Antibacterial Activity of Simple Coumarins: Structural Requirements for Biological Activity

Abstract

The antibacterial activity of a series of simple coumarins was evaluated against 8 microor ganisms, including three Gram-positive (Staphylococcus aureus, beta-hemolytic Streptococcus and Streptococcus pneum oniae) and five Gram-negative bacteria (Escherichia coli, Klebsiella pneum oniae, Pseudom onas aeruginosa, Proteus mirabilis and H aemophilus influenzae), using the microdilution broth method. The coumarins tested showed broad diversity regarding growth inhibitory activity with minimum inhibitory concentrations ranging from 0.9 to >12.4 (j.M . This study, presenting the first systematic analysis of structure-activity relationships among this group of coumarins, revealed some interesting structural requirements. While coumarins with a methoxy function at C-7 and, if present, an OH group at either the C-6 or C-8 position are invariably effective against the spectrum of tested standard bacteria (Gramnegative microorganisms including the Gram-positive bacterium Staphylococcus aureus), the presence of an aromatic dimethoxy arrangement is apparently favourable against those mi croorganisms which require special growth factors (beta-hemolytic Streptococcus, Streptococ cus pneum oniae and Haem ophilus influenzae). A combination of these structural features, two methoxy functions and at least one additional phenolic group as reflected by the highly oxygenated coumarins, identify promising candidates with antibacterial broad-spectrum ac tivity.

Phytochemical and Antibacterial Properties of Leaf Extract of Stereospermum kunthianum (Bignoniaceae)

“…It is perhaps not surprising that higher fatty acids were found present in the lipophilic extract (Table 1). Coumarins have been found to exhibits great diversity with respect to growth inhibition activity against both Gram positive and negative bacteria (Kayser and Kolodziej, 1999). Thus, the spectra of activity displayed by the crude lipophilic extract can be explained by the combined effects of terpenoids, coumarins and steroids or due to synergism.…”

Isolation and characterisation of silver(I) complexes of substituted coumarin-4-carboxylates which are effective against Pseudomonas aeruginosa biofilms

“…Coumarin and its derivatives have shown a diverse array of biological activities including antimicrobial [17], chemotherapeutic [18,19], anticoagulant [20] and antiinflammatory [21]. A number of both naturally occurring and synthetic coumarins including aminocoumarins [22,23], hydroxycoumarins [24,25], pyranocoumarins [26], and furanocoumarins [27] have been reported to have significant antimicrobial activity against a wide range of microbes. Following on from our previous work on a series of Ag(I) complexes of coumarin-3-carboxylates, which have proven antimicrobial activity and potential as effective biocides in hygienic coatings, a novel series of Ag(I) complexes of coumarin-4-carboxylates has been synthesised and screened for their antibacterial activity.…”

Antifungal Activity of Coumarins

“…Warfarin is a particular well-known coumarin which is used as an 0939Ð5075/2008/0100Ð0021 $ 06.00 " 2008 Verlag der Zeitschrift für Naturforschung, Tübingen · http://www.znaturforsch.com · D oral anticoagulant (Pineo and Hull, 2003), but the coumarins also have long been recognized to possess antioxidant (Tyagy et al, 2005), anti-inflammatory (Kontogiorgis and Hadjipavlou-Litina, 2003), antifilarial (Tripathy et al, 2000), antiulcerogenic (Bighetti et al, 2005), trypanocidal (Alvim et al, 2005), antibacterial (Kayser and Kolodziej, 1999), antitumour (Kempen et al, 2003) and anti-HIV activities (Uchiumi et al, 2003).…”