Visceral leishmaniasis (VL) is a debilitating, often fatal disease caused by Leishmania donovani complex; however, it is a neglected tropical disease. L. donovani complex comprises two closely related species, L. donovani that is mostly anthroponotic and L. infantum that is zoonotic. Differentiation between these two species is critical due to the differences in their epidemiology and pathology. However, they cannot be differentiated morphologically, and their speciation using isoenzyme-based methods poses a difficult task and may be unreliable. Molecular characterization is now the most reliable method to differentiate between them and to determine their phylogenetic relationships. The present study aims to characterize Leishmania species isolated from bone marrows of Yemeni pediatric patients using sequence analysis of the ribosomal internal transcribed spacer-1 (ITS1) gene. Out of 41 isolates from Giemsa-stained bone marrow smears, 25 isolates were successfully amplified by nested polymerase chain reaction and sequenced in both directions. Phylogenetic analysis using neighbor joining method placed all study isolates in one cluster with L. donovani complex (99% bootstrap). The analysis of ITS1 for microsatellite repeat numbers identified L. infantum in 11 isolates and L. donovani in 14 isolates. These data suggest the possibility of both anthroponotic and zoonotic transmission of VL-causing Leishmania species in Yemen. Exploring the possible animal reservoir hosts is therefore needed for effective control to be achieved.
New series of quinoline-based thiadiazole analogs (1-20) were synthesized, characterized by EI-MS, 1H NMR and 13C NMR. All synthesized compounds were subjected to their antileishmanial potential. Sixteen analogs 1-10, 12, 13, 16, 17, 18 and 19 with IC50 values in the range of 0.04 ± 0.01 to 5.60 ± 0.21 µM showed tremendously potent inhibition as compared to the standard pentamidine with IC50 value 7.02 ± 0.09 µM. Analogs 11, 14, 15 and 20 with IC50 8.20 ± 0.35, 9.20 ± 0.40, 7.20 ± 0.20 and 9.60 ± 0.40 µM respectively showed good inhibition when compared with the standard. Structure-activity relationships have been also established for all compounds. Molecular docking studies were performed to determine the binding interaction of the compounds with the active site target.
Three new 5,1'-coupled naphthylisoquinoline alkaloids, ancistrobenomine A (1), 6-O-demethylancistrobenomine A (2), and 5'-O-demethylancistrocline (3), have been isolated from the stem bark of a botanically as yet undescribed highland liana Ancistrocladus sp., proposed to be named "A. benomensis" according to the region in Peninsular Malaysia where it has been discovered on the mountain of Gunung Benom. Two of the compounds possess an unprecedented structure with a novel hydroxymethylene group at C-3 of the fully dehydrogenated isoquinoline moiety. The structural elucidation was achieved by chemical, spectroscopic, and chiroptical methods. As typical of the so-called Ancistrocladaceae type, all of the compounds isolated bear an oxygen at C-6. Biological activities of these alkaloids against different protozoic pathogens are described.
The EtOH extract of the leaves of Holarrhena curtisii yielded five new steroidal alkaloids: 17-epi-holacurtine (3), 17-epi-N-demethylholacurtine (4), holacurtinol (5), 3alpha-amino-14beta-hydroxypregnan-20-one (7), and 15alpha-hydroxyholamine (8), in addition to the known compounds, holacurtine (1), N-demethylholacurtine (2), and holamine (6). All eight compounds showed significant cytotoxic and leishmanicidal activities.
This study was aimed to identify and characterize Leishmania amastigote, and axenic form antigens. Two in vitro techniques were used to change leishmania parasite isolates from promastigote form to amastigotes and amastigote like (axenic) forms. The main strategy relied upon in vitro infection of murine macrophages cell line J774 with leishmania promastigote, at 37°C with 5% CO2, while the second technique relied upon the culture of promastigote at 37°C with low pH (5.5), and 5-10% CO2. Proteins were extracted and fractionated utilizing 12% Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS PAGE). Antigens were recognized using both immune dot blot and western blot procedures. PCR was performed for recognition of leishmania parasites in infected J774 macrophages. L. major was quicker in infectivity of macrophages cell line than L. donovani. Shared proteins ranging from 26-116 kDa were identified by SDS PAGE in all stages. Immune Dot-blot method showed positive outcomes, while western blot identified an exceptional antigen band of 16 kDa in amastigote, this unique band could be of value in diagnosis and vaccination of leishmaniasis. PCR results confirmed presence of both isolates demonstrating that coinfection is conceivable, and no indications of hereditary recombination at kinetoplast DNA (kDNA) were identified in macrophages simultaneously infected by L. major and L. donovani.
Treatment of drug resistant protozoa, bacteria, and viruses requires new drugs with alternative chemotypes. Such compounds could be found from Southeast Asian medicinal plants. The present study examines the cytotoxic, antileishmanial, and antiplasmodial effects of 11 ethnopharmacologically important plant species in Malaysia. Chloroform extracts were tested for their toxicity against MRC-5 cells and Leishmania donovani by MTT, and chloroquine-resistant Plasmodium falciparum K1 strain by Histidine-Rich Protein II ELISA assays. None of the extract tested was cytotoxic to MRC-5 cells. Extracts of Uvaria grandiflora, Chilocarpus costatus, Tabernaemontana peduncularis, and Leuconotis eugenifolius had good activities against L. donovani with IC50