1.Aporphines and Parkinson's disease: Medical tools for the future.
Nabavi SF, Uriarte E, Rastrelli L, Sobarzo-Sánchez E1. Curr Top Med Chem. 2016 Feb 4. [Epub ahead of print]
Parkinson's disease is a motor dysfunction that have been widely studied but many of the reports on commercial drugs for the treatment of this disease have afforded some undesirable side effects that generate an extensive and unviable treatment by economic costs and due to the bioavailability of the assayed compounds. At present, some molecules are used as L-DOPA agonists or can change the dopamine concentrations in the CNS. Thus, the use of aporphine-type alkaloids has given a real alternative due to the diverse natural sources where can be isolated or to obtain them by means of conventional syntheses. Isoquinoline alkaloids as Liriodenine, phenanthrene-type alkaloids, alkoxy-hydroxyaporphine, aminothiazole-aporphine or Lipoic ester aporphine derivatives are some of the examples to be considered in this mini-review, wherein the applied pharmacological effects to reduce the motor disorders and the possible medical properties of these alkaloids on the dopaminergic receptors are analyzed.
2.Ultraviolet-visible study on acid-base equilibria of aporphine alkaloids with antiplasmodial and antioxidant activities from Alseodaphne corneri and Dehaasia longipedicellata.
Zahari A1, Ablat A2, Omer N1, Nafiah MA3, Sivasothy Y1, Mohamad J2, Khan MN1, Awang K1. Sci Rep. 2016 Feb 22;6:21517. doi: 10.1038/srep21517.
The UV-vis spectra of isocorydine 1, norisocorydine 2 and boldine 3 were studied in 2% v/v acetonitrile, at constant ionic strength (0.1 M NaCl, 35 degree Celsius). The pKa values of isocorydine 1 and norisocorydine 2 were 11.75 and 12.07, respectively. Boldine 3 gave a pKa value of 9.16 and 10.44. All of the alkaloids 1-3 were stable at physiological pH; thereby all of them will not ionize, thus permitting the basic nitrogen to be protonated and accumulated within the acidic food vacuole of Plasmodium via pH trapping. Subsequently, acidic food vacuoles that have been neutralized by alkaloids would result in enhancement of the antiplasmodial activity. The alkaloids showed antiplasmodial activity against Plasmodium falciparum and antioxidant activities; DPPH radical scavenging, metal chelating and ferric reducing power. The antioxidant properties of the alkaloids under investigation revealed that in addition to the antiplasmodial activity, the alkaloids can also prevent oxidative damage.
3.Aporphine alkaloid contents increase with moderate nitrogen supply in Annona diversifolia Saff. (Annonaceae) seedlings during diurnal periods.
Orozco-Castillo JA1,2, Cruz-Ortega R3, Martinez-Vázquez M4, González-Esquinca AR1. Nat Prod Res. 2016 Feb 25:1-6. [Epub ahead of print]
Aporphine alkaloids are secondary metabolites that are obtained in low levels from species of the Annonaceae family. Nitrogen addition may increase the alkaloid content in plants. However, previous studies published did not consider that nitrogen could change the alkaloid content throughout the day. We conducted this short-term study to determine the effects of nitrogen applied throughout the diurnal period on the aporphine alkaloids via measurements conducted on the roots, stems and leaves of Annona diversifolia seedlings. The 60-day-old seedlings were cultured with the addition of three levels of nitrogen (0, 30 and 60 mM), and alkaloid extracts were analysed using high-performance liquid chromatography. The highest total alkaloid content was measured in the treatment with moderate nitrogen supply. Further, the levels of aporphine alkaloids changed significantly in the first few hours of the diurnal period. We conclude that aporphine alkaloid content increased with moderate nitrogen supply and exhibited diurnal variation.