scholarly journals Chemical Composition of a Supercritical Fluid (Sfe-CO2) Extract from Baeckea frutescens L. Leaves and Its Bioactivity Against Two Pathogenic Fungi Isolated from the Tea Plant (Camellia sinensis (L.) O. Kuntze)

Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1119
Author(s):  
Hao Jiang ◽  
Mengting Zhang ◽  
Li Qin ◽  
Dongxu Wang ◽  
Feng Yu ◽  
...  

Colletotrichum gloeosporioides and Pseudopestalotiopsis camelliae-sinensis are the two most important tea plant (Camellia sinensis L.) pathogenic fungi. Interest in natural plant extracts as alternatives to synthetic chemical fungicides to control plant pathogens is growing. In this study, the volatile fraction of Baeckea frutescens L. was extracted by supercritical fluid extraction (SFE-CO2), and its chemical composition was analyzed, and investigated for its antifungal activity against C. gloeosporioides and P. camelliae. The major constituents of the volatile fraction were β-caryophyllene (28.05%), α-caryophyllene (24.02%), δ-cadinene (6.29%) and eucalyptol (5.46%) in B. frutescens SFE-CO2 extracts. The terpineol, linalool, terpinen-4-ol and eucalyptol showed strong contact antifungal activity against P. camelliae and C. gloeosporioides with median inhibitory concentration (MIC50) in the range of 0.69 μL/mL to 2.79 μL/mL and 0.62 μL/mL to 2.18 μL/mL, respectively. Additionally, the volatile fraction had high fumigation antifungal activity against P. camelliae and C. gloeosporioides with an inhibition rate between 20.87% and 92.91%. Terpineol presented the highest antifungal activity in the contact and fumigation toxicity assays. Terpineol, linalool, terpinen-4-ol and eucalyptol were associated with the most active chemical compounds in the volatile fraction against the fungi. The results suggest that B. frutescens SFE-CO2 extracts are potential ingredients to develop a natural fungicide for control of tea plant pathogens.

2013 ◽  
Vol 726-731 ◽  
pp. 4525-4528
Author(s):  
Ping Yang ◽  
Qian Xu

T. asperellum is an important biocontrol fungus owing to their ability to antagonize plant pathogenic fungi. The biocontrol effects of T. asperellum were played by secreting many kinds of hydrolytic enzymes and antibiotics. T. asperellum producing more cell wall degrading enzymes when meeting plant pathogens. Moreover, the growth of the plant pathogens was inhibited by T. asperellum secondary metabolites. The yield of antibiotic 6-PP was 1.32 mg 6-PP/g mycelial dry weight. T. asperellum control plant pathogens through secreting cell wall degrading enzymes and producing antifungal metabolites.


2012 ◽  
Vol 59 (2) ◽  
pp. 51-58 ◽  
Author(s):  
Alicja Saniewska ◽  
Anna Jarecka ◽  
Zbigniew Biały ◽  
Marian Jurzysta

Antifungal activity of total saponins originated from roots of <i>Medicago hybrida</i> (Pourret) Trautv. were evaluated <i>in vitro</i> against six pathogenic fungi and eight individual major saponin glycosides were tested against one of the most susceptible fungi. The total saponins showed fungitoxic effect at all investigated concentrations (0.01%, 0.05% and 0.1%) but their potency was different for individual fungi. The highest saponin concentration (0.1%) was the most effective and the inhibition of <i>Fusarium oxysporum</i> f. sp. <i>callistephi</i>, <i>Botrytis cinerea</i>, <i>Botrytis tulipae</i>, <i>Phoma narcissi</i>, <i>Fusarium oxysporum</i> f. sp. <i>narcissi</i> was 84.4%, 69.9%, 68.6%, 57.2%, 55.0%, respectively. While <i>Fusarium oxysporum</i> Schlecht., a pathogen of <i>Muscari armeniacum</i>, was inhibited by 9.5% only. Eight major saponin glycosides isolated from the total saponins of <i>M. hybrida</i> roots were tested against the mycelium growth of <i>Botrytis tulipae</i>. The mycelium growth of the pathogen was greatly inhibited by hederagenin 3-O-<i>β</i>-D-glucopyranoside and medicagenic acid 3-O-<i>β</i>-D-glucopyranoside. Medicagenic acid 3-O-<i>β</i>-D-glucuronopyranosyl-28-O-<i>β</i>-D-glucopyranoside and oleanolic acid 3-O-[<i>β</i>-D-glucuronopyranosyl(1→2)-<i>α</i>-L-galactopyranosyl]-28-O-<i>β</i>-D-glucopyranoside showed low fungitoxic activity. Medicagenic acid 3-O-a-D-glucopyranosyl- 28-O-β-D-glucopyranoside, hederagenin 3-O-[α-L- hamnopyranosyl(1→2)-β-D-glucopyranosyl(1→2)-β-D-glucopyranosyl]- 28-O-α-D-glucopyranoside and hederagenin 3-O-<i>β</i>-D-glucuronopyranosyl-28-O-<i>β</i>-D- lucopyranoside did not limit or only slightly inhibited growth of the tested pathogen. While 2<i>β</i>, 3<i>β</i>-dihydroxyolean-12 ene-23-al-28-oic acid 3-O-<i>β</i>-D-glucuronopyranosyl-28-O-<i>β</i>-D-glucopyranoside slightly stimulated mycelium growth of <i>B. tulipae</i>.


2016 ◽  
Vol 6 (1) ◽  
pp. 26-31 ◽  
Author(s):  
Maria Diana Cerqueira Sales ◽  
Helber Barcellos Costa ◽  
Patrícia Machado Bueno Fernandes ◽  
José Aires Ventura ◽  
Debora Dummer Meira

Author(s):  
Rosemary I. Uchegbu ◽  
Jacinta N. Akalazu ◽  
Chinweotuto E. Sokwaibe

Aim: This work was carried out to determine the chemical compositions of Ocimum gratissimum leaf (Fig. 1) using GC-MS and its antifungal potential against some plant pathogenic fungi. Study Design: The study was designed to determine its chemical compositions by GC-MS and to test the inhibitory ability of the plant extract on plant pathogens. Place and Duration of Study: Department of Chemistry, Alvan Ikoku Federal College of Education, Owerri and Department of Plant Science and Biotechnology, Imo State University, Owerri, Nigeria, between February to July 2017. Methodology: The ethanol extract of the leaf of Ocimum gratissimum was evaluated using GC-MS to determine the chemical compositions of the plant. The identification of compounds was done by comparing spectrum of the unknown component with the spectrum of the known components stored in the NIST library. The essential oil of the plant was used to analyze the antifungal potential of the plant. This was done against some plant pathogenic fungi using disc diffusion method and MIC using broth micro dilution method. Results: The GC-MS analysis revealed eight compounds (Fig. 2) with n- Hexadecanoic acid constituting the bulk of the oil (37.21%), followed by Oleic acid (25.38%) and Octadecanoic acid (16.19%). Other compounds present in the plant are Glycyl alcohol (2.47%), Methyl alpha –D- Glucopyranoside (8.33%), Tetradecanoic acid (5.77%), Palmitic amide (2.72%) and d-Glucose, 2,3- diethyl-4,5-dithioacetyl (1.93%). Ocimum gratissimum exhibited different degrees of antifungal activity against the mycelial growth of Aspergillus niger, Botryodiploidia theobromae, Rhizopus stolonifer, Penicillium expansum and Colletotrichum spp and Fusarium oxysporium. The maximum percentage degree inhibition of Ocimum gratissimum oil was observed on A. niger at different concentrations while the least inhibition was observed in Colletotrichum spp at different concentrations. Analysis of some of the compounds found in Ocimum gratissimum such as Methyl alpha.-d-glucopyranoside, Oleic acid etc, reveals the rich pharmacological potential of this medicinal plant and the inhibitory potential of the plant against fungi justify the use of Ocimum gratissimum as a medicine traditionally.


2011 ◽  
Vol 3 (3) ◽  
pp. 375-379
Author(s):  
R. R. Thanighai arassu ◽  
◽  
Balwin Nambikkairaj ◽  
P. Sivamani P. Sivamani

Agronomy ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 136 ◽  
Author(s):  
Silvina López ◽  
Graciela Pastorino ◽  
Mario Franco ◽  
Rocio Medina ◽  
César Lucentini ◽  
...  

Tomato (Solanum lycopersicum L.) is probably the most important vegetable consumed around the world, and like other produce is affected by stresses and diseases that reduce the yield and production. The purpose of this work was to study the phytobiome of the tomato seeds of two hybrids in order to understand first of all whether tomato cultivars host similar groups of organisms, as well as their effect on the community structure, particularly of those microbes with the potential to promote growth and/or control plant pathogens. Different cultivars of tomato (genotypes) host significantly different endophytic communities, which is also reflected at the order level. These communities are particularly rich in spore-forming bacteria that have the ability either to promote plant growth or synthetize antimicrobial compounds that deter plant pathogens. We conclude that the seeds of the tomato cultivars Elpida and Silverio are sources of endophytic bacteria capable of synthetizing antifungal substances that could potentially be used for biocontrol against plant-pathogenic fungi.


Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 825
Author(s):  
Imad El-Alam ◽  
Robin Raveau ◽  
Joël Fontaine ◽  
Anthony Verdin ◽  
Frédéric Laruelle ◽  
...  

(1) Background: The use of natural products based on essential oils (EO) is nowadays arousing great interest as an alternative method to control plant pathogens and weeds. However, EO possess low bioavailability and are highly volatile, and their encapsulation in hydroxypropyl-ß-cyclodextrin (HP-β-CD) could be a means to enhance their stability and maintain their bioactivity. Thus, the current study aims at investigating, in the presence and the absence of HP-β-CD, the antifungal and phytotoxic activities of nine EO, distilled from plant species belonging to Alliaceae, Apiaceae, and Cupressaceae families, with considerations for their chemical composition. (2) Methods: EO antifungal activity was assessed by direct contact and volatility assays against Fusarium culmorum, a major phytopathogenic fungi, while phytotoxic effects were evaluated against lettuce (Lactuca sativa L.) and rye-grass (Lolium perenne L.), by seedling’s emergence and growth assays. (3) Results: These EO inhibit fungal growth in both direct contact and volatility assays, with half-maximal inhibitory concentrations (IC50) ranging from 0.01 to 4.2 g L−1, and from 0.08 up to 25.6 g L−1, respectively. Concerning phytotoxicity, these EO have shown great potential in inhibiting lettuce (IC50 ranging from 0.0008 up to 0.3 g L−1) and rye-grass (IC50 ranging from 0.01 to 0.8 g L−1) seedlings’ emergence and growth. However, the EO encapsulation in HP-β-CD has not shown a significant improvement in EO biological properties in our experimental conditions. (4) Conclusion: All tested EO present antifungal and phytotoxic activities, with diverse efficacy regarding their chemical composition, whilst no increase of their biological effects was observed with HP-β-CD.


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