title: Antioxidant properties and quantitative UPLC-MS analysis of phenolic compounds from extracts of fenugreek (Trigonella foenum-graecum) seeds and bitter melon (Momordica charantia) fruit.
abstract: Freeze-dried fenugreek (Trigonella foenum-graecum) seeds and bitter melon (Momordica charantia) fruit were extracted sequentially using non-polar to polar solvents, with further separation carried out on polar extracts by molecular weight cut off dialysis. The fenugreek ethyl acetate crude extract (FGE3) demonstrated the highest antioxidant activity, in terms of Trolox Equivalents (TE), for both the DPPH (35.338±0.908 mg TE/g) and FRAP (77.352±0.627 mg TE/g) assays. This extract also contained the highest phenolic content, in terms of Gallic Acid Equivalents (GAE) (106.316±0.377 mg GAE/g). Despite having considerably lower antioxidant activity than fenugreek, the highest antioxidant activities for bitter fruit were observed in the hexane (BME1) and methanol hydrophilic<3.5 kDa dialysed (BME4<3.5 kDa) extracts, while the highest phenolic content was found in the methanol hydrophilic>3.5 kDa (BME4>3.5 kDa) dialysed extract. UPLC-MS was used to quantify 18 phenolic compounds from fenugreek and 13 from bitter melon in active crude extracts. The flavonoids apigenin-7-O-glycoside (1955.55 ng/mg) and luteolin-7-O-glycoside (725.50 ng/mg) were the most abundant compounds in FGE3, while bitter melon extracts contained only small amounts of mainly phenolic acids. A further 5 fenugreek and 1 bitter melon compounds were identified in trace amounts from the same extracts, respectively.
authors.affiliation: Department of Food Biosciences, Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland.
authors.forename: O
authors.initials: O
authors.lastname: Kenny
authors.forename: T J
authors.initials: TJ
authors.lastname: Smyth
authors.forename: C M
authors.initials: CM
authors.lastname: Hewage
authors.forename: N P
authors.initials: NP
authors.lastname: Brunton
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D005638:Fruit / Q000737:chemistry; D013058:Mass Spectrometry; D029777:Momordica charantia / Q000737:chemistry*; D010636:Phenols / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry*; D029910:Trigonella / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D010636:Phenols; D010936:Plant Extracts; C056164:fenugreek seed meal
keywords: Antioxidant; Bitter melon; Dialysis; Fenugreek; Phenolics and flavonoids; Sequential extraction; UPLC-MS