Plant metabolomics, lipidomics, ionomics, fluxomics, and peptidomics are essential approaches for exploring how plants respond to epigenetic, pathological, and environmental stimuli through comprehensive chemical profiling. Over the past decades, significant progress has been made in protocols and methodologies to address the challenges in sample collection and extraction. Despite these advancements, sample preparation remains intricate, with ongoing debates about the most effective strategies. This review emphasizes the importance of clear research questions and well-designed experiments to minimize complexity, save time, and enhance reproducibility. It provides an overview of the key steps in these fields, including harvesting, drying, extraction, and data pre-acquisition for major analytical platforms. By discussing best practices and common challenges, this review aims to streamline methods and promote more consistent and reliable research outcomes.

Currently, the search for new alternatives to conventional antibiotics to combat bacterial resistance is an urgent task, as many microorganisms threaten human health due to increasing bacterial resistance to traditional medicines. Thus, new molecules such as antimicrobial peptides have emerged as promising alternatives because of their low induction of resistance and broad spectrum of action. In this context, in the past few years, our research group has synthesized and characterized a peptide derived from the C-terminal region of the Lys⁴⁹ PLA₂-like BthTX-I, named p-BthTX-I. After several studies, the peptide (p-BthTX-I)₂K was proposed as the molecule with the most considerable biotechnological potential. As such, the present work aimed to evaluate whether the modifications made on the peptide (p-BthTX-I)₂K can be applied to other molecules originating from the C-terminal region of PLA₂-like Lys⁴⁹ from snake venoms. The peptides were obtained through the solid-phase peptide synthesis technique, and biochemical and functional characterization was carried out using dichroism techniques, mass spectrometry, antimicrobial activity against ESKAPE strains, hemolytic activity, and permeabilization of lipid vesicles. The antimicrobial activity of the peptides was promising, especially for the peptides (p-AppK)₂K and (p-ACL)₂K, which demonstrated activity against all strains that were tested, surpassing the model molecule (p-BthTX-I)₂K in most cases and maintaining low hemolytic activity. The modifications initially proposed for the (p-BthTX-I)₂K peptide were shown to apply to other peptides derived from Lys⁴⁹ PLA₂-like from snake venoms, showing promising results for antimicrobial activity. Future assays comparing the activity of the dimers obtained through this strategy with the monomers of these peptides should be carried out.

Background: Malaria significantly impacts the health of populations living in poverty and vulnerable conditions. Resistance to current antimalarial drugs remains a major challenge and highlights the urgent need for novel, effective, and safer therapies. Violacein, a purple pigment, has demonstrated potent antiplasmodial activity, making it a promising antimalarial candidate. However, to date, no in vitro metabolism studies of violacein have been published. In this study, the metabolic stability of violacein was evaluated using human (HLMs), mouse (MLMs), and rat (RLMs) liver microsomes and the metabolites generated by HLMs and RLMs were assessed. Methods: Liquid chromatography quadrupole mass spectrometry (LC-MS/MS) was used to investigate the metabolic stability of violacein, while liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) was used to identify the metabolites. In silico analyses were used to support in vitro metabolite identification by providing insights into potential metabolic pathways and predicting metabolite structures, thereby enhancing the accuracy and efficiency of the identification process. Results: The half-life (t_1/2) for violacein in RLMs, MLMs, and HLMs was 36, 81, and 216 min, respectively. The in vitro intrinsic clearance (CL_{int, in vitro}) values were 38.4, 17.0, and 6.4 µL/min/mg for RLMs, MLMs, and HLMs, respectively, while the in vivo intrinsic clearance (CL_{int, in vivo}) was 93.7, 67.0, and 6.6 mL/min/kg, respectively. A slow elimination profile was observed in HLMs followed by MLMs, with rapid elimination in RLMs, indicating greater stability of violacein in HLMs and MLMs when compared with RLMs. Four violacein metabolites were identified in HLMs and RLMs, two of which were formed by phase I metabolism, one by phase II metabolism, and one by phase I + II metabolism. Conclusions: This study provides the first published analysis of the metabolic stability of violacein.

Antimicrobial peptides such as Melittin exhibit potent broad-spectrum activity but are limited by high cytotoxicity. The rational design of bioinspired Melittin-derived analogues represents a promising strategy to reduce toxicity while maintaining antimicrobial efficacy. In this study, Melittin and analogues (TT-1, FKW, and WKW) were synthesized using solid-phase peptide synthesis (SPPS) and characterized for biological and biophysical essays. Antimicrobial and hemolytic activity, serum stability, secondary structure, and membrane interaction were analysed. FKW and WKW exhibited broad-spectrum antimicrobial activity, with minimum inhibitory concentration (MIC) as low as 8 and 16 µg/mL against Staphylococcus aureus and Enterococcus faecium. Both analogues also showed improved activity against Klebsiella pneumoniae (32 µg/mL) and Pseudomonas aeruginosa (128 and 256 µg/mL for FKW and WKW, respectively) compared to Melittin (64 and 512 µg/mL). In terms of cytotoxicity, FKW and WKW showed significantly reduced hemolytic activity, with HC₅₀ values of 264.8 µg/mL and 237.2 µg/mL, respectively, resulting in improved selectivity indexes relative to Melittin (HC₅₀ of 7.9 µg/mL). In liposomes, both adopt α-helical structures and cause disruption via pore formation or detergent-like mechanisms. TT-1 showed minimal toxicity but weak antimicrobial activity (MIC > 256 µg/mL). Although FKW and WKW exhibited limited serum stability (half-lives of 2.2 and 1.5 h), their degradation may reduce systemic toxicity. Overall, these analogues demonstrate an improved balance between antimicrobial activity and safety.