Occurrence of sesquiterpene derivatives in Scleria striatonux de wild (Cyperaceae).

Scleria striatonux (Cyperaceae), a spice traditionally used in Cameroon, displayed an antiplasmodial activity. Two new sesquiterpenes, 1 (sclerienone A) and 2 (sclerienone B), have subsequently been isolated from the methylene chloride/methanol extract of the rhizome. Their separation involved a combination of methods including repeated silica gel open column chromatography, Sephadex LH-20 and semi-preparative HPLC.

Determination of pyrrolizidine alkaloids in senecio species by liquid chromatography/thermospray-mass spectrometry and liquid chromatography/nuclear magnetic resonance spectroscopy.

A new method using direct on-line coupling between HPLC, MS and (1 )H-NMR was developed for the detection and identification of pyrrolizidine alkaloids (PAs) in crude extracts of Senecio species. The PAs present in the extracts were separated on a C-18 reversed-phase column with an alkaline acetonitrile-water gradient. Molecular weight information of each peak was obtained by LC/MS and specific fragments were recorded by complementary MS/MS experiments.

On-line identification of further flavone C- and O-glycosides from sugarcane (Saccharum officinarum L., Gramineae) by HPLC-UV-MS.

HPLC-UV-MS (APCI-MS/MS and CID/MS) was utilised for the identification of eight additional flavone glycosides from sugarcane (Saccharum officinarum L., Gramineae) extracts of bagasse, leaves and juice ('garapa'). Relevant information about substitution patterns was obtained through UV detection using post-column addition of shift reagents, while tandem MS provided structural information confirming the proposed structures of the C-glycosides vitexin, orientin, luteolin-8-C-(rhamnosylglucoside), 4',5'-dimethyl-luteolin-8-C-glycoside and the isomeric pair schaftoside-isoschaftoside, besides the O-glycosides tricin-7-O-neohesperidoside and tricin-7-O-glycoside.

Identification of flavonols in leaves of Maytenus ilicifolia and M. aquifolium (Celastraceae) by LC/UV/MS analysis.

A comparative analysis of the flavonoid components of the leaves of two medicinal plants known in Brazil as "espinheira santa", namely, Maytenus ilicifolia Mart. ex Reiss. and M.

On-line identification of sugarcane (Saccharum officinarum L.) methoxyflavones by liquid chromatography-UV detection using post-column derivatization and liquid chromatography-mass spectrometry.

Sugarcane (Saccharum officinarum L., Gramineae) bagasse and leaves were investigated for their flavonoid content and transgenic sugarcane ("Bowman-Birk" and "Kunitz") was compared with non-modified ("control") plants. Analyses were carried out by high-performance liquid chromatography coupled to diode array UV detection (LC/UV), also using post-column addition of shift reagents, and tandem MS (atmospheric pressure chemical ionization-MS/MS and collision-induced dissociation-MS).