CDC Light traps were used to study the attractant effect of CO2 and 1-octen-3-ol on trap catches of mosquito populations at three different locations in Malaysia. There was a significant increase in the number of mosquitos caught in traps baited with CO2 and CO2 with 1-octen-3-ol. The number of mosquitos caught in the CDC light trap and in the CDC light trap baited with 1-octen-3-ol alone were very few. 1-octen-3-ol and CO2 acted synergistically in attracting significantly greater numbers of Culex tritaeniorhynchus. However Anopheles sp. were not very attracted to light traps even with attractants added to them.
Rhodinol is a mixture of geraniol and citronellol. It is the second fraction in fractional distillation of commercially grown Cymbopogon nardus. The physical and chemical similarities of these two compounds made them inseparable. The individual use of each compound is of great importance. A selective oxidation (hydrogen peroxide activated by platinum black) of geraniol (in rhodinol) to geranial was done while remaining citronellol intact in order to separate the two compounds into different chemical functionality. A yield of 81% geranial achieved while minimizing citronellal formation from citronellol to 17%. Chemical separation using sodium hydrogen sulfite (NaHSO3) was done to separate the aldehydes from the unreacted citronellol. Purification using fractional distillation was done to obtain pure geraniol and remove minor fraction of citronellal.
A simple validated LC-UV method for the phytochemical analysis of four bioactive quassinoids, 13alpha(21)-epoxyeurycomanone (EP), eurycomanone (EN), 13alpha,21-dihydroeurycomanone (ED) and eurycomanol (EL) in rat plasma following oral (200 mg/kg) and intravenous administration (10 mg/kg) of a standardized extract Fr 2 of Eurycoma longifolia Jack was developed for pharmacokinetic and bioavailability studies. The extract Fr 2 contained 4.0%, 18.5%, 0.7% and 9.5% of EP, EN, ED and EL, respectively. Following intravenous administration, EP displayed a relatively longer biological half-life (t1/2 = 0.75 +/- 0.25 h) due primarily to its lower elimination rate constant (k(e)) of 0.84 +/- 0.26 h(-1)) when compared with the t1/2 of 0.35 +/- 0.04 h and k(e) of 2.14 +/- 0.27 h(-1), respectively of EN. Following oral administration, EP showed a higher C(max) of 1.61 +/- 0.41 microg/mL over that of EN (C(max) = 0.53 +/- 0.10 microg/mL). The absolute bioavailability of EP was 9.5-fold higher than that of EN, not because of chemical degradation since both quassinoids were stable at the simulated gastric pH of 1. Instead, the higher log K(ow) value of EP (-0.43) contributed to greater membrane permeability over that of EN (log K(ow) = -1.46) at pH 1. In contrast, EL, being in higher concentration in the extract than EP, was not detected in the plasma after oral administration because of substantial degradation by the gastric juices after 2 h. Similarly, ED, being unstable at the acidic pH and together with its low concentration in Fr 2, was not detectable in the rat plasma. In conclusion, upon oral administration of the bioactive standardized extract Fr 2, EP and EN may be the only quassinoids contributing to the overall antimalarial activity; this is worthy of further investigation.
The esterification of palm-based 9,10-dihydroxystearic acid (DHSA) and 1-octanol in hexane as catalyzed by lipase from Rhizomucor meihei (Lipozyme IM) followed Michaelis-Menten kinetics. The esterification reaction follows a Ping-Pong, Bi-Bi mechanism. The maximum rate was estimated to be 1 micromol min(-1) mg(-1) catalyst in hexane at 50 degrees C, and the Michaelis-Menten constants for DHSA and 1-octanol were 1.3 M and 0.7 M, respectively.
A series of ester compounds derived from ricinoleic acid to be used as biolubricants base stock have been synthesized. The resulting products were confirmed by FTIR and NMR analyses. The synthesis was carried out in three stages: epoxidation of ricinoleic acid; synthesis of 10,12-dihydroxy-9-acyloxystearic acid from epoxidized ricinoleic acid with various fatty acids and esterification of the acyloxystearic acid products with octanol to yield octyl-10,12-dihydroxy-9-acyloxystearate. The viscosities, flash points and pour points (PP) behavior of the products were measured. The resulting esters had an increased in molar weight and viscosity and decreased in pour points as compared to ricinoleic acid.