Emilia Abd Malek

Formulation optimization of palm kernel oil esters nanoemulsion-loaded with chloramphenicol suitable for meningitis treatment

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.

A new coumarin from Calophyllum hosei

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 1H NMR, 13C NMR, COSY, DEPT, HMQC and HMBC experiments.

Design of a Simple Organocatalysts for Asymmetric Direct Aldol Reactions in Aqueous Medium

AbstractA novel and simple organocatalyst derived from proline was designed, synthesized and tested for its catalytic potential in a direct asymmetric aldol reaction between 4-nitrobenzaldehyde and cychlohexanone in aqueous media. The relatively inexpensive and safe solvent, water stabilized the transition state, and increased reactivity and selectivity of catalyst. The diastereo- and enantio-selective products of the reaction were obtained in excellent yields. Graphical Abstract

A New Pyranoxanthone from the Stem Bark of Calophyllum buxifolium

A new pyranoxanthone, buxixanthone (1), was isolated from the stem bark of Calophyllum buxifolium along with three other chemical constituents, ananixanthone (2), pyranojacareubin (3), and macluraxanthone (4). The structures of these compounds were confirmed through spectroscopic analysis, which included 1D and 2D NMR, GC/MS, and IR experiments.

OPTIMIZATION OF LIPASE-CATALYZED SYNTHESIS OF N-trans-FERULOYLTYRAMINE USING RESPONSE SURFACE METHODOLOGY (RSM)

Enzymatic synthesis of N-trans-feruloyltyramine amide was optimized by response surface methodology (RSM) using 4-hydroxy-3-methoxycinnamic acid and tyramine hydrochloride in a one-step lipase catalyzed reaction using Lipozyme TL IM. Response surface methodology (RSM) based on five-level, four-variable central composite rotatable design (CCRD) was used to evaluate the interaction of synthesis, reaction time (24–96 h), temperature (30°–50°C), amount of enzyme (50–500 mg, 12.5–125.0 IUN), and substrate molar ratio (cinnamic acid:tyramine HCl) 1:1–8:1 mmol on the percentage yield of N-trans-feruloyltyramine amide. The optimum conditions derived via RSM were: reaction time 52 h, temperature 43°C, amount of enzyme 260 mg (65.0 IUN), and substrate molar ratio (cinnamic acid:tyramine HCl) 6.2:1. The actual experimental yield was 96.3% under optimum conditions, which compared well to the maximum predicted value of 97.2%.

Lipase catalysed synthesis of N-trans-feruloyltyramine and a quantitative HPLC-UV method for analysis

Abstract N-trans feruloyltyramine amide was successfully synthesized from 4-hydroxy-3-methoxycinnamic acid and tyramine hydrochloride in a one-step lipase catalysed reaction. The use of immobilized lipase, lipozyme TL IM as the catalyst in the reaction allowed simple isolation of the enzyme from the products and other components in the reaction mixture. N-feruloyltyramine amide was characterized using Fourier Transform Infrared (FTIR) Spectroscopy, Proton Nuclear Magnetic Resonance (1H NMR) and elemental analysis. Under optimized conditions 93.5% yield was obtained when the process was carried out for 48 h using a molar ratio of cinnamic acid:tyramine HCl, 6:1 at 40°C. In addition, a rapid simple and sensitive HPLC-UV method was developed for the determination of N-feruloyltyramine using an ®Rp-8 endcapped column. The optimum mobile phase used was acetonitrile:disodium hydrogen phosphate, 30:70(v/v.). N-feruloyltyramine amide was detected at a retention time of 12 min. The calibration curve was linear over the range of 5.27–12.30 × 10−4 M with correlation factor r = 0.9958. Consequently, the method was considered valid for quantitative analysis samples of N-trans-feruloyltyramine amide.

Secondary Metabolites from Calophyllum Sclerophyllum and Calophyllum Hoseii

Calophyllum spp have been known for their biological activities. This genus belongs to the Guttifereae family where are rich with secondary metabolites such as xanthones, flavonoids and coumarins. Our recent phytochemical study on the bark of Calophyllum sclerophyllum and Calophyllum hoseii has led to the isolation of six xanthones, one coumarin and one flavanoid. These compounds are macluraxanthone (1), trapezifolixanthone (2), rubraxanthone (3), thwaitesixanthone (4), dombakinaxanthone (5), osajaxanthone (6), calopolyanolide A (7) and catechin (8). We report here the structural elucidations of these compounds based on the basis of detailed 1D-NMR (H, C and DEPT) and 2D-NMR (COSY, HMQC and HMBC) spectroscopic analysis.