Antibacterial spectrum and cytotoxic activities of serrulatane compounds from the Australian medicinal plant Eremophila neglecta

Abstract

Aims: To determine the antibacterial spectrum and cytotoxic activities of serrulatane compounds from the Australian plant Eremophila neglecta. Methods and Results: Antimicrobial activities of serrulatane compounds 8,19‐dihydroxyserrulat‐14‐ene (1) and 8‐hydroxyserrulat‐14‐en‐19‐oic acid (2) were tested against Gram‐negative and Gram‐positive bacteria including human and veterinary pathogens and some multidrug‐resistant isolates. Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of the compounds were determined by broth microdilution assay. Both compounds exhibited antibacterial activity against all Gram‐positive test strains. They showed antimycobacterial activity against isolates of Mycobacterium fortuitum and Mycobacterium chelonae. Of the five Gram‐negative bacteria tested, only Moraxella catarrhalis showed susceptibility to the compounds. Cytotoxic activities were tested in the Vero cell line. Compound 1 showed more activity than 2 in both antibacterial and cytotoxicity assays with cytotoxicity at concentrations similar to the MBC. Conclusions: Serrulatane compounds showed significant activity against medically important bacteria, with 1 exhibiting stronger antibacterial activity. However, they also displayed toxicity to mammalian cells. Significance and Impact of the Study: Serrulatanes are of interest as novel antibacterial compounds for use in biomedical applications; this study reports data obtained with a range of bacterial strains and mammalian cells, essential for assessing the capabilities and limitations of potential applicability of these compounds.

ToF-SIMS multivariate analysis of surface-grafted small bioactive molecules

“…28 These compounds are found in Australian desert plants that were used by Aboriginal people for medicinal recipes. Amphiphilic serrulatanes have been shown to be active against a number of Gram-positive bacteria; 29,30 hence, there was interest in exploring whether they could be used as grafted antibacterial layers. Grafting was performed in three steps: first, a propanal plasma polymer was deposited onto polymeric substrates and Si wafers, then polyallylamine was grafted onto its surface aldehyde groups, and finally, the carboxylic acid group of 8-hydroxyserrulat-14-ene-19-oic acid 29 was reacted with surface amine groups by carbodiimide chemistry (Fig.…”

In Vitro Study to Evaluate Antibacterial and Non-hemolytic Activities of Four Iranian Medicinal Plants

“…Plants, specifically medicinal plants, are widely used in medicine and pharmacological sciences. These medicinal plants contain some organic compounds such as polyphenols, aliphatic compounds and peptides which have antimicrobial properties (4)(5)(6)(7)(8)(9)(10). Medicinal herbs have antibacterial compounds which are effective in the treatment of diseases (11)(12)(13)(14)(15)(16)(17).…”

The genus Eremophila (Scrophulariaceae): an ethnobotanical, biological and phytochemical review

“…The only activity for the two compounds against five Gram-negative bacteria tested was observed against Moraxella catarrhalis, which can cause chronic obstructive pulmonary disease, with minimum inhibitory concentrations (MIC) of 3.1 and 6.2 mg/ml for the two compounds, respectively. [47] In the same context, o-naphthoquinone (126) and 20-acetoxy-8-hydroxyserrulat-14-en-19-oic acid (115), isolated from the leaves of E. serrulata, showed antimicrobial activity against S. aureus. The o-naphthoquinone was the most active with an MIC of 15.6 mg/ml and a minimum bactericidal concentration (MBC) of 125 mg/ml.…”

“…It should be noted that the leaf oil which is chemically distinct from the wood or root oils, also exhibited significant cytotoxic effects. [17] In a recent study, Anakok et al [47] evaluated the antibacterial and antiproliferative activity of 8,19-dihydroxyserrulat-14-ene (103) and 8-hydroxyserrulat-14-en-19-oic acid (105), two serrulatanes isolated from E. neglecta. Both compounds showed a very promising activity against Vero cells with IC50values of 9.2 and 20.0 mg/ml.…”