A new ent-clerodane diterpenoid from Crassocephalum bauchiense Huch. (Asteraceae)

A phytochemical investigation of the whole plant of Crassocephalum bauchiense Huch. resulted in the isolation of a new clerodane diterpenoid, ent-2β,18,19-trihydroxycleroda-3,13-dien-16,15-olide (1), together with two known flavonoids 3′,5-dihydroxy-4′,5′,6,7,8-pentamethoxyflavone (2) and 4′,5-dihydroxy-3′,5′,6,7,8-pentamethoxyflavone (3). The compounds were tested against the chloroquine-sensitive 3D7 strain of Plasmodium falciparum. Compound 2 showed weak activity (IC₅₀ = 10.1 g/mL) whilst compounds 1 and 3 were inactive. The structures of the compounds were elucidated by using detailed spectral analyses, especially ¹H and ¹³C NMR, ¹H–¹H COSY, NOESY, HMBC and HR-ESI-MS.     

Separation and purification of five alkaloids from Aconitum duclouxii by counter‐current chromatography

C₁₉‐diterpenoid alkaloids are the main components of Aconitum duclouxii Levl. The process of separation and purification of these compounds in previous studies was tedious and time consuming, requiring multiple chromatographic steps, thus resulted in low recovery and high cost. In the present work, five C₁₉‐diterpenoid alkaloids, namely, benzoylaconine ( 1 ), N‐deethylaconitine ( 2 ), aconitine ( 3 ), deoxyaconitine ( 4 ), and ducloudine A ( 5 ), were efficiently prepared from A. duclouxii Levl (Aconitum L.) by ethyl acetate extraction followed with counter‐current chromatography. In the process of separation, the critical conditions of counter‐current chromatography were optimized. The two‐phase solvent system composed of n‐hexane/ethyl acetate/methanol/water/NH₃·H₂O (25%) (1:1:1:1:0.1, v/v) was selected and 148.2 mg of 1 , 24.1 mg of 2 , 250.6 mg of 3 , 73.9 mg of 4, and 31.4 mg of 5 were obtained from 1 g total Aconitum alkaloids extract, respectively, in a single run within 4 h. Their purities were found to be 98.4, 97.2, 98.2, 96.8, and 96.6%, respectively, by ultra‐high performance liquid chromatography analysis. The presented separation and purification method was simple, fast, and efficient, and the obtained highly pure alkaloids are suitable for biochemical and toxicological investigation.     

Isolation and Crystal Structure of Ent-kaurane Diterpenes from Rubus corchorifolius L. f.

In this study, ent-Kaurane-3β,16β,17-triol(1) and ent-kaurane-2α,16β,17-triol(2), were isolated from the leaves of Rubus corchorifolius L. f. Their structures were elucidated based on extensive spectroscopic analysis. NMR experiments identified the two compounds and X-ray crystallographic analysis confirmed their crystal structures. The crystal of 1 belongs to monoclinic with space group P21 and a = 10.7641(3), b = 7.2789(3), c = 11.7862(4) , β = 95.275(3)°, V = 919.55(6) 3, Z = 2, C20H34O4, Mr = 322.49 g/mol, Dc = 1.230 g/m3, F(000) = 376, λ = 1.54178 , μ = 0.661 mm-1, R = 0.0319, and wR = 0.0811 for 10889 observed reflections(Ⅰ 2σ(Ⅰ)). The crystal of 2 is classified as orthorhombic with space group P212121 and a = 10.7641(3), b = 12.72224(19), c = 21.3929(3) , V = 1748.94(4) 3, Z = 4, C20H34O4, Mr = 322.47, Dc = 1.225 Mg/m3 F(000) = 712, λ = 1.54184 , μ = 0.625 mm-1, R = 0.0303 and w R = 0.0759 for 10470 observed reflections(Ⅰ 2σ(Ⅰ)). Meanwhile, the compound revealed low inhibitory activities toward Hep G2, MCF-7, and SCG-7901 cells.     

Cytotoxic cassane diterpenoids from the seeds of Caesalpinia sappan

Phytochemical investigation on the seeds of Caesalpinia sappan led to the isolation of five new cassanetype diterpenoids, named 11-oxo-phanginin A(1), caesalsappanins O–Q(2–4) and phanginin U(5),together with five known compounds. The structures of the new compounds were elucidated by extensive analysis of mass spectrometric and 1D and 2D NMR spectroscopic data. All the new compounds showed moderate cytotoxic effects on human breast cancer MCF-7 and human colon cancer HCT116 cell lines.     

Sinulariols A-S, 19-oxygenated cembranoids from the Chinese soft coral Sinularia rigida

Chemical examination of a Chinese soft coral Sinularia rigida resulted in the isolation and characterization of 19 new cembrane-type diterpenoids, designated as sinulariols A-S (1-19). Their structures were determined on the basis of extensive spectroscopic (2D NMR, IR, and MS) analysis in association with modified Mosher’s method. All compounds featured unusual 19-oxygenated functionalities, which are rarely found from cembranoid family. The biogenetic transformation of the isolated compounds is postulated. Part of the isolated cembranoids showed significant anti-fouling activity.     

A new daphnane diterpenoid from Excoecaria venenata with inhibitory effect on human leukaemia HL-60 cells

A new daphnane diterpenoid, venenatin (1), along with six known compounds, was isolated from the aerial parts of Excoecaria venenata. The structure of 1 was elucidated on the basis of extensive spectroscopic analysis. Compound 1 exhibited growth inhibitory effect on human leukaemia HL-60 cell line with IC₅₀ value of 28.10 μM.     

Configuration Confirmation of Euphorbia Factor L1 by Single-crystal X-ray Diffraction

A 6,（17）-epoxylathyrol diterpenoid （（2S＊3S＊4R＊5R＊6S＊9S＊11S＊15R＊）-5,15-diacetoxy-3- phenylacetoxy-14-oxolathyra-6（17）,（12E）-diene-6（17）-epoxide） was isolated from the seeds of Euhporbia lathyris L. Its configuration was puzzled because of the incomplete X-ray results reported before. In this work, the atom connectivity and configuration were confirmed by single-crystal X-ray diffraction together with ESI-MS, ^1H-, and ^13C-NMR spectroscopy. The compound crystallizes in monoclinic, space group P21 with a = 11.386（1）, b = 8.2839（7）, c = 17.192（2） A, β = 108.305（2）°, Z = 2, V = 1539.5（2）A^3, C32H40O8, Mr = 552.64, Dc = 1.192 g/m^3, /7（000） = 592,μ（MoKα） = 0.085 mm^-l, T = 293（2） K, the final R = 0.0398 and wR = 0.0950 for 2057 observed reflections with Ⅰ 〉 2α（Ⅰ）. The molecule shows a tricyclic terpenoid skeleton, consisting of fused five-, eleven- and three-membered rings. The configuration at C（5） is R^＊ and that at C（6） S^＊.     

Two new abietane diterpenoid glycosides from Clinopodium chinense

Two new abietane diterpenoid glycosides, named clinopoditerpenes B (1) and C (2), were isolated from Clinopodium chinese. The structures of the new compounds were determined on the basis of extensive spectral analysis. Compound 1 exhibited cardioprotective effect against H₂O₂-induced apoptosis in H9c2 cells.     

一种新的DENUDATINE型C20二萜生物碱结构的NMR研究

从内蒙西伯利亚乌头中分离得一个新的C20二萜生物碱,采用选择性远程DEPT,同核和异核二维NMR技术相结合进行了研究,其结构确定为Lepenine的C－11基向立体异构体,定名为11a－hydroxylapenine．结果表明,选择性远程DEPTNMR技术对于连接这类化合物中被季碳和杂原子分割的NMR自旋体系,测定基本骨架和确定信号归属都有独到之处．     

一种新的DENUDATINE型C20二萜生物碱结构的NMR研究

从内蒙西伯利亚乌头中分离得一个新的C₂₀二萜生物碱,采用选择性远程DEPT,同核和异核二维NMR技术相结合进行了研究,其结构确定为Lepenine的C-11基向立体异构体,定名为11a-hydroxylapenine.结果表明,选择性远程DEPTNMR技术对于连接这类化合物中被季碳和杂原子分割的NMR自旋体系,测定基本骨架和确定信号归属都有独到之处.