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Essential oils obtained from Croton pulegiodorus leaf are renowned for their biological activities; however, data on their toxicity are limited. Therefore, this study aimed to evaluate the acute oral toxicity and genotoxicity of a C. pulegiodorus leaf essential oil (CPLEO). Chemical characterization of CPLEO was conducted by gas chromatography coupled to mass spectrometry (GC-MS). In vitro assay was performed to verify the hemolytic capacity of the oil in mice erythrocytes. Next, an acute oral toxicity study was conducted on female mice at CPLEO doses of 2000, 1000, 500, 250, 100, and 50 mg/kg. Hematological, biochemical, and histopathological markers were assessed in mice from groups were no death occurred. Relative consumption of water and food and the weight of animals and their organs were also recorded. Finally, a genotoxicity analysis was performed using the micronucleus and comet assays. The extraction yield of CPLEO was 1.149% and its major compounds were ascaridole (23.18%), eucalyptol (17.20%), camphor (14.20%), p-cymene (7.91%), α-terpineol (4.69%), and isobornyl acetate (4.57%). CPLEO showed a hemolytic effect only at high concentrations (185.5-1000 mg/mL). It showed acute oral toxicity in mice with a LD 50 of 460.42 mg/kg. CPLEO (50-250 mg/kg) caused some significant changes in hematological and biochemical parameters. Histopathological evaluation indicated alterations in liver and kidneys but transaminases, urea and creatinine levels remained like the negative control. CPLEO administration impaired weight gain and reduced water and food consumption. Finally, it was not genotoxic by both comet and micronucleus tests. The results highlight the need for attention when choosing doses to evaluate the bioactivities of CPLEO., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study investigated the morphology of Rhinella crucifer cutaneous glands, as well as the protein/peptide profiles and bioactivities of body gland secretions (BGS) and parotoid macrogland secretions (PS). The parotoid as well as dorsal and ventral skin fragments of male and female individuals were processed for histological analysis. The protein and peptide profiles of male and female gland secretions were evaluated. Male secretions were also assessed for proteolytic, trypsin inhibiting, hemagglutinating, hemolytic, antimicrobial, and anticoagulant activities. The R. crucifer skin structure presented protuberances that are clearly visible and formed by the integument, which has cutaneous glands throughout the body. An average of 438 and 333 glands were identified in males in females, respectively. No significant differences were observed in the distribution of glands across the body as well as for area and perimeter of glands. Differences were observed in protein composition between the PS and BGS from males and females, and secretions from animals collected from undisturbed and anthropogenically disturbed areas. Proteins with similarities to catalase and elongation factor 1-alpha were detected in the PS. Zymography revealed proteolytic activity in both male BGS and PS. Male BGS showed antibacterial activity against Enterococcus faecalis and Escherichia coli and anticoagulant activity, being able to prolong prothrombin time by 6.34-fold and activated partial thromboplastin time by 2.17-fold. Finally, male PS and BGS caused a maximum hemolysis degree of 1.4%. The data showed that the cutaneous secretions of R. crucifer are potentially promising for biotechnological prospecting., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Lippia alba is an aromatic shrub known to produce a diversity of essential oils, which can be classified into chemotypes. This study reports on the insecticidal activity of essential oil from L. alba leaves collected at Caatinga and its major compound against termite Nasutitermes corniger and maize weevil Sitophilus zeamais. The chromatographic analysis revealed the presence of 19 compounds, with 1,8-cineole being the most common (70.01%). When ingested, the oil promoted the mortality of N. corniger (LC 50 : 18.25 and 8.4 nL/g for workers and soldiers, respectively). The compound 1,8-cineole was also termiticidal for workers (LC 50 : 13.7 nL/g). The oil inhibited the activity of N. corniger exoglucanase, xylanase, and proteases. Toxicity by ingestion to S. zeamais was detected for the oil (LC 50 : 0.297 μL/g) but not for 1,8-cineole; however, both the oil and 1,8-cineole showed anti-nutritional effects. Fumigant effects of the oil and 1,8-cineole against S. zeamais (LC 50 of 78.0 and 13.64 μL/L in air, respectively) were detected. This is the first record of a chemotype VI oil from L. alba collected at Caatinga and the first report of the insecticidal activity of a chemotype VI oil. Our study demonstrates that essential oil from L. alba and 1,8 cineole have the potential for the development of natural insecticides., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Schinus terebinthifolia leaf lectin (SteLL) was reported to be an antimicrobial and antitumor agent. In this work, we evaluated the immunomodulatory activity of SteLL on mice splenocytes and also determined its native molecular mass and putative sequence similarities with plant proteins. The effects of SteLL (12.5 μg/mL) on viability, cytosolic Ca 2+ concentration ([Ca 2+ ] cyt ), cytosolic and mitochondrial levels of reactive oxygen species (ROS), and mitochondrial transmembrane potential (ΔΨm) of mice splenocytes were determined. In addition, the culture supernatants were collected for quantification of interleukins (IL), tumor necrosis factor (TNF), interferon-gamma (IFN-γ) and nitric oxide (NO). SteLL showed a native molecular mass of 12.4 kDa and tandem mass spectrometry (MS/MS) ions search revealed similarities with adenosine triphosphate (ATP) synthase and F1-ATPase from plants (4% and 6% coverage, respectively). SteLL was not toxic to splenocytes, did not alter the [Ca 2+ ] cyt and ROS levels, and slightly reduced ΔΨm. The presence of SteLL stimulated the cells to release pro-inflammatory cytokines (IL-17A, TNF-α, IFN-γ and IL-2) and also of IL-4, an anti-inflammatory cytokine that can prevent exacerbated inflammation. SteLL induced decrease in the secretion of NO. In conclusion, SteLL has biotechnological potential as an immunomodulator agent for use in studies employing cultures of immune cells. In addition, the anti-infectious and antitumor properties of the leaves may involve the immunomodulation property of SteLL., Competing Interests: Conflict of interestThe authors declare that they have no conflict of interest in the publication., (© King Abdulaziz City for Science and Technology 2020.)

Lectins are carbohydrate-binding proteins broadly distributed in plants and have several biological functions, including antimicrobial action. Portulaca elatior is a Caatinga plant whose chemical composition and biotechnological potential have not been extensively studied. In this work, a lectin was isolated from P. elatior root extract and evaluated for antimicrobial activity. The P. elatior root lectin (PeRoL) showed native molecular mass of 33 kDa, pI 3.8 and is comprised of two subunits of 15 kDa linked by disulfide bonds. No sequence similarities with Viridiplantae proteins were observed. The PeRoL hemagglutinating activity (HA) was not affected by heating and was detected in a pH ranging from 4.0 to 8.0. Trehalose was identified as an endogenous inhibitor of PeRoL present in the roots. Bacteriostatic activity was detected against Enterococcus faecalis, Pseudomonas aeruginosa and Staphylococcus aureus (minimal inhibitory concentration of 8.1, 32.5 and 4.06 μg/mL, respectively). PeRoL induced the death of Candida albicans, Candida parapsilosis, Candida krusei, and Candida tropicalis cells, with a minimal fungicidal concentration of 16 μg/mL. The lectin (100 μg/mL) was not cytotoxic to human peripheral blood mononuclear cells (PBMCs) and did not show hemolytic activity. In conclusion, the roots of P. elatior contain a trehalose-binding, thermostable, and antimicrobial lectin., (Copyright © 2018 Elsevier B.V. All rights reserved.)

This work describes purification of a protease from the visceral mass of the mussel Mytella charruana as well as evaluation of its ability to hydrolyze milk casein to generate antimicrobial peptides. The enzyme showed pI of 4.1 and a single polypeptide band of 83.1 kDa after SDS-PAGE. Sequence similarities with tropomyosin and myosin from mollusks were detected. The protease showed a trypsin-like activity with optimal temperature of 40 °C and stability in a wide pH range (3.0-9.0). K m was 4.28 ± 0.34 mM of the synthetic substrate N-benzoyl-dl-arginyl-ρ-nitroanilide, whereas V max was 0.056 ± 0.001 nmol min -1 . The enzyme hydrolyzed casein, and the hydrolysate inhibited the growth of Escherichia coli, Micrococcus luteus, Bacillus subtilis, and Klebsiella pneumoniae at a minimal inhibitory concentration of 5.0 µg mL -1 . In conclusion, the visceral mass of M. charruana contains a trypsin-like protease that can generate peptides from casein that have a bacteriostatic effect., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

In this study, we report the purification and characterization of a multifunctional lectin (MvFL) from Microgramma vacciniifolia fronds as well as its immunomodulatory properties on human peripheral blood mononuclear cells (PBMCs). MvFL (pI 4.51; 54kDa) is a glycoprotein able to inhibit trypsin activity and that has sequence similarities (32% coverage) with a plant RNA-binding protein. Hemagglutinating activity of MvFL was not altered by heating at 100°C for 30min, but was reduced in alkaline pH (8.0 and 9.0). Fluorimetric analyses showed that this lectin did not undergo marked conformational changes when heated. However, the MvFL conformation changed depending on the pH. MvFL at 6.25-25μg/mL was not cytotoxic to lymphocytes present among PBMCs. The PBMCs incubated for 24h with the lectin (12.5μg/mL) showed increased TNF-α, IFN-γ, IL-6, IL-10, and nitric oxide production. MvFL also stimulated T lymphocytes from PBMCs to differentiate into CD8 + cells. The activation (indicated by CD28 expression) of these cells was also stimulated. In conclusion, MvFL is a heat-stable and multifunctional protein, with both lectin and trypsin inhibitor activities, and capable of inducing predominantly a Th1 response in human PBMCs as well as activation and differentiation of T lymphocytes., (Copyright © 2017 Elsevier B.V. All rights reserved.)

This work describes the isolation of a lectin (CasuL) from the leaf pinnulae of Calliandra surinamensis and the evaluation of its cytotoxic, antimicrobial and antibiofilm properties. Proteins from pinnulae extract were precipitated with ammonium sulphate (60% saturation) and submitted to Sephadex G-75 chromatography, which yielded isolated CasuL (purification factor: 113). Native CasuL is an acidic protein (pI 5.82) with a relative molecular mass of 48kDa. This lectin is also an oligomeric protein composed of three subunits and mass spectrometry revealed similarities with a Sorghum bicolor protein. CasuL did not undergo unfolding when heated but changes in conformation and hemagglutinating activity were detected at basic pH. CasuL did not reduce the viability of human peripheral blood mononuclear cells but was toxic to leukemic K562 cells (IC 50 67.04±5.78μg/mL) and breast cancer T47D cells (IC 50 : 58.75±2.5μg/mL). CasuL (6.25-800μg/mL) only showed bacteriostatic effect but was able to reduce biofilm formation by Staphylococcus saprophyticcus and Staphylococcus aureus (non-resistant and oxacillin-resistant isolates). CasuL showed antifungal activity against Candida krusei causing alterations in cell morphology and damage to cell wall. In conclusion, the pinnulae of C. surinamensis leaves contain a thermo-stable lectin with biotechnological potential as cytotoxic, antibiofilm, and antifungal agent., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Aedes aegypti transmits the viruses that cause yellow and dengue fevers. Vector control is essential, since a vaccine for dengue has not as yet been made available. This work reports on the larvicidal activity of Myracrodruon urundeuva leaf lectin (MuLL) against A. aegypti fourth-stage larvae (L(4)). Also, the resistance of MuLL to digestion by L(4) gut proteases and the effects of MuLL on protease, trypsin-like and α-amylase activities from L(4) gut were evaluated to determine if lectin remains active in A. aegypti gut and if insect enzyme activities can be modulated by MuLL. MuLL promoted mortality of L(4) with LC(50) of 0.202 mg/ml. Haemagglutinating activity of MuLL was detected even after incubation for 96 h with L(4) gut preparation containing protease activity. MuLL affected the activity of gut enzymes, inhibiting protease and trypsin activities and stimulating α-amylase activity. The results suggest that MuLL may become a new biodegradable larvicidal agent for dengue control. Larvicidal activity of MuLL may be linked to its resistance to proteolysis by larval enzymes and interference in the activity of digestive larval enzymes.