Toxins

While tropical regions have traditionally been the focus of studies on natural bioactive products, works published within the last decade demonstrate that cyanobacteria from the Baltic Sea also possess significant biotechnological and pharmaceutical potential. The Baltic Pseudanabaena galeata CCNP1313 previously demonstrated activity against breast cancer cell lines (MCF7 and T47D) and several viruses. In the present study, the cytotoxicity of cellular extract and flash chromatography fractions from the strain were evaluated against a wider panel of cancer cells (A549, C-33A, CaSki, DoTC2, HeLa, PC3, SiHa, and T47D). To gain better insight into the compounds potentially responsible for the observed effects, high-resolution mass spectrometry was combined with bioactivity-based molecular networking. Both the extract and hydrophobic fractions showed strong cytotoxicity, particularly against breast cancer cells and selected cervical cancer cells. While HRMS analyses confirmed the production of previously characterised peptides by CCNP1313 (Pseudanabaena galeata peptides and galeapeptins), neither of them was found to be responsible for the activity. Instead, the molecular networking approach linked the cytotoxicity to specific lipid classes, including diacylglycerols (DAGs) and monogalactosyldiacylglycerols (MGDGs). This study highlights the necessity of integrating traditional methods with advanced bioinformatics for the successful discovery of bioactive natural products, especially when complex samples, such as extract or chromatographically separated fractions, are analysed.

Polygalae Radix, a traditional Chinese medicine for insomnia and memory disorders, is highly susceptible to fungal contamination and mycotoxin production (especially by Aspergillus flavus) during storage, compromising its safety and efficacy. Therefore, in this study, high-throughput sequencing was employed to evaluate the dynamic changes in fungal communities during the storage of Polygalae Radix and to analyze common mycotoxin-producing genera. Furthermore, the inhibitory effects of peppermint essential oil (PEO) on A. flavus were assessed through fumigation treatments, combined with colony counting and quantification of aflatoxins. Results showed the following: (1) Storage for 1–3 months significantly altered the fungal structure, promoting saprophytic and pathogenic fungi (e.g., Wallemia, Paraphoma, Didymella, Cladosporium…) and increasing the relative abundance of mycotoxin producers like Penicillium, Aspergillus, and Fusarium (notably, Penicillium increased from 0.28–2.33% to 5.39–80.43%). Additionally, A. flavus, capable of producing aflatoxins, was detected in samples stored for two months (RM2). (2) Antifungal tests demonstrated that PEO significantly inhibited the common fungi in Polygalae Radix. At 10 μL/g, it suppressed fungal growth and significantly reduced aflatoxin B₁ (AFB₁) and total aflatoxins (AFT, including AFB₁, AFB₂, AFG₁, and AFG₂) levels (p < 0.05). At 10 μL/g, AFB₁ and AFT were reduced to undetectable levels. PEO can serve as a green and effective protective strategy to inhibit A. flavus during the storage of Polygalae Radix and control aflatoxin contamination.

Scorpion venom toxins are important peptides being studied for their clinical significance. These peptides act by binding to ion channels in the membrane of nerve cells, causing the symptoms associated with scorpion stings (scorpionism). They principally affect the function of voltage-gated sodium channels (Nav) and are valuable for studying ion channels. Scorpions from the Buthidae family contain toxins that affect sodium channels and have a high affinity for mammalian channels. In this study, two sodium toxins isolated from the venom of the scorpion Centruroides hirsutipalpus, a member of the Buthidae family, were identified as belonging to the beta-type subfamily. These toxins were purified from whole venom using molecular exclusion, cationic-exchange, and reverse-phase chromatography techniques. Their molecular masses were determined using mass spectrometry, while their amino acid sequences were obtained by Edman degradation. A comparative analysis revealed that the sequences are identical to ChiNaBet60 and ChiNaBet50 toxins (now named Chirp7 and Chirp9, respectively) previously identified in the venom gland transcriptomics from C. hirsutipalpus. Furthermore, toxicity studies showed that these toxins were lethal to mammals. Electrophysiological analysis revealed that these peptides act as sodium channel–modulating toxins. In addition, interaction assays with antibodies were performed to analyze the structural determinants governing the binding mechanism.