Ayinampudi Sree

Diversity of marine bacteria producing beta-glucosidase inhibitors

BackgroundBeta-glucosidase inhibitors are being extensively studied for use as anti-diabetics, anti-obesity and anti-tumour compounds. So far, these compounds have been reported in large numbers from plants, mushrooms, algae and fungi. There are very few reports of such inhibitors from bacteria in the open literature, particularly marine bacteria; although the best known inhibitor deoxynojirimycin was isolated from bacilli and actinomycete. Through this study, we tried to discover the diversity of microbial associates of marine sponge and sediment producing β-glucosidase inhibitors.ResultsWe found 41 (22.7%) out of 181 bacteria, produced such inhibitors. The inhibitors are abundant in bacterial associates of marine sponge Aka coralliphaga. When these bacteria were phylogenetically analyzed, it was found that marine bacteria producing glucosidase inhibitors belong to the phylum Firmicutes (23), Actinobacteria (9), Proteobacteria (7) and Bacteroidetes (1).ConclusionA significant number of marine bacteria belonging to a wide range of bacterial taxa were found to produce β-glucosidase inhibitors. These compounds are abundantly present in bacteria of the phylum Firmicutes followed by the phylum Actinobacteria. The results nurture a hope of finding new compounds, which can inhibit glucosidases, in the bacterial domain of marine organisms. Thus, marine microbial cells can be utilized as producers of pharmacologically essential enzyme inhibitors.

A marine sponge associated strain of Bacillus subtilis and other marine bacteria can produce anticholinesterase compounds

BackgroundAcetylcholinesterase (AChE) inhibitors or anticholinesterases reduce the activity of enzyme acetylcholinesterase that degrades the neurotransmitter acetylcholine in the brain. The inhibitors have a significant pharmacological role in neurodegenerative diseases like Alzheimer’s and Parkinson’s etc. Although plants have been a significant source of these compounds, there are very few sporadic reports of microorganisms producing such inhibitors. Anticholinesterase activity in bacterial associates of marine soft corals and sponges were not previously reported.ResultsWe screened 887 marine bacteria for the presence of acetylcholinesterase inhibitors, in a microplate based assay, and found that 140 (15.8%) of them inhibit the electric eel enzyme, acetylcholinesterase. Majority of the active isolates were bacterial associates of soft corals followed by sediment isolates while most of the potent inhibitors belonged to the bacterial associates of marine sponges. Maximum inhibition (54%) was exhibited by a bacterial strain M18SP4P (ii), isolated from the marine sponge Fasciospongia cavernosa. Based on phenotypic characterization and 16S rDNA sequencing, the strain was identified as Bacillus subtilis - revealing yet another activity in a strain of the model organism that is considered to be a cell factory. TLC bioautography of the methanol extract of this culture, showed the presence of two major components having this activity, when compared to Galanthamine, the positive control.ConclusionFrom the results of our study, we conclude that acetylcholinesterase inhibitors are quite prevalent in marine bacteria, particularly the bacterial associates of marine invertebrates. Several potential AChE inhibitors in marine bacteria are waiting to be discovered to provide easily manipulable natural sources for the mass production of these therapeutic compounds.

A novel method for screening beta-glucosidase inhibitors

BackgroundFew beta-glucosidase inhibitors have so far been reported from microorganisms due to the practical difficulties in performing the inhibition tests and subsequent interpretation of results. In an effort to investigate marine microbial extracts for β-glucosidase inhibitors, we developed a new protocol, using esculin as substrate in an agar plate based assay, to screen a large number of microbial extracts in a short span of time.ResultsWith the new method, pale yellowish zones against the blackish brown background could be visually observed with more clarity in sample extracts where β-glucosidase inhibitor was present. The new method was compared with the closest existing method and established beyond doubt. This agar plate based procedure required about one hour for minimum 12 samples and the throughput increases with the size of the agar gel plate used.ConclusionsThe new protocol was simple, rapid and effective in detecting beta-glucosidase inhibitors in microbial extracts.

Chemical investigation of Finlaysonia obovata : part I – a rare triterpene acid showing antibacterial activity against fish pathogens

The antibacterial screening of extracts of the leaves of Finlaysonia obovata with hexane, chloroform and alcohol was carried out against fresh water fish pathogenic bacteria viz., Micrococcus Sp. (multidrug resistant strain), Aeromonas hydrophila, Pseudomonas aeruginosa, Vibrio alginolyticus, Staphylococcus aureus, Escherichia Coli, Edwardsiella tarda by disc-assay method. The hexane and chloroform extracts were found active against four and five pathogens, respectively. The highly active chloroform extract was taken up for fractionations, further screening and isolation of secondary metabolites by chromatographic techniques. The triterpene acid Urs-3β-hydroxy-12-en-27-oic acid (3), which is very rarely found from plant sources is isolated first time from this plant along with known compounds; Lupeol acetate (1) and β-Sitosterol (2). This article presents for the first time all the spectral data for Urs-3β-hydroxy-12-en-27-oic acid (3), which showed moderate activity against four pathogens. This is the first report of antibacterial activity of a triterpene against fish pathogens.

Isolation of a deoxy lupane triterpene carboxylic acid from Finlaysonia obovata (a mangrove plant)

A deoxy lupane triterpene carboxylic acid, lup-20(29)-en-24-oic acid (1), was isolated from the active chloroform extract of Finlaysonia obovata, a latex exuding mangrove plant. Its structure was evaluated on the basis of different spectroscopic methods, including extensive 1D and 2D NMR spectroscopy. Lup-20(29)-en-24-oic acid (1) has shown moderate antimicrobial activity, against some fish pathogens.

Antibacterial study and fatty acid analysis of lipids of the sponge Myrmekioderma granulata

The composition of the lipophilic extract of the sponge Myrmekioderma granulata (Esper) collected from 13 m depth of the Bay of Bengal of the Orissa coast was investigated. Fatty acids as well as volatiles and sterols were identified. 4,8,12-Trimethyltridecanoic acid was identified for the first time along with the important PUFAs such as linoleic acid (n-6, C18:2), dihomo-γ-linolenic acid (n-6, C20:3), 5,8,11,14-eicosatetraenoic acid (n-3, C20:4), and 5,8,11,14,17-eicosapentaenoic acid (EPA) (n-3, C20:5) from this species. The branched polyunsaturated fatty acids like br-C26:2, 25-methyl-5,9-heptacosadienoic acid and 24-methyl-5,9heptacosadienoic acid were also identified by GC-MS. The lipid extract exhibited limited activity against different pathogens.

Chemical investigation and antibacterial study of hexane extract of leaves of Finlaysonia obovata

Finlaysonia obovata, a latex – exuding mangrove plant (Fam. Periplocaceae), is found in the tidal flats in India, Burma, and Malay, the leaves of which are reported to be eaten as salad in the Moluccas. Mangrove latex-bearing plants were found to show antibacterial and antiviral activity [1]. Earlier we have studied the antibacterial activity, performed the GCMS analysis of extracts, studied the lipids of the leaf, and isolated a rare antibacterial triterpene from F. obovata [2, 3]. The present paper deals with the antibacterial screening of column fractions of an active hexane extract, and isolation and spectral characterization of stigmast-4-en-3β-ol from leaves of F. obovata. The antibacterial assay of the hexane extract of leaves of F. obovata was carried out against seven freshwater fish pathogenic bacteria (see Experimental) [3]. The hexane extract was found active against all except S. aureus and E. tarda. This extract was further taken up for fractionations and isolations of secondary metabolites. The results of anti-pathogenic screening of the active column fraction of the hexane extract [compound 2 is isolated] are presented in Table1. The column fraction (EtOAc:hexane-1:9) showed activity against S. aureus, which clearly proves the enrichment of the active components during

Fatty acid profile and sterol composition of the marine sponge Azorica pfeifferae

0009-3130/12/4801-0122 2012 Springer Science+Business Media, Inc. Natural Product Department, Institute of Minerals & Materials Technology, Bhubaneswar, 751013, Orissa, India, fax: 91 674 2581637, e-mail: pravatmanjari@yahoo.co.in; pravatmanjari@immt.res.in. Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 110–112, January–February, 2012. Original article submitted December 13, 2010. Chemistry of Natural Compounds, Vol. 48, No. 1, March, 2012 [Russian original No. 1, January–February, 2012]

Fatty Acids of Marine Sponges

Among all organisms, thus also marine sponges, accumulate fatty acids (FAs) with a very rich chemistry and are the source of an unprecedented diverse range of chemical structures. This chapter accounts the most recent developments concerning the occurrence of different FA structures in marine sponges and their potential applications. While the first section of the chapter deals with the importance of FAs in various applications, the second section of the chapter focuses on the diversity of FAs with different structural features in marine sponges. FAs in marine sponges differ in the number of olefinic bonds, the extent of branching, the length of the hydrocarbon chain, and the number of functional groups. The last section of the chapter deals with the biomedical potential of the FAs of marine sponges including antibacterial, antifungal, antimalarial, and cytotoxic activities, etc.

Fatty Acid Profile and Sterol Composition of the Marine Sponge Petrosia testudinaria

The interest of chemists, biochemists, and biotechnologists in lipids and fatty acids from marine sponges has been stimulated because among aquatic animals, sponges possess the greatest diversity of fatty acids, sterols, etc. Various applications of lipids, phospholipids, and saturated and unsaturated fatty acids in pharmaceutical formulations have been reported [1, 2]. Some unusual FAs of sponges exhibit biological activity. Petrosia testudinaria (Lamarck) is a barrel marine sponge widely distributed in the Bay of Bengal of the Odisha coast [3]. Sponges of the genus Petrosia have yielded various types of secondary metabolites, viz. isoquinoline antibiotic alkaloids, bisquinolizidine alkaloids, polyacetylenes, and steroids [3–8]. A novel steroid, 23-ethyl-24-methyl-27-norcholesta-5,25-diene-3 -23-diol, is isolated from the sponge P. testudinaria [9]. The methanol and dichloromethane extract of this species have shown broad-spectrum larvicidal and insecticidal activity [10]. The present paper deals with the study of the FA profile and sterol of the lipid composition of P. testudinaria, collected from the Bay of Bengal region of the Odisha coast. The study of the FA and sterols of the lipophilic extract of P. testudinaria was carried out mainly to search for new FA structures, to evaluate a new source of major polyunsaturated fatty acids (PUFAs) of biological interest, and to get valuable information on its chemotaxonomy. Analysis of Fatty Acids. Twenty-three fatty acids were identified in the mixture of total lipids of P. testudinaria by GC-MS analysis (Table 1). Peak identification was carried out by comparison of the mass spectra with those available in the NIST and WILEY libraries and also confirmed by comparison of their chromatographic retention times as well as mass fragmentations with those of authentic standards C4–C24 (Supelco standard FAME mixtures). Among the identified FAs, linear saturated FAs constituted 45.26% of the total FA content. Generally among linear saturated FAs, 16:0 and 18:0 dominated in most of the marine sponges. In the present analysis, 19:0 (17.13%) was the major one among the linear FAs. Fatty acids 18:0 (9.76%) and 16:0 (7.44%) were also present in good amount. Branched saturated FAs constituted 15.26% of the total FA content, and 13-methyl-14:0 (7.42%) was the major one. The position of the methyl branch was confirmed by analysis of their pyrrolidide derivatives and further confirmed by comparing their key mass fragments with those already reported for similar fatty acids. In the mass spectrum of 13-methyl-14:0 (iso), there was a gap of 28 amu between two peaks at m/z 252 and 280 due to the loss of carbon 13 with its methyl group. Similarly in the mass spectrum of 12-methyl-14:0 (anteiso), two peaks m/z 238 and 266 occurred at a gap of 28 amu due to the loss of carbon 12 and its methyl group. In the mass spectrum of 10-methyl-15:0, there was a gap of 28 amu between two peaks at m/z 210 and 238 due to loss of carbon 10 with its methyl group. A gap of 28 amu between two peaks at m/z 196 and 224 in the mass spectrum of 9-methyl-16:0 is due to the loss of carbon 9 with its methyl group, and the structure is confirmed. In the mass spectrum of 6-methyl-18:0 there was a gap of 28 amu between two key mass fragments m/z 154 and 182 due to the loss of carbon 6 with its methyl group, whereas in 18-methyl-20:0, two peaks m/z 322 and 350 occurred at a gap of 28 amu due to the loss of carbon 18 and its methyl group. It is considered that saturated iso and anteiso C15–C20 acids have a bacterial origin [11]. Thus, in the sponge P. testudinaria, the content of iso and anteiso may be due to symbiotic bacteria.