The intake of heterocyclic amines is influenced by the amount and type of meat and fish ingested, frequency of consumption, cooking methods, cooking temperature, and duration of cooking. In this study, the dietary intake of heterocyclic amines in Malaysia and their main sources were investigated. Forty-two samples of meat and fish were analysed by high-performance liquid chromatography with photodiode array detector to determine the concentration of the six predominant heterocyclic amines, namely: 2-amino-3-methylimidazo[4,5-f] quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5-f] quinoline(MeIQ), 2-amino-3,8-dimethylimidazo[4,5-f] quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f] quinoxaline (4,8-DiMeIQx), 2-amino-3,7,8-trimethylimidazo[4,5-f] quinoxaline (7,8-DiMeIQx), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). Dietary intake data were obtained using a food-frequency questionnaire when interviewing 600 Malaysian respondents. The level of total heterocyclic amines in food samples studies ranged from not detected to 38.7 ng g(-1). The average daily intake level of heterocyclic amine was 553.7 ng per capita day(-1). The intake of PhIP was the highest, followed by MeIQx and MeIQ. The results reveal that fried and grilled chicken were the major dietary source of heterocyclic amines in Malaysia. However, the heterocyclic amine intake by the Malaysian population was lower than those reported from other regions.
Two seco-tabersonine alkaloids, jerantiphyllines A and B, in addition to a tabersonine hydroxyindolenine, jerantinine H, and a recently reported vincamine alkaloid 7, were isolated from the leaf extract of the Malayan Tabernaemontana corymbosa and the structures were established using NMR and MS analysis. Biomimetic conversion of jerantinines A and E to their respective vincamine and 16-epivincamine derivatives were also carried out.
A preliminary study on selected insect communities of Tasik Chini was conducted from 27th May to 2nd June 2004 along three trails namely trail to Sg. Gumum, trail to Kampung Melai and trail to old tin mining area. A total of eight Malaise traps were installed along the trail to Sg. Gumum while sweeping net and 10 yellow pan traps per trail were used to sample insects along the other two trails. A total of 502 insect individuals consisting of eight orders and 46 families were successfully collected. Of these, the hymenopterans (ants and wasps) had the most number (298 individuals and 11 families) while the Blattaria was the least number (six individuals and two families). Of the hymenopterans, the ichneumonids had the most individuals collected (52) followed by evaniid (50) and vespid wasps (41). For the Coleopterans, Cleridae were the most collected (26) during this short study followed by Anthribidae (13). There were 62 of individuals Odonata consisting of 9 species identified.
Investigation on the leaves of Melicope bonwickii (F.Muell.) T.Hartley (Rutaceae) afforded a new 7-(2'-hydroxy-3'-chloroprenyloxy)-4-methoxyfuroquinoline (1) together with the known 7-(2',3'-epoxyprenyloxy)-4-methoxyfuroquinoline (2), evellerine (3) kokusaginine (4) and an amide aurantiamide acetate (5). Compounds 1 and 2 showed significant activity against cervical cell lines (Hela).
The in-vitro susceptibility of quinupristin/dalfopristin, levofloxacin and moxifloxacin against methicillin-resistant Staphylococcus aureus (MRSA) strains, which are also resistant to fusidic acid and rifampicin were carried out to determine whether these antibiotics can be used as an alternative treatment for multiply resistant MRSA strains. The minimum inhibitory concentrations (MIC) of these antibiotics were determined by E-test. Quinupristin/dalfopristin had good activity (MIC90 = 1 mg/L) against these strains while most of the strains showed intermediate resistance to moxifloxacin with MIC90 = 2 mg/L). However, more than 90% of these strains were resistant to levofloxacin with the MICs that ranged from 8 mg/L to 16 mg/L with the majority inhibited at 8 mg/L.
A novel proaporphine-tryptamine dimer alkaloid, named phoebegrandine C 1, was isolated from the leaves of Phoebe grandis (Nees) Merr. Its structural elucidation was carried out using spectroscopic techniques, notably 2D NMR.
The drug susceptibility of 70 isolates of Plasmodium falciparum to standard and experimental antimalarials was evaluated using a radioisotope microdilution method. All isolates were from forest fringe dwelling Orang Asli, the aborigines of Peninsular Malaysia. The geometric mean IC50 values were: chloroquine, 10 ng/ml; amodiaquine, 4.7 ng/ml; mefloquine, 2.8 ng/ml; quinine, 40.5 ng/ml; halofantrine, 1.5 ng/ml; enpiroline, 3 ng/ml; and pyrimethamine, 21 ng/ml. Four isolates exhibited decreased susceptibility to chloroquine (IC50 greater than 60 ng/ml), and one exhibited decreased susceptibility to quinine (IC50 = 161 ng/ml). Three isolates showed decreased susceptibility to mefloquine (IC50 = 10-11 ng/ml). The lack of drug pressure may account for the high prevalence of P. falciparum isolates susceptible to chloroquine.
A single dose pharmacokinetic study of a combined antimalarial formulation of mefloquine, sulphadoxine and pyrimethamine (Fansimef) has been performed in 10 healthy adult male Malaysian volunteers. The dose consisted of two tablets containing 250 mg mefloquine base, 500 mg sulphadoxine base and 25 mg pyrimethamine base each. Plasma concentrations of mefloquine and pyrimethamine were measured by GC-ECD, those of sulphadoxine by h.p.l.c. Time to peak concentrations (mean +/- s.d. for mefloquine (5.70 +/- 0.95 h), sulphadoxine (3.75 +/- 2.03 h) and pyrimethamine (3.30 +/- 1.98 h) were similar to those observed by others after administration of the single compounds. This was also true for elimination half-lives (t1/2). The t1/2s for mefloquine, sulphadoxine and pyrimethamine were 387 +/- 98 h, 255 +/- 61 h and 114 +/- 42 h, respectively.
Plasmodium falciparum drug sensitivities to chloroquine and mefloquine were assessed with WHO in vitro microtechnique test kits in 5 localities near the border with Thailand in Peninsular Malaysia. 105 of 113 (92.9%) parasite isolates were successfully tested and 103 (98.1%) showed resistance to chloroquine with parasite growth even at greater than or equal to 5.7 pmol of the drug. All these isolates were sensitive to mefloquine, parasite growth being inhibited at less than or equal to 11.3 pmol of the drug.