Phytochemical analysis of Striga hermonthica by DART-MS and HPLC-MS
A parasitic plant, Striga hermonthica (Del.) Benth., is one of the biggest biological constraints to cereal production in sub-Saharan Africa and western Kenya. It commonly infects major crops such as sorghum, maize, millet, and rice, lowering grain yield. For this reason, reseach on S. hermonthica has mainly focused on controling this weed, but little is known about the constituents of this plant. Thus, DART-MS and LC-ESI-MS were used in order to identify secondary metabolites in S. hermonthica. Direct analysis in real time (DART) is a new ionization technique which is conducted in the open air, allowing for the rapid and direct analysis of various types of samples (solid, lipid and gases) with no previous sample preparation. From the dry powder analysed by DART-MS and the methanol extract analysed by LC-ESI-MS, the flavonoids apigenin (m/z 271), luteolin (m/z 287) and chrysoeriol (m/z 301) and coumaric acid (m/z 165) were first identified. β-sitosterol (m/z 415) and the alkaloid venoterpine (m/z 150), which already have been reported in this plant, also were detected. These results are expected to serve as basic information for further phytochemical studies on S. hermonthica and to discriminate among different chemotypes as well as Striga spp.