Secondary Metabolites from the Endophytic Botryosphaeria dothidea of Melia azedarach and Their Antifungal, Antibacterial, Antioxidant, and Cytotoxic Activities

Abstract

Two new metabolites, an α-pyridone derivative, 3-hydroxy-2-methoxy-5-methylpyridin-2(1H)-one (1), and a ceramide derivative, 3-hydroxy-N-(1-hydroxy-3-methylpentan-2-yl)-5-oxohexanamide (2), and a new natural product, 3-hydroxy-N-(1-hydroxy-4-methylpentan-2-yl)-5-oxohexanamide (3), along with 15 known compounds including chaetoglobosin C (7) and chaetoglobosin F (8) were isolated from the solid culture of the endophytic fungus Botryosphaeria dothidea KJ-1, collected from the stems of white cedar (Melia azedarach L). The structures were elucidated on the basis of spectroscopic analysis (1D and 2D NMR experiments and by mass spectrometric measurements), and the structure of 1 was confirmed by X-ray single-crystal diffraction. These metabolites were evaluated in vitro for antimicrobial, antioxidant, and cytotoxicity activities. Pycnophorin (4) significantly inhibited the growth of Bacillus subtilis and Staphyloccocus aureus with equal minimum inhibitory concentration (MIC) values of 25 μM. Stemphyperylenol (5) displayed a potent antifungal activity against the plant pathogen Alternaria solani with MIC of 1.57 μM comparable to the commonly used fungicide carbendazim. Both altenusin (9) and djalonensone (10) showed markedly DPPH radical scavenging activities. In addition, stemphyperylenol (5) and altenuene (6) exhibited strong cytotoxicity against HCT116 cancer cell line with a median inhibitory concentration (IC50) value of 3.13 μM in comparison with the positive control etoposide (IC50 = 2.13 μM). This is the first report of the isolation of these compounds from the endophytic B. dothidea.

Endophytes from medicinal plants and their potential for producing indole acetic acid, improving seed germination and mitigating oxidative stress

“…Endophytes that inhabit medicinal plants exhibit potent biological activity, such as antioxidant, antimalarial, antimicrobial, and anticancer activities (Strobel et al, 2004;Xiao et al, 2014). In the current study, endophytes isolated from medicinal plants were assessed for their antioxidant activity.…”

Mycoparasitic nature of Bionectria sp. strain 6.21

“…The production of secondary metabolites, such as antibiotics, also play an important role and they have been extensively investigated. Some of these studies not only isolated microorganisms with the ability to control pathogens, but also identified the molecules responsible for such action, as observed in the studies performed by Vinale et al (2006) and Xiao et al (2014). They obtained new molecules with activity against Rhizoctonia solani, Pythium ultimum, Gaeumannomyces graminis var.…”

Diversity and bioactive potential of endophytic fungi from Nothapodytes foetida, Hypericum mysorense and Hypericum japonicum collected from Western Ghats of India

“…Other genera such as Botryosphaeria sp., Bipolaris sp., Cylindrocarpon sp., Cylindrotrichum sp., Lasiodiplodia sp., Monodictys sp., and Myrothecium sp. were also reported for their endophytic occurrence in medicinal plants, though not as often as the previously mentioned dominant genera (Gao et al 2014;Sultan et al 2014;Yang et al 2014). Gliocladium spp., isolated as endophytes from Eucryphia cordifolia, were reported to produce low molecular weight volatile hydrocarbons (Strobel et al 2008).…”