Cytotoxic sesquiterpenes from Ligularia platyglossa

Multicomponent synthesis of chromophores – The one-pot approach to functional π-systems

Multicomponent reactions, conducted in a domino, sequential or consecutive fashion, have not only considerably enhanced synthetic efficiency as one-pot methodology, but they have also become an enabling tool for interdisciplinary research. The highly diversity-oriented nature of the synthetic concept allows accessing huge structural and functional space. Already some decades ago this has been recognized for life sciences, in particular, lead finding and exploration in pharma and agricultural chemistry. The quest for novel functional materials has also opened the field for diversity-oriented syntheses of functional π-systems, i.e. dyes for photonic and electronic applications based on their electronic properties. This review summarizes recent developments in MCR syntheses of functional chromophores highlighting syntheses following either the framework forming scaffold approach by establishing connectivity between chromophores or the chromogenic chromophore approach by de novo formation of chromophore of interest. Both approaches warrant rapid access to molecular functional π-systems, i.e. chromophores, fluorophores, and electrophores for various applications.

Chemical Constituents of Ligularia Species (Asteraceae) and Their Diversity in East Asia

More than 100 Ligularia species and those of several related genera (Cremanthodium, Cacalia, Senecio, and others) in the plant family Senecioneae grow in East Asia. For many years, researchers have studied the chemical constituents of these plants, and terpenoids, flavonoids, sterols, alkaloids, and aromatic compounds have been isolated. Among these, in particular, numerous sesquiterpenoids were reported. In this contribution, relevant chemical studies are described mainly from literature reports appearing since 2000, inclusive of investigations performed by the present authors, on the diversity in secondary metabolites of Ligularia growing in the Hengduan Mountains area of China, focusing on eremophilane sesquiterpenoids and other metabolites. Terpenoids and aromatic compounds (totaling 1049), both new and known, are listed. Genetic studies and synthesis investigations are also reviewed briefly.

High performance liquid chromatography time of flight electrospray ionization mass spectrometry for quantification of sesquiterpenes in Chrysanthemi indici Flos active extract

Background:

Chrysanthemi indici Flos, a traditional herbal medicine is used to clearing heat–toxicity, removing the liver fire, and improving eyesight. In our preliminary work, an active extract of CTC in C. An indici Flos with anti-hepatitis B virus and liver protective activity was found by HepG2.2.1.5 test and experiment of protein synthesis in mice's injured liver. In this work, we aimed to study the active faction CTC further by qualitative and quantitative analysis method.

Materials and Methods:

High performance liquid chromatography time of flight electrospray ionization mass spectrometry (HPLC TOF ESI-MS) analysis method of the CTC was established. Cumambrin A and angeloylcumambrin B in CTC were analyzed by high performance liquid chromatography-ultraviolet-evaporative light scattering detector (HPLC-UV-ELSD) analysis methods. A binary gradient elution program was conducted for chromatographic separation with acetonitrile (A) and ultrapure water (B) as follows: 0–10 min, 42–46% A; 10–20 min, 46–55% A; 20–25 min, 55–60% A; and 25–35 min, 60–75% A. The column temperature and UV wavelength were set at 30°C and 205 nm.

Result:

Ten constituents including (3R, 5R, 6S, 7S, 10R)-7-(2-hydroxy-2-propyl)-10-methyl-4-methyleneperhy, dronaphthal-ene-3, 5, 6-triol acetone solvate; (+)-edusmance-4, (14)-ene-11, 13-diol; linarin; luteolin; apigenin; tricin; 5, 3’,4’- trimethyl-6,7-dimethoxy flavones; cumambrin A; acacetin; and angeloylcumambrin B in CTC were identified by HPLC TOF ESI-MS. The contents of sesquiterpenes in CTC were decreased by storing years.

Conclusions:

The results showed that both UV and ELSD methods were feasible, accurate, and the determination results were in good consistency. The contents of two sesquiterpenes decreased with storing years. Two sesquiterpenes could be used as quality control for C. indici flos CTC.

Lactones with methylcyclohexane systems obtained by chemical and microbiological methods and their antimicrobial activity

Eight new lactones (δ-chloro-, δ-bromo- and δ-iodo-γ-lactones), each with a methylcyclohexane ring, were obtained by chemical means from (4-methylcyclohex-2-en-1-yl) acetic acid or (6-methylcyclohex-2-en-1-yl) acetic acid. Whole cells of ten fungal strains (Fusarium species, Syncephalastrum racemosum and Botrytis cinerea) were tested on their ability to convert these lactones into other products. Some of the tested fungal strains transformed chloro-, bromo- and iodolactone with a methyl group at C-5 into 2-hydroxy-5-methyl-9-oxabicyclo[4.3.0]nonan-8-one during hydrolytic dehalogenation. When the same lactones had the methyl group at C-3, no structural modifications of halolactones were observed. In most cases, the optical purity of the product was low or medium, with the highest rate for chlorolactone (45.4%) and iodolactone (45.2% and 47.6%). All of the obtained compounds were tested with reference to their smell. Seven halolactones and the hydroxylactone obtained via biotransformation of halolactones with 5-methylcyclohexane ring were examined for their antimicrobial activity. These compounds were capable of inhibiting growth of some bacteria, yeasts and fungi.

A cytotoxic dimeric furanoheliangolide from Piptocoma rufescens

A new sesquiterpene lactone, rufescenolide C (1), the first furanoheliangolide dimer, was isolated from the leaves of Piptocoma rufescens, collected in the Dominican Republic. Its structure was determined by analysis of its spectroscopic data, with the absolute configuration being established by analysis of the CD spectrum. A plausible biogenesis of this dimer is proposed. This compound showed potent cytotoxicity with an IC50 value of 150 nM, when tested against HT-29 human colon cancer cells.

Eremophilane-type sesquiterpenes from cultured lichen mycobionts of Sarcographa tricosa

Spore-derived mycobionts of the crustose lichen Sarcographa tricosa were cultivated on a malt-yeast extract medium supplemented with 10% sucrose. Chemical investigation of the cultivated colonies led to isolation of three eremophilane-type sesquiterpenes, 3-epi-petasol (1), dihydropetasol (2) and sarcographol (3), together with six known eremophilanes and ergosterol peroxide. These structures were elucidated by spectroscopic and chemical methods. This is the first report of eremophilane-type sesquiterpenes from the cultured mycobionts of lichen.

Phytochemicals and biological activities of Ligularia species

Ligularia, an important genus of the Compositae family, has captured the interest of natural product chemists for years. Phytochemical investigations on the title genus have led to isolation of hundreds of secondary metabolites with various skeletons. Herein, we summarized the chemical constituents of this genus and their biological activities over the past few decades.

Cadinane sesquiterpenes from Curcuma parviflora

Two new cadinane sesquiterpenes (1 and 2) were isolated from Curcuma parviflora, and their structures were elucidated by spectroscopic data. Compound 1, 4alpha-acetoxycadina-2,9-diene-1,8-dione, possesses two conjugated enone chromophores, while compound 2, 1alpha,3alpha,4beta-trihydroxy-9-cadinen-8-one, has an enone moiety with three hydroxy groups. Isolation of these cadinane monomers may reasonably suggest that parviflorenes are biogenetically classified as cadinane dimers.