1.Determination of alkaloids in onion nectar by micellar electrokinetic chromatography.
Carolina Soto V;Jofré VP;Galmarini CR;Silva MF Electrophoresis. 2016 Jul;37(13):1909-15. doi: 10.1002/elps.201600060. Epub 2016 May 2.
Nectar is the most important floral reward offered by plants to insects. Minor components such as alkaloid compounds in nectar affect bee foraging, with great influence in seed production. CE is an advantageous tool for the analysis of unexplored samples such as onion nectar due to the limited amounts of samples. Considering the importance of these compounds, a simultaneous determination of nicotine, theophylline, theobromine, caffeine, harmaline, piperine in onion nectar by MEKC-UV is herein reported. The extraction of alkaloid compounds in nectar was performed by SPE using a homemade miniaturized column (C18 ). Effects of several important factors affecting extraction efficiency as well as electrophoretic performance were investigated to acquire optimum conditions. Under the proposed conditions, the analytes can be separated within 15 min in a 50 cm effective length capillary (75 μm id) at a separation voltage of 20 kV in 20 mmol/L sodium tretraborate, 100 mmol/L SDS.
2.NMDA receptor-mediated increase in cyclic GMP in the rat cerebellum in vivo is blocked by alaproclate and GEA-857.
Hu PS;Ross SB Pharmacol Toxicol. 1997 Feb;80(2):97-102.
The effects of alaproclate and GEA-857 (2-(4-chlorophenyl)-1,1-dimethylethyl 2-amino-3-methylbutanoate) on the production of cyclic GMP in the rat cerebellum in vivo induced by stimulation of N-methyl-D-aspartate (NMDA) receptors were studied. Alaproclate per se at a dose of 20 mg/kg subcutaneously, did not influence the basal cGMP level. The increase in cGMP induced by harmaline (20 mg/kg subcutaneously) was dose-dependently antagonized by alaproclate (5-40 mg/kg subcutaneously). S-(-)-Alaproclate was 2-5 times more potent than the R-(+)-enantiomer. GEA-857 which in contrast to alaproclate is a very weak 5-HT uptake inhibitor shared the ability of alaproclate to inhibit the effect of harmaline on cGMP accumulation with similar potency to S-(-)-alaproclate. Alaproclate at 15 mg/kg subcutaneously blocked the increase in cGMP in cerebellum caused by NMDA itself at 200 mg/kg subcutaneously. In contrast to alaproclate, the K+ channel antagonist, 4-aminopyridine, 5 mg/kg subcutaneously, produced per se an increase in cGMP levels in the rat cerebellum by 300% which was antagonized by the NMDA receptor antagonists, dizocilpine, phencyclidine and (+/-)-CCP, the nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester and by alaproclate.
3.The Potential of β Carbolin Alkaloids to Hinder Growth and Reverse Chloroquine Resistance in Plasmodium falciparum.
Ibraheem ZO;Abdul Majid R;Mohd Noor S;Mohd Sidek H;Basir R Iran J Parasitol. 2015 Oct-Dec;10(4):577-83.
BACKGROUND: ;Nowadays, scourge of malaria as a fatalistic disease has increased due to emergence of drug resistance and tolerance among different strains of Plasmodium falciparum. Emergence of chloroquine (CQ) resistance has worsened the calamity as CQ is still considered the most efficient, safe and cost effective drug among other antimalarials. This urged the scientists to search for other alternatives or sensitizers that may be able to augment CQ action and reverse its resistance.;METHOD: ;Three β-carbolin derivatives, namely, harmalin, harmol and harmalol were tested for their anti-plasmodial and CQ resistance reversal effects against P. falciparum 3D7 and K1. SYBRE Green-1 based drug sensitivity assay and isobologram analysis were used to screen the mentioned effects respectively.;RESULTS: ;All of them showed moderate anti-plasmodium effect and harmalin was the most effective as compared to the others in reversing CQ resistance and tolerance.