Secondary metabolites from endophytic Streptomyces aureofaciens CMUAc130 and their antifungal activity

Abstract

Streptomyces aureofaciens CMUAc130 was isolated from the root tissue of Zingiber officinale Rosc. (Zingiberaceae). It was an antagonist of Colletotrichum musae and Fusarium oxysporum, the causative agents of anthracnose of banana and wilt of wheat, respectively. Evidence for the in vitro antibiosis of S. aureofaciens CMUAc130 was demonstrated by the zone of fungal-growth inhibition. Microscopic observations showed thickness and bulbous structures at the edges of the inhibited fungal hyphae. The culture filtrate and crude extract from this strain were all inhibitory to tested phytopathogenic fungi. The major active ingredients from the culture filtrate of S. aureofaciens CMUAc130 were purified by silica gel-column chromatography and identified to be (i) 5,7-dimethoxy-4-p-methoxylphenylcoumarin and (ii) 5,7-dimethoxy-4-phenylcoumarin by NMR and mass-spectral data, respectively. Bioassay studies showed that compounds (i) and (ii) had antifungal activities against tested fungi, and their MICs were found to be 120 and 150 mg ml "1 , respectively. This is the first report of compounds (i) and (ii) from micro-organisms as active ingredients for the control of phytopathogenic fungi.

Antifungal screening of endophytic fungi fromGinkgo bilobafor discovery of potent anti-phytopathogenic fungicides

“…Fungal culture broth (200 lL) was transferred to an Oxford cup (6 9 7.8 9 10 mm) to screen antifungal activity against three common pathogenic fungi -F. graminearum, Sclerotinia sclerotiorum and Phytophthora capsici according to the method reported by Taechowisan et al, (2005). Briefly, fungi blocks (5 mm in diameter) were made with a cork borer from the edge of the fresh fungi cultured on PDA medium and subsequently placed in the central of new PDA culture plates, cultivating at 25°C.…”

Isolation and partial purification of an antimicrobial agent from halotolerant alkaliphilic Streptomyces aburaviensis strain Kut-8

“…Remya and Vijayakumar (2008) reported that ethyl acetate extract of Streptomyces strain RM42 showed maximum activity against Escherichia coli followed by Salmonella typhi, Stphylococcus aureus, Candida albicans and Bacillus subtilis. Similarly, the extraction of antibiotics has been carried out from actinomycetes by using various solvents including ethyl acetate and methanol (Taechowisan et al 2005;Ilic et al 2005;Saha et al 2005).…”

Identification and characterization of a Streptomyces sp. isolate exhibiting activity against multidrug-resistant coagulase-negative Staphylococci

“…The medium (200 ml in 500 ml Erlenmeyer flask) was inoculated with 5 ml of homogenous bacteria suspension (620 nm, 0.08 O.D.) and incubated at 30°C on a rotary shaker (120 rpm) for five days (Taechowisan et al 2005). The Streptomyces sp.…”