<p>Streptomyces hygroscopicus (S.hygroscopicus) is a Gram-positive soil bacterium that can produce secondary metabolites from fermentation that have a therapeutic effect. The fermented S. hygrocospicus metabolites that are still in the form of crude extracts are difficult to develop as drug preparations because the active compounds are not yet known, so it will be challenging to determine the dosage of drugs that have a therapeutic effect. Therefore, it is necessary to carry out exploratory research to narrow down the secondary metabolite profile from the fermentation of S. hygroscopicus, using extraction and fractionation methods, which are then identified by Thin-Layer Chromatography (TLC) using a combination of solvents. This study used the extraction method with a separating funnel. The fractionation was carried out using the BUCHI (Sepacore®) Flash Chromatography and Reveleris® PREP Purification System column chromatography gradually using ethyl acetate and n-hexana.  47 and 60 of the fractionation results were taken as samples, that further were profiled using TLC and given the appearance of 10% KOH stains and p-Anisaldehyde - sulfuric acid, so that various classes of compounds with different Rf values were obtained, namely Monoterpenes, Triterpenes, Steroids, Saponins, Coumarin, Scopoletin, and Alkaloids.</p>

Background: Malaria eradication has been complicated by the repeated emergence of antimalarial drug resistances. We aimed to determine whether a metabolite extract of Streptomyces hygrocopicus subsp. hygroscopicus could decrease the viability of Plasmodium falciparum 3D7 in vitro. Methods: S. hygroscopicus subsp. hygroscopicus isolates were inoculated and fermented on the ISP4 medium. The fermented S. hygroscopicus was mixed with ethylacetate 1:5 (v/v), and the solvent phase was evaporated. Several concentrations of isolated extract was added to the P. falciparum 3D7 culture containing trophozoite and schizont stages in 24 wells plates when the degree of parasite-infected erythrocytes reached 5%, then incubated for 8 hours. DNA parasite density was measured using flow cytometry, parasite degree and morphology were observed under microscopic by Giemsa-stained smears.  Results: The metabolite extract affected the morphology of almost all of parasite asexual stages. Schizonts and trophozoites failed to grow and appeared damaged with pycnotic cores and loss of cytoplasmic content. At 8 hours there was a significant decrease in DNA parasite density in culture exposed to 2.6 mg/ml and 13 mg/ml (P = 0.002; P = 0.024) of the extract. The degree of parasite-infected erythrocytes was decreased from the beginning of exposure (0.02 mg/ml of the extract). There was a significant inverse correlation between the concentration of extract and the degree of parasite-infected erythrocytes as well as the density of DNA parasite (r = -0.772, P = 0.000; r =-0.753; P =0.000). Conclusion: Metabolite extract of S. hygroscopicus subsp. hygroscopicus causes morphological damage, decreases the degree of parasite-infected erythrocytes and the DNA density of P. falciparum 3D7 in vitro.

This study aimed to obtain a microbial active compound as a novel antimalarial drug from Indonesian isolates. Target-based assays were used to screen for antimalarial activity against the parasite mitochondrial, Plasmodium falciparum malate:quinone oxidoreductase (PfMQO) enzyme. In total, 1600 crude extracts, composed from 800 fungi and 800 actinomycetes extracts, were screened against PfMQO, yielding six active extracts as primary hits. After several stages of stability tests, one extract produced by Aspergillus sp. BioMCC f.T.8501 demonstrated stable PfMQO inhibitory activity. Several purification stages, including OCC, TLC, and HPLC, were performed to obtain bioactive compounds from this active extract. All purification steps were followed by an assay against PfMQO. We identified the active compound as nornidulin based on its LC-MS and UV spectrum data. Nornidulin inhibited PfMQO activity at IC50 of 51 µM and P. falciparum 3D7 proliferation in vitro at IC50 of 44.6 µM, however, it had no effect on the growth of several mammalian cells. In conclusion, we isolated nornidulin from Indonesian Aspergillus sp. BioMCC f.T.8501 as a novel inhibitor of PfMQO, which showed inhibitory activity against the proliferation of P. falciparum 3D7 in vitro.

Contexto: La malaria sigue siendo un grave problema sanitario mundial debido al desarrollo de resistencia a los fármacos. Es necesario encontrar nuevos fármacos con mecanismos renovables que sean eficaces para matar a los parásitos. Nuestra investigación anterior ha analizado más de un compuesto del grupo ionóforo poliéter en el extracto de acetato de etilo de Streptomyces hygroscopicus subsp. hygroscopicus. Se sabe que el poliéter ionóforo tiene un mecanismo de acción similar al de la cloroquina, que es potente inhibidor de gutatión S-transferasa de Plasmodiun falciparum (PfGST). Objetivos: Evaluar el efecto potencial del poliéter ionóforo hacia la PfGST como proteína diana a través del acoplamiento molecular. Métodos: PfGST se obtuvo del Banco de Datos de Proteínas. Los ligandos de prueba (poliéter ionóforo) y los ligandos de control (cloroquina) se obtuvieron de PubChem. El análisis farmacocinético se realizó con SwissADME, el acoplamiento molecular con PyRx 0.9, la visualización con LigPlot y PyMOL, y la dinámica molecular con YASARA para la mejor actividad del ligando. Resultados: La lenoremycina tuvo la mayor afinidad de unión a PfGST (-8,53 kcal/mol) entre otros poliéteres ionóforos, y la nigericina tuvo la mejor unión de residuos con hidrófobos e hidrógenos con una afinidad de unión de -8,25 kcal/mol en comparación con el complejo de cloroquina en el acoplamiento molecular y la simulación dinámica molecular. Conclusiones: El ionóforo poliéter podría servir como agente antimalárico mejor que la cloroquina, siendo la nigericina el mejor candidato para inhibir el PfGST en comparación con otros ionóforos poliéter.