@article {828, title = {The Interactive Antimicrobial Activity of Conventional Antibiotics and Petalostigma spp. Extracts Against Bacterial Triggers of some Autoimmune Inflammatory Diseases}, journal = {Pharmacognosy Journal}, volume = {11}, year = {2019}, month = {March 2019}, pages = {292-309}, type = {Research Article}, chapter = {292}, abstract = {

Introduction: An increase in antibiotic resistance and a corresponding decrease in antimicrobial discovery have directed researchers towards alternative therapies, including plant-based medicines. However, synergistic combinations of plant extracts with conventional antibiotics are a far more effective approach in overcoming resistance and potentiating the activity of antibiotics that are otherwise ineffective against resistant bacterial strains. Methods: In this study, Petalostigma spp. (native Australian medicinal plants) extracts were combined with a range of conventional antibiotics and tested against various microbial triggers of autoimmune diseases. The fruit and leaves were extracted separately with solvents of varying polarity and investigated for the ability to inhibit bacterial growth using disc diffusion and liquid dilution MIC techniques. Results: The methanolic and water extracts showed low to moderate inhibitory activity against several microbes. However, combinations of the mid-low polarity extracts with conventional antibiotics proved significantly more effective in inhibiting the growth of Proteus mirabilis and Acinetobacter baylyi (bacterial triggers of rheumatoid arthritis and multiple sclerosis respectively). In total, 14 different combinations proved to be synergistic. Notably, two antibiotics (chloramphenicol and erythromycin) with no inhibitory activity against P. mirabilis alone were shown to have substantial activity when tested in combination with Petalostigma spp. extracts. Conclusion: Although the mechanisms of synergy are still unclear, studies indicate that compounds within Petalostigma spp. may mimic the actions of resistance modifying agents, thus potentiating the activity of several antibiotics that are relatively ineffective alone. Isolation of these agents may be highly beneficial in drug design against several bacteria including the microbial triggers of rheumatoid arthritis and multiple sclerosis.

}, keywords = {ankylosing spondylitis, Conventional antimicrobials, Drug combinations, Efflux pump inhibitor, Interaction, Medicinal plants, multiple sclerosis, rheumatoid arthritis, Synergy}, doi = {10.5530/pj.2019.11.45}, author = {Aishwarya Ilanko and Ian Edwin Cock} } @article {709, title = {Interactive Antimicrobial and Toxicity Profiles of Scaevola spinescens R.Br. Extracts with Conventional Antibiotics}, journal = {Pharmacognosy Journal}, volume = {10}, year = {2018}, month = {August 2018}, pages = {1024-1035}, type = {Original Article}, chapter = {1024}, abstract = {

Background: Scaevola spinescens was traditionally used by Australian Aborigines to treat a variety of conditions including bacterial and viral infections, inflammation and cancer. Conventional antibiotics are amongst the most commonly prescribed groups of drugs in allopathic medicine. Therefore, these therapies may be used concurrently by practitioners of complementary medicine and there is a need to evaluate their effects in combination. Methods: Plant extracts were prepared using solvents of varying polarity and subjected to qualitative phytochemical screening analysis. Antimicrobial activity was assessed using disc diffusion and liquid dilution minimum inhibitory concentration (MIC) assays against a panel of pathogenic triggers of some autoimmune diseases. Interactions between the S. spinescens extracts and conventional antibiotics were studied and classified by determining the sum of the fractional inhibitory concentration (\ΣFIC). Synergistic interactions were further examined across a range of ratios using isobolograms analysis. The toxicity of the individual samples and of the combinations was assessed using the Artemia lethality assay (ALA) and an MTS HDF cell viability assays. Results: Methanolic, aqueous and ethyl acetate extracts showed moderate to good inhibitory activity against several bacterial pathogens known to trigger autoimmune inflammatory diseases in genetically susceptible individuals. However, combinations of the methanolic, aqueous, ethyl acetate and hexane extracts with conventional antibiotics proved significantly more effective in inhibiting the growth of Klebsiellia pneumoniae and Streptococcus pyogenes (bacterial triggers of ankylosing spondylitis and rheumatic fever respectively). In total, 4 combinations proved to be synergistic, all of which contained tetracycline as the conventional antibiotic component. Furthermore, all conventional antibiotics and S. spinescens leaf extracts were determined to be nontoxic when tested alone in the Artemia nauplii and HDF bioassays. Combining the extracts and antibiotics did not significantly affect the toxicity of the combinations. Conclusion: S. spinescens extracts were effective inhibitors of the growth of several bacterial triggers of autoimmune inflammatory diseases when tested alone. Additionally, the methanolic, aqueous and ethyl acetate extracts potentiated the activity of tetracycline against bacterial otherwise resistant to its actions. Isolation of the synergising compounds in these extracts may be beneficial in drug design against several bacteria including the microbial triggers of ankylosing spondylitis and rheumatic fever.

}, keywords = {Antibiotic resistance, Australian plant, Conventional antimicrobials, Interaction, Maroon bush, Medicinal plants, Synergy, Toxicity}, doi = {10.5530/pj.2018.5.174}, author = {Baxter Blonk and Ian E.Cock} }