Faujan B. H. Ahmad

Anticancer Activity of 3-O-Acylated Betulinic Acid Derivatives Obtained by Enzymatic Synthesis

An easy and efficient strategy to prepare betulinic acid esters with various anhydrides was used by the enzymatic synthesis method. It involves lipase-catalyzed acylation of betulinic acid with anhydrides as acylating agents in organic solvent. Lipase from Candida antarctica immobilized on an acrylic resin (Novozym 435) was employed as a biocatalyst. Several 3-O-acyl-betulinic acid derivatives were successfully obtained by this procedure. The anticancer activity of betulinic acid and its 3-O-acylated derivatives were then evaluated in vitro against human lung carcinoma (A549) and human ovarian (CAOV3) cancer cell lines. 3-O-glutaryl-betulinic acid, 3-O-acetyl-betulinic acid, and 3-O-succinyl-betulinic acid showed IC50<10 μg/ml against A549 cancer cell line tested and showed better cytotoxicity than betulinic acid. In an ovarian cancer cell line, all betulinic acid derivatives prepared showed weaker cytotoxicity than betulinic acid.

Repellency of essential oils against the domiciliary cockroach, Periplaneta americana

The essential oil extracts of six Malaysian plants, i.e. Curcuma longa, Zingiber officinale, Pandanus odorus, Cinnamomum zeylanicum, Syzygium aromaticum and Cymbopogon citratus, were evaluated for repellent activity against Periplaneta americana using a modification of the “two-cylinders” method. Dose-dependent repellency ranging from 57.1 to 100% was exhibited by all six extracts at the lowest concentration tested (12 ppm).RésuméLes extraits d’huiles essentielles de six plantes de Malaisie, à savoir Curcuma longa, Zingiber officinale, Pandanus odorus, cinnamomun zeylanicum, Syzygium aromaticum et Cymbopogon citratus, ont été évalués pour leur activité répulsive contre Periplaneta americana en utilisant une modification de la méthode de “cylindre de verre en terre”. Tous les extraits testés ont présenté une répellence dose-dépendante variant de 57,1 à 100% à la plus basse concentration (12 ppm).

Kinetic probe to study the structure of micelles: effects of inert inorganic and organic salts on the rate of alkaline hydrolysis of phthalimide in the presence of cationic micelles

Pseudo-first-order rate constants (kobs) for the alkaline hydrolysis of phthalimide (PTH), obtained at a constant concentration of cetyltrimethylammonium bromide (CTABr) and 35°C, vary with the increase in the concentration of sodium phenylacetate and sodium sulfate (MX) according to the relationship: kobs=(k0+θK[MX])/(1+K[MX]) where θ and K are empirical parameters. The value of θ/khW (where khW=kobs at [CTABr]T=[MX]=0) is the measure of the extent of expulsion of ionized PTH (S−) from CTABr micellar pseudophase to aqueous pseudophase by an inert anion (X−) provided S− is fully micellized in the absence of X−. Thus, the values of θ/khW for sodium phenylacetate (≈1) and sodium sulfate (≈0.12–0.19) are attributed to deeper micellar penetration of S− and phenylacetate ions compared to that of sulfate ions.

Enzymatic synthesis of betulinic acid ester as an anticancer agent: Optimization study

Abstract Immobilized Candida antarctica lipase, Novozym 435, was used to catalyze the esterification reaction between betulinic acid and phthalic anhydride to synthesize 3-O-phthalyl betulinic acid in n-hexane/chloroform. Response surface methodology based on a five-level, four-variable central composite rotatable design was employed to evaluate the effects of synthesis parameters such as reaction time, reaction temperature, enzyme amount and substrate molar ratio on the yield of ester. Based on the response surface model, the optimal enzymatic synthesis conditions were predicted to be: reaction time 20.3 h, reaction temperature 53.9°C, enzyme amount 145.6 mg, betulinic acid to phthalic anhydride molar ratio 1:1.11. The predicted yield was 65.8% and the actual yield was 64.7%.

The Application of Response Surface Methodology for Lead Ion Removal from Aqueous Solution Using Intercalated Tartrate-Mg-Al Layered Double Hydroxides

Layered double hydroxide intercalated with tartrate (tartrate-Mg-Al) was used as an adsorbent to remove lead ions from aqueous solutions. The effects of various optimization parameters such as contact time, solution pH, lead ion concentrations, and adsorbent dosage were investigated by the use of Response Surface Methodology (RSM). The Response Surface Methodology (RSM) based on a four-level four-variable Central Composite Rotatable Design (CCRD) was employed to evaluate the interactive effects of the various optimization parameters. The parameters were contact time (6–10 h), solution pH (1–3), adsorbent dosage (0.06–0.1 g), and lead ion concentrations (10–30 mg/L). The percentage of lead ions removal for each of the parameters studied was determined by Inductively Coupled Plasma-Optical Emission Spectrophotometer. Simultaneously by increasing contact time and amount of dosage of tartrate-Mg-Al used the percentage of lead ions removal from aqueous solution will increase; however, the percentage removal decreases with an increase in pH and concentrations of lead ions. The experimental percentage removal recorded under optimum conditions was compared well with the maximum predicted value from the RSM, which suggest that Central Composite Rotatable Design of RSM can be used to study the removal of lead from aqueous solution by the use of tartrate-Mg-Al as an adsorbent.

Temperature, salt and solvent effects on intramolecular general base-catalyzed methanolysis of ionized phenyl salicylate (PS−)

Pseudo-first order rate constants (kobs) for methanolysis of− PS− show a decrease and increase of nearly 14 and 40% with increase in MeCN content from 2 to 20 or 30 and from 20 or 30 to 60 or 70 vol.%, respectively. The increase in [KCl] from 0.0 to 3.0 mol dm−3 decreases kobs by nearly 25%.

Effect of humidity on evaporation from aqueous and nonaqueous microemulsion with perfume

Abstract The weight loss during evaporation from an aqueous and nonaqueous microemulsion with limonene was followed gravimetrically at two different humidities. Result showed that at lower humidity the weight loss is greater for both of the systems. The weight loss is a however, higher for the aqueous counterpart.

Acyl migrations in Diels–Alder adducts of acyl-1,4-benzoquinones

Treatment of several 4a-acyl-4a,5,8,8a-tetra-hydro-1,4-naph thoquinones with boiling acetic anhydride gives the 1,4-diacetoxy-2-acyl-5,8-dihydronaphthalenes, and the corresponding 1,4-dihydroxy-compounds are formed when acetic acid is used, but the latter are more readily obtained, via the Δ8a,1enols, by treatment with pyridine or pyridine–methanol, these basic reagents cause deformylation of the 4a-formyl analogues, but transfer of the formly group to the oxygen at C-4 can be effected with imidazole.

Synthesis of 2-Acetyl-5,8-dihydro-1,4-dihydroxy-3-methyl Naphthalene: A Product from the Isomerisation of Diels-Alder Adducts of Both 5-Methyl- and 6-Methyl-2-acetyl-1,4-benzoquinone with 1,3-Butadiene

2-Acetyl-5,8-dihydro-1,4-dihydroxy-3-methyl-naphthalene was synthesised via Diels-Alder addition of 2-acetyl-3-methyl-1,4-benzoquinone to buta-1,3-diene followed by enolisation. It was identical with material obtained by pyridine-induced acetyl migration from the 1,3-butadiene adducts of both 3- and 6-methyl-2-acetyl-1,4-benzoquinone.

Isomerization of Diels-Alder Adducts of Benzoyl-1,4-benzoquinones: A Route to the Anthracyclinone Ring system

Abstract Base-induced [1,5laroyl migration in the Diels-Alder adduct of [2-(1,3-dioxolan-2-yl)benzoyl]-1, 4-benzoquinone and trans-penta-1, 3-diene followed by acid-mediated cyclisation affords the corresponding hydroxynaphthacenequinone.