Identification of Harman as the Antibiotic Compound Produced by a Tunicate-Associated Bacterium

Aassila, Hinde; Bourguet‐Kondracki, Marie‐Lise; Rifai, Saida; Fassouane, A.; Guyot, Michèle

doi:10.1007/s10126-002-0060-7

Cited by 31 publications

(19 citation statements)

References 10 publications

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“…Unsubstituted biphenyl and 2-hydroxybiphenyl, for example, are used as preservatives for citrus fruits and are listed with the EG-numbers E230 and E231 (Wallhäußer, 1995). There are also few reports about an antibacterial activity of the β-carbolines norharmane (Zheng et al, 2005) and harmane (Aassila et al, 2003). By the quantification of the antialgal activity (determination of minimum toxic quantities) of 4, 4 -dihydroxybiphenyl and the β-carbolines the present work led to an enlargement of knowledge about the antimicrobial activity of these compounds.…”

Section: Discussionmentioning

confidence: 91%

Antialgal Activity of Several Cyanobacterial Exometabolites

Volk

2006

J Appl Phycol

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The isolation of norharmalane (3,4-dihydro-9H-pyrido(3,4-b)indole) from culture media of the cyanobacterium Nodularia harveyana is described. The minimum toxic quantities against selected cyanobacteria of this compound, of the two known cyanobacterial exometabolites 4,4 -dihydroxybiphenyl and norharmane (9H-pyrido(3,4-b)indole) and in addition of harmane (1-methyl-9H-pyrido(3,4-b)indole) were determined using a special TLC plate assay. The three β-carbolines harmane, norharmane and norharmalane were tested both as bases and as hydrochlorides. All four test compounds were found to be cytotoxic against the cyanobacterial test organisms in low quantities (0.5 to 18.0 μg). For the β-carbolines the following structure-response relationships were revealed: the double bond in position 3-4 and possibly the 1-methyl-group increased the cytotoxic effect of these indole alkaloids. Minimum toxic quantities detected for β-carboline bases were in general lower than those of equimolar amounts of the corresponding hydrochlorides. The possible applicability of both β-carbolines and biphenyls as agents in antifouling systems is discussed.

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Section: Discussionmentioning

confidence: 91%

Antialgal Activity of Several Cyanobacterial Exometabolites

Volk

2006

J Appl Phycol

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“…For AgNO 3 , solutions with lower concentrations deposited in the substrate enabled better results, as can be seen in Figure 4a. A decreasing of harmane signal was observed for higher amounts of AgNO 3 due to a pre-filter effect caused by the formation of a dark film on the surface of the substrates spotted with silver solutions.…”

Section: Maximization Of the Harmane Rtp Signalmentioning

confidence: 75%

“…Studies to maximize the RTP signal were performed using either AgNO 3 or TlNO 3 in the substrate. A more specific study to evaluate the influence of the pH (Britton-Robinson buffer with pH values between 2 and 12) of the analyte solution to be spotted on the substrate was also performed.…”

Section: Maximization Of the Harmane Rtp Signalmentioning

confidence: 99%

“…The 0.25 mol L -1 TlNO 3 solution (255 μg of thallium for 5 μL solution volume) was then selected. Higher concentrations of TlNO 3 were not tested because of limitations on the solubility of the salt and also because the single addition of solutions onto substrates was the chosen approach.…”

Section: Maximization Of the Harmane Rtp Signalmentioning

confidence: 99%

“…They also have hallucinogenic and antioxidative properties 3,4 . Although harmane has not yet been used as the active principle of any commercial medicine, studies have indicated that this substance has antileishmanial and anti-HIV activity [5][6][7] .…”

Section: Introductionmentioning

confidence: 99%

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Heavy atom enhanced room-temperature phosphorimetry for ultratrace determination of harmane

2008

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Harmane has been proposed for the treatment of epilepsy, AIDS and leshmaniosis. Its room-temperature phosphorescence was induced using either AgNO 3 or TlNO 3 , enabling absolute limits of detection of 0.12 and 2.4 ng respectively, with linear dynamic ranges extending up to 456 ng (AgNO 3 ) and 911 ng (TlNO 3 ). Relative standard deviations around 3% were observed for substrates containing 46 ng of harmane. Such sensitivity and precision are needed because harmane intake must be strictly controlled to achieve proper therapeutic response. Interference studies were performed using thalidomide, reserpine and yohimbine. Recovery of 104±6% was achieved using solid surface room-temperature phosphorimetry. The result was comparable to the one obtained by micellar electrokinetic chromatography.

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Deciphering binding affinity, energetics, and base specificity of plant alkaloid Harmane with AT and GC hairpin duplex DNA

2022

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Insights into binding efficacy and thermodynamic aspects of small molecules are important for rational drug designing and development. Here, the interaction of Harmane (Har), a very important bioactive indole alkaloid, with AT and GC hairpin duplexÀDNAs has been reported using various biophysical tools. Detailed molecular mechanism with special emphasis on binding nature, base specificity, and thermodynamics have been elucidated via probing nucleic acids with varying base compositions. Har bound to both the DNA strands exhibited hypochromic effect in absorbance whereas bathochromic and hypochromic effects in fluorescence spectra.The binding constants estimated were in the order of 10 5 M À1 (higher for GC sequence compared with AT) with 1:1 stoichiometry. Noncooperative binding mode has been observed via intercalation in both the cases. The thermodynamic profile was obtained from temperature-dependent fluorescence experiments. Both Har-AT and Har-GC complexations were exothermic in nature associated with positive entropy and negative enthalpy changes. Salt-dependent studies revealed that the binding interaction was governed by nonpolyelectrolytic and hydrophobic interaction forces. The ligand-induced structural perturbation of the DNA structures was evident from the circular dichroism data. Molecular modelling data indicated towards the involvement of hydrophobic forces and hydrogen bonding.

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Identification of Harman as the Antibiotic Compound Produced by a Tunicate-Associated Bacterium

Abstract: The alkaloid harman, previously reported from some marine invertebrates, was identified as the antibiotic substance of the tunicate-associated bacterium Enterococcus faecium. It exhibited antibacterial activity (MIC, 0.017 mM) against the ichthyopathogenic strain Vibrio anguillarum.

Cited by 31 publications

References 10 publications

Antialgal Activity of Several Cyanobacterial Exometabolites

Antialgal Activity of Several Cyanobacterial Exometabolites

Heavy atom enhanced room-temperature phosphorimetry for ultratrace determination of harmane

Deciphering binding affinity, energetics, and base specificity of plant alkaloid Harmane with AT and GC hairpin duplex DNA

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