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ObjectivesThis study investigated the antidepressant and antinociceptive effects of ethanolic extract (SLEE) and pure fruticuline A obtained from Salvia lachnostachys leaves on rats and mice.MethodsIn this study, SLEE (100 mg/kg, p.o. route) was evaluated for its effects on spared nerve injury (SNI) in rats. The animals were submitted to mechanical sensitivity, forced swim (FST) and cold sensitivity tests 10 and 15 days after surgery. SLEE (100 mg/kg, p.o.) and fruticuline A (3 mg/kg, p.o.) were also evaluated with respect to nociceptive behavior induced by formalin. In addition, clonidine-induced depressive-like behavior was also analyzed.ResultsThe oral administration of SLEE for up to 15 days and the subcutaneous injection of 10 mg/kg of ketamine (positive control) significantly inhibited SNI-induced mechanical hyperalgesia and decreased immobility in the FST. On the 15th day of oral treatment, SLEE prevented the SNI-induced increase in cold sensitivity. In the formalin test, SLEE and fruticuline A significantly reduced the frequency of paw licking during the first and second phases and decreased the formation of edema. In locomotor analysis (open field test without clonidine treatment), SLEE and fruticuline A did not alter the response. SLEE and fruticuline A significantly attenuated clonidine-induced suppression of spontaneous locomotor activity (squares invaded and licking) and emotionality (grooming and freezing) compared with controls, similar to the naive group.ConclusionSLEE exhibits antihyperalgesic, antidepressant, and antinociceptive effects, and fruticuline A appears to be at least partly responsible for the effects of SLEE. Together, these results demonstrate the antidepressive effects of SLEE and fruticuline A and indicate that both derivatives obtained from S. lachnostachys act against spontaneous neuropathic pain.

Staphylococcus aureus is one of the main aetiological agents causing food‐borne diseases. Some strains produce enterotoxins responsible for food poisoning. In addition, they can form biofilms on several surfaces such as plastics, glass and stainless steel making it difficult to eliminate them. The present study evaluated, for the first time, the antibacterial and antibiofilm activities of the synthetic compound LMM6 against S. aureus. The minimum inhibitory concentration was 0·97, 1·95 and 1·95 μg ml−1 against S. aureus ATCC 25923, S. aureus 629/94 and S. aureus FRI S‐6, respectively. The time‐kill curves showed that 96 h treatment with LMM6 reduced approximately 4 log CFU per ml at all tested concentrations. Furthermore, LMM6 reduced S. aureus preformed biofilm by approximately 1 log CFU per cm2. During biofilm formation, a reduction of approximately 4 log CFU per cm2 was observed. LMM6 also reduced biofilm biomass during (~60%) and after biofilm formation (~25 to 45%), as shown by the crystal violet assay. Based on these results, we conclude that LMM6 exhibits antibacterial and antibiofilm activity and may be an innovative synthetic molecule for controlling S. aureus.

In order, understanding the antimicrobial action of photodynamic therapy and how this technique can contribute to its application in the control of pathogens. The objective of the study was to employ a proteomic approach to investigate the protein profile of Staphylococcus aureus after antimicrobial photodynamic therapy mediated by rose bengal (RB‐aPDT). S. aureus was treated with RB (10 nmoL L−1) and illuminated with green LED (0.17 J cm−2) for cell viability evaluation. Afterward, proteomic analysis was employed for protein identification and bioinformatic tools to classify the differentially expressed proteins. The reduction in S. aureus after photoinactivation was ~2.5 log CFU mL−1. A total of 12 proteins (four up‐regulated and eight down‐regulated) correspond exclusively to alteration by RB‐aPDT. Functionally, these proteins are distributed in protein binding, structural constituent of ribosome, proton transmembrane transporter activity and ATPase activity. The effects of photodamage include alterations of levels of several proteins resulting in an activated stress response, altered membrane potential and effects on energy metabolism. These 12 proteins required the presence of both light and RB suggesting a unique response to photodynamic effects. The information about this technique contributes valuable insights into bacterial mechanisms and the mode of action of photodynamic therapy.

Foodborne diseases and microbiological control represent the major challenge for the food industry. New technologies using natural agents have attracted increasing interest. Therefore, this study aimed to evaluate the in vitro susceptibility of Staphylococcus aureus and Escherichia coli to water-soluble curcumin (WSC) combined with acidic pH and blue LED light. The minimum inhibitory concentration (MIC) and bacterial photoinactivation were conducted using different photosensitizer concentrations. For S. aureus, the combination of WSC with lactic acid and 2.5 min illumination time reduced MIC from 500 µg/mL to 15.62 µg/mL, and WSC with citric acid reduced MIC from 125 µg/mL to 7.81 µg/mL after 5 min of light exposure. WSC without illumination did not inhibit E. coli growth (MIC >1,000 µg/mL), however, when applied with photodynamic therapy (5 min blue LED illumination), WSC at 62.5 µg/mL with lactic acid and WSC at 7.81 µg/mL with citric acid eliminated E. coli cells. The results obtained suggest that water-soluble curcumin with organic acids when combined with a blue LED light was effective against foodborne pathogens.