Five flavonoid glycosides were isolated from then -butanol soluble fraction of the ethanolic extract of Rapistrum rugosum and their structures were assigned from 1H- and 13C-NMR spectra (DEPT) with 2D NMR as quercetin-3- O-a-L-rhamnopyranoside (1), quercetin-3- O-b-D-xyloside (2), quercetin, 3-O-a- L-arabinopyranoside, 7- O-a-L-rhamnopyranoside (3), kaempferol 3- O-a-L-arabinopyranoside, 7- O-a-L-rhamnopyranoside (4) and rutin (5). The SRB cytotoxic assay was used to investigate the antitumor activities of n -butanol extract, compound 3 and its hexaacetate 3a, for the first time. Compounds 3 and 3a showed cytotoxic activity against the human cancer cell line, namely, HepG2 (hepatocellular carcinoma cell line) with IC50 (concentration of compound required to reduce cell survival by 50%) 0.86 mg/mL and 3.50 mg/mL, respectively. These results proved that compound 3, the major flavonoid of the n -butanol soluble fraction, has significant cytotoxic activity compared with the standard antitumor drug doxorubicin (0.60 mg/mL).

Citrullus colocynthis (L.) Schrad. (Cucurbitaceae) is an Iranian medicinal plant that has traditionally been used as an abortifacient and to treat constipation, oedema, bacterial infections, cancer and diabetes. As part of our on-going studies on Iranian medicinal plants, thorough phytochemical investigation was carried out on this plant. The reversed-phase preparative HPLC was employed to isolate compounds from the butanol fraction of the hydro-methanolic (70%) extract of the fruits of the locally grown C. colocynthis. Structures of the isolated compounds [1-5] were elucidated by spectroscopic means. The antioxidant property of the flavonoids 1-3 was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Three flavone glucosides, isosaponarin [1], isovitexin [2] and isoorientin 3’-O-methyl ether [3] and two cucurbitacin glucosides, 2-O-β-D-glucopyranosylcucurbitacin I [4) and 2-O-β-D-glucopyranosylcucurbitacin L [5] were isolated and identified. Flavonoids 1-3 showed significant antioxidant properties. Since reactive oxygen species are important contributors to tissue injury, inflammation, cancer and many other ailments, the antioxidant properties of 1-3 probably contribute, at least to some extent, to the pharmacological and traditional medicinal uses of the C. colosynthis.    

High performance liquid chromatography (HPLC) with diode array detection (DAD) and electrospray ionization tandem mass spectrometry (ESI/MS/MS) was used to analyze the main components in the methanol extract of Fructus Aurantii (FA) and the metabolites in rat biological samples after oral administration of the methanol extract of FA. There were 31 constituents identified in the extract of FA including 2 alkaloids, 1 coumarin, 10 flavonoid glycosides and 18 ploymethoxylated flavones. According to the UV spectrum and MS fragment character of main components in the methanol extract of FA, 18 parent constituents and 11 metabolites were tentatively identified in rat biological samples. Three groups of components in biological samples detected included flavonoid glycosides, their glucuronides and ploymethoxylated flavones. It was interested that flavonoid glycosides, their glucuronides and ploymethoxylated flavones can be investigated in rat plasma and urine, while in rat feces samples only flavonoid glycosides were detected. Triglycosyl, naringenin, neoeriocitrin, neoeriocitrin narirutin and hesperidin were the main components in rat feces which were found either in the plasma or in urine samples. However, naringin and neohesperidin were the main flavonoid glycosides which absorbed after oral administration. Except flavonoid glycosides and their glucuronides, ploymethoxylated flavones also the constituents absorbed because it was investigated mainly in rat plasma and urine but not in feces samples. The identification and elucidation of parent and metabolism components analyzed in biological samples provided the data for further pharmacological and clinical research on FA.