A new coumarin, hoseimarin (1), together with four other xanthones, trapezifolizanthone (2), osajaxanthone (3), β-mangostin (4) and caloxanthone A (5), were isolated from the stem bark of Calophyllum hosei. The structures of these compounds were established by using spectroscopic analysis which included (1)H NMR, (13)C NMR, COSY, DEPT, HMQC and HMBC experiments.
Palm kernel oil esters nanoemulsion-loaded with chloramphenicol was optimized using response surface methodology (RSM), a multivariate statistical technique. Effect of independent variables (oil amount, lecithin amount and glycerol amount) toward response variables (particle size, polydispersity index, zeta potential and osmolality) were studied using central composite design (CCD). RSM analysis showed that the experimental data could be fitted into a second-order polynomial model. Chloramphenicol-loaded nanoemulsion was formulated by using high pressure homogenizer. The optimized chloramphenicol-loaded nanoemulsion response values for particle size, PDI, zeta potential and osmolality were 95.33nm, 0.238, -36.91mV, and 200mOsm/kg, respectively. The actual values of the formulated nanoemulsion were in good agreement with the predicted values obtained from RSM. The results showed that the optimized compositions have the potential to be used as a parenteral emulsion to cross blood-brain barrier (BBB) for meningitis treatment.
The incorporation of noble metals with metal-organic frameworks (MOFs) are conducive to the simultaneous electrochemical detection of analytes owing to multiple accessible reaction sites. Herein, Au@Cu-metal organic framework (Au@Cu-MOF) is successfully synthesized and modified as a screen-printed carbon electrode (SPCE), which serves as an excellent electrocatalyst for the oxidation of dopamine (DA) and uric acid (UA). The sensor shows a linear range from 10 μM to 1000 μM, with sensitivity and detection limit of 0.231 μA μM-1 cm-2 and 3.40 μM for DA, and 0.275 μA μM-1 cm-2 and 10.36 μM for UA. Au@Cu-MOF could realize the individual and simultaneous electrochemical sensing of DA and UA, with distinguishable oxidation peak potentials. Moreover, it exhibits reproducibility, repeatability, and stability. Ultimately, the sensor provides an avenue for an ultrasensitive label-free electrochemical detection of DA and UA.