Ahm Khurshid Alam

A comparative study on the antioxidant activity of methanolic extracts from different parts of Morus alba L. (Moraceae)

BackgroundAntioxidants play an important role to protect damage caused by oxidative stress (OS). Plants having phenolic contents are reported to possess antioxidant properties. The present study was designed to investigate the antioxidant properties and phenolic contents (total phenols, flavonoids, flavonols and proanthrocyanidins) of methanolic extracts from Morus alba (locally named as Tut and commonly known as white mulberry) stem barks (TSB), root bark (TRB), leaves (TL) and fruits (TF) to make a statistical correlation between phenolic contents and antioxidant potential.MethodsThe antioxidant activities and phenolic contents of methanolic extractives were evaluated by in vitro standard method using spectrophotometer. The antioxidant activities were determined by total antioxidant capacity, DPPH (1,1-diphenyl-2-picrylhydrazine) radical scavenging assay, hydroxyl radical scavenging assay, ferrous reducing antioxidant capacity and lipid peroxidation inhibition assay methods.ResultsAmong the extracts, TSB showed the highest antioxidant activity followed by TRB, TF and TL. Based on DPPH and hydroxyl radical scavenging activity, the TSB extract was the most effective one with IC50 37.75 and 58.90 μg/mL, followed by TRB, TF and TL with IC50 40.20 and 102.03; 175.01 and 114.63 and 220.23 and 234.63 μg/mL, respectively. The TSB extract had the most potent inhibitory activity against lipid peroxidation with IC50 145.31 μg/mL. In addition, the reducing capacity on ferrous ion was in the following order: TSB > TRB > TL > TF. The content of phenolics, flavonoids, flavonols and proanthocyanidins of TSB was found to be higher than other extractives.ConclusionThe results indicate high correlation and regression (p-value <0 .001) between phenolic contents and antioxidant potentials of the extracts, hence the Tut plant could serve as effective free radical inhibitor or scavenger which may be a good candidate for pharmaceutical plant-based products. However, further exploration is necessary for effective use in both modern and traditional system of medicines.

Estimation of total phenol and in vitro antioxidant activity of Albizia procera leaves

BackgroundResearch on natural products has gained a wide popularity due to the potential of discovering active compounds. The antioxidant properties contained in plants have been proposed as one of the mechanisms for the observed beneficial effect. Therefore, the present study investigated the antioxidant activity and total phenolic contents of various solvent extracts of Albizia procera leaves.MethodsAntioxidant activity of the methanol extract and its derived fractions petroleum ether (APP), carbon tetrachloride (APC), dichloromethane (APD), ethyl acetate (APE), and residual aqueous fraction (APA) of the leaves of Albizia procera was performed by in vitro chemical analyses. Total phenolic content of the APM and other five fractions were also determined. APM and its derived fractions were also subjected to preliminary phytochemical screening test for various constituents.R esultsPhytochemical screening revealed the presence of saponins, steroids, tannins, glycosides and flavonoids in the extracts. Amongst the extracts, APE showed the highest total phenolic content (449.18 ± 18.41mg of gallic acid equivalent/g of extract). In DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging test, the IC50 value of APM, APP, APC, APD, APE and APA was 43.43, 63.60, 166.18, 41.15, 11.79, and 63.06 μg/mL, respectively. Therefore, among the APM and its derived fractions, APE showed the highest antioxidant activity which is comparable to that of standard ascorbic acid (AA) (IC50 10.12 μg/mL). The total antioxidant capacity was found to be varied in different fractions. The reducing activity on ferrous ion was ranked as APE > APD > APM > APA > APC.C onclusionThe above evidences suggest that APE of A. procera leaf is a potential source of natural antioxidant and can be used to prevent diseases associated with free radicals.

Evaluation of antioxidant and anticancer properties of the seed extracts of Syzygium fruticosum Roxb. growing in Rajshahi, Bangladesh

BackgroundThe use of plants and their derived substances increases day by day for the discovery of therapeutic agents owing to their versatile applications. Current research is directed towards finding naturally-occurring antioxidants having anticancer properties from plant origin since oxidants play a crucial role in developing various human diseases. The present study was designed to investigate the antioxidant and anticancer properties of Sygygium fruticosum (Roxb.) (abbreviated as SF).MethodsThe dried coarse powder of seeds of SF was exhaustively extracted with methanol and the resulting crude methanolic extract (CME) was successively fractionated with petroleum ether, chloroform and ethyl acetate to get petroleum ether (PEF), chloroform (CHF), ethyl acetate (EAF) and lastly aqueous (AQF) fraction. The antioxidant activities were determined by several assays: total antioxidant capacity assay, DPPH free radical scavenging assay, hydroxyl radical scavenging assay, ferrous reducing antioxidant capacity and lipid peroxidation inhibition assay. The in vivo anticancer activity of SF was determined on Ehrlich’s Ascite cell (EAC) induced Swiss albino mice.ResultsAll the extractives showed strong antioxidant activities related to the standard. The total antioxidant capacity (TAC) of the fractions was in the following order: EAF>AQF>CME>PEF>CHF. The TAC of EAF at 320 μg/mL was 2.60±0.005 which was significantly higher (p < 0.01) than that of standard catechin (1.37 ± 0.005). The ferrous reducing antioxidant capacity of the extracts was in the following order: EAF>AQF>CME>AA>CHF>PEF. In DPPH free radical scavenging assay, the IC50 value of EAF was 4.85 μg/mL, whereas that of BHT was 9.85 μg/mL. In hydroxyl radical scavenging assay and lipid peroxidation inhibition assay, the EAF showed the most potent inhibitory activity with IC50 of 43.3 and 68.11 μg/mL, respectively. The lipid peroxidation inhibition assay was positively correlated (p < 0 .001) with both DPPH free radical scavenging and hydroxyl radical scavenging assay. The total phenolic contents of SF were also positively correlated (p < 0 .001) with DPPH free radical scavenging, hydroxyl radical scavenging and lipid peroxidation inhibition assay. Based on antioxidant activity, EAF was selected for cytotoxic assay and it was found that EAF inhibited 67.36% (p < 0.01) cell growth at a dose of 50 mg/kg (ip) on day six of EAC cell incubation.ConclusionsOur results suggest that EAF of seeds of SF possess significant antioxidant and moderate anticancer properties. Seeds of SF may therefore be a good source for natural antioxidants and a possible pharmaceutical supplement.

In vitro acetylcholinesterase inhibitory activity and the antioxidant properties of Aegle marmelos leaf extract: implications for the treatment of Alzheimer's disease.

Alzheimers disease (AD) is a progressive neurodegenerative disorder clinically characterized by loss of memory and cognition. The effective therapeutic options for AD are limited and thus there is a demand for new drugs. Aegle marmelos (Linn.) (A. marmelos) leaves have been used in traditional medicine to promote intellect and enhance memory. In this study, we evaluated A. marmelos for its acetylcholinesterase (AChE) inhibitory activity and antioxidant property in vitro in the treatment of AD.

Alternative splicing produces structural and functional changes in CUGBP2

BackgroundCELF/Bruno-like proteins play multiple roles, including the regulation of alternative splicing and translation. These RNA-binding proteins contain two RNA recognition motif (RRM) domains at the N-terminus and another RRM at the C-terminus. CUGBP2 is a member of this family of proteins that possesses several alternatively spliced exons.ResultsThe present study investigated the expression of exon 14, which is an alternatively spliced exon and encodes the first half of the third RRM of CUGBP2. The ratio of exon 14 skipping product (R3δ) to its inclusion was reduced in neuronal cells induced from P19 cells and in the brain. Although full length CUGBP2 and the CUGBP2 R3δ isoforms showed a similar effect on the inclusion of the smooth muscle (SM) exon of the ACTN1 gene, these isoforms showed an opposite effect on the skipping of exon 11 in the insulin receptor gene. In addition, examination of structural changes in these isoforms by molecular dynamics simulation and NMR spectrometry suggested that the third RRM of R3δ isoform was flexible and did not form an RRM structure.ConclusionOur results suggest that CUGBP2 regulates the splicing of ACTN1 and insulin receptor by different mechanisms. Alternative splicing of CUGBP2 exon 14 contributes to the regulation of the splicing of the insulin receptor. The present findings specifically show how alternative splicing events that result in three-dimensional structural changes in CUGBP2 can lead to changes in its biological activity.

The Antioxidative Fraction of White Mulberry Induces Apoptosis through Regulation of p53 and NFκB in EAC Cells.

In this study, the antioxidative fraction of white mulberry (Morus alba) was found to have an apotogenic effect on Ehrlich’s ascites carcinoma cell-induced mice (EAC mice) that correlate with upregulated p53 and downregulated NFκB signaling. The antioxidant activities and polyphenolic contents of various mulberry fractions were evaluated by spectrophotometry and the ethyl acetate fraction (EAF) was selected for further analysis. Strikingly, the EAF caused 70.20% tumor growth inhibition with S-phase cell cycle arrest, normalized blood parameters including red/white blood cell counts and suppressed the tumor weight of EAC mice compared with untreated controls. Fluorescence microscopy analysis of EAF-treated EAC cells revealed DNA fragmentation, cell shrinkage, and plasma membrane blebbing. These characteristic morphological features of apoptosis influenced us to further investigate pro- and anti-apoptotic signals in EAF-treated EAC mice. Interestingly, apoptosis correlated with the upregulation of p53 and its target genes PARP-1 and Bax, and also with the down-regulation of NFκB and its target genes Bcl-2 and Bcl-xL. Our results suggest that the tumor- suppressive effect of the antioxidative fraction of white mulberry is likely due to apoptosis mediated by p53 and NFκB signaling.

Phytochemical and Antimicrobial Properties of Tiliacora triandra Stem Bark

Aim: Tiliacora triandra (T. triandra), a species of Menispermaceae family, has folkloric reputation for the treatment of several diseases including infectious diseases in Thailand and neighboring countries. The present study aimed at screening the stem bark of T. triandra for its phytochemical constituents and its antimicrobial potential against selected bacteria and fungi. Materials and Methods: The dried stem bark of T. triandra was extracted with methanol and qualitative phytochemical analysis was performed. The antimicrobial activity was determined by disc diffusion assay method against some bacteria and fungi. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by serial dilution method to establish the antimicrobial potential of the extract. Results: Qualitative phytochemical analysis revealed the presence of phenolics, flavonoids, Original Research Article Rahman et al.; BJPR, 17(2): 1-9, 2017; Article no.BJPR.34059 2 terpenoids, alkaloids, saponins and cardiac glycosides. Susceptibility testing by disc diffusion assay showed significant antimicrobial activity against the tested pathogens. The highest antibacterial activity was observed against a Gram-negative bacterium Escherichia coli (E. coli) where the zones of inhibition were 15 mm and 21 mm at the potencies of 250 and 500 μg/disc, respectively. The stem bark extract also showed moderate activity against Shigella sonnei (14 mm), Shigella dysenteriae (13 mm), Agrobacterium spp (13 mm) bacteria and fungus, Aspergillus niger (14 mm) at 250 μg/disc. The results also revealed equal MIC and MBC values of 62.5ug/mL against E. coli. Conclusions: Our findings revealed that the methanol extract of T. triandra possesses potent antimicrobial activity which may be attributed to the identified phytochemical components of the plant extract.

Chemical and structural characterization of α-N-acetylgalactosaminidase I and II from starfish, asterina amurensis

BackgroundThe marine invertebrate starfish was found to contain a novel α-N-acetylgalactosaminidase, α-GalNAcase II, which catalyzes removal of terminal α-N-acetylgalactosamine (α-GalNAc), in addition to a typical α-N-acetylgalactosaminidase, α-GalNAcase I, which catalyzes removal of terminal α-N-acetylgalactosamine (α-GalNAc) and, to a lesser extent, galactose. The interrelationship between α-GalNAcase I and α-GalNAcase II and the molecular basis of their differences in substrate specificity remain unknown.ResultsChemical and structural comparisons between α-GalNAcase I and II using immunostaining, N-terminal amino acid sequencing and peptide analysis showed high homology to each other and also to other glycoside hydrolase family (GHF) 27 members. The amino acid sequence of peptides showed conserved residues at the active site as seen in typical α-GalNAcase. Some substitutions of conserved amino acid residues were found in α-GalNAcase II that were located near catalytic site. Among them G171 and A173, in place of C171 and W173, respectively in α-GalNAcase were identified to be responsible for lacking intrinsic α-galactosidase activity of α-GalNAcase II. Chemical modifications supported the presence of serine, aspartate and tryptophan as active site residues. Two tryptophan residues (W16 and W173) were involved in α-galactosidase activity, and one (W16) of them was involved in α-GalNAcase activity.ConclusionsThe results suggested that α-GalNAcase I and II are closely related with respect to primary and higher order structure and that their structural differences are responsible for difference in substrate specificities.