Jamaludin Mohamad

Potential of apoptotic pathway-targeted cancer therapeutic research: Where do we stand?

Underneath the intricacy of every cancer lies mysterious events that impel the tumour cell and its posterity into abnormal growth and tissue invasion. Oncogenic mutations disturb the regulatory circuits responsible for the governance of versatile cellular functions, permitting tumour cells to endure deregulated proliferation, resist to proapoptotic insults, invade and erode normal tissues and above all escape apoptosis. This disruption of apoptosis has been highly implicated in various malignancies and has been exploited as an anticancer strategy. Owing to the fact that apoptosis causes minimal inflammation and damage to the tissue, apoptotic cell death-based therapy has been the centre of attraction for the development of anticancer drugs. Increased understanding of the molecular pathways underlying apoptosis has enabled scientists to establish unique approaches targeting apoptosis pathways in cancer therapeutics. In this review, we reconnoitre the two major pathways (intrinsic and extrinsic) targeted cancer therapeutics, steering toward chief modulators of these pathways, such as B-cell lymphoma 2 protein family members (pro- and antiapoptotic), inhibitor of apoptosis proteins, and the foremost thespian of extrinsic pathway regulator, tumour necrosis factor-related apoptosis-inducing agent. Together, we also will have a look from clinical perspective to address the agents (drugs) and therapeutic strategies adopted to target these specific proteins/pathways that have entered clinical trials.

Evaluation of Antidiabetic and Antioxidant Properties of Brucea javanica Seed

The ethanol extract of B. javanica seed was fractionated with solvents of different polarities and tested for antioxidant activities by several assays including DPPH radical scavenging activity, ferric reducing antioxidant power (FRAP), ferrous ion chelating activity (FCA), and nitric oxide radical scavenging activity (NORSA) along with their polyphenolic contents. Antidiabetic activity was evaluated both in vitro and in vivo using a glycogen phosphorylase α (GPα) inhibition assay and oral glucose tolerance test (OGTT) in nondiabetic rats. The ethyl acetate fraction (EAF), rich in tannin, exhibited the strongest antioxidant activities to DPPH, FRAP, and NORSA, except for FCA. The EAF also exerted a dose-depended inhibition of GPα (IC50 = 0.75u2009mg/ml). Further evaluation of hypoglycemic effect on OGGT indicated that rats treated with EAF (125u2009mg/kgu2009bw) showed a 39.91% decrease (P < 0.05) in blood glucose levels at 30u2009min, and continuous fall (P < 0.05) of 28.89% and 20.29% was observed in the following hours (60 and 90u2009min) compared to the normal control during OGTT. The EAF was applied to polyamide column chromatography, and the resulting tannin-free fraction was tested for both GPα inhibition and antioxidant (DPPH only) activity. The GPα inhibitory activity was retained, while antioxidant activity was lost (4.6-fold) after tannin removal. These results concluded that the GPα inhibitory activity initially detected was primarily due to the compounds other than tannins, whereas antioxidant activity was mainly due to the tannins.

Isolation and Characterisation of Acetylcholinesterase Inhibitors from Aquilaria subintegra for the Treatment of Alzheimer s Disease (AD.

Aquilaria subintegra, locally known as Gaharu, belongs to the Thymelaeceae family. This plants leaves have been claimed to be effective for the treatment of Alzheimers disease (AD) by Malay traditional practitioner in Malaysia. In this research, the chloroform extracts of the leaves and stem of A. subintegra were tested for acetylcholinesterase (AChE) inhibitory activity. The Thin Layer Chromatography (TLC) results indicated the presence of phenols, flavonoids, terpenoids, and alkaloids compounds in the extracts. Analysis of the stem chloroform extracts with LCMS/MS displayed that it contains kaempferol 3,4,7-trimethyl ether. The AChE inhibitory activity of leaves and stem chloroform extracts and kaempferol were 80%, 93% and 85.8%, respectively. The Brine Shrimp Lethality Assay (BSLA) exhibited low to moderate toxicity of the chloroform extract from leaves (LC50=531.18 ± 49.53 μg/ml), the stem chloroform extract (LC50=407.34 ± 68.05 μg/ml) and kaempferol (LC50=762.41 ± 45.09 μg/ml). The extracts and kaempferol were not cytotoxic to human umbilical vein endothelial cells (HUVEC), human normal gastric epithelial cell line (GES-1) and human normal hepatic cell line (WRL-68). The effect of leaf and stem chloroform extracts and kaempferol were determined in the Radial Arm Maze (RAM) after administration by oral gavage to ICR male and female mice with valium-impaired memory. Administration of kaempferol to the mice significantly reduced the number of repeated entries into the arms of maze in males and females. In conclusion, the inhibition of AChE by leaf and stem chloroform extracts of A. subintegra could be due to the presence of kaempferol. This extract is safe for use as a natural AChE inhibitor as an alternative to berberine for the treatment of AD.

Antiplasmodial Alkaloids from the Bark of Cryptocarya nigra (Lauraceae)

A dichloromethane extract of the stem bark of Cryptocarya nigra showed strong in vitro inhibition of Plasmodium falciparum growth, with an IC50 value of 2.82 μg/mL. The phytochemical study of this extract has led to the isolation and characterization of four known alkaloids: (+)-N-methylisococlaurine (1), atherosperminine (2), 2-hydroxyathersperminine (3), and noratherosperminine (4). Structural elucidation of all alkaloids was accomplished by means of high field 1D- and 2D-NMR, IR, UV and LCMS spectral data. The isolated extract constituents (+)-N-methylisococlaurine (1), atherosperminine (2) and 2-hydroxy-atherosperminine (3) showed strong antiplasmodial activity, with IC50 values of 5.40, 5.80 and 0.75 μM, respectively. In addition, (+)-N-methylisocolaurine (1) and atherosperminine (2) showed high antioxidant activity in a DPPH assay with IC50 values of 29.56 ug/mL and 54.53 ug/mL respectively. Compounds 1 and 2 also both showed high antioxidant activity in the FRAP assay, with percentages of 78.54 and 70.66 respectively and in the metal chelating assay, with IC50 values of 50.08 ug/mL and 42.87 ug/mL, respectively.

Biosynthesis of lathyrine; a novel synthase activity

Abstract Comparison of [U- 14 C]serine and [3- 14 C]serine as precursors of the alanine side-chain of the pyrimidinyl amino acid lathyrine, indicate that serine donates all three of its carbon atoms as a unit. Isotope incorporation studies identified the precursor of the pyrimidine moiety as 2-amino-4-car☐ypyrimidine. Studies with enzymic extracts of Lathyrus seedlings showed the presence of a pyridoxal phosphate-dependent lathyrine synthase which simultaneously decar☐ylates the pyrimidine precursor alanylates its C-4 position. The enzyme is stimulated by biotin. Unlike a number of other plant synthases catalysing formation of heterocyclic β-substituted alanines, lathyrine synthase requires serine and not O -acetylserine as a substrate. The action of the synthase was successfully modelled in a non-enzymic pyridoxal-catalysed reaction in the presence of either Al 3+ or Ga 3+ ions. The latter were much more effective in this respect.

In vitro antiplasmodial and antioxidant activities of bisbenzylisoquinoline alkaloids from Alseodaphne corneri Kosterm

OBJECTIVEnTo study antiplasmodial and antioxidant activities of the isolation of alkaloids from the active dichloromethane extract of Alseodaphne corneri.nnnMETHODSnPhytochemical studies of the crude extract led to the isolation of six alkaloids using recycle high performance liquid chromatography and preparative thin layer chromatography. The antiplasmodial activity of the isolated compounds was evaluated using the histidine-rich protein II assay. The isolated alkaloids were also tested for their antioxidant activity using three different assays; DPPH, ferric reducing ability of plasma and metal chelating assays.nnnRESULTSnMalaria infection caused the formation of free radicals which subsequently led to oxidative stress and apoptosis. The antioxidant properties of the alkaloids under investigation revealed that in addition to the antiplasmodial activity, the alkaloids could also prevent oxidative stress. (+)-laurotetanine and (+)-norstephasubine exhibited strong antiplasmodial activities with IC50 values of 0.189 and 0.116xa0μM, respectively.nnnCONCLUSIONSnInterestingly, the two most potent compounds that exhibit antiplasmodial activity also exhibit good antioxidant activities. The crude dichloromethane extract and the isolated compounds exert substantial antiplasmodial and antioxidative activities which in turn suppress oxidative stress and cause less damage to the host.

(+)-Kunstlerone, a new antioxidant neolignan from the Leaves of Beilschmiedia kunstleri gamble.

A new neolignan, 3,4-dimethoxy-3′,4′-methylenedioxy-2,9-epoxy-6,7-cyclo-1,8-neolign-11-en-5(5H)-one, which has been named (+)-kunstlerone (1), together with six known alkaloids: (+)-norboldine (2), (+)-N-methylisococlaurine (3), (+)-cassythicine (4), (+)-laurotetanine (5), (+)-boldine (6) and (-)-pallidine (7), were isolated from the leaves of Beilschmiedia kunstleri. The structures were established through various spectroscopic methods notably 1D- and 2D-NMR, UV, IR and LCMS-IT-TOF. (+)- Kunstlerone (1) showed a strong antioxidant activity, with an SC50 of 20.0 µg/mL.

Antiplasmodial and antioxidant isoquinoline alkaloids from Dehaasia longipedicellata

The crude extract of the bark of Dehaasia longipedicellata exhibited antiplasmodial activity against the growth of Plasmodium falciparum K1 isolate (resistant strain). Phytochemical studies of the extract led to the isolation of six alkaloids: two morphinandienones, (+)-sebiferine (1) and (-)-milonine (2); two aporphines, (-)-boldine (3) and (-)-norboldine (4); one benzlyisoquinoline, (-)-reticuline (5); and one bisbenzylisoquinoline, (-)-O-O-dimethylgrisabine (6). Their structures were determined on the basis of 1D and 2Du2009NMR, IR, UV, and LCMS spectroscopic techniques and upon comparison with literature values. Antiplasmodial activity was determined for all of the isolated compounds. They showed potent to moderate activity with IC50 values ranging from 0.031 to 30.40u2009µM. (-)-O-O-dimethylgrisabine (6) and (-)-milonine (2) were the two most potent compounds, with IC50 values of 0.031 and 0.097u2009µM, respectively, that were comparable to the standard, chloroquine (0.090u2009µM). The compounds were also assessed for their antioxidant activities with di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium (IC50u2009=u200918.40-107.31u2009µg/mL), reducing power (27.40-87.40u200a%), and metal chelating (IC50u2009=u200964.30 to 257.22u2009µg/mL) having good to low activity. (-)-O-O-dimethylgrisabine (6) exhibited a potent antioxidant activity of 44.3u200a% reducing power, while di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium and metal chelating activities had IC50 values of 18.38 and 64.30u2009µg/mL, respectively. Thus it may be considered as a good reductant with the ability to chelate metal and prevent pro-oxidant activity. In addition to the antiplasmodial and antioxidant activities, the isolated compounds were also tested for their cytotoxicity against a few cancer and normal cell lines. (-)-Norboldine (4) exhibited potent cytotoxicity towards pancreatic cancer cell line BxPC-3 with an IC50 value of 27.060u2009±u20091.037u2009µM, and all alkaloids showed no toxicity towards the normal pancreatic cell line (hTERT-HPNE).

Partial purification and properties of lathyrine synthase

Abstract The enzyme catalysing the simultaneous decarboxylation of 2-amino-4-carboxypyrimidine and its condensation with serine to form lathyrine [β-(2-aminopyrimidin-4-yl)alanine] has been partially purified (150-fold) by selective heat denaturation, fractionation with ammonium sulphate, and affinity chromatography on a column of avidin (monomeric)-agarose. In addition to a requirement for pyridoxal 5-monophosphate, the enzyme is stimulated by biotin and inhibited by avidin. It exhibits a bimodal pH optimum curve with a major peak at pH 4.5 and a secondary peak at pH 7.2. CoA, ATP and a range of metal ions were without effect. The activity of the enzyme was assayed by incorporation of [3- 14 C]serine into lathyrine, isolated by sequential chromatography and electrophoresis.

Preventive effect of Pueraria mirifica on testosterone- induced prostatic hyperplasia in Sprague Dawley rats

Pueraria mirifica (PM) extract contains phytoestrogen daidzein and genistein. In this study, we investigated the protective effect of PM extract, daidzein and genistein on a testosterone‐induced prostatic hyperplasia in rats. Testosterone was administered at 3 mg kg−1 to rats followed by the PM extract, daidzein and genistein for a period of 30 days with finasteride as positive control. The testosterone level was increased, indicating inhibition of 5α‐reductase converting testosterone to dihydrotestosterone. This was confirmed by prostate‐specific antigen level that significantly decreased when treated with PM extract, daidzein and genistein. The PM extract, daidzein and genistein reduced the increase in the prostate/body weight ratio in testosterone‐induced rats. This gives indication that PM extract, daidzein and genistein possessed protective activity for the treatment of benign prostatic hyperplasia. The analysis of histoarchitechture of the prostate has also shown that there was a significant improvement in prostatic cells of the testosterone‐induced rats when treated with PM extract, daidzein and genistein.