谷氨酸棒状杆菌异源合成萜类化合物的研究进展

萜类化合物具有可观的商业价值,但生产过程复杂,产量低,利用微生物异源合成萜类化合物已成为热点。谷氨酸棒状杆菌内含合成萜类色素的途径,具有异源合成萜类化合物的天然优势和研究前景。首次对谷氨酸棒状杆菌合成萜类化合物进行了综述,从萜类合成途径、关键酶和全局调控机制三个方面进行了途经介绍。概述了谷氨酸棒状杆菌中单萜、倍半萜、四萜类化合物的异源合成,并对利用谷氨酸棒状杆菌高效合成萜类化合物所需解决的问题进行讨论,为谷氨酸棒状杆菌高效合成萜类化合物提供建议。     

Chemosystematics of the hepaticae

Most liverworts (Hepaticae) contain oil bodies which are composed of lipophilic terpenoids and aromatic compounds. The chemosystematics of 36 families of the Jungermannidae and seven families of the Marchantiidae of the Hepaticae are discussed using terpenoid and aromatic components.     

A flavone and an unusual 23-carbon terpenoid from Andrographis paniculata

Phytochemical investigation of the roots and aerial parts of Andrographis paniculata Nees yielded a new flavone, 5-hydroxy-7,2',6'-trimethoxyflavone and an unusual 23-carbon terpenoid, 14-deoxy-15-isopropylidene-11,12-didehydroandrographolide together with five known flavonoids and four known diterpenoids. The structures of these compounds were determined on the basis of spectral and chemical studies.     

Natural products with calmodulin inhibitor properties

This review summarizes properties of various naturally occurring compounds with reported calmodulin (CaM)-inhibitory properties which include about 159 natural products belonging to different structural classes. Most inhibitors are alkaloid and peptide type of compounds and have been isolated from a wide variety of natural sources, including many plant species. Among the most potent natural anti-CaM substances, however, are several animal venoms and the antibiotic polymixin. The largest number of compounds described were discovered by means of enzymatic functional assays.     

Terpenoids from Achillea distans Waldst. & Kit. ex Willed

The flower heads of Achillea distans afforded nine new sesquiterpene lactones (one glaucolide, six guaianolides and two dimeric lactones) in addition to 18 known terpenoids. The structures and stereochemistry of the new compounds were elucidated by spectroscopic methods. The stereochemistry of 11,13-dihydroezomontanin was revised.     

Determination of bioactive markers in Cleome droserifolia using cell-based bioassays for antidiabetic activity and isolation of two novel active compounds

The antidiabetic activities of the aqueous (AqEx) and ethanolic (AlEx) extracts of Cleome droserifolia (Forssk.) Del., were tested in cultured C2C12 skeletal muscle cells and 3T3-L1 adipocytes. An 18-h treatment with the AqEx increased basal glucose uptake by 33% [insulin equivalent (IE)=1.3±0.04] in muscle cells comparable to a 25.5% increase caused by 100 nM insulin (IE=1±0.03). Fractionation of the tested AqEx yielded hexane (HxFr), chloroform (ClFr) and ethyl acetate (EtFr) fractions which exerted 38, 52 and 35% increase in the glucose uptake corresponding to an IE of 1.5±0.06, 2.0±0.04 and 1.4±0.04, respectively. Only the ClFr and EtFr accelerated the triglyceride accumulation [rosiglitazone equivalent (RE) was 0.9±0.13 and 0.63±0.12, respectively] in pre-adipocytes undergoing differentiation comparably with 10 μM rosiglitazone. Six terpenoids (C1-C6) and three flavonol glycosides (F1-F3) were isolated from the active ClFr and EtFr, respectively, and identified. C5, C2 and C4 had an IE of 0.86±0.05, 1.01±0.04 and 0.9±0.08, while F1, F2 and F3 gave an IE of 1.3±0.05, 2.3±0.05 and 2.0±0.04, respectively. We could conclude that the reported antihyperglycemic activity of Cleome droserifolia is attributed to significant insulin-like effects in peripheral tissues, and that compounds F2 and F3, being highly active, could be used as bioactive markers to standardize the C. droserifolia herbal extract.     

Structural characterization of phytotoxic terpenoids from Cestrum parqui

Isolation, chemical characterization and phytotoxicity of nine polyhydroxylated terpenes (five C13nor-isoprenoids, two sesquiterpenes, a spirostane and a pseudosapogenin) from Cestrum parqui L'Herr are reported. In this work we completed the phytochemical investigation of the terpenic fraction of the plant and described the structural elucidation of polar isoprenoids using NMR methods. All the configurations of the compounds have been assigned by NOESY experiments. Four new structures have been identified as (3S,5R,6R,7E,9R)-5,6,9-trihydroxy-3-isopropyloxy-7-megastigmene, 5alpha-spirostan-3beta,12beta,15alpha-triol, and 26-O-(3'-isopentanoyl)-beta-d-glucopyranosyl-5alpha-furost-20(22)-ene-3beta,26-diol, and as an unusual tricyclic sesquiterpene. The compounds have been assayed for their phytotoxicity on lettuce at the concentrations ranging between 10(-4) and 10(-7)M. The activities of some compounds were similar to that of the herbicide pendimethalin.     

Isolation, DNA topoisomerase-II inhibition, and cytotoxicity of three new terpenoids from the bark of Macaranga tanarius

One new pimarane-type diterpenoid (1) and two new taraxerane-based triterpenoids (2 and 3) were isolated from the bark of Macaranga tanarius, along with seven known compounds. Their structures were identified by spectroscopic methods including NMR and MS analyses. Compounds 1-5 were tested for their in vitro inhibition of DNA topoisomerase II, as well as for their cytotoxicities against human lung carcinoma A549 cells (Table 3). The triterpenoids 2-5 showed strong activities in both assays, but the diterpenoid 1 was only moderately active.