Thaiz Rodrigues Teixeira

The discovery of structurally novel natural products remains central to expanding biologically relevant chemical space, particularly within underexplored marine metabolite classes. Herein, we report the discovery and complete structural elucidation of canalesolide A, a new polyhydroxylated macrolide isolated from the marine cyanobacterium Okeania sp. The compound was identified through an integrated workflow combining phenotypic screening against Trypanosoma brucei and LC-MS/MS-based molecular networking, enabling rapid prioritization of bioactive fractions and dereplication of known metabolite families. Spectroscopic analysis revealed that canalesolide A belongs to the bastimolide-related class of macrolides but exhibits a distinct structural architecture. Its structure was established by integrating ultrahigh-resolution NMR spectroscopy, empirical configurational analysis of polyol systems, targeted model compound synthesis, and controlled chemical degradation and derivatization. This combined strategy resolved stereochemical motifs that were inaccessible by direct analysis of the intact macrolide alone, providing a transferable approach for assigning densely oxygenated marine macrolides. Genome mining identified the putative biosynthetic gene cluster and proposed biosynthetic pathway for a bastimolide-related macrolide. Canalesolide A displays potent, low nanomolar antitrypanosomal activity against human-infective subspecies of T. brucei with rapid elimination of parasites within 1 h at 1 μM. Although moderate mammalian cytotoxicity was observed, preliminary in vivo efficacy/toxicity studies in infected mice suggest a narrow therapeutic window highlighting the need for improved selectivity. This study expands the structural and biosynthetic diversity of polyhydroxylated macrolides and establishes a generalizable framework for resolving stereochemically complex natural products.

Boavistamide A ( 1 ), a new alkyne-containing cyclic depsipeptide featuring the rare 3-amino-2-methyl-7-octynoic acid (AMOYA) moiety, was discovered along with two structurally related analogs, boavistamides B and C ( 2 and 3 ), from a filamentous marine cyanobacterium collected on Boa Vista Island, Cabo Verde. Their isolation was guided by antiplasmodial activity, GNPS MS/MS molecular networking, LC-MS profiling, and dereplication using the MarinLit database. The planar structures of boavistamides A–C ( 1 – 3 ) were elucidated through comprehensive HRMS and 1D/2D NMR analyses, with annotation support from AI-based tools SMART-NMR 2.1 and DeepSAT. The absolute configurations were established using Marfey’s analysis and L-Phe-OMe coupling, complemented by NMR-based conformational studies. Boavistamides A and B exhibited moderate antiplasmodial activity with no mammalian cell cytotoxicity. Microscopic observations and metagenomic binning identified the producer strain as belonging to the genus Okeania (Microcoleaceae). These results expand the chemical diversity of AMOYA-containing cyanobacterial metabolites and highlight the utility of integrated metabolomics and AI-assisted workflows for natural product discovery from environmental samples. GRAPHICAL

Zika virus (ZIKV) is involved in the etiology of serious nervous system pathologies. Currently, there are no specific and effective vaccines or antiviral drugs to prevent the diseases caused by ZIKV. This study aimed to assess the activity of flavonoids present in crude hydroethanolic extract (CHE) and fractions obtained from B. holophylla leaves against ZIKV. O-glycosylated flavonoids were characterized by high-performance liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS/MS). The cytotoxic concentration and the effective concentration for 50% of the cells (CC₅₀ and EC₅₀, respectively) were determined, and the selectivity index (SI) was calculated. Molecular networks were constructed based on the chemical composition of the samples and global antiviral activity data using the Global Natural Products Social Molecular Networking (GNPS) platform. Protein–ligand docking was performed in the NS2B-NS3 protease, NS3 helicase, and NS5 methyltransferase of the ZIKV. CHE showed greater antiviral activity at a multiplicity of infection (MOI) of 1.0, with an EC₅₀ of 11.93 µg/mL, SI = 13.38, and reduced cytopathic effects. Molecular networks indicated that O-glycosylated flavonoids are responsible for the activity against ZIKV, being quercetin-O-deoxyhexoside more selective and effective. Molecular docking confirmed the inhibitory activity of quercetin-O-deoxyhexoside, which showed an affinity for the tested targets, especially for NS2B-NS3 protease. The results showed that B. holophylla has flavonoids with potential for future therapeutic applications against ZIKV.

Phaeurus antarcticus is a member of the Desmarestiaceae family endemic to the Antarctic Peninsula. Reports addressing its chemical composition and biological activities are scarce. Herein, bioactive non‐polar compounds of P. antarcticus against pathogenic bacteria, Leishmania amazonensis and Neospora caninum parasites were targeted through GC‐MS Molecular Networking and multivariate analysis (OPLS‐DA). The effects on horseradish peroxidase (HRP) were also evaluated. P. antarcticus exhibited selective bacteriostatic and bactericidal activities against Staphylococcus aureus with MIC and MBC values from 6.25–100 μg mL⁻¹. Fractions HX‐FC and HX‐FD were the most active against L. amazonensis with EC₅₀ ranging from 18.5–62.3 μg mL⁻¹. Additionally, fractions HX‐FC and HX‐FD showed potent inhibition of N. caninum at EC₅₀ values of 2.8 and 6.3 μg mL⁻¹, respectively. All fractions inhibited HRP activity, indicating possible interactions with Heme proteins. It was possible to annotate compounds from tree mains clusters, containing terpenoids, steroids, fatty acids, and alcohols by correlating the spectral data of the GC‐MS analysis with Molecular Networking and the OPLS‐DA results.

Brazil has a megadiversity that includes marine species that are distributed along 800 km of shoreline. This biodiversity status holds promising biotechnological potential. Marine organisms are important sources of novel chemical species, with applications in the pharmaceutical, cosmetic, chemical, and nutraceutical fields. However, ecological pressures derived from anthropogenic actions, including the bioaccumulation of potentially toxic elements and microplastics, impact promising species. This review describes the current status of the biotechnological and environmental aspects of seaweeds and corals from the Brazilian coast, including publications from the last 5 years (from January 2018 to December 2022). The search was conducted in the main public databases (PubChem, PubMed, Science Direct, and Google Scholar) and in the Espacenet database (European Patent Office—EPO) and the Brazilian National Property Institute (INPI). Bioprospecting studies were reported for seventy-one seaweed species and fifteen corals, but few targeted the isolation of compounds. The antioxidant potential was the most investigated biological activity. Despite being potential sources of macro- and microelements, there is a literature gap regarding the presence of potentially toxic elements and other emergent contaminants, such as microplastics, in seaweeds and corals from the Brazilian coast.

Trypanosoma cruzi (Chagas diseases – also named American trypanosomiasis) and T. brucei (human African trypanosomiasis – HAT) negatively impact public health, being endemic in several countries and leading to thousands of deaths per year.

This study evaluated the effect of the extract and fractions of Bauhinia holophylla on Candida albicans planktonic growth, biofilm formation, mature biofilm, and hyphae growth. Three C. albicans strains (SC5314, ATCC 18804, and ATCC 10231) were tested. The crude extract and the fractions were obtained by exhaustive percolation and liquid–liquid partition, respectively. Phytochemical analyses of B. holophylla extract and fractions were performed using high-performance liquid chromatography coupled with a diode-array detector and mass spectrometry (HPLC-DAD-MS). A microdilution assay was used to evaluate the effect of the B. holophylla extract and fractions on C. albicans planktonic growth, and crystal violet staining was used to measure the total biomass of the biofilm. Hyphae growth was analyzed using light microscopy. Thirteen flavonoids were identified, with a predominance of the flavonol-3-O-glycoside type based on quercetin, myricetin, and kaempferol. Flavonoid-rich fractions of B. holophylla leaves displayed antifungal activity and inhibited both biofilm formation and hyphae growth in all the tested strains, but were not effective on C. albicans planktonic growth and mature biofilm. This study indicates that flavonoid-rich fractions from B. holophylla leaves interfere with the virulence of Candida species and support the use of Bauhinia spp. in folk medicine to treat infections.

Leishmaniasis is a group of diseases that have limited and high toxic therapeutic options. Herein, we evaluated the antileishmanial potential and cytotoxicity of hexanic extract obtained from the Antarctic brown alga Ascoseira mirabilis using bioguided fractionation against Leishmania amazonensis and murine macrophages, which was fractionated by SPE, yielding seven fractions (F1-F7). The fraction F6 showed good anti-amastigote activity (IC₅₀ = 73.4 ± 0.4 μg mL⁻¹) and low cytotoxicity (CC₅₀ > 100 μg mL⁻¹). Thus, in order to identify the bioactive constituent(s) of F6, the fraction was separated in a semipreparative HPLC, yielding four fractions (F6.1-F6.4). F6.2 was the most bioactive fraction (IC₅₀ = 66.5 ± 4.5 μg mL⁻¹) and GC-MS analyses revealed that the compounds octadecane, propanoic acid, 1-monomyristin and azelaic acid correspond to 61% of its composition. These data show for the first time the antileishmanial potential of the Antarctic alga A. mirabilis.

Leishmaniasis, malaria, and neosporosis are parasitic diseases that affect humans and animals, causing public health problems and billions in economic losses. Despite the advances in the development of new drugs, the severe side effects of available leishmaniasis treatments, the Plasmodium spp. resistance to antimalarial drugs, and the lack of a specific treatment against neosporosis lead us to the search for new anti-protozoan molecules from underexplored sources such as the Antarctic marine environment. Herein, we describe for the first time the chemical profile of Desmarestia antarctica crude extract and fractions using GC-MS and LC-MS/MS (molecular networking) approaches, and evaluate their antiparasitic activity against Leishmania amazonensis, Neospora caninum, and multi-drug-resistant Plasmodium falciparum. Furthermore, the cytotoxicity in 3T3 BALB/c fibroblasts and Vero cells was evaluated. D. antarctica fraction E ( IC₅₀ of 53.8±4.4 μg mL^− 1 and selectivity index of 3.3) exhibited anti-promastigote activity and was fourfold more selective to L. amazonensis rather than to the host cells. D. antarctica fraction D (IC₅₀ of 1.6±1.3 μg mL^− 1 and selectivity index of 27.8), D. antarctica fraction F (IC₅₀ of 3.1±2.1 μg mL^− 1 and selectivity index of 23.1), and D. antarctica fraction H (IC₅₀ of 3.1±2.0 μg mL^− 1 and selectivity index of 12.9) presented the highest antiparasitic effects against N. caninum with no cytotoxic effects. Also, D. antarctica fraction D presented a significant antiplasmodial inhibitory effect (IC₅₀ of 19.1±3.9 μg mL^− 1 and selectivity index of 6.0). GC-MS analysis indicated palmitic acid, myristic acid, fucosterol, phthalic acid, di(2-methylbutyl) ester, loliolide, and neophytadiene as the main components in the active fractions. In addition, this is the first report of a biological screening of macroalgae secondary metabolites against N. caninum parasites. Received: 06 May 2020 Received: 20 June 2020 Accepted: 13 July 2020 Publication Date: 21 August 2020 (online) © 2020. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/). © Georg Thieme Verlag KG Stuttgart · New York