A coumarin with an unusual structure from Cuphea ignea, its cytotoxicity and antioxidant activities.

Phenolic metabolite profiling using two dimensional paper chromatographic analysis (2 DPC) was used for assaying the complex mixture of phenolics of an aqueous ethanol aerial part extract of Cuphea ignea (Lytheraceae). A coumarin with a rare structure, namely, 7-hydroxy 3-methoxy coumarin 5-O-ß-glucopyranoside was isolated from the investigated extract. The structure was elucidated by conventional methods and spectral analysis, including one and two dimensional NMR (1D and 2D NMR), as well as by interpretation of the spectra obtained by high resolution electrospray ionization mass technique (HRESIMS). The rare coumarin significantly inhibited reactive oxygen species production with an ED50 value of 6.31±1.64 µg/ml and 5.78±0.66 µg/ml as determined by the the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) and the oxygen radical absorption capacity (ORAC) assay respectively. The isolated coumarin presented a cytotoxic activity assessed by using the neutral red assay (NRU) against lung cancer cell line (H23) with IC50 of 40.38±2.75 µg/ml.

A cytotoxic flavonol glycoside from Melaleuca leucadendra leaves extract with immunostimulant activity.

Leaves of Melaleuca leucadendra contain the novel flavonol glycoside, myricetin 3-O-ß-4C1-galactopyranuronoid. In addition, known fifteen phenolics were identified. All isolates are characterized for the first time from this plant. Structures were established by conventional methods and confirmed by spectral methods of analysis, including one and two-dimensional nuclear magnetic resonance spectroscopy (1D and 2D-NMR) and high resolution electro-spray ionization mass spectrometry (HRESIMS), as well. Assessment of some immunological and biological efficacy, of the extract in combination with a parallel cytotoxicity evaluation, using the method of cellular reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) technique was carried out. Besides, evaluation of the antioxidant effectiveness, using the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) and the oxygen radical absorption capacity (ORAC) methods was performed. In addition, the cytotoxicity against liver (Huh-7), breast (MCF-7) and prostate (PC-3) cancers using the neutral red assay (NRU) technique for the extract and the new flavonol glycoside also, was assessed.

Beta vulgaris subspecies cicla var. flavescens (Swiss chard): flavonoids, hepatoprotective and hypolipidemic activities.

The novel flavonoids, 2",2"'-di-O-α-rhamnopyranosyl-vicenin II, a di-C-glycosyl flavone, and herbacetin 3-O-ß-xylopyranosyl- (1"' --> 2")-O-ß-glucopyranoside, were isolated from the leaves of Beta vulgaris subspecies cicla L. var. flavescens, an edible plant which is consumed in the Mediterranean areas, additional to the known flavonoids, 6-C-glucosyl isoscutellarein, vitexin-(1"' --> 2")-O-ß-xylopyranosyl, vitexin-(1'" --> 2")-O-α-rhamnopyranosyI and vitexin. All metabolites were established by conventional methods of analysis and their structures were confirmed by spectroscopic analysis, including 1 D and 2D-NMR and by HR-ESIMS, as well. The extract of the plant leaves shows hepatoprotective effects in rats intoxicated by administration of acetaminophen and exhibits hypolipidemic activity in rats with high-fat-diet induced hypercholesterolemia. The evaluation was done through measuring the liver function enzymes (aspartate and alanine aminotransferases and alkaline phosphatase, the lipid profile (total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol and triglycerides) and histopathological analysis of liver slides.

Phenolic profiling of an extract from Eugenia jambos L. (Alston)--the structure of three flavonoid glycosides--antioxidant and cytotoxic activities.

Phenolic metabolite profiling and identification using high performance liquid chromatography (HPLC) coupled to high resolution accurate mass spectrometry (HR-ESI-MS) with detection of negative ions was used for assaying the complex mixture of phenolics of an aqueous ethanol leaf extract of Eugeniajambos L. (Myrtaceae). Eight known polyphenolics were tentatively identified, and, in addition, three hitherto unknown flavonol-O-glycosides were detected in the extract. These unknowns were taken as the targets and isolated by means of consecutive polyamide S6, MCI gel and repeated Sephadex LH-20 column fractionation. The isolation and purification were monitored by HPLC/ESI-MS. The isolates were subsequently identified as quercetin 3-O-xylosyl-(1"' --> 2")-O-xyloside, myricetin 7-methylether 3-O-xylosyl-(1"' --> 2")-rhamnoside and myricetin 3',5'-dimethyl ether 3-O-xylosyl-(1"'-->* 2")-O-rhamnoside. All known metabolites were also separated by applying the same chromatographic techniques. ESI-MS, ¹H and ¹³C NMR spectra were then recorded, completely interpreted and confirmed by HR-ESI-MS and 2D NMR spectroscopy. In order to get information about biological activities of E. jambos the extract was tested for radical scavenging activity by DPPH and ORAC assay. In addition, its cytotoxicity was assessed by the neutral red assay against non-tumorigenic HaCaT keratinocytes and the human bladder carcinoma cell line 5637.