Four new compounds from Imperata cylindrica
Four new compounds, impecylone (1), deacetylimpecyloside (2), seguinoside K 4-methylether (3) and impecylenolide (4), were isolated from Imperata cylindrica along with two known compounds, impecyloside (5) and seguinoside K (6). Their structures were elucidated mainly by spectroscopic analyses including 1D- and 2D-NMR techniques, and the absolute configuration of 1 was confirmed by X-ray diffraction analysis. In calcium assay, the result indicated that compounds 1, 2, 4 and 5 cannot obviously inhibit the calcium peak value compared with the negative control, and suggested that the four compounds could not have anti-inflammatory activity.
Grasses in South African traditional medicine: A review of their biological activities and phytochemical content
Abstract Certain grass species are used as remedies against diseases and as nourishing food for both humans and livestock. The review aims to explore the grasses used in South African traditional medicine and highlight their pharmacological and phytochemical properties as well as safety. Chemical compounds were drawn using ChemDraw Ultra 7.0, structures were confirmed or authenticated using chemical structure databases such as PubChem, Chemical Books, NIST Chemistry Books and ChemSpider. In terms of pharmacological properties of these grasses, antimicrobial, anti-mutagenic, anti-tumour, anti-diarrhoeal, anti-diabetic, diuretic, hepato-protective, anti-inflammatory, anti-plasmodial and antioxidant activities have been indicated. Diverse classes of phytochemicals such as sterols, alkaloids, phenolics, terpenes and cardiac glycosides have been isolated. Toxicity and cytotoxicity studies of extracts and the isolated compounds from the grasses suggest their relative safety. Grasses play a substantial role in primary health care needs and may serve as novel sources of bioactive compound(s). However, when compared to other plant families often used in South African traditional medicine, there is limited scientific evidence on their pharmacological and phytochemical properties as well as cytotoxicity. Thus, more research efforts are required to unlock the potential embedded in this important group of plants.
Epicatechin carbonyl-trapping reactions in aqueous maillard systems: Identification and structural elucidation.
Recently, our group reported via labeling experiments that epicatechin in Maillard reaction aqueous glucose-glycine model systems formed adduct reaction products with C2, C3, and C4 sugar fragments. In the current study, we investigated the identity of the sugar fragment precursors responsible for adduct generation by directly comparing the liquid chromatography-mass spectrometry properties of these reported epicatechin (EC)-sugar fragments adducts with those generated from reactions consisting of only EC and well-known Maillard-generated glucose fragments (i.e., glyoxal, glycolaldehyde, methylglyoxal, glyceraldehyde, etc.). The structural properties of an EC-methylglyoxal adduct reaction product were also analyzed by NMR. The most likely precursors for the C2, C3, and C4 sugar moiety of the EC-sugar fragment adducts were identified as glyoxal, hydroxyacetone, and erythrose, respectively. 1H NMR analysis of the EC-methylglyoxal indicated that the analyte underwent rapid conformational/constitutional exchange. Using cold temperature (-25 degrees C) two-dimensional NMR analyses (heteronuclear multiple bond coherence, heteronuclear multiple quantum coherence, and 1H-(1)H correlation spectroscopy), the structure of one of the isomers was reported to consist of a covalent linkage between the C1 position of the methylglyoxal and either the C6 or the C8 position of the EC A ring, presumably generated by hydroxyalkylation and aromatic substitution reactions.