Secondary Metabolite Profiles Research Articles

Secondary metabolite profiles and anti-SARS-CoV-2 activity of ethanolic extracts from nine genotypes of Cannabis sativa L.

This study deals with the comprehensive phytochemical composition and antiviral activity against SARS-CoV-2 of acidic (non-decarboxylated) and neutral (decarboxylated) ethanolic extracts from seven high-cannabidiol (CBD) and two high-Δ9-tetrahydrocannabinol (Δ9-THC) Cannabis sativa L. genotypes. Their secondary metabolite profiles, phytocannabinoid, terpenoid, and phenolic, were determined by LC-UV, GC-MS, and LC-MS/MS analyses, respectively. All three secondary metabolite profiles, cannabinoid, terpenoid, and phenolic, varied significantly among cannabinoid extracts of different genotypes. The dose-response analyses of their antiviral activity against SARS-CoV-2 showed that only the single predominant phytocannabinoids (CBD or THC) of the neutral extracts exhibited antiviral activity (all IC50 < 10.0 μM). The correlation matrix between phytoconstituent levels and antiviral activity revealed that the phenolic acids, salicylic acid and its glucoside, chlorogenic acid, and ferulic acid, and two flavonoids, abietin, and luteolin, in different cannabinoid extracts from high-CBD genotypes are implicated in the genotype-distinct antagonistic effects on the predominant phytocannabinoid. On the other hand, these analyses also suggested that the other phytocannabinoids and the flavonoid orientin can enrich the extract's pharmacological profiles. Thus, further preclinical studies on cannabinoid extract formulations with adjusted non-phytocannabinoid compositions are warranted to develop supplementary antiviral treatments.

Evaluation of Fumigant Toxicity of Eucalyptus globulus Essential oil (Family: Myrtaceae) against the Mechanical Vector, American Cockroach, Periplaneta Americana (Linnaeus, 1758) (Blattodea: Blattidae)

The American cockroach, Periplaneta americana (Linnaeus, 1758), one of the largest and most resilient cockroach species, possess significant threats to public health and food safety due to its ability to transmit diseases and contaminate food. The widespread application of chemical pesticides to control cockroach infestations raises significant public health concerns due to its residual toxicity. The continued use of insecticides results in resistance development in cockroach populations which demands alternative pest management strategies wherein the chemical insecticides were completely restricted in human dwelling areas such as apartments, hospitals, restaurants and food preparation areas. The plant’s diverse profile of bioactive compounds and secondary metabolites, coupled with its complex nature, renders it a promising natural resource for the development of safe alternative against cockroach management. The median lethal dosage LD50 of E. globulus essential oil was found to be 16.74784 µL against the male American Cockroach, P. americana analysed using probit analysis. The present study was conducted to evaluate the fumigant toxicity of eucalyptus essential oil (Eucalyptus globulus) against the male American Cockroach, Periplaneta americana in a laboratory experiment. Five different doses of E. globulus essential oil 5, 10, 20, 30, 40 and 50 µL against male American Cockroach, P. americana were evaluated and compared to the untreated control (negative control). Results, indicated a dose dependent response with 100 per cent mortality achieved at 50 µL of eucalyptus essential oil followed by 40 (80%), 30 (60%), 20 (46.67%) and 5 (26.67) µL. The Eucalyptus globulus essential oil can be used as a potent fumigant against the male American Cockroach, P. americana which is an ecofriendly management of cockroach infestation.

Phytochemicals and health-promoting evaluations of Ophiorrhiza puffii, a chinese endemic plant

There has been no phytochemical or and pharmacological report of the Chinese endemic plant Ophiorrhiza puffii till now. At present, seven structurally diverse compounds were obtained, including six triterpenoids (1–6) and one anthraquinone (7). Interestingly, 1–6 furnished three distinct carbon skeletons. Additionally, these phytochemical constituents showed multiple health-promoting effects. Triterpene 3 displayed considerable tyrosinase inhibitory activity (IC50 = 5.42 μM). Components 4 and 5 demonstrated significant antioxidant activity (IC50 = 4.23 and 2.03 mM, respectively). Meanwhile, compounds 2 and 5 exhibited moderate α-glucosidase inhibitory activity (IC50 = 0.89 and 0.72 mM, respectively). Moreover, the binding mechanisms for bioactive compounds 2, 3 and 5 and the corresponding α-glucosidase and tyrosinase proteins were preliminarily inspected by molecular docking experiments. This study filled up the knowledge gap of the unexplored chemical and biological profiles of secondary metabolites from the plant O. puffii for the first time.

Unlocking the biochemical and computational parameters of Ceropegia foetida: A scientific approach for functional bioactive compounds from a medicinal food plant

Investigating the therapeutic potentials of medicinal plants remains pivotal in the discovery of novel bioactive compounds for food and pharmaceutical applications. This research delves into the phytochemical composition and biological activities of Ceropegia foetida's methanol extract, employing comprehensive UHPLC-MS for secondary metabolites profiling. The study quantifies the extract's substantial phenolic (76.12 mg GAE/g) and flavonoid (21.58 mg QE/g) contents, revealing a promising correlation with robust antioxidant activities, as evidenced by notable ABTS, FRAP, and CUPRAC assay outcomes. Furthermore, the extract demonstrates significant inhibitory effects on key enzymes implicated in neurodegenerative disorders and diabetes, including acetylcholinesterase (3.56 mg GALAE/g), butyrylcholinesterase (2.91 mg GALAE/g), and tyrosinase (128.31 mg KAE/g). UHPLC-MS analysis confirms the presence of 39 distinct phytochemicals across six primary categories, affirming the extract's complex bioactive profile. In complement to experimental assays, computational analyses via molecular docking simulations provided insights into the interaction mechanisms of identified phytochemicals with the target enzymes. These simulations revealed a substantial binding affinity of the plant's constituents towards enzymes compared to standard inhibitors, highlighting the compounds responsible for C. foetida's bioactivity. Such computational insights, alongside empirical data, suggest that C. foetida merits further exploration as a natural source of therapeutic agents. Overall, the efficacious enzyme inhibition, coupled with the identified phytochemical diversity, underscores the potential of C. foetida as a valuable natural resource for developing nutraceuticals and therapeutic agents. These findings support the further investigation of C. foetida for its applicability in enhancing health and treating chronic conditions.

Secondary Metabolite Profiling and Antibacterial Activities of Indigenous Serratia marcescens

Serratia marcescens produces secondary metabolites, which are bioactive chemicals generated during its non-essential metabolic activities. These secondary metabolites are renowned for their antibacterial, antifungal, and anticancer capabilities. This work analyzed the chemical composition and antibacterial properties of the secondary metabolite of Serratia marcescens isolated from the local environment. Serratia marcescens was isolated using standard microbiological techniques and identified based on morphological and biochemical characteristics. Gas chromatographymass spectrometric analysis revealed the presence of eighteen (18) bioactive compounds, comprising oleic acid as the most abundant compound (21.9013 %), 9,12-Octadecadien-1-ol, (Z, Z)- (11.9854 %), and other compounds with less than 6 % abundance. The metabolite has antibacterial activities against Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris, and Bacillus subtilis. Antibacterial activity was higher against Bacillus subtilis (42.00±2.65 mm) and Proteus vulgaris (32.67±1.15 mm), and least with Pseudomonas aeruginosa (10.00±2.00 mm) at 400 mg metabolite concentration. The antibacterial effect decreased with a decrease in the concentration of the metabolite. The results show that Serratia marcescens exhibits potential as an antibacterial agent within the pharmaceutical and food sectors.

Arbuscular mycorrhizal fungi and intercropping Vicia villosa mediate plant biomass, soil properties, and rhizosphere metabolite profiles of walnuts

Intercropping is a prevalent soil management strategy within orchards, whereas it is unclear how inoculation with arbuscular mycorrhizal (AM) fungi and intercropping affect tree growth, soil properties, and rhizosphere metabolite profiles. This study investigated the effects of inoculation with Diversispora spurca and intercropping with hairy vetch (Vicia villosa) on biomass production, soil available nutrients, water-stable aggregate (WSA) distribution, phosphatase activity, and secondary metabolite profiles in walnuts (Juglans regia). The intercropping only elevated soil nitrate N levels and WSA distribution at the 0.5–2 mm size, and also triggered 2159 differential metabolites (1378 up-regulated and 781 down-regulated), with armillaramide as the most prominently up-regulated metabolite, followed by the substance diminished upon D. spurca inoculation. Conversely, D. spurca inoculation increased walnut biomass, WSA distribution across the 0.25 − 2 mm size, and acid and neutral phosphatase activities, as well as triggered 2489 differential metabolites (897 up-regulated and 1592 down-regulated), with pteroside D being highest up-regulated differential metabolite, allowing a competitive advantage to AM plants in combating soil pathogens. Despite significantly suppressing root AM fungal colonization and biomass production in AM walnuts, intercropping significantly increased soil ammonium and nitrate N levels in AM walnuts as well as WSAs at the 1–4 mm size, exhibiting a synergistic effect. Flavone and flavonol biosynthesis and pyruvate metabolism were simultaneously involved following AM inoculation or intercropping. Co-application of AM inoculation and intercropping triggered 1006 differential metabolites, with urocanic acid being the most up-regulated metabolite, although it decreased following AM inoculation, suggesting the involvement of mycorrhizal hyphae in soil histidine uptake. Under intercropping, AM inoculation elicited 418 differential metabolites, with the most up-regulated metabolite being implicated in flavonoid pathways. AM inoculation primarily triggered the biosynthesis of unsaturated fatty acids, regardless of intercropping or not, implying a potential increase in unsaturated fatty acid contents of walnut kernels. It concluded that AM inoculation and intercropping interactively affected walnut growth, soil attributes, and soil microenvironment.Graphical

In silico profiling, docking analysis, and protein interactions of secondary metabolites in Musa spp. Against the SGE1 protein of Fusarium oxysporum f. sp. cubense

Banana Fusarium Wilt (BFW), caused by Fusarium oxysporum f. sp. cubense (Foc), threatens banana crops globally, with the pathogen's virulence partially regulated by the Sge1 transcription factor, which enhances disease severity. Certain Musa species display resistance to Foc, suggesting inherent genetic traits that confer immunity against Sge1Foc. This study utilized bioinformatics tools to investigate the mechanisms underlying this resistance in Musa accuminata subsp. aalaccensis. Through in silico analyses, we explored interactions between Musa spp. and Foc, focusing on the Sge1 protein. Tools such as Anti-SMASH, AutoDockVina 4.0, STRING, and Phoenix facilitated the profiling of secondary metabolites in Musa spp. and the identification of biosynthetic gene clusters involved in defense. Our results indicate that secondary metabolites, including saccharides, terpenes, and polyketides, are crucial to the plant's immune response. Molecular docking studies of selected Musa metabolites, such as 3-Phenylphenol, Catechin, and Epicatechin, revealed 3-Phenylphenol as having the highest binding affinity to the Sge1Foc protein (-6.7 kcal/mol).Further analysis of gene clusters associated with secondary metabolite biosynthesis in Musa spp. identified key domains like Chalcone synthase, Phenylalanine ammonia-lyase, Aminotran 1–2, and CoA-ligase, which are integral to phenylpropanoid production—a critical pathway for secondary metabolites. The study highlights that the phenylpropanoid pathway and secondary metabolite biosynthesis are vital for Musa spp. resistance to Foc. Flavonoids and lignin may inhibit Sge1 protein formation, potentially disrupting Foc's cellular processes. These findings emphasize the role of phenylpropanoid pathways and secondary metabolites in combating BFW and suggest that targeting these pathways could offer innovative strategies for enhancing resistance and controlling BFW in banana crops. This research lays the groundwork for developing sustainable methods to protect banana cultivation and ensure food security.

Unraveling the Antidiabetic Effect of Alternantera brasiliana (L.) Kuntze: A Combined in Vitro and in Vivo Approach

Background of the study This study established the antidiabetic efficacy of Alternantera brasiliana in vitro and in vivo, identified the most active fraction and profiled the chemical constituents of the most active fraction. Methodology The leaf of A. brasiliana was air-dried, pulverized and extracted with methanol and evaluated for its α-amylase activity at different concentrations using in vitro method. The in vivo antidiabetic activity of the extract and glibenclamide was evaluated in glucose loaded and streptozotocin-induced diabetic rats using various doses, while the most active partitioned fraction was identified using glucose loaded method followed by identification of its chemical constituents through GC-MS analysis. Results The extract elicited good α-amylase inhibitory potential with IC50 = 0.45 mg/mL. Also, the 50 mg/kg dose demonstrated the highest percentage blood glucose level reduction and significantly ( P &gt; 0.05) comparable to glibenclamide (5 mg/kg) from 0.5 to 4 h. The streptozotocin-induced antidiabetic assay showed that the 50 mg/kg demonstrated better activity than glibenclamide (5 mg/kg) and was significantly comparable on days 10 and 14. The aqueous methanol fraction was the most active fraction with 53% blood glucose level reduction at 4 h. The secondary metabolite profiling identified 30 chemical compounds whereby 1H-Indole-2-carboxylic acid, 6-(4-ethoxyphenyl)-3-methyl-4-oxo-4,5,6,7-tetrahydro-, isopropyl ester, Benzo[h]quinoline, 2,4-dimethyl-, thymol and 13,5-trioxane as the major constituents. Conclusion The antidiabetic activity demonstrated by the A. brasiliana extract established its antidiabetic efficacy

Morphological, cytogenetic, and phytochemical estimation of Lychnis flos-cuculi L. cell cultures: can cell biomass be a source of bioactive compounds?

The ragged robin (Lychnis flos-cuculi L.) from the Caryophyllaceae family contains flavonoids, phenolic acids, flavonoids, triterpenoid saponins, and ecdysteroids, making it potential for biological and medicinal application. Plant cell culture technologies could be beneficial for obtaining low-cost biomass sources with valuable phytochemicals sustainably. The current study reports the induction and proliferation of ragged robin cell culture and evaluation of various plant growth regulators (PGRs) impact on the secondary metabolites profile using UPLC-HRMS/MS. Callus was initiated from different explants on the Murashige and Skoog medium with various combinations and concentrations of PGRs. It was found that prolonged proliferation on MS medium enriched with a combination of 1.0 mg l− 1 2,4-Dichlorophenoxyacetic acid and 0.1 mg l− 1 N6-furfuryl adenine (Kinetin) yields the maximum biomass with 504.05% growth index. The results of flow cytometric analysis suggested no genetic alteration between differentiated and dedifferentiated cultures. Furthermore, the UPLC-HRMS/MS result distinguished 101 significant signals that were manually identified as ecdysteroids (16 metabolites), flavonoids (11 metabolites), phenolic acids (10 metabolites), triterpene saponins and sapogenins (53 metabolites), and some primary metabolites. Our study demonstrates that the cell culture of L. flos-cuculi displays significant differences in its phytochemical makeup to plants cultivated in vitro. Moreover, the type of growth regulators used for callus cultures was identified to cause substantial shifts in the identified metabolites.Graphical

Comprehensive Secondary Metabolite Profiling and Antioxidant Activity of Aqueous and Ethanol Extracts of Neolamarckia cadamba (Roxb.) Bosser Fruits.

Neolamarckia cadamba (Rubiaceae) is a well-recognized medicinal plant with recorded therapeutical attributes. However, a thorough assessment of active compounds in its fruits is lacking, limiting their use and valorization in pharmacological industries. Thus, this study investigated variations in the fruits' secondary metabolite (SM) profiles, as well as antioxidant activities in aqueous (WA) and ethanol (ET) extracts. Liquid chromatography-electrospray ionization tandem mass spectrometry identified 541 SMs, of which 14 and 1 (di-O-glucosylquinic acid) were specifically detected in ET and WA, respectively. Phenolic acids (36.97%), flavonoids (28.10%), terpenoids (12.20%), and alkaloids (9.98%) were the dominant SMs. The SM profiles of the fruits in WA and ET were quite different. We revealed 198 differentially extracted (DE) metabolites between WA and ET, including 62 flavonoids, 57 phenolic acids, 45 terpenoids, 14 alkaloids, etc. Most DE flavones (36 out of 40), terpenoids (45 out of 45), and alkaloids (12 out of 14) had higher content in ET. Catechin and its derivatives, procyanidins, and tannins had higher content in WA. ABTS and DPPH assays showed that the antioxidant activity of ET was significantly higher than that of WA. Our findings will facilitate the efficient extraction and evaluation of specific active compounds in N. cadamba.

CALLUS INDUCTION FROM THE FRONDS OF GREATER DUCKWEED (&lt;i&gt;Spirodela polyrhiza &lt;/i&gt;(L.) Schleid) AND ASSESSMENT OF ITS ANTIMICROBIAL EFFICACY

Greater duckweed (Spirodela polyrrhiza (L.) Schleid. are known to propagate excessively in stagnant eutrophic water bodies resulting in the contamination of daughter fronds which can affect their secondary metabolite profile. The present study was aimed in establish organogenic callus from the fronds of greater duckweeds; to optimize a protocol by utilizing different plant growth regulators for future use and to screen the antimicrobially potent metabolites present in callus. The induction of callus was successful using sterile fronds of Spirodela polyrrhiza (L.) Schleid as explants in MS, B5 and SH media fortified with plant growth regulators namely IBA and BAP. SH basal medium fortified with IBA and BA in 2:1 ratio was most effective in callus induction. B5 medium fortified with 2.0 µM IBA + 4.0 µM BAP showed highest callus induction in S. polyrrhiza with lower days to callus induction as reflective in their overall biomass. The callus extract showed efficient antimicrobial effect on Pseudomonas aeroginosa (MTCC accession No. 3451) with ampicillin and chloramphenicol as reference antibiotics. Presence of flavonoids like orientin, genistin and apigetrin were indicated in the LC-MS data which might be responsible for antimicrobial activity in a synergistic manner.

Headspace aroma and secondary metabolites profiling in 3 Pelargonium taxa using a multiplex approach of SPME‐GC/MS and high resolution‐UPLC/MS/MS coupled to chemometrics

AbstractBACKGROUNDThe present study focuses on the aroma and secondary metabolites profiling of three Pelargonium graveolens cultivars, baladi (GRB), sondos (GRS) and shish (GRSH), grown in Egypt. Utilizing a multiplex approach combining high resolution‐ultraperformance liquid chromatography (HR‐UPLC)/tandem mass spectrometry (MS/MS) and gas chromatography (GC)‐MS coupled with chemometrics, the study aims to identify and profile various secondary metabolites and aroma compounds in these cultivars.RESULTSHR‐UPLC/MS/MS analysis led to the annotation of 111 secondary metabolites, including phenolics, flavonoids, terpenes and fatty acids, with several compounds being reported for the first time in geranium. Multivariate data analysis identified vinylanisole, dimethoxy‐flavonol, and eicosadienoic acid as discriminatory metabolites among the cultivars, particularly distinguishing the GRS cultivar in its phenolics profile. In total, 34 aroma compounds were detected using headspace solid‐phase microextraction coupled with GC‐MS, including alcohols, esters, ketones, ethers and monoterpene hydrocarbons. The major metabolites contributing to aroma discrimination among the cultivars were β‐citronellol in GRB, α‐farnesene in GRS and isomenthone in GRSH.CONCLUSIONThe study provides a comprehensive profiling of the secondary metabolites and aroma compounds in the three Pelargonium graveolens cultivars. The GRS cultivar was identified as particularly distinct in both its phenolics and aroma profiles, suggesting its potential as a premium variety for cultivation and use. Future studies should focus on isolating and investigating the newly detected metabolites and exploring the biological effects of these compounds in food applications and other uses. © 2024 Society of Chemical Industry.

Hormetic effect of UV-C radiation on red mustard microgreens growth and chemical composition

Brassica microgreens are rich in phytochemicals and are attractive crops for controlled vertical farming systems where the light spectrum can be precisely manipulated. Understanding the effects of pre-harvest hormetic UV-C light doses on plant composition and growth parameters represents a novel and largely unexplored area for precision agriculture and nutrition. Therefore, the objective of this work was to investigate the impact of exposing red mustard microgreens to low/hormetic doses of UV-C radiation on their growth, chemical composition and colour. Plants were grown in a controlled environment and exposed to 0.3 kJ m−2, 254 nm UV-C radiation at the end of the cultivation period. Treatments included a single pulse on day 7, or three pulses at days 7, 8, and 9 and harvest on day 10. UV-C radiation presented a hormetic effect, while 1 pulse of UV-C stimulated growth and productivity without significant colour changes in microgreens, 3 pulses of UV-C radiation to did not show significant effects when compared to controls (no UV-C exposure). Moreover, strong negative correlations were observed between growth parameters and chemical composition (p < 0.05). Microgreens with enhanced growth parameters showed a decrease in phenolic compounds content and antioxidant activity. Interestingly, regardless of quantification, untargeted metabolomics using UHPLC-Q-Orbitrap-MS/MS revealed that the secondary metabolites profile remained similar between control and microgreens treated with UV-C radiation.

Analysis of the Immunomodulator Profile of Secondary Metabolites Derived from Streptomyces sp.

Analysis of the Immunomodulator Profile of Secondary Metabolites Derived from Streptomyces sp.

Temperature seasonality and soil phosphorus availability shape ginseng quality via regulating ginsenoside contents

The accumulation of secondary metabolites in Panax ginseng Meyer (P. ginseng) exhibits significant geographical variation, normally due to environmental factors. The current study aimed at elucidating the key environmental factors modulating the accumulation of secondary metabolites in P. ginseng. Plant and the associated soil samples were collected from ten geographical locations within the latitudinalrange of 27.09°N − 42.39°N and longitudinal range of 99.28°E − 128.19°E. 12 secondary metabolites in P. ginseng toots were measured. And the correlation between secondary metabolites with a series of soil properties and 7 climatic factors were investigated through Pearson’s correlation, mantel test, random forest and pathway analysis. The results revealed that climatic factors were stronger drivers of ginseng secondary metabolite profile than soil nutrients. Specifically, temperature seasonality (TS) and soil available phosphorus (AP) were the most effective environments to have significantly and positively influence on the secondary metabolites of ginseng. This findings contribute to identifying optimal cultivation areas for P. ginseng, and hopefully establishing methods for interfering/shaping microclimate for cultivating high-quality P. ginseng.

Secondary Metabolite Profiles: Trichoderma, Aspergillus flavus Glocladium and Penicillium as Biocontrol Agents

A fungus is utilized as a biocontrol agent to suppress plant diseases by employing an antagonistic mechanism, wherein it releases enzymes that degrade the cell walls of pathogens and inhibit their growth. The antibiosis mechanism is initiated by biocontrol fungi through the production of secondary molecules or metabolites. The objective of the research was to examine the secondary metabolite composition of the biocontrol fungi Trichoderma spp., Aspergillus flavus, and Gliocladium sp. and Penicillium species The implementation approach involved the use of qualitative phytochemical testing and HPLC analysis. The outcomes of the investigation into the metabolite profiles of Trichoderma spp., Aspergillus flavus, and Gliocladium sp. were observed. and Penicillium species The presence of alkaloids, phenolics, and flavonoids was detected in the samples. The results of the High-Performance Liquid Chromatography (HPLC) analysis indicated the presence of 10-11 compounds, as evidenced by the peaks observed in the chromatogram. These compounds are presumed to be associated with the phenolic and alkaloid groups.

Differences in artificial light spectrum using light emitting diode on secondary metabolite profiles in Kasturi mango seedlings from Tembilahan, Riau, Indonesia

Differences in artificial light spectrum using light emitting diode on secondary metabolite profiles in Kasturi mango seedlings from Tembilahan, Riau, Indonesia

Chemotaxonomic and molecular phylogenetic studies of selected Hypoxylon species from the Neotropics

ABSTRACT Members of the genus Hypoxylon (Ascomycota) are pleomorphic fungi mostly forming conspicuous teleomorphs, consisting of perithecia embedded into stromal tissue, and their morphology has traditionally served for species delineation. However, analysis in tandem with other phenotypic characters, such as chemical and genetic traits, proved to be a more stable predictor of interspecies and intergeneric relationships. During 2014 and 2015, a set of species identified as Hypoxylon were described from the Neotropics, exclusively relying on morphological traits. The secondary metabolite profiles of their stromata were analysed by HPLC/DAD-ESI-MS, corroborating their classification within Xylariales. Additionally, molecular data for ex-type strains of H. dussii and H. sofaiense were incorporated into an inferred molecular phylogeny of the Hypoxylaceae and allies. Furthermore, a freshly collected specimen from North Carolina was selected as epitype of Sphaeria perforata Schweinitz (syn. Hypoxylon perforatum), as its morphological/chemotaxonomic characters matched those of the holotype. Our findings demonstrate that the secondary metabolism of Hypoxylon closely correlates with both morphological features and molecular data, serving as a complement for species identification.

Reappraisal of Didymella macrostoma causing white tip disease of Canada thistle as a new species, Didymella baileyae, sp. nov., and bioactivity of its major metabolites

ABSTRACT Bioherbicides are expected to be a supplement to integrated pest management, assisting in the control of problematic weed species. For instance, bioherbicides (Phoma and BioPhoma) were recently registered in Canada and the USA for the control of some perennial dicotyledonous weeds in lawns. These products are based on strains of the fungus Didymella macrostoma (syn. Phoma macrostoma) that causes white tip disease (WTD) in Canada thistle (Cirsium arvense). In this study, WTD was reported for the first time in the Russian Federation. Analysis of the internal transcribed spacer (ITS) region of nuc rDNA and secondary metabolite profiling confirmed the identity of Russian WTD isolates to Canadian biocontrol strains identified as D. macrostoma. Multilocus phylogenetic analysis based on sequencing of the ITS region, partial large subunit nuc rDNA region (28S), RNA polymerase II second largest subunit gene (rpb2), and partial β-tubulin gene (tub2) has differentiated the WTD isolates from C. arvense and D. macrostoma isolates from other plant hosts. Based on phylogenetic, morphological, and chemotaxonomic features, these WTD isolates were described as a new species named Didymella baileyae, sp. nov. This study also demonstrated the low pathogenicity of the ex-type D. baileyae isolate VIZR 1.53 to C. arvense seedlings and its asymptomatic development in the leaves of aboveground shoots. The organic extracts from mycelium and culture filtrate of D. baileyae, as well as macrocidin A and macrocidin Z, displayed phytotoxicity both to C. arvense leaves and seedlings. Macrocidin A was only detected in the naturally infected leaf tissues of C. arvense showing WTD symptoms. Macrocidins A and Z demonstrated low antimicrobial and cytotoxic activities, exhibiting no entomotoxic properties. The data obtained within this study on the pathogenicity and metabolites of D. baileyae may be important for the rational evaluation of its prospects as a biocontrol agent.

Comparison of phytochemical and brewing characteristics of Cascade and Kazbek hop cultivars

A four-year study compared the secondary metabolite profile of two flavour hops, the widely used Cascade and the new Czech variety Kazbek. The average alpha-acids and total essential oil of Kazbek and Cascade grown in Europe did not differ, while alpha-acids were 20 % higher in Cascade grown in the USA. Cluster analysis of essential oil composition distinguished the varieties, the markers being mainly farnesene derivatives. US-Cascade had higher terpenoids (geraniol, geranial) and lower fatty acid methyl esters than EU-Cascade. Both varieties have high and comparable levels of geraniol esters (230–360 mg/kg total) and low levels of free geraniol. The sulphur-containing volatile profile of US-Cascade and EU-Cascade hops differed significantly, probably as a result of treatment with different pesticides. The profile of hop-associated essential oils and aroma components of the single-variety experimental beers Kazbek and Cascade was similar for both whirlpool-hopped and additionally dry-hopped beers. Citrus and fruit notes were the dominant descriptors. Two independent sensory panels did not clearly distinguish or prefer beers hopped with Cascade and Kazbek hops, demonstrating the possibility of alternating between the two varieties in brewing. A new finding is that genetically distant hop varieties can provide similar sensory profiles in late- and dry-hopped beers.