Antibacterial activity of orsellinates

Abstract

In order to obtain new compounds with antibacterial activity, the derivatives 2,4-dihydroxy-6-methylbenzoic acid (orsellinic acid) and 2,4-dihydroxy-6-methylbenzoates (orsellinates) were obtained through alcoholyses of lecanoric acid. All these substances were tested against Gram-positive and Gram-negative bacteria by a microdilution method. Staphylococcus aureus, Xanthomonas campestris var. vesicatoria and Ralstonia solanacearum were most sensitive to n-propyl 2,4-dihydroxy-6-methylbenzoate, n-pentyl 2,4-dihydroxy-6-methylbenzoate and n-hexyl 2,4-dihydroxy-6-methylbenzoate with MIC (Minimal Inhibitory Concentration) values ranging from 62.5 to 7.8 µg⋅mL -1 . These results showed that homologation in carbon chain may lead to compounds with more pronunced activities.

Radical-Scavenging Activity of Orsellinates

“…The lecanoric acid isolated from the lichen Parmotrema tinctorum, and the orsellinates obtained through reactions of this acid with alcohols were evaluated against Artemia salina and microorganisms. [22][23][24] In continuing our investigations, we are relating here the results of the antioxidant activity of the lecanoric acid (1), orsellinic acid (2) and the methyl (3), ethyl (4), n-propyl (5), n-butyl (6), iso-propyl (7), sec-butyl (8) and tert-butyl (9) orsellinates. With the aim of establishing a qualitative correlation structure-activity we have also included the antioxidant activity of orcinol (10), resorcinol (11) and gallic acid (12).…”

The Antibacterial Activity of Compounds Isolated from Oakmoss against <i>Legionella pneumophila</i> and Other <i>Legionella</i> spp.

“…Although the antibacterial activity of the oakmoss compounds varied considerably, all 20 of the compounds we isolated were active against clinical and environmental isolates of L. pneumophila and other Legionella spp. While the reported MICs against Gram-negative bacteria such as P. aeruginosa and E. coli range between 30 and 1000 µg/mL for the compounds identified as phenol derivatives, 13,14) the MICs against L. pneumophila were lower, ranging between 8.0 and 213.3 µg/ mL, which suggests that L. pneumophila is more susceptible to these compounds than are P. aeruginosa and E. coli. Atranorin is a didepside compound that exhibits antibacterial activity against Gram-positive bacteria such as B. mycoides, B. subtilis and S. aureus, and against Gram-negative bacteria such as Enterobacter cloacae, E. coli and Klebsiella pneumoniae, 4) with a reported MIC of 31 µg/mL.…”

“…[1][2][3][4] The antimicrobial activity of these compounds against various fungi and Gram-positive and Gram-negative bacteria has also been demonstrated in previous reports. 13,14) However, an examination of the antibacterial activity of these oakmoss components against L. pneumophila and Legionella spp. has not been reported.…”

Effects of Oakmoss and its Components on <i>Acanthamoeba</i><i> castellanii</i> ATCC 30234 and the Uptake of <i>Legionella pneu</i><i>mophila</i> JCM 7571 (ATCC 33152) into <i><i>A. castellanii</i></i>

“…The differences in the effects of these compounds on A. castellanii may be attributed to the type of the ester group and methoxyl group on position 4. It is reported that the lipophilic nature of the molecule affect antibacterial and cytotoxic activity Gomes et al, 2003 and2006 . Three compounds 9, 10 and 16 out of four didepside derivatives were inactive against A. castellanii. The chemical structures of these didepside derivatives are closely related to each other.…”