Evaluation of antibacterial, antioxidant activity and Calmodulin gene expression of Scoparia dulcis Linn.

In Thailand, Scoparia dulcis is being used as a traditional medicine. The extract displays the best inhibitory effect against Pseudomonas aeruginosa and its minimum inhibitory concentration (MIC) was 400 µg/mL followed by Escherichia coli and Staphylococcus aureus with MIC 500 µg/mL. The presence of the extract significantly protected Sf9 cells against H2O2- induced cell death. In addition, the extract also showed DNA damage inhibitory effect in a concentration-dependent manner (0.5- 4 mg/mL). However, at higher concentrations (7.5-30 mg/mL) it might induce damage to the DNA. The prevention of DNA damage differs in different parts of the plant. To support secondary metabolite synthesis in different parts of S. dulcis, we investigated the expression of the Calmodulin gene that is involved in secondary metabolite production. The Calmodulin gene showed the highest expression in the fruit. This finding justifies the use of S. dulcis in the treatment of diseases caused by bacteria and free radicals

Antimicrobial potential of endophytic fungi derived from three seagrass species: Cymodocea serrulata, Halophila ovalis and Thalassia hemprichii.

Endophytic fungi from three commonly found seagrasses in southern Thailand were explored for their ability to produce antimicrobial metabolites. One hundred and sixty endophytic fungi derived from Cymodoceaserrulata (Family Cymodoceaceae), Halophilaovalis and Thalassiahemprichii (Family Hydrocharitaceae) were screened for production of antimicrobial compounds by a colorimetric broth microdilution test against ten human pathogenic microorganisms including Staphylococcus aureus ATCC 25923, a clinical isolate of methicillin-resistant S. aureus, Escherichia coli ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Candida albicans ATCC 90028 and NCPF 3153, Cryptococcus neoformans ATCC 90112 and ATCC 90113 and clinical isolates of Microsporumgypseum and Penicilliummarneffei. Sixty-nine percent of the isolates exhibited antimicrobial activity against at least one test strain. Antifungal activity was more pronounced than antibacterial activity. Among the active fungi, seven isolates including Hypocreales sp. PSU-ES26 from C. serrulata, Trichoderma spp. PSU-ES8 and PSU-ES38 from H. ovalis, and Penicillium sp. PSU-ES43, Fusarium sp. PSU-ES73, Stephanonectria sp. PSU-ES172 and an unidentified endophyte PSU-ES190 from T. hemprichii exhibited strong antimicrobial activity against human pathogens with minimum inhibitory concentrations (MIC) of less than 10 µg/ml. The inhibitory extracts at concentrations of 4 times their MIC destroyed the targeted cells as observed by scanning electron microscopy. These results showed the antimicrobial potential of extracts from endophytic fungi from seagrasses

Antimicrobial activity of endophytic fungal crude extracts against each test microorganism.

<p>SA, <i>Staphylococcus aureus</i> ATCC 25923; MRSA, methicillin-resistant <i>S. aureus</i>; EC, <i>Escherichia coli</i> ATCC 25922; PA, <i>Pseudomonas aeruginosa</i> ATCC 27853; CA1, <i>Candida albicans</i> ATCC 90028; CA2, <i>C. albicans</i> NCPF 3153; CN1, <i>Cryptococcus neoformans</i> ATCC 90112 (flucytosine-sensitive); CN2, <i>C. neoformans</i> ATCC 90113 (flucytosine-resistant); MG, <i>Microsporum</i><i>gypseum</i> clinical isolate; PM, <i>Penicillium</i><i>marneffei</i> clinical isolate.</p

Scanning electron micrographs of test microorganisms with strongly active crude extracts.

<p><i>Cryptococcus neoformans</i> ATCC 90112 (A–E), <i>Cryptococcus neoformans</i> ATCC 90113 (F), <i>Candida albicans</i> NCPF 3153 (G–I) and a clinical isolate of <i>Microsporum</i><i>gypseum</i> (K–L) after incubation with 10% DMSO (A, G and J), amphotericin B (B and H), miconazole (K), hexane extract from the mycelia of <i>Penicillium</i> sp. PSU-ES43 (C), hexane extract from the mycelia of PSU-ES190 (D), ethyl acetate extract from the mycelia of <i>Fusarium</i> sp. PSU-ES73 (E and F), ethyl acetate extract from the mycelia of <i>Trichoderma</i> sp. PSU-ES38 (I), and hexane extract from the mycelia of Hypocreales sp. PSU-ES26 (L) for 16 h at 4 times their MIC values.</p

Phylogenetic tree based on ITS1-5.8S-ITS2 sequences of strongly active endophytic fungi.

<p>The number of each branch point represents percentage bootstrap support from Maximum Parsimony (MP BS) and Neighbour Joining (NJ BS) with 100 replications shown on the branch. MP BS values ≥50% are shown before the slash; NJ BS values ≥50% are shown after the slash. Length; 37 steps; consistency index (CI); 0.8108; retention index (RI); 0.9391; homoplasy index (HI); 0.1892; rescaled consistency index (RC); 0.7615.</p