ABSTRACT
The replacement of petrochemicals by oleochemical feedstocks in many industrial and domestic applications has resulted in an increase in demand for biobased products and as such recognizing and increasing the benefits of using renewable materials. In line with this, the oil extracted from the seed of Hura crepitans was characterized by an iodine value of 120.10 ± 0.70 g Iodine/100 g and a saponification number of 210.10 ± 0.40 mg KOH/g with the dominant fatty acid being C18:2 (52.8 ± 0.10%). The epoxidised fatty acid methyl esters prepared from the oil were used to synthesise the azidohydrin with a yield of 91.20%. The progress of the reaction was monitored and confirmed using FTIR and NMR. This showed the seed oil of Hura crepitans as a renewable resource that can be used to make valuable industrial and domestic products.
ABSTRACT
There is increasing evidence for biological functions of human C-peptide. Recently, we have described that proinsulin C-peptide increases nutritive capillary blood flow and restores erythrocyte deformability in type 1 diabetic patients, whereas it has no such effect in non-diabetic subjects. The aim of the current study was to elucidate cellular mechanisms of this vasodilator effect in vitro by measuring the nitric oxide (NO)-mediated increase of cGMP production in a RFL-6 reporter cell assay and by demonstrating endothelial calcium influx with the Fluo-3 technique. C-peptide increased the release of NO from endothelial NO synthase (eNOS) in bovine aortic endothelial cells in a concentration- and time-dependent manner. At physiological concentrations of C-peptide, endothelial NO production was more than doubled (208+/-12% vs control; p<0.001). The NO release was abolished by the inhibitor of NO synthase N(G)-nitro-L-arginine or when Ca(2+) was removed from the medium superfusing the endothelial cells. C-peptide stimulated the influx of Ca(2+) into endothelial cells. No change in Ser-1179 phosphorylation of eNOS was detected after 6.6nM C-peptide. C-peptide did not change eNOS mRNA levels after 1, 6 or 24h. These data indicate that C-peptide is likely to stimulate the activity of the Ca(2+)-sensitive eNOS by increasing the influx of Ca(2+) into endothelial cells. We suggest that this effect may contribute to the increase in skin and muscle blood flow previously demonstrated in human in vivo.