Isolation and structure elucidation of antioxidant compounds from leaves of Laurus nobilis and Emex spinosus.

In recent years, there has been increasing interest in finding naturally occurring antioxidants from plants for use in food and medicinal materials to replace synthetic antioxidants since such antioxidants are being restricted due to their side effects like carcinogenicity. The aim of this work was to examine the in vitro antioxidant activity of Laurus nobilis and Emex spinosus leaves and to isolate and structurally elucidate the active compounds in those leaves. The aqueous ethanolic extracts (70%) of Laurus nobilis and Emex spinosus leaves exhibited free radical scavenging action against 1,1-diphenyl-2-picrylhydrazyl (DPPH). Their concentrations of 50% inhibition (IC(50)) were 25.3 and 20.73 µg/mL, respectively. Activity-guided separation of these extracts using a combination of different chromatographic methods (TLC and column chromatography) resulted in the isolation of five chromatographically pure compounds (three from Laurus nobilis and two from Emex spinosus leaves). Spectroscopic methods ((1)H, (13)C-NMR, UV and MS) and chemical methods (detection tests and acidic hydrolysis) revealed the isolated antioxidant compounds to be flavonoid substances that were identified as kaempferol, kaempferol-3-rhamnopyranoside, and kaempferol-3,7-dirhamnopyranoside from Laurus nobilis extract and luteolin and rutin from Emex spinosus extract. The five flavonoids had varying ability to inhibit DPPH radicals (IC(50) from 4 to 35.8 µg/mL). Luteolin and rutin had strong scavenging action with an IC(50) of 4 and 4.6 µg/mL, respectively, and this action was stronger than that of synthetic antioxidant BHA, i.e., butylated hydroxyanisole (IC50 = 5.6 µg/mL).

Associations of polymorphisms in the vitamin D receptor gene (BsmI and FokI) with bone mineral density in postmenopausal women in Malta.

Previous studies have suggested that variations in the vitamin D receptor (VDR) gene are related to bone mineral density (BMD). In this study, the T-->C transition in the start codon and the G-->A polymorphism at the 3' end of the VDR gene, identified by endonucleases FokI and BsmI, respectively, were analysed and correlated with BMD in postmenopausal Maltese women ( n=104). Genotype frequencies observed for the VDR start codon polymorphism (SCP) were CC: 60.4%; CT: 30.7% and TT: 8.9%, while those observed for the 3' in this study were GG: 16.4%; GA: 51.9%; AA: 31.7%. In postmenopausal women, both lumbar and femoral BMD were observed to be highest in CC homozygotes for the FokI genotype and in GG homozygotes for the BsmI genotype, although in both groups the difference between the genotypes was not statistically significant, even after adjusting BMD for age, BMI and years since menopause. No evidence of linkage disequilibrium between the two alleles was observed.