhibited good antibacterial activity towards Enterococcus faecalis ATCC299212 with MIC value of 15.99 µg/mL, and anti-candidal action against Candida albicans ATCC10231 with MIC value of 33.68 µg/mL. the chemical constituents and antimicrobial activity of the essential oils were being reported for the first time.

A new iridoid glycoside, cornusglucoside I (1), and a new natural product methyl 4-(3′,4′-dihydroxyphenyl)-4-oxobutanoate (2), together with two known isolated compounds (3-4) were obtained from the 30% ethanol extract of the wine-processed Corni fructus. Their structures were clarified by spectroscopic analysis and literature data. The absolute configuration of 1 was elucidated by ECD calculation. By evaluating the NO production induced by LPS in RAW 264.7 cells to assess the anti-inflammatory activities of isolated compounds. Among the tested compounds, compounds 3 and 4 exhibited stronger anti-inflammatory activity than the positive drug dexamethasone (6 μM), which may be potential anti-inflammatory drugs.