Stigmasterol- an Acetylcholinesterase Inhibitor from Phormidium retzii with relevance to Alzheimer's disease Therapy

This study observed in vitro screening, purification and identification of cholinesterase inhibitors from the microalgae Phormidium retzii. Mixed microalgal culture was screened from freshwater samples for Phormidium sp. Single colony was purified and authenticated as P. retzii. Acetylcholinesterase (AChE) enzyme was purified from hRBC ghost. Sequential extraction of P. retzii was performed using organic solvents. Cholinesterase enzyme activity and its inhibition by various extracts were then tested. The active fractions were then subjected to partial purification and characterization. Petroleum ether extract of P. retzii showed maximum inhibition of 68.6 % against AChE while other solvent extracts showed no inhibition. Seven fractions were obtained from the active extract using thin layer chromatography. Among which fraction no. 5 showed maximum inhibition of 86.37 % towards AChE. Fraction no. 5 when subjected to GC-MS led to determination of the active principle as stigmasterol. The maximum inhibition of stigmasterol (0.45µM) was 81.2±0.08% with IC50 value of 0.214. Stigmasterol from P. retzii inhibited AChE projecting itself as safer drug for Alzheimer's disease with minimal side effects.

In vitro hepatoprotective activity of Sargassum wightii against CCl4 induced hepatic damage

In vitro hepatoprotective activity of Sargassum wightii methanolic extract was checked using established cell culture (Hep G2) and primary rat hepatocytes. In Hep G2 cells, the extract concentrations varying from 31.25-500 μg/ml were studied using 1% CCl4 as toxicant. All the extracts showed moderate protectivity against toxicity induced by CCl4 in Hep G2 cells. All the biochemical constraints were determined and compared with that of the control. In this study, an innovator product (silymarin) was used along with the test extracts. In vitro hepatoprotective activity was evaluated by analyzing various parameters such as ALAT, ASAT, ALP, total protein, total bilirubin, TGL and albumin. The results stated that the hepatoprotective potential exhibited by the methanolic extract of Sargassum wightii (SWMH) is active and comparable with the standard.

Fucoidan - An α-amylase inhibitor from Sargassum wightii with relevance to NIDDM

The present experiment was conducted to screen the α-amylase inhibitory activity of fucoidan extracted from Sargassum wightii collected at the coastal area of Mandapam, Tamil Nadu, India. Fucoidan was extracted from the sporophyll of S. Wightii by ethanol and CaCl2 precipitation method. The average yield was 1.8±0.16% and the extracted fucoidan was found to contain 53±0.52% of fucose and 36±0.60% of sulphate. Structural elucidation (FT-IR and NMR) and in vitro α-amylase activity of purified fucoidon were performed. Fucoidan at the concentration of 62.5, 125 and 250μg exhibited 24.81, 62.50 and 99.24% inhibition against α-amylase, respectively, in a dose dependent manner. Fucoidan from S. wightii also inhibits α-glucosidase which clearly indicates dual inhibitory activity of the compound. The IC50 value against α-amylase of fucoidan is found to be 103.83μg which is more effective than that of acarbose (16mg).

Potential antibacterial activity of crude extracts and silver nanoparticles synthesized from Sargassum wightii

The present work investigates the antibacterial activity of silver nanoparticles (Ag-NPs) synthesized by biological method using Sargassum wightii. The fresh live seaweed was collected from the Mandapam coast of Tamilnadu, India. Solvent extract was prepared using acetone, petroleum ether and methanol. Aqueous extract of the seaweed was also used for the synthesis of silver Ag-NPs. Seaweed extract is used as a reducing agent of 2mM silver nitrate solution for the synthesis of Ag-NPs. Periodical monitoring of reaction mixture was done using UV-vis spectroscopy at 300-750 nm. The scanning electron microscopy (SEM) of the sample confirms the presence of Ag-NPs. The antibacterial activity of solvent extract was done by Minimal inhibitory concentration (MIC) assay. The methanol extract of the seaweed at a concentration of 250µg/ml exhibited potent antimicrobial activity against the test microorganism. The zone of inhibition ranging from 8-14 mm was observed with different extracts. The antibacterial activity of the synthesized Ag-NPs against the organism was also done by MIC test. The MIC of Ag-NPs was found to be 130µg/ml for all pathogenic microorganisms selected for the study. The zone of inhibition against Bacillus cereus, Bacillus anhtracis, Staphylococcus aureus and Vibrio alginoyticus were found to be 10, 8, 10 and 9 mm, respectively. The synthesized Ag-NPs exhibited significant antimicrobial activity against the selected microorganisms than the solvent extract of seaweed.DOI: http://dx.doi.org/10.3329/icpj.v3i10.20337 International Current Pharmaceutical Journal, September 2014, 3(10): 322-325