A broad-based characterisation of a pharmacologically active dichloromethane extract from Isatis tinctoria leaves was carried out. For a comprehensive picture we also included the polar constituents of I. tinctoria (MeOH extract) and for comparative purposes, the taxonomically closely related plant I. indigotica. Diode array detector, evaporative light scattering detector, atmospheric pressure chemical ionisation and electrospray ionisation mass spectrometry, and electrospray ionisation time-of-flight mass spectrometry detectors were used in parallel to ensure a wide coverage of secondary metabolites with highly diverging analytical properties. Off-line microprobe nuclear magnetic resonance spectroscopy after peak purification by semi-preparative high-pressure liquid chromatography served for structure elucidation of some minor constituents. More than 65 compounds belonging to various structural classes such as alkaloids, flavonoids, fatty acids, porphyrins, lignans, carotenoids, glucosinolates and cyclohexenones were unambiguously identified, and tentative structures were proposed for additional compounds. Numerous compounds were identified for the first time in the genus Isatis, and an indolic alkaloid was discovered.
In a screen of 880 extracts from plants and fungi for antiplasmodial, antitrypanosomal, and leishmanicidal activity, an ethyl acetate extract of the mushroom Ganoderma lucidum showed antiplasmodial activity with 79% inhibition at 4.9 microg/mL. HPLC-based activity profiling and subsequent isolation of the antiplasmodial compounds yielded seven lanostanes (1-7), of which three (2, 3, and 7) were new. A new benzofuran derivative (8) of the farnesyl hydroquinone ganomycin B was also identified. The structures and relative configurations of the new compounds were elucidated by comprehensive spectroscopic analysis and by comparison of their NMR data with those of related compounds. The lanostanes exhibited in vitro antiplasmodial activity with IC(50) values from 6 to greater than 20 microM.
An EtOAc extract from the roots of Sophora flavescens (Kushen) potentiated γ -aminobutyric acid (GABA)-induced chloride influx in Xenopus oocytes transiently expressing GABA A receptors with subunit composition, α 1 β 2 γ 2S . HPLC-based activity profiling of the extract led to the identification of 8-lavandulyl flavonoids, kushenol I, sophoraflavanone G, (-)-kurarinone, and kuraridine as GABA A receptor modulators. In addition, a series of inactive structurally related flavonoids were characterized. Among these, kushenol Y (4) was identified as a new natural product. The 8-lavandulyl flavonoids are first representatives of a novel scaffold for the target.
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