Antibacterial Performance of Terpenoids from the Australian Plant <i>Eremophila lucida</i>

Plants in the Australian genus Eremophila (Scrophulariaceae) have attracted considerable recent attention for their antimicrobial compounds, which possess a wide range of chemical structures. As they are typically associated with the oily-waxy resin layer covering leaves and green branchlets, and Eremophila lucida is prominent among the species containing a pronounced sticky resin layer, this species was considered of interest for assessing its antibacterial constituents. The n-hexane fraction of the crude acetone extract of the leaves exhibited antibacterial activity against Staphylococcus aureus. Isolation led to the known compounds cembratriene, (3Z, 7E, 11Z)-15-hydroxycembra-3,7,11-trien-19-oic acid (1), the sesquiterpenoid, farnesal (2) and the viscidane diterpenoid, 5&#945;-hydroxyviscida-3,14-dien-20-oic acid (3). The purified compounds were tested for antibacterial activity with 2 and 3 showing moderate antibacterial activity against Gram-positive bacteria

Two labdane diterpenoids and a seco-tetranortriterpenoid from Turreanthus africanus

Seeds of Turreanthus africanus afforded two labdane (1, 2) diterpenoids and a limonoid (3). Their structures were elucidated by extensive NMR spectroscopy and mass spectrometry. Examination of the methylene chloride soluble portion of the acetone extract of the seeds of Turreanthus africanus yielded two labdane diterpenoids 12,15-epoxylabda-8(17),12,14-trien-16-al (1) and 16-acetoxy-12(R),15-epoxy-15β-hydroxylabda-8(17),13(16)-diene (2) and a limonoid, 17-epi 12-dehydroxyheudebolin (3). Structures elucidation was based on the analysis of spectroscopic data

A novel natural product compound enhances cAMP-regulated chloride conductance of cells expressing CFTRΔf508

Background: Cystic fibrosis (CF) results from mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, which encodes a chloride channel localized at the plasma membrane of diverse epithelia. The most common mutation leading to CF, ΔF508, occurs in the first nucleotide-binding domain (NBD1) of CFTR. The ΔF50

Navigating through chemical space and evolutionary time across the Australian continent in plant genus <i>Eremophila</i>

Eremophila is the largest genus in the plant tribe Myoporeae (Scrophulariaceae) and exhibits incredible morphological diversity across the Australian continent. The Australian Aboriginal Peoples recognize many Eremophila species as important sources of traditional medicine, the most frequently used plant parts being the leaves. Recent phylogenetic studies have revealed complex evolutionary relationships between Eremophila and related genera in the tribe. Unique and structurally diverse metabolites, particularly diterpenoids, are also a feature of plants in this group. To assess the full dimension of the chemical space of the tribe Myoporeae, we investigated the metabolite diversity in a chemo-evolutionary framework applying a combination of molecular phylogenetic and state-of-the-art computational metabolomics tools to build a dataset involving leaf samples from a total of 291 specimens of Eremophila and allied genera. The chemo-evolutionary relationships are expounded into a systematic context by integration of information about leaf morphology (resin and hairiness), environmental factors (pollination and geographical distribution), and medicinal properties (traditional medicinal uses and antibacterial studies), augmenting our understanding of complex interactions in biological systems

Biological activity and LC-MS/MS profiling of extracts from the Australian medicinal plant <i>Acacia ligulata</i> (Fabaceae)

<p><i>Acacia ligulata</i> A.Cunn. ex Benth. (Fabaceae: Mimosoideae) is a native Australian plant used traditionally by Australian Aboriginal groups. This study was undertaken to investigate the bioactivity of <i>A. ligulata</i> extracts and to evaluate their chemical composition. Potential antibacterial, cytotoxic and enzyme inhibitory effects relevant to traditional medicinal and food uses of the species were examined and LC-MS/MS was performed to investigate the chemical composition. Antibacterial activity was observed for bark and leaf extracts with an MIC for the bark extract of 62.5 μg/mL against <i>Streptococcus pyogenes.</i> Pod extracts showed cytotoxic effects against cancer cells, with the highest activity against melanoma SK-MEL28 cells with IC₅₀ values between 40.8 and 80.6 μg/mL. Further, the leaf and pod extracts also inhibited α-amylase EC-3.2.1.1 and α-glucosidase EC-3.2.1.20 with IC₅₀ values between 9.7–34.8 and 12.6–64.3 μg/mL, respectively. The LC-MS/MS profiling indicated that several different saponins were present in the active extracts.</p

Serrulatane Diterpenoid from <i>Eremophila neglecta</i> Exhibits Bacterial Biofilm Dispersion and Inhibits Release of Pro-inflammatory Cytokines from Activated Macrophages

The purpose of this study was to assess the biofilm-removing efficacy and inflammatory activity of a serrulatane diterpenoid, 8-hydroxyserrulat-14-en-19-oic acid (<b>1</b>), isolated from the Australian medicinal plant <i>Eremophila neglecta.</i> Biofilm breakup activity of compound <b>1</b> on established <i>Staphylococcus epidermidis</i> and <i>Staphylococcus aureus</i> biofilms was compared to the antiseptic chlorhexidine and antibiotic levofloxacin. In a time-course study, <b>1</b> was deposited onto polypropylene mesh to mimic a wound dressing and tested for biofilm removal. The <i>ex-vivo</i> cytotoxicity and effect on lipopolysaccharide-induced pro-inflammatory cytokine release were studied in mouse primary bone-marrow-derived macrophage (BMDM) cells. Compound <b>1</b> was effective in dispersing 12 h pre-established biofilms with a 7 log₁₀ reduction of viable bacterial cell counts, but was less active against 24 h biofilms (approximately 2 log₁₀ reduction). Compound-loaded mesh showed dosage-dependent biofilm-removing capability. In addition, compound <b>1</b> displayed a significant inhibitory effect on tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) secretion from BMDM cells, but interleukin-1 beta (IL-1β) secretion was not significant. The compound was not cytotoxic to BMDM cells at concentrations effective in removing biofilm and lowering cytokine release. These findings highlight the potential of this serrulatane diterpenoid to be further developed for applications in wound management

Biological activity and LC-MS/MS profiling of extracts from the Australian medicinal plant <i>Acacia ligulata</i> (Fabaceae)

Published Online 21 April 2017Acacia ligulata A.Cunn. ex Benth. (Fabaceae: Mimosoideae) is a native Australian plant used traditionally by Australian Aboriginal groups. This study was undertaken to investigate the bioactivity of A. ligulata extracts and to evaluate their chemical composition. Potential antibacterial, cytotoxic and enzyme inhibitory effects relevant to traditional medicinal and food uses of the species were examined and LC-MS/MS was performed to investigate the chemical composition. Antibacterial activity was observed for bark and leaf extracts with an MIC for the bark extract of 62.5 μg/mL against Streptococcus pyogenes. Pod extracts showed cytotoxic effects against cancer cells, with the highest activity against melanoma SK-MEL28 cells with IC50 values between 40.8 and 80.6 μg/mL. Further, the leaf and pod extracts also inhibited α-amylase EC-3.2.1.1 and α-glucosidase EC-3.2.1.20 with IC50 values between 9.7-34.8 and 12.6-64.3 μg/mL, respectively. The LC-MS/MS profiling indicated that several different saponins were present in the active extracts.Diana Jæger, Bradley S. Simpson, Chi P. Ndi, Anna K. Jäger, Christoph Crocoll, Birger Lindberg Møller, Philip Weinstein and Susan J. Sempl