Serine protease inhibition and modulatory-antibiotic activity of the proteic extract and fractions from Amburana cearensis.

This study investigated the inhibitory activity of serine protease, as well as antibacterial and antibiotic modifying activities of the crude extract and fractions of A. cearensis seeds. Microdilution assay was used to evaluate the antibacterial activity and the antibiotic resistance-modulating effects of samples against multiresistant bacteria Staphylococcus aureus (SA10) and Escherichia coli (EC06). In the inhibition test for serine protease, all the samples showed inhibition of enzymatic activity. Crude extract and fractions of A. cearensis seeds showed a Minimum Inhibitory Concentration ≥1024 µg/mL for all microorganisms tested. However, the samples acted as resistance modifying agent, presenting synergism when associated with gentamicin, norfloxacin and penicillin. The present study provides data indicating a possible use of the seeds extract of A. cearensis in association with antibiotics in the fight against bacterial infections.

Growth Impairment Caused by Raw Linseed Consumption: Can Trypsin Inhibitors Be Harmful for Health?

Linseed (Linun usitatissimum L.) is an important oilseed whose nutritional value can be impaired due to presence of antinutritional factors and low protein digestibility. Protein fractions from raw linseed meal were extracted, isolated and analyzed in vitro and in vivo. Globulins, the major protein fraction of linseed, showed low in vitro susceptibility to trypsin and chymotrypsin, but its in vivo digestibility was 93.2 %. Albumin fraction had high trypsin inhibition activity (5250 Inhibition Units g(-1)) and presented low molecular mass protein bands, similar to known trypsin inhibitors. Raw linseed consumption caused negative effects on rat growth and reduction of intestinal villi. Results indicate that raw linseed meal must not be used as an exclusive source of protein regardless of the major proteins have high digestibility; digestive enzymes inhibitors in raw linseed probably reduces the protein utilization.

Holothuria grisea agglutinin (HGA): the first invertebrate lectin with anti-inflammatory effects.

Holothuria grisea agglutinin (HGA) is a dimeric lectin of molecular mass 228 kDa by gel filtration with monomers of 105 kDa by SDS-PAGE. The lectin is highly thermostable as it retains full activity for 1 h at 70 °C. Unlike other lectins purified from marine invertebrates, the hemagglutination activity of HGA does not require any divalent metal ions. The affinity analysis of HGA showed that only mucin was able to inhibit the hemagglutinating activity. HGA administered intravenously was tested in classical models of nociception and inflammation. HGA was able to inhibit neutrophil migration into the peritoneal cavity induced by carrageenan. This inhibitory effect was 68% at a dose of 1 mg/kg. In acetic acid-induced writhing tests, a significant antinociceptive effect was observed by treatment with HGA (0.1; 1 or 10 mg/kg) reducing constrictions by 27, 90 and 84%, respectively. In formalin tests, HGA at a dose of 10 mg/kg showed antinociceptive effect only in the inflammatory phase (phase 2). Nevertheless, in hot-plate tests, HGA did not show any nociceptive effect. In rota-rod and open-field tests, HGA did not alter the animals' behavior. The treatment with HGA 10 mg/kg presented diminished myeloperoxidase activity activity (81.6% inhibition) and raised the circulating levels of NO by 50.4% when compared with the carrageenan group. HGA has demonstrated the ability to modulate the inflammatory response in models of inflammation in vivo. HGA is the first marine invertebrate lectin that showed an anti-inflammatory effect. This finding opens a new perspective on the potential of lectins from the marine environment.