No abstract

Bioassay-directed fractionation of extracts from the fermentation broth and mycelium of the fungus Edenia sp. led to the isolation of five antileishmanial compounds, preussomerin EG1 (1), palmarumycin CP 2 (2), palmarumycin CP 17 (3), palmarumycin CP 18 (4), and CJ-12,371 (5). Compounds 3 and 4 are new natural products, and this is only the second report of compound 1. The structures of compounds 1−5 were established by spectroscopic analyses (HRMS and NMR). All metabolites caused significant inhibition of the growth of Leishmania donovani in the amastigote form, with IC 50 values of 0.12, 3.93, 1.34, 0.62 and 8.40 μM, respectively. Compounds 1−5 were inactive when tested against Plasmodium falciparum or Trypanasoma cruzi at a concentration of 10 μg/mL, indicating that they have selective activity against Leishmania parasites. Compounds 1−5 showed weak cytotoxicity to Vero cells (IC 50 of 9, 162, 174, 152 and 150 μM, respectively), however, the therapeutic window of these compounds is quite significant with 75, 41, 130, 245 and 18 times (respectively) more anti-leishmanial activity than cytotoxicity.Leishmaniasis is a major tropical disease which largely affects populations those of the developing world. According to the World Health Organization (WHO), leishmaniasis can be classified into four main forms: visceral leishmaniasis (the most dangerous because it can be mortal), cutaneous leishmaniasis (the most common form, which causes a variety of skin lesions), mucocutaneous leishmaniasis (which begins with skin ulcers that can spread, causing tissue destruction, mainly of the nose and mouth), and diffuse cutaneous leishmaniasis (produces chronic skin lesions which are very difficult to cure). 1 Current treatment against leishmaniasis is based on toxic chemotherapeutic compounds, such as sodium stibogluconate and meglumine antimonate, that have several serious side effects which themselves can be fatal to patients. 1,2 Moreover, these agents are expensive and therapies are required for relatively long durations, two characteristics which combine to exclude many patients from having access to any treatment. 1,2 While approximately 600,000 infections are officially reported each year, *Author to whom correspondence should be addressed. (Table 1), interpreted from multiplicity-edited HSQC data as 10 quaternary, two methylene, and eight methine carbons. This spectrum also had resonances for a cyclic ketone (δ C 202.0, C-4) and a naphthalene ring system [δ C 146.3 (C-1'); 110.5 (C-2'); 127.6 (C-3'); 121.9 (C-4'); 134.1 (C-4a'); 121.9 (C-5'); 127.6 (C-6'); 110.5 (C-7'); 146.3 (C-8'); 113.5 (C-8a')]. HMBC correlations supported these assignments as did data comparisons with known compounds 2 and 5. The chemical shift of the two-carbon resonance at δ C 146.3 was consistent with the placement of a dioxin bridge to C-1' and C-8' of the naphthalene core. Finally, the chemical shifts of the signals at δ C 157.2 and 147.6 were consistent with the positioning of phenolic hydroxy groups at C-5 and C-8. HMBC correlati...

P-glycoprotein (P-gp) is a protein belonging to the ATP-binding cassette (ABC) transporters superfamily that has clinical relevance due to its role in drug metabolism and multi-drug resistance (MDR) in several human pathogens and diseases. P-gp is a major cause of drug resistance in cancer, parasitic diseases, epilepsy and other disorders. This review article aims to summarize the research findings on the marine natural products with P-glycoprotein inhibitor properties. Natural compounds that modulate P-gp offer great possibilities for semi-synthetic modification to create new drugs and are valuable research tools to understand the function of complex ABC transporters.