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The discovery of bioactive natural products is often challenged by the complexity of isolating and characterizing active compounds within diverse mixtures. Previously, we introduced a 1H NMR-based weighted gene correlation network analysis (WGCNA) approach to identify spectral features linked to growth inhibitory activity of Piper (Piperaceae) leaf extracts against model plant, fungal, and bacterial organisms. This method enabled us to prioritize specific spectral features linked to bioactivity, offering a targeted approach to natural product discovery. In this study, we validate the predictive capacity of the WGCNA by isolating the compounds responsible for the bioactivity-associated resonances and confirming their antifungal efficacy. Using growth inhibition assays, we verified that the isolated compounds, including three novel antifungal agents, exhibited significant bioactivity. Notably, one of these compounds contains a rare imidazolium heterocyclic motif, marking a new structural class in Piper. These findings substantiate the 1H NMR-based WGCNA as a reliable tool for identifying structural types associated with biological activity, streamlining the process of discovering bioactive natural products in complex extracts.
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Rapid spectrophotometric detection for optimized production of landomycins and characterization of their therapeutic potential
Abstract Microbial‐derived natural products remain a major source of structurally diverse bioactive compounds and chemical scaffolds that have the potential as new therapeutics to target drug‐resistant pathogens and cancers. In particular, genome mining has revealed the vast number of cryptic or low‐yield biosynthetic gene clusters in the genusStreptomyces. However, low natural product yields—improvements to which have been hindered by the lack of high throughput methods—have slowed the discovery and development of many potential therapeutics. Here, we describe our efforts to improve yields of landomycins—angucycline family polyketides under investigation as cancer therapeutics—by a genetically modifiedStreptomyces cyanogenus136. After simplifying the extraction process fromS. cyanogenuscultures, we identified a wavelength at which the major landomycin products are absorbed in culture extracts, which we used to systematically explore culture medium compositions to improve total landomycin titers. Through correlational analysis, we simplified the culture optimization process by identifying an alternative wavelength at which culture supernatants absorb yet is representative of total landomycin titers. Using the subsequently improved sample throughput, we explored landomycin production during the culturing process to further increase landomycin yield and reduce culture time. Testing the antimicrobial activity of the isolated landomycins, we report broad inhibition of Gram‐positive bacteria, inhibition of fungi by landomycinone, and broad landomycin resistance by Gram‐negative bacteria that is likely mediated by the exclusion of landomycins by the bacterial membrane. Finally, the anticancer activity of the isolated landomycins against A549 lung carcinoma cells agrees with previous reports on other cell lines that glycan chain length correlates with activity. Given the prevalence of natural products produced byStreptomyces, as well as the light‐absorbing moieties common to bioactive natural products and their metabolic precursors, our method is relevant to improving the yields of other natural products of interest.
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- Award ID(s):
- 2246963
- PAR ID:
- 10515709
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Biotechnology and Bioengineering
- ISSN:
- 0006-3592
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1002/bit.28725
