Teh Lay Kek

Activity-Guided Isolation of Bioactive Constituents with Antinociceptive Activity from Muntingia calabura L. Leaves Using the Formalin Test

The present study was conducted to determine the antinociceptive potential of methanol extract of Muntingia calabura L. (MEMC) and to isolate and identify the bioactive compound(s) responsible for the observed antinociceptive activity. The MEMC and its partitions (petroleum ether (PEP), ethyl acetate (EAP), and aqueous (AQP) partitions), in the dose range of 100, 500, and 1000 mg/kg, were tested using the formalin-induced nociceptive test. The PEP, which exerted the most effective activity in the respective early and late phase, was further subjected to the fractionation procedures and yielded seven fractions (labelled A to G). These fractions were tested, at the dose of 300 mg/kg, together with distilled water or 10% DMSO (negative controls); morphine and aspirin (positive controls) for potential antinociceptive activity. Of all fractions, Fraction D showed the most significant antinociceptive activity, which is considered as equieffective to morphine or aspirin in the early or late phase, respectively. Further isolation and identification processes on fraction D led to the identification of three known and one new compounds, namely, 5-hydroxy-3,7,8-trimethoxyflavone (1), 3,7-dimethoxy-5-hydroyflavone (2), 2′,4′-dihydroxy-3′-methoxychalcone (3), and calaburone (4). At the dose of 50 mg/kg, compound 3 exhibited the highest percentage of antinociceptive activity in both phases of the formalin test. In conclusion, the antinociceptive activity of MEMC involved, partly, the synergistic activation of the flavonoid types of compounds.

Mechanisms of α-Mangostin-Induced Antinociception in a Rodent Model:

Objective: Elucidate the antinociceptive mechanisms of α-mangostin isolated from Garcinia malaccensis Linn. Methods: Male mice/rats (n = 6/group) were used in this between-group study. To determine α-mangostin’s antinociceptive profile, animals were given α-mangostin orally (3, 30, or 100 mg/kg) 60 min before the start of the abdominal constriction or formalin tests. In the hot plate test, the noxious stimulus was applied before and 60, 90, 120, 150, 180, and 210 min after treatment with test solutions. Positive controls received 100 mg/kg acetylsalicylic acid (ASA; oral) or 5 mg/kg morphine (intraperitoneal injection) for the abdominal constriction and hot plate tests, respectively, and either ASA or morphine for the formalin test. Negative controls received vehicle only. To explore α-mangostin’s mechanisms of action, we performed (i) the hot plate test with naloxone (5 mg/kg) pretreatment to verify involvement of opioid receptors; (ii) the abdominal constriction test with 20 mg/kg l-arginine, NG-nitro-l-arginine methyl esters (l-NAME), methylene blue (MB), l-arginine plus l-NAME, or l-arginine plus MB or 10 mg/kg glibenclamide pretreatment to verify involvement of the l-arginine/nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) and K+-ATP pathways; and (iii) the paw-licking test using capsaicin (1.6 μg capsaicin/paw), glutamate (10 μmol glutamate/paw), or phorbol 12-myristate 13-acetate (PMA; 0.05 µg/paw) to verify involvement of vanilloid receptors, the glutamatergic system, and protein kinase C (PKC). Results: α-mangostin significantly inhibited nociception (p < .05) in all models. Only naloxone, l-arginine, methylene blue, PMA, and glibenclamide affected α-mangostin antinociception significantly (p < .05). Conclusion: α-mangostin exhibits peripheral and central antinociception through modulation of opioid and vanilloid receptors, the glutamatergic system, and the l-arginine/NO/cGMP/PKC/K+-ATP pathways.

Effects of the Total Alkaloidal Extract of Murraya koenigii Leaf on Oxidative Stress and Cholinergic Transmission in Aged Mice

Alzheimers disease (AD) is characterized by signs of major oxidative stress and the loss of cholinergic cells. The present study was designed to investigate the role of the total alkaloidal extract from Murraya koenigii (MKA) leaves on age related oxidative stress and the cholinergic pathway in aged mice. Ascorbic acid (100 mg/kg, p.o.) was used as a standard drug. The MKA improved the level of protective antioxidants such as glutathione peroxidase (GPx), reduced glutathione (GSH), glutathione reductase (GRD), superoxide dismutase (SOD) and catalase (CAT) in brain homogenate at higher doses (20 and 40 mg/kg, p.o.). Moreover, a dose dependent decline was noted in lipid peroxidation (LPO) and the nitric oxide assay (NO) at all doses of MKA (10, 20 and 40 mg/kg, p.o.). Interestingly, significant progress was noted with the supplementation of MKA by an improvement of the acetylcholine (ACh) levels and a reduction in the acetylcholinesterase (AChE) activity in aged mouse brain. In addition, a significant elevation of serum albumin (ALBU), alkaline phosphatase (ALP), alanine transaminase (ALT), aspartate transaminase (AST) and total protein as well as a decline in creatinine, total cholesterol, urea nitrogen and glucose levels with MKA also ameliorated the hepatic and renal functions in normal ageing process. The results showed the possible utility of Murraya koenigii leaves in neuroprotection against neurodegenerative disorders such as Alzheimers disease. Copyright

Antinociceptive activity of a synthetic oxopyrrolidine-based compound, ASH21374, and determination of its possible mechanisms

This study was carried out to determine the antinociceptive activity of a novel synthetic oxopyrrolidine-based compound, (2R,3R,4S)-ethyl 4-hydroxy-1,2-dimethyl-5-oxopyrrolidine-3-carboxylate (ASH21374), and to elucidate the involvement of the opioid, vanilloid, glutamate, and nitric oxide - cyclic guanosine monophosphate (NO/cGMP) systems in modulating the observed antinociception. ASH21374, in the doses of 2, 10, and 100 mg/kg body mass, was administered orally to mice 60 mins prior to exposure to various antinociceptive assays. From the results obtained, ASH21374 exhibited significant (P < 0.05) antinociceptive activity in the abdominal constriction, hot-plate, and formalin tests that was comparable with 100 mg/kg acetylsalicylic acid or 5 mg/kg morphine, respectively. ASH21374 also attenuated capsaicin- and glutamate-induced paw licking. Pre-treatment with 5 mg/kg naloxone significantly (P < 0.05) inhibited the activity in all assays, while pretreatment with 10 mg/kg β-funaltraxamine, 1 mg/kg naltrindole, or 1 mg/kg nor-binaltorphimine significantly (P < 0.05) reversed the activity in the abdominal constriction test. l-Arginine, N(G)-nitro-l-arginine methyl esters (l-NAME), methylene blue, and their combinations, failed to inhibit the ASH21374 antinociceptive activity. In conclusion, ASH21374 demonstrated antinociceptive activities on the peripheral and central nervous systems, mediated through the activation of opioid receptors, inhibition of the glutamatergic system, and attenuation of vanilloid-mediated nociceptive transmission. Further studies have been planned to determine the pharmacological potential of ASH21374.

Combined extract of Moringa oleifera and Centella asiatica modulates oxidative stress and senescence in hydrogen peroxide-induced human dermal fibroblasts

Moringa oleifera Lam. and Centella asiatica (L.) Urb. leaves have been previously reported to exhibit antioxidant activity. The objective of the present study is to determine the in vitro antioxidant activity of the combined extracts of M. oleifera and C. asiatica (TGT-PRIMAAGE) and its effect on hydrogen peroxide (H 2O2)-induced oxidative stress in human dermal fibroblasts. TGTPRIMAAGE acted on the mechanism of hydrogen transfer as it showed scavenging activity in the DPPH assay. This is due to the presence of phenolics and flavonoids in TGT-PRIMAAGE. TGT-PRIMAAGE effectively reduced cellular generation of reactive oxygen species induced by H O2. The activities of superoxide dismutase and catalase were also increased in cells treated with TGT-PRIMAAGE. 2 Treatment with TGT-PRIMAAGE showed significant reduction (P < 0.05) in the number of senescent cells. Significant reduction (P < 0.05) of malondialdehyde was also seen in cells treated with TGT-PRIMAAGE. The p53 protein level was reduced in TGT-PRIMAAGEtreated cells, which indicates its potential in protecting the cells from oxidative stress induced by H2O2.

High-Throughput Structure-Based Drug Design of Chalcones Scaffolds as Dual Inhibitor of Cyclooxygenase-2 and Microsomal Prostaglandin E Synthase-1

Cyclooxygenase-2 (COX-2) inhibitors had been extensively used to treat inflammatory disorders. However, the increased incidence of cardiovascular side effects had limited the usage of the drugs. The emergence of microsomal prostaglandin E synthase-1 (mPGES-1) as newly recognized therapeutic target for inflammation and pain gave new hope to develop anti-inflammatory drug with minimal adverse effects. Thus, selective inhibition of COX-2 and mPGES-1 is expected to provide anti-inflammatory effects without the side effects. Chalcone is a compound derived from nature with various pharmacological activities. Based on its favorable activity, chalcone framework had been used to identify novel derivatives for anti-inflammatory properties. Hence, the present study aims to identify chalcone derivatives that can reduce the production of the inducible PGE2 by targeting COX-2 and mPGES-1 using structure-based drug design. A hybrid pharmacophore model of COX-2 named as “phore 1” was developed and used to screen chalcone derivatives from ASINEX database. Forty-two compounds were successfully mapped on “phore 1” and only 15 compounds were selected based on docking. These compounds were then subjected to pharmacophore screening and followed by docking for mPGES-1. Three lead compounds (BAS00384673, BAS00643043 and BAS02557914) were found to be selective towards COX-2 and have good binding interaction with mPGES-1.

Genome Sequencing and Annotation of Mycobacterium tuberculosis PR08 strain.

Mycobacterium tuberculosis is an acid fast bacterial species in the family Mycobacteriaceae and is the causative agent of most cases of tuberculosis. Here, we report the genomic features of Mycobacterium tuberculosis isolated from the cerebrospinal fluid (CSF) of a patient diagnosed with both pulmonary and extrapulmonary tuberculosis (TB). The isolated strain was identified as Mycobacterium tuberculosis PR08 (MTB PR08). Genomic DNA of the MTB PR08 strain was extracted and subjected to whole genome sequencing using MiSeq (Illumina, CA,USA). The draft genome size of MTB PR08 strain is 4,292,364 bp with a G + C content of 65.2%. This strain was annotated to have 4723 genes and 48 RNAs. This whole genome shotgun project has been deposited at DDBJ/EMBL/GenBank under the accession number CP010895.

Nodamura virus B2 amino terminal domain sensitivity to small interfering RNA

Nodamura virus (NoV) B2, a suppressor of RNA interference, binds double stranded RNAs (dsRNAs) and small interfering RNAs (siRNAs) corresponding to Dicer substrates and products. Here, we report that the amino terminal domain of NoV B2 (NoV B2 79) specifically binds siRNAs but not dsRNAs. NoV B2 79 oligomerizes on binding to 27 nucleotide siRNA. Mutation of the residues phenylalanine49 and alanine60 to cysteine and methionine, respectively enhances the RNA binding affinity of NoV B2 79. Circular dichroism spectra demonstrated that the wild type and mutant NoV B2 79 have similar secondary structure conformations.