Thai ethnomedicinal plants as resistant modifying agents for combating Acinetobacter baumannii infections

ABSTRACTS: BACKGROUND: Acinetobacter baumannii is well-recognized as an important nosocomial pathogen, however, due to their intrinsic resistance to several antibiotics, treatment options are limited. Synergistic effects between antibiotics and medicinal plants, particularly their active components, have intensively been studied as alternative approaches. METHODS: Fifty-one ethanol extracts obtained from 44 different selected medicinal plant species were tested for resistance modifying agents (RMAs) of novobiocin against A. baumannii using growth inhibition assay. RESULTS: At 250 μg/ml, Holarrhena antidysenterica, Punica granatum, Quisqualis indica, Terminalia bellirica, Terminalia chebula, and Terminalia sp. that possessed low intrinsic antibacterial activity significantly enhanced the activity of novobiocin at 1 μg/ml (1/8xminimum inhibitory concentration) against this pathogen. Holarrhena antidysenterica at 7.8 μg/ml demonstrated remarkable resistant modifying ability against A. baumannii in combination with novobiocin. The phytochemical study revealed that constituents of this medicinal plant contain alkaloids, condensed tannins, and triterpenoids. CONCLUSION: The use of Holarrhena antidysenterica in combination with novobiocin provides an effective alternative treatment for multidrug resistant A. baumannii infections

Immunomodulatory effects of Rhodomyrtus tomentosa leaf extract and its derivative compound, rhodomyrtone, on head kidney macrophages of rainbow trout (Oncorhynchus mykiss)

Rhodomyrtus tomentosa is a medicinal plant that shows biological effects including immunomodulatory activity on human and other mammals but not in fish. In this study, we evaluated the in vitro immunomodulatory effects of R. tomentosa leaf extract and its active compound, rhodomyrtone, on the immune responses, using rainbow trout (Oncorhynchus mykiss) head kidney (HK) macrophages as a model. The tested immune functions included the expression of genes involved in innate immune and inflammatory responses and the production of reactive oxygen species (ROS). Gene expression was evaluated after exposure to 10 μg mL⁻¹ of R. tomentosa and 1 μg mL⁻¹ of rhodomyrtone for 4 and 24 h. R. tomentosa and rhodomyrtone induced changes in the expression of pro-inflammatory cytokines (il1β, il8, and tnfα), anti-inflammatory cytokines (il10 and tgfβ), inducible enzymes (inos, cox2, and arginase), and an antioxidant enzyme (gpx1). Co-exposure of R. tomentosa with LPS resulted in a prominent reduction in the expression of genes related to an inflammatory process (il1β, il8, tnfα, inos, saa, hepcidin, and gpx1), suggesting anti-inflammatory effects. Similarly, co-exposure of rhodomyrtone with LPS led to a downregulation of inflammation-related genes (il1β, inos, saa, and hepcidin). In addition, exposure to both natural plant products caused a reduction in cellular ROS levels by HK macrophages. The present results indicate that R. tomentosa and rhodomyrtone exerted immunostimulatory and anti-inflammatory effects on fish macrophages, thus opening up the possibility of using these natural products to further develop immunostimulants for health management in aquaculture

Immunomodulatory effects of Rhodomyrtus tomentosa leaf extract and its derivative compound, rhodomyrtone, on head kidney macrophages of rainbow trout (Oncorhynchus mykiss)

Rhodomyrtus tomentosa is a medicinal plant that shows biological effects including immunomodulatory activity on human and other mammals but not in fish. In this study, we evaluated the in vitro immunomodulatory effects of R. tomentosa leaf extract and its active compound, rhodomyrtone, on the immune responses, using rainbow trout (Oncorhynchus mykiss) head kidney (HK) macrophages as a model. The tested immune functions included the expression of genes involved in innate immune and inflammatory responses and the production of reactive oxygen species (ROS). Gene expression was evaluated after exposure to 10 μg mL⁻¹ of R. tomentosa and 1 μg mL⁻¹ of rhodomyrtone for 4 and 24 h. R. tomentosa and rhodomyrtone induced changes in the expression of pro-inflammatory cytokines (il1β, il8, and tnfα), anti-inflammatory cytokines (il10 and tgfβ), inducible enzymes (inos, cox2, and arginase), and an antioxidant enzyme (gpx1). Co-exposure of R. tomentosa with LPS resulted in a prominent reduction in the expression of genes related to an inflammatory process (il1β, il8, tnfα, inos, saa, hepcidin, and gpx1), suggesting anti-inflammatory effects. Similarly, co-exposure of rhodomyrtone with LPS led to a downregulation of inflammation-related genes (il1β, inos, saa, and hepcidin). In addition, exposure to both natural plant products caused a reduction in cellular ROS levels by HK macrophages. The present results indicate that R. tomentosa and rhodomyrtone exerted immunostimulatory and anti-inflammatory effects on fish macrophages, thus opening up the possibility of using these natural products to further develop immunostimulants for health management in aquaculture

USING FOURIER TRANSFORM INFRARED (FTIR) TO CHARACTERIZE TSUNAMI DEPOSITS IN NEAR-SHORE AND COASTAL WATERS OF THAILAND

Understanding the tsunami cycle requires a simple method for identification of tsunami backwash deposits. This study investigates Fourier transform infrared (FTIR) spectroscopy followed by careful analysis of variance (ANOVA), Gaussian distribution, hierarchical cluster analysis (HCA) and principal component analysis (PCA) for the discrimination of typical marine sediments and tsunami backwash deposits. In order to test the suitability of FTIR spectra as innovative methods for classifications of tsunami deposits, typical marine sediments and terrestrial soils were classified into three zones, namely zone-1 (i.e. typical marine sediments), zone-2 (i.e. including tsunami backwash deposits) and zone-3 (i.e. coastal terrestrial soils). HCA was performed to group the spectra according to their spectral similarity in a dendrogram and successfully separate FTIR spectra of all three sampling zones into two main clusters with five sub-clusters. The simplicifolious (i.e. single-leafed) type of dendrogram was observed with the strong dissimilarity of terrestrial components in subcluster- 5. Graphical displays of PC1 vs PC2 highlight the prominent features of zone-1, which is explicitly different from those of zone-2 and zone-3. The acceptable discrimination of typical marine sediments and tsunami backwash deposits, even six years after the tsunami on Boxing Day 2004, dramatically demonstrates the potential of the method for the identification of paleotsunami

Assessment of gold nanoparticle effects in a marine teleost (Sparus aurata) using molecular and biochemical biomarkers

Gold nanoparticles (AuNP) are increasingly employed in a variety of applications and are likely tobe increasing in the environment, posing a potential emerging environmental threat. Information onpossible hazardous effects of engineered nanoparticles is urgently required to ensure human and envi-ronmental safety and promote the safe use of novel nanotechnologies. Nevertheless, there is a lack ofcomprehensive knowledge on AuNP effects in marine species. The present study aimed to assess AuNPeffects in a marine teleost, Sparus aurata, by combining endpoints at different biological levels (molecu-lar and biochemical). For that purpose, fish were exposed via water for 96 h to 4, 80 and 1600 g L−1ofAuNP (∼40 nm) coated with citrate or polyvinylpyrrolidone (PVP). Results revealed a significant impact ofAuNP-PVP in the hepatic expression of antioxidant, immune and apoptosis related genes. Total oxidativestatus was increased in plasma after exposure to the lowest concentration of AuNP-PVP, although with-out altering the total antioxidant capacity. Furthermore, AuNP did not induce significant damage in theliver since the activity of neither hepatic indicator (aspartate aminotransferase and alkaline phosphatase)increased. Overall, the present study demonstrated that AuNP, even with a biocompatible coating is ableto alter oxidative status and expression of relevant target genes in marine fish. Another important findingis that effects are mainly induced by the lowest and intermediate concentrations of the PVP coated AuNPrevealing the importance of different coatings