2 research outputs found
Extraction and evaluation of antimicrobial activities of essential oils from orange peel (Citrus nobilis) grown in Can Tho City, Vietnam
ABSTRACT: This study determined the extraction conditions, chemical composition, and antimicrobial activities of the essential oils of Citrus nobilis. The results illustrated that soaking in the 9% (w/v) NaCl solution for 2 h with a sample and solvent ratio of 1:3 (w/v) and a subsequent extraction time of 45 min yielded the highest extraction efficiency, reaching 3.66% (w/w). The main chemical components of the essential oils were limonene (90.42%), β-myrcene (4.7%), and α-pinene (1.22%). The minimum inhibitory concentration (MIC) at the density of 5x104, 5x105, and 5x106 cells/mL of Escherichia coli were 100, 125, and 125 mg/mL, respectively; for Staphylococcus aureus were 75, 100, and 125 mg/mL, respectively; and for Bacillus cereus were 50, 75, and 100 mg/mL, respectively. The minimum bactericidal concentration (MBC) at densities of 5x104, 5x105, 5x106 cells/mL of E. coli were 175, 225, 225 mg/mL, S. aureus were 150, 200, 225 mg/mL, and B. cereus were 125, 175, 200 mg/mL, respectively. The inhibitory activities of Aspergillus flavus of orange essential oils according to the agar dilution method at concentrations of 0.025-0.1%) on the 5th day were 8.84-30.61%
Monitoring of Antibiotic Residues in Aquatic Products in Urban and Rural Areas of Vietnam
Antibiotic
residues in aquatic products in Vietnam were investigated.
A total of 511 fish and shrimp samples were collected from markets
in Ho Chi Minh City (HCMC), Thai Binh (TB), and Nha Trang (NT) from
July 2013 to October 2015. The samples were extracted with 2% formic
acid in acetonitrile and washed with dispersive C18 sorbent. Thirty-two
antibiotics were analyzed by LC-MS/MS. Of the 362 samples from HCMC,
antibiotic residues were found in 53 samples. Enrofloxacin was commonly
detected, at a rate of 10.8%. In contrast, samples from TB and NT
were less contaminated: only 1 of 118 analyzed samples showed residues
in TB and only 1 of 31 showed residues in NT. These differences were
attributed to the local manufacturing/distribution systems. To understand
the current status of antibiotic use and prevent adverse effects that
may be caused by their overuse, continual monitoring is required