Lívia Soman de Medeiros

Microbial metabolites play a critical role in regulating ecosystems, including the human body and its microbiota. However, understanding the physiologically relevant role of these molecules, especially through liquid chromatography tandem mass spectrometry (LC-MS/MS)-based untargeted metabolomics, poses significant challenges and often requires manual parsing of a large amount of literature, databases, and webpages. To address this gap, we established the Collaborative Microbial Metabolite Center knowledgebase (CMMC-KB), a platform that fosters collaborative efforts within the scientific community to curate knowledge about microbial metabolites. The CMMC-KB aims to collect comprehensive information about microbial molecules originating from microbial biosynthesis, drug metabolism, exposure-related molecules, food, host-derived molecules, and, whenever available, their known activities. Molecules from other sources, including host-produced, dietary, and pharmaceutical compounds, are also included. By enabling direct integration of this knowledgebase with downstream analytical tools, including molecular networking, we can deepen insights into microbiota and their metabolites, ultimately advancing our understanding of microbial ecosystems.

Microorganisms can produce a wide range of secondary metabolites with different activities, including larvicidal activities. Colletotrichum is a widespread fungal genus worldwide, and some species of this genus can establish mutualistic interactions with plants. In this study, the endophytic fungus Colletotrichum siamense was isolated from the hemiparasitic plant Passovia stelis to evaluate the chemical profile of the microorganism and its larvicidal activity against Aedes aegypti. This mosquito is one of the main transmitters of arboviruses, and the use of synthetic insecticides to fight the mosquito has generated resistance in its populations. For the larvicidal tests, the organic extract of fungal metabolites was obtained by partitioning with ethyl acetate after the cultivation of C. siamese in potato dextrose broth. The assay results indicated that the C. Siamese extract was active against Ae. aegypti, with an LC50 of 248 µg/mL for a 72-hour treatment. The extract was then subjected to chemical dereplication using the Global Natural Products Social Molecular Networking (GNPS) platform. The metabolites culmorin and cytochalasin D were found in the extract, the latter of which is representative of a biosynthetic class with previously reported activities against Aedes aegypti larvae.

The chemical study of the ethanolic extract from the roots of Vicia faba led to the isolation of two isoflavonoids, alfalone and 8‐O‐methylretusine, as well as a mixture of rotenoids, including clitoriacetal and clitoriacetal B, the latter of which is reported for the first time. These compounds were characterized through nuclear magnetic resonance and vibrational circular dichroism spectroscopies, and density functional theory calculations. The rotenoid mixture exhibited cytotoxic activity against HCT‐116, MCF‐7, and 501Mel cell lines, while showing no significant toxicity to NIH/3T3 cells. The predictive analysis identified several shared therapeutic targets across colorectal cancer, breast cancer, and melanoma. Key sites, including hypoxia‐inducible factor 1‐alpha (HIF1A), estrogen receptor, heat shock protein HSP 90‐beta, and heat shock protein HSP 90‐alpha, were highlighted for their critical roles in tumor progression and therapeutic resistance. Notably, clitoriacetal demonstrated an affinity for HIF1A, suggesting its involvement in the observed antitumor effects, likely through modulation of the HIF1A pathway. These findings underscore the potential of V. faba root‐derived compounds as promising candidates for targeted cancer therapies.

Stingless bees are vital pollinators in tropical and neotropical regions, emphasizing the need to conserve these species. However, resource scarcity, particularly pollen, during certain periods negatively impacts bee health and pollination efficiency. To address this, we developed a fermented protein feed using microorganisms from pollen of Melipona quadrifasciata, a species commonly found in the Brazilian Atlantic Forest. The fermented feed consisted of a protein bran mixture, sugar syrup, and an inoculant derived from species’ fermented pollen. To assess the feed quality, nutritional evaluation and metabolomic analyses were conducted (UHPLC/DAD-HRMS/MS and GC-MS). The metabolomic analysis identified 85 compounds in positive and 102 in negative ionization modes. Shared metabolites, such as isoquercetin and palatinose, highlighted similarities between the feed and natural fermented pollen. Laboratory tests with caged bees showed comparable consumption between the feed and fermented pollen with no statistical difference (mean: 0.067 g vs. 0.060 g; p = 0.53). The feed exhibited a favorable pH transition (5.30 pre-fermentation to 4.41 after the fermentation process) and remained stable for six months at ±2 °C. These findings demonstrate a biotechnological advance in stingless bee nutrition, offering a viable solution during resource scarcity and promoting the health of M. quadrifasciata.

Oosporein (OOS) is the major specialized metabolite produced by the fungus Arcopilus amazonicus, an endophyte from Paullinia cupana. Genes related to the biosynthesis of this molecule in A. amazonicus diverge from those found in Beauveria bassiana. Furthermore, high-resolution liquid chromatography coupled with mass spectrometry combined with molecular networking, revealed the production of analogous compounds with varying degrees of oxygenation. Based on these analytical data, the analogues were annotated as phoenicin diquinol (2), phoenicin quinol (4) and phoenicin (5). By combining mass spectrometry and genome mining, a comprehensive biosynthetic pathway is proposed for these compounds, including the feasibility of a novel putative biphenol oxidation pathway mediated by the monooxygenase gene AAm15, which is exclusive to A. amazonicus. Additionally, the production of OOS, 2, 4 and 5 by a single fungal species is reported for the first time.

Understanding the distribution of hundreds of thousands of plant metabolites across the plant kingdom presents a challenge. To address this, we curated publicly available LC-MS/MS data from 19,075 plant extracts and developed the plantMASST reference database encompassing 246 botanical families, 1,469 genera, and 2,793 species. This taxonomically focused database facilitates the exploration of plant-derived molecules using tandem mass spectrometry (MS/MS) spectra. This tool will aid in drug discovery, biosynthesis, (chemo)taxonomy, and the evolutionary ecology of herbivore interactions.