Diterpenoids from Acacia leucophloea: revision of the structures of leucophleol and leucophleoxol

Undescribed compounds from Clinopodium chinense (Benth.) O. Kuntze and their coagulation activity studies

Four rare compounds (1-4), including one 1,4-epoxy-benzoxepane derivative and one ringed prenylated naphthoquinoid skeleton, as well as one isopimarane-type diterpenoid and one megastigmane-type glycoside, along with three known megastigmane-type glycosides (5-7) were isolated from the ethanol extracts of C. chinense. Their structures were determined on the basis of 1D, 2D NMR, HR-ESI-MS and DP4+ analysis. Meanwhile, the in vitro evaluation indicated that compound 2 and 6 exhibited excellent procoagulant activities, which can significantly shorten prothrombin time (PT) and activated partial thromboplastin time (APTT), respectively.

20-nor-Isopimarane and isopimarane diterpenoids produced by Aspergillus sp. WT03

Five new uncommon 20-nor-isopimarane diterpenoids, aspewentins N-R (1-5), and three related known congeners (6-8), along with an isopimarane diterpenoid, sphaeropsidin C (9), were isolated from a Coptis chinensis Franch. rhizosphere soil-derived fungal strain, Aspergillus sp. WT03. The structures of compounds 1-9 were characterized based on the comprehensive analysis of the spectroscopic data, and their absolute configurations were elucidated by single crystal X-ray diffraction and time-dependent density functional theory (TDDFT)-ECD calculations. Compounds 1-5 represent rare examples of 20-nor-isopimarane analogues featuring a 1,2,3,4-tetrahydronaphthalene and 3,4-dihydronaphthalen-1(2H)-one moiety. The biosynthetic pathway of these diterpenoids was also proposed. Additionally, compounds 1, 3 and 4 showed moderate cytotoxic activity against MCF-7, A549 and HT-29 cell lines.

Anti-inflammatory abietanes diterpenes and triterpenoids isolated from Clinopodium polycephalum

Two previously undescribed diterpenes (1 and 2), as well as one curious triterpenoid were isolated from Clinopodium polycephalum, a medicinal plant distributed in southwestern and eastern China. Their structures were elucidated using MS analyses, UV spectrum, and extensive 2D-homo and heteronuclear NMR data interpretations. Among them, 1 had an unusual skeletal characteristic produced by a rare methyl migration pathway. All monomer compounds exhibited inhibitory effects on NO production in LPS-induced RAW 264.7 cells without affecting cell viabilities, which were comparable to that of positive control.

Gastrointestial and respiratory activities of Acacia leucophloea

ETHNOPHARMACOLOGICAL RELEVANCE

The barks of Acacia leucophloea (Fabaceae) are used in Pakistan traditional medicine as an astringent, a bitter, a thermogenic, a styptic, a preventive of infections, an anthelmintic, a vulnery, a demulcent, an expectorant, an antipyretic, an antidote for snake bites and in the treatment of bronchitis, cough, vomiting, wounds, ulcers, diarrhea, dysentery, internal and external hemorrhages, dental caries, stomatitis, and intermittent fevers and skin diseases.

MATERIALS AND METHODS

A study was carried out for the possible elucidation of mechanisms justifying the traditional medicinal uses of A. leucophloea (Fabaceae) in gastrointestinal and respiratory diseases. In vitro experiments were carried out over isolated rabbit jejunum and guinea-pig ileum in order to determine spasmolytic and bronchorelaxant activities, while in vivo studies were conducted in mice for antidiarrheal properties.

RESULTS

A methanol crude extract of barks of the plant caused a concentration-dependent relaxation (0.1-3 mg/ml) of isolated rabbit jejunum preparations in a pattern similar to that of nifedipine and dicyclomine, suggesting a Ca(2+) channel-blocking mechanism in addition to an anticholinergic effect. In guinea-pig ileum the extract caused a parallel shift in the Ach-curves without suppression of maximum contractile response, followed by a non-parallel shift with the suppression of maximum contractile response at higher concentration similar to that caused by dicyclomine. Moreover, in rabbit trachea, it also caused the relaxation of carbachol (1 μM) and high K(+)-induced contractions at a dose ranging between 0.1578 and 0.734 mg/ml and 0.46-0.94 mg/ml, respectively. These findings indicate that the extract possesses spasmolytic and bronchodilator activities, mediated possibly through blockade of Ca(2+) channels, thus justifying its medicinal use in diarrhea and asthma. Acacia leucophloea methanol extract exhibited dose-dependent (100-500 mg/ml) protective effect against castor oil induced diarrhea.

CONCLUSIONS

The data obtained contribute to the validation of the traditional use of Acacia leucophloea bark in treating gastrointestinal and respiratory disorders, providing an hypothesis on the possible mechanisms of action.