Natural products such as essential oils (EOs) are secondary metabolites that can be obtained from either plant or animal sources or produced by microorganisms. Much attention has been given to exploring the use of secondary metabolites as natural antibacterial agents. This study investigates the antibacterial activity and mechanism of β-caryophyllene, a compound that can be found in various EOs, against Bacillus cereus. The minimum inhibitory concentration of β-caryophyllene against B. cereus was 2.5% (v/v), whereas killing kinetics of β-caryophyllene at minimum inhibitory concentration recorded complete bactericidal activity within 2 hours. Zeta-potential measurement in the cells treated with half the minimum inhibitory concentration of β-caryophyllene at 1.25% (v/v) showed an increase in the membrane permeability surface charge to –3.98 mV, compared to untreated cells (–5.46 mV). Intracellular contents leakage of UV-absorbing materials was detected in the cells treated with β-caryophyllene. Additionally, β-caryophyllene does not interfere with the efflux activity of B. cereus via the ethidium bromide influx/efflux activity. The results revealed that β-caryophyllene was able to alter membrane permeability and integrity of B. cereus, leading to membrane damage and intracellular content leakage, which eventually caused cell death.
METHODS: Patients diagnosed with invasive breast cancer (BC) from 2005 to 2013 at our tertiary institution were included and divided according to race and subtypes. Demographic and clinical information of non-metastatic TNBC patients were analyzed. Log-rank test, univariate and multivariate Cox proportional hazard regression models were used to find associated risk factors related with overall survival (OS) and disease-free survival (DFS).
RESULTS: Among 1227 BC patients, 129 (10.5%) had TNBC. TNBC patients had the worst OS (P: 0.0005) and DFS (P: 0.0016) among the subtypes. However, variations in race did not have any difference in OS or DFS among TNBC patients. Axillary lymph node involvement, invasive lobular histology, larger tumor size, and the presence of lymphovascular invasion (LVI) were factors associated with both poor DFS and OS among TNBC patients.
CONCLUSIONS: Racial variation did not have any impact on the prognosis of the TNBC.