Antibacterial Activities of Bacterial Endophytes Isolated From Zataria multiflora, Achillea willhelmsii and Calendula officinalis L. Against Some Human Nosocomial Pathogens

Abstract

Background: Endophytes are microorganisms which live within plant tissues without causing any apparent harm to their host. Endophytes have been found in nearly all plant families and can be a source of metabolites that are potential source of antibacterial drugs. Objectives: In this study, we focused on the isolation of bacterial endophytes from three medicinal plants; Zataria multiflora, Achillea willhelmsii and Calendula officinalis L. and screening them for activities against some human bacterial pathogens isolated from nosocomial infections. Methods: In this descriptive study random samples from asymptomatic leaves and branches of three medicinal plants namely: Zataria multiflora, Achillea willhelmsii and Calendula officinalis L. were collected from Chaharmahal Va Bakhtiari province of Iran in spring 2013. For isolation of endophytic bacteria, the disinfected portions of the plants were distributed onto the isolation media. To examine endophytic bacterial contents, the bioassays were conducted with using growing colonies in peptone agar (PA) and yeast extract agar (YEA) media, then inactivated them by chloroform. To assay antibacterial activity of endophytic bacterial culture broth, filter-sterilized supernatants were poured in cylinders on each bacterial plate. Results: Nine discernible bacterial endophytes were isolated in purification from three medicinal plants. Generally, all isolated endophytes showed acceptable effects against indicator bacteria, however endophytes isolated from Zataria multiflora and Achillea willhelmsii were more effective against Staphylococcus aureus than other endophytes. Conclusions: Endophytes of examined medicinal plants could be a good source of antibacterial substances.

Diversity and biological activity of culturable endophytic bacteria associated with marigold (<i>Calendula officinalis</i> L.)

“…The root and shoot (10 g fresh weight) were separated and sterilized with 99.9% ethanol for 2 minutes and 10% NaClO for 1 min and rinsed with sterile distilled water two times for 5 min [39] . The sterile leaves and roots were ground with a mortar and pestle, and 1 g of each sample was transferred into plastic tubes with 9 mL sterile phosphate-buffered saline (PBS) and then serially diluted (10 1 –10 5 ).…”

Calendula officinalis—A Great Source of Plant Growth Promoting Endophytic Bacteria (PGPEB) and Biological Control Agents (BCA)

“…Calendula officinalis is a native medicinal plant with a range of pharmaceutical and medicinal abilities, hosting multiple endophytic and rhizospheric bacteria [ 33 , 34 , 35 ]. Growing under dry environments with high temperature, C. officinalis could establish a beneficial relationship with bacterial endophytes improving growth, yield and resistance of plant to different biotic and abiotic stresses.…”

In vitro Antagonistic Activity of Endophytic Fungi Isolated from Shirazi Thyme (Zataria multiflora Boiss.) against Monosporascus cannonballus

“…Several medicinal properties of Z. multiflora , including antiseptic, anesthetic, antispasmodic, antioxidant, antibacterial, and immunomodulatory activities, have been documented ( Sajed et al 2013 ). However, studies on the endophytic microorganisms inhabiting Z. multiflora are limited ( Mohammadi et al 2016 ).…”