Phytochemical investigation on volatile compositions and methoxylated flavonoids of Agrostis gigantea Roth

In this study, methoxylated flavonoids and volatile constitutions of Agrostis gigantea Roth (Poaceae) were investigated for the first time. The flavonoids were identified by spectroscopic methods (1H-NMR, 13C-NMR, COSY, NOSEY, TCOSY, and HMBC). The volatile constitutions of aerial parts and seeds were analyzed by gas chromatography–mass spectrometry (GC-MS). Two methoxylated flavonoids, luteolin 5-methyl ether (1), cirsilineol (2) were isolated from the aerial parts of this plant. According to the GC-MS data the main constitutions of these volatile oils belong to the simple phenolic category which include coniferyl alcohol (18.80%) and eugenol (12.19%) in aerial parts and seeds, respectively. By using the computer- aided molecular modeling approaches, the binding affinity of these compounds was predicted in the catalytic domains of aryl hydrocarbon receptor (AhR). These two isolated flavonoids were investigated in vitro for their inhibitory activity on 4T1 breast carcinoma cells. It was predicted that these compounds could be well-matched in aryl hydrocarbon receptor (3H82) active site. but based on the in vitro assay, he IC50 values on cytotoxicity were 428.24 ±3.21 and 412.7±3.02 μg/ml for luteolin 5-methyl ether and cirsilineol, respectively. Thus it can be concluded that, these flavonoids exhibit low cytotoxicity against 4T1 breast carcinoma cell line.