Postinfectional inhibitors from plants. XXIII. Sesquiterpenoid phytoalexins from fruit capsules of Datura stramonium

1976 ◽  
Vol 54 (1-2) ◽  
pp. 25-29 ◽  
Author(s):  
E. W. B. Ward ◽  
C. H. Unwin ◽  
G. L. Rock ◽  
A. Stoessl

Datura stramonium fruit capsules inoculated with Monilinia fructicola or several other non-pathogenic fungi produced diffusates inhibitory to M. fructicola in spore germination assays. Detailed analysis of diffusates that are induced by M. fructicola indicated that they were complex and that antifungal activity was widely distributed through a number of column chromatographic fractions. Four compounds were isolated. These were sesquiterpenes, three of which, lubimin, hydroxylubimin, and capsidiol, have been described from other Solanaceae. The fourth, 2,3-dihydroxygermacrene, is a new compound with moderate antifungal activity but which is of especial interest as a possible precursor of several phytoalexins in the Solanaceae.

Author(s):  
Cong You ◽  
Jun Yu ◽  
Guangjiong Qin ◽  
JinPeng Yang ◽  
Chunlei Yang ◽  
...  

Abstract Background Artemisia hedinii is a well-known traditional Chinese medicine. It can be used to extract dihydroartemisinin (DHA). Objective The purpose of this study was to explore the optimal conditions for the homogenate extraction of DHA from A. hedinii and the antifungal activity of DHA. Methods In this study, single factor experiments and response surface method were used to determine the optimal extraction conditions of crude extract and DHA, the method of spore germination was used to study the antifungal activity of DHA to Alternaria alternata. Result The optimal conditions were found as fellow: ratio of liquid to material 22 mL/g; Extraction time 60 s; soaking time 34 min. Under these conditions, extraction yield of DHA was (1.76 ± 0.04%). When the concentration of crude extract were 0.5 and 8 mg/mL, the spore germination inhibition rates of Alternaria alternata were (17.00 ± 2.05%) and (92.56 ± 2.01%), which were 3.34 and 1.15 times that of DHA standard, respectively. Conclusion Homogenate extraction technology is a fast and efficient method to extract DHA from A. hedinii. The crude extract has significant antifungal activity against A. alternata with low cost, which provides a possibility for the use of DHA in the prevention and treatment of plant pathogenic fungi. Highlights The optimum conditions of the extraction of DHA from A. hedinii by homogenate extraction were obtained. DHA has antifungal activity against A. alternata. Compared with pure DHA, the crude extract has stronger antifungal activity against A. alternata.


2020 ◽  
Vol 21 (21) ◽  
pp. 7912 ◽  
Author(s):  
Tatyana Odintsova ◽  
Larisa Shcherbakova ◽  
Marina Slezina ◽  
Tatyana Pasechnik ◽  
Bakhyt Kartabaeva ◽  
...  

Hevein-like antimicrobial peptides (AMPs) comprise a family of plant AMPs with antifungal activity, which harbor a chitin-binding site involved in interactions with chitin of fungal cell walls. However, the mode of action of hevein-like AMPs remains poorly understood. This work reports the structure–function relationship in WAMPs—hevein-like AMPs found in wheat (Triticum kiharae Dorof. et Migush.) and later in other Poaceae species. The effect of WAMP homologues differing at position 34 and the antifungal activity of peptide fragments derived from the central, N- and C-terminal regions of one of the WAMPs, namely WAMP-2, on spore germination of different plant pathogenic fungi were studied. Additionally, the ability of WAMP-2-derived peptides to potentiate the fungicidal effect of tebuconazole, one of the triazole fungicides, towards five cereal-damaging fungi was explored in vitro by co-application of WAMP-2 fragments with Folicur® EC 250 (25% tebuconazole). The antifungal activity of WAMP homologues and WAMP-2-derived peptides varied depending on the fungus, suggesting multiple modes of action for WAMPs against diverse pathogens. Folicur® combined with the WAMP-2 fragments inhibited the spore germination at a much greater level than the fungicide alone, and the type of interactions was either synergistic or additive, depending on the target fungus and concentration combinations of the compounds. The combinations, which resulted in synergism and drastically enhanced the sensitivity to tebuconazole, were revealed for all five fungi by a checkerboard assay. The ability to synergistically interact with a fungicide and exacerbate the sensitivity of plant pathogenic fungi to a commercial antifungal agent is a novel and previously uninvestigated property of hevein-like AMPs.


1975 ◽  
Vol 53 (10) ◽  
pp. 964-971 ◽  
Author(s):  
E. W. B. Ward ◽  
C. H. Unwin ◽  
A. Stoessl

Orchinol, loroglossol, and several related phenanthrenes and stilbenes obtained by laboratory synthesis were tested for antifungal activity, primarily in spore germination assays against Monilinia fructicola and Phytophthora infestons. The most active stilbene tested was 3,5-dimethoxy-3′-hydroxystilbene (mean effective dose (ED50) 5 × 10−5 M), at least comparable with the reported activity of the stilbene phytoalexin, pinosylvin. All the phenanthrenes and dihydrophenanthrenes tested were active, although assays were complicated by solubility problems. ED50 for orchinol was (5 × 10−5 M) and loroglossol had similar activity against P. infestons. Several phenanthrenes had higher activity, notably dehydroorchinol (ED50 vs. P. infestons 5 × 10−6 M), and warrant further study. A striking feature of the response of the test fungi to the phenanthrenes and dihydrophenanthrenes was the production of distorted and ruptured germ tubes, which may indicate a direct interference with growth processes at the tip. No evidence was obtained for translocation of orchinol in higher plant tissue.


1997 ◽  
Vol 75 (1) ◽  
pp. 207-211 ◽  
Author(s):  
B. Prithiviraj ◽  
U. P. Singh ◽  
M. Manickam ◽  
A. B. Ray

The antifungal activity of anacardic acid and two of its derivatives was tested against some plant pathogenic fungi and the inhibitory effect was compared with that of salicylic acid. Anacardic acid was found to be most effective and it inhibited Colletotrichum capsici spore germination at 125–150 μg mL−1. The results suggest that salicylic acid with appropriate structural modifications may prove to be a superior antifungal agent and can be utilized in controlling certain plant diseases under field conditions. Key words: salicylic acid derivatives, antifungal activity, fungal spore germination.


2019 ◽  
Vol 26 (6) ◽  
pp. 414-422
Author(s):  
Jia Liu ◽  
Ping Song ◽  
Jie Zhang ◽  
Ziyan Nangong ◽  
Xiaobei Liu ◽  
...  

Background: Genome sequence analysis (GenBank access No.: FN667742.1) shows that Xenorhabdus nematophila ATCC19061 contains one gene (Xn-cbp) encoding chitin binding protein (Xn-CBP). Objective: The present work aims to clarify the characteristics and function of Xn-CBP from X. nematophila HB310. Methods: In this study, the Xn-cbp gene was cloned and expressed in Escherichia coli BL21 (DE3). Substrate binding assays were performed to explain the ability of Xn-CBP combined with the polysaccharide. The insecticidal toxicity of Xn-CBP against the second-instar larvae of Helicoverpa armigera was determined by feeding method. Besides, the antifungal activity of Xn-CBP against Coniothyrium diplodiella, Verticillium dahlia, and Fusarium oxysporum was tested by spore germination assay and hyphal extension assay. Results: Xn-CBP encoded 199 amino acids with a calculated mass of 28 kDa, which contained a signal peptide and a chitin binding domain. The Bmax and Kd values of Xn-CBP to colloidal chitin were 2.46 and 4.08, respectively. Xn-CBP had insecticidal activity against the H. armigera with a growth inhibition rate of 84.08%. Xn-CBP had the highest spore germination inhibitory effect on C. diplodiella with the inhibition rate of 83.11%. The hyphal growth inhibition rate of Xn-CBP to F. oxysporum, 41.52%, was higher than the other two fungi. Conclusion: The Xn-CBP had the highest binding ability to colloidal chitin and it showed insecticidal activity and antifungal activity. The present study laid a foundation for further exploitation and utilization of X. nematophila.


Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1567
Author(s):  
Ippolito Camele ◽  
Daniela Gruľová ◽  
Hazem S. Elshafie

Several economically important crops, fruits and vegetables are susceptible to infection by pathogenic fungi and/or bacteria postharvest or in field. Recently, plant essential oils (EOs) extracted from different medicinal and officinal plants have had promising antimicrobial effects against phytopathogens. In the present study, the potential microbicide activity of Mentha × piperita cv. ‘Kristinka’ (peppermint) EO and its main constituents have been evaluated against some common phytopathogens. In addition, the cell membrane permeability of the tested fungi and the minimum fungicidal concentrations were measured. The antifungal activity was tested against the following postharvest fungi: Botrytis cinerea, Monilinia fructicola, Penicillium expansum and Aspergillus niger, whereas antibacterial activity was evaluated against Clavibacter michiganensis, Xanthomonas campestris, Pseudomonas savastanoi and P. syringae pv. phaseolicola. The chemical analysis has been carried out using GC-MS and the main components were identified as menthol (70.08%) and menthone (14.49%) followed by limonene (4.32%), menthyl acetate (3.76%) and β-caryophyllene (2.96%). The results show that the tested EO has promising antifungal activity against all tested fungi, whereas they demonstrated only a moderate antibacterial effect against some of the tested bacteria.


2018 ◽  
Vol 280 ◽  
pp. S27
Author(s):  
Enriqueta Martinez Rojas ◽  
Fatuma Hassan ◽  
Filip Boratynski ◽  
Teresa Olejniczak ◽  
Karl Steffens ◽  
...  

2019 ◽  
Vol 41 (3) ◽  
pp. 549-549
Author(s):  
Xuesong Wang and Xiaorong Tang Xuesong Wang and Xiaorong Tang

A series of novel benzamide derivatives according to fluopicolide were designed and synthesized following the rule of combination carboxylic acid amides and amines derivatives together. The antifungal activity of the 15 new compounds were evaluated in vitro against five pathogenic fungi, including Sclerotinia sclerotiorum, Gibberella zeae, Rhizoctonia solani, Helminthosporium maydis and Botrytis cinerea. Almost all the structure have not been reported, except compounds 3, 5 and 6. A surprising finding is that all the five tested fungi breed faster than negative controls when supplementary with compound 715 , respectively.


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