Investigation on antimicrobial agents of the terrestrial Streptomyces sp. BCC71188

Abstract

The terrestrial actinomycete strain BCC71188 was identified as Streptomyces by its morphology (having spiral chain spore on the aerial mycelium), chemotaxonomy (containing LL-diaminopimelic acid in the cell wall), and 16S rRNA gene sequence analysis [showing high similarity values compared with Streptomyces samsunensis M1463 (99.85 %) and Streptomyces malaysiensis NBRC 16446 (99.40 %)]. The crude extract exhibited antimalarial against Plasmodium falciparum (IC 0.19 μg/ml), anti-TB against Mycobacterial tuberculosis (MIC 6.25 μg/ml), and antibacterial against Bacillus cereus (MIC 1.56 μg/ml) activities. Therefore, chemical investigation was conducted by employing bioassay-guided method and led to the isolation of 19 compounds including two cyclic peptides (1-2), five macrolides (3-7), new naphthoquinone (8), nahuoic acid C (9), geldanamycin derivatives (10-13), cyclooctatin (14), germicidins A (15) and C (16), actinoramide A (17), abierixin, and 29-O-methylabierixin. These isolated compounds were evaluated for antimicrobial activity, such as antimalarial, anti-TB, and antibacterial activities, and for cytotoxicity against both cancerous (MCF-7, KB, NCI-H187) and non-cancerous (Vero) cells. Compounds 1-7, 10-14 exhibited antimalarial (IC 0.22-7.14 μg/ml), and elaiophylin analogs (4-6) displayed anti-TB (MIC 0.78-12.00 μg/ml) and B. cereus (MIC 0.78-3.13 μg/ml) activities. Compounds 1, 2, 14, and abierixin displayed weak cytotoxicity, indicating a potential for antimicrobial agents.

HSQC-TOCSY Fingerprinting-Directed Discovery of Antiplasmodial Polyketides from the Marine Ascidian-Derived Streptomyces sp. (USC-16018)

“…Elaiophylin ( 2 ) inhibited both the 3D7 and Dd2 parasites with similar potency, IC 50 = 778 nM and 598 nM, respectively. Antiplasmodial activity in the same range (IC 50 214 nM) against the K1 strain was previously reported in the literature [ 26 ]. Herbimycin G showed no cytotoxicity and some degree of parasite growth inhibition, corresponding to a 77% inhibition against 3D7 at 40 μM.…”

Biological and Chemical Diversity of Bacteria Associated with a Marine Flatworm

“…GM, previously isolated from Streptomyces hygroscopicus , is a benzoquinone antibiotic containing the typical structures of benzoquinone and dienamide. This class of compounds showed various bioactivities, including anticancer, anti-protozoa, antimalarial and antifungal activities [ 34 , 35 ]. Based on extensive investigation of the literatures and the analyses of UPLC-MS data, it is concluded that these compounds with HR-ESI-MS [M − H] − 547.2805 (retention time at 8.0 min), 533.2992 and 547.2636 (retention time at 12.0 min) are very likely novel GMs produced by the strain XY-FW47 (see Figure S10 ).…”

Antiplasmodial natural products: an update

“…Two benzoquinone polyketides, geldanamycin ( 409 ) and 17-demethoxyreblastatin ( 410 ), were isolated from the extract and showed antiplasmodial activity against the K1 strain. The quinone moiety in 409 appears to contribute to the cytotoxicity since the structural analogue 410 with a phenol group instead of the quinone was more selective against the parasite [254]. Two new antiplasmodial azaphilones, longirostrerone A ( 411 ) and C ( 412 ), were isolated from the ethyl acetate extract of the Thailand soil fungus Chaetomium longirostre .…”