Combined effect of brazilin-rich extract and lawsone methyl ether against infection-causing bacteria.

Bacterial contamination and infection widely affect the food, pharmaceutical and biomedical industries. Additionally, these bacteria developed resistance to synthetic antibiotics causing public health danger, globally. Natural plant extracts (NPE) are suitable alternatives to synthetic antibiotics to tackle antimicrobial resistance problems. Furthermore, a blend or combination of different NPEs exerts a wide spectrum of antimicrobial activity. Therefore, the combined effect of brazilin-rich extract (BRE) and lawsome methyl ether (LME) against infection-causing common bacteria were evaluated. BRE had a lower minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against most of the Gram-negative bacteria (Salmonella typhi, Salmonella typhimurium and Pseudomonas aeruginosa) while LME was active against most of the Gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus, and Staphylococcus epidermidis). The combination of BRE and LME at 2:1 and 1:1 concentration significantly reduced the MIC value of each compound as compared to either BRE or LME concentration alone (P < 0.05). Further time-kill kinetics revealed a 3.0-3.5 log reduction in Gram-positive bacteria and a 2.5-3.0 log reduction in Gram-negative bacteria during 120 min of incubation, respectively. Therefore, a combination of BRE and LME was recommended as natural antibacterial to synthetic antibiotics for food and pharmaceutical applications.

Carcass characteristics and meat evaluation of cattle finished in temperate pasture and supplemented with natural additive containing clove, cashew oil, castor oils, and a microencapsulated blend of eugenol, thymol, and vanillin.

BACKGROUND: Forty crossbred steers were supplemented with different doses (from 0 control to 6000 mg/animal/day) of natural additive blend containing clove essential oil, cashew oil, castor oil, and a microencapsulated blend of eugenol, thymol, and vanillin for 80 days. Carcass characteristics, drip loss, and antioxidant activity were evaluated 24 h post mortem on longissimus thoracis, and the effects of aging (until 14 days) were evaluated for water losses (thawing/aging and cooking), texture, color, and lipid oxidation. RESULTS: The use of the natural additive blend did not modify (P > 0.05) carcass characteristics but did, however, modify body composition (P < 0.05). Drip losses were unaffected by the treatments tested (P > 0.05). There was an observed quadratic effect (P < 0.05) on losses from thawing/aging on the first day of storage. Regarding the effects of natural additives on cooking losses, there was a quadratic effect (P < 0.05) among the treatments on day 7 of aging. Differences between days of aging were only observed with control treatment. Shear force was similar among treatments on days 1 and 7 of aging. On day 14 a linear effect (P < 0.05) was observed. Also, a linear effect (P < 0.05) appeared on meat lightness, meat from the control group being clearer on day 1. No changes were observed in redness among treatments or days of storage (P > 0.05). Yellowness was not modified by the treatments (P > 0.05)but only by the days of storage in control and the lowest dosage used. CONCLUSION: The blend of natural additives has potential use in pasture feeding and could improve meat quality. However, doses should be adjusted. © 2021 Society of Chemical Industry.