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BackgroundChalcone, an important intermediate of flavonoid synthetic pathway, has been shown to exhibit diverse biological and pharmacological activities such as anti- cancer, antioxidant, anti-inflammatory, etc.ResultsIn this study, a novel series of chalcones fatty acid esters 5b-e and 6b-e have been synthesized via the reaction of the respective chalcones with either palmitic or stearic acid. Another related class of compounds comprising 2,3-disubstituted chalcones 7b-d and 8b(b’)-d as well as 2-amino-6-(substituted-phenyl)-4-substitutedphenyl-nicotinonitrile derivatives 9a,c,e have been also prepared by both electrophilic and Michael addition reactions, respectively, with the corresponding chalcones. The structures of all compounds are confirmed via a wide range of spectroscopic techniques including IR, 1H and 13C NMR, and mass spectra. Significantly, all synthesized compounds have been tested for their promising antioxidant activities via utilization of 1,1-biphenyl-2-picrylhydrazyl as a free radical scavenging reagent. Surprisingly, the results demonstrated that compound 5e (68.58% at C = 2 μg/ml) was more effective as an antioxidant agent than the ascorbic acid, a commonly used antioxidant. Furthermore, the role and contribution of different functional groups on the antioxidant activity of the synthesized chalcone derivatives are also probed and rationalized in terms of their electronic and structural effect.ConclusionGood activity was noted for chalcone fatty acid esters, with some members recorded higher antioxidant activity than ascorbic acid.

The total alcohol extracts of Euphorbia cuneata Vahl.(Euphorbiaceae) were screened for antiulcerogenic activity using an ethanol-induced ulcer model at doses of 125, 250 and 500 mg/kg. The extracts possessed antiulcerogenic activity in a dose-dependent manner. Four flavonoidal compounds were isolated and identified as naringenin, aromadendrin, apigenin and 4'-O-methoxy-luteolin-7-O-rhamnoglucoside, each demonstrating antiulcerogenic activity with curative ratios ranging from 75.78% to 88.23%. In addition, the alcohol extracts and isolated compounds were shown to scavenge the 1,1-diphenyl,2-picrylhydrazyl radical by different ratio, with the most effective being 4'-O-methoxy-luteolin-7-O-rhamnoglucoside (91.14%). The antioxidant activity of the alcohol extracts and the isolated compounds may explain the antiulcerogenic properties. No side effects were observed on either liver or kidney functions.

The phytochemical investigation of Casimiroa edulis Llave et Lex (Rotaceae) afforded four coumarins: umbelliferone (1), esculetin (2), imperatorin (3) and xanthotoxol (4). The identification of these compounds was achieved by using a combination of m.p., UV, EI-mass, ¹H NMR and ¹³C NMR spectroscopy. Essential oil extracts were analysed by GC/MS leading to the identification of 60 components. Sesquiterpene hydrocarbons accounted for the major make up of the oil. Microbiological screenings of the oil and successive plant fractions were performed, showing promising activity against a number of microorganisms with Minimum inhibitory concentrations (MIC) comparable to the standard antibiotics such as chloramphenicol and kanamycin. The plant ethanol extract (400 mg/kg) and the isolated coumarins (60 mg/kg) showed anticoagulant activity. Analyses to determine the activity of the extracts on liver and kidney function were performed, revealing no negative or detrimental effects.

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