Identification of novel compounds, oleanane- and ursane-type triterpene glycosides, from Trevesia palmata: their biocontrol activity against phytopathogenic fungi

Fighting Tomato Fungal Diseases with a Biocontrol Product Based on Amoeba Lysate

New solutions to reduce the use of chemical pesticides to combat plant diseases and to meet societal and political demands are needed to achieve sustainable agriculture. Tomato production, both in greenhouses and in open fields, is affected by numerous pathogens. The aim of this study is to assess the possibility of controlling both late blight and powdery mildew in tomatoes with a single biocontrol product currently under registration. The biocontrol product AXP12, based on the lysate of Willaertia magna C2c Maky, has already proved its efficacy against downy mildew of grapevine and potato late blight. Its ability to elicit tomato defenses and its efficacy in the greenhouse and in the field were tested. This study establishes that AXP12 stimulates the tomato genes involved in plant defense pathways and has the capacity to combat in greenhouse and field both late blight (Phytophtora infestans) and powdery mildew (Oidium neolycopersici and Leveillula taurica) of tomato.

Anticancer properties and mechanism insights of α-hederin

α-Hederin is a natural bioactive molecule very abundant in aromatic and medicinal plants (AMP). It was identified, characterized, and isolated using different extraction and characterization technologies, such as HPLC, LC-MS and NMR. Biological tests have revealed that this natural molecule possesses different biological properties, particularly anticancer activity. Indeed, this activity has been investigated against several cancers (e.g., esophageal, hepatic, breast, colon, colorectal, lung, ovarian, and gastric). The underlying mechanisms are varied and include induction of apoptosis and cell cycle arrest, reduction of ATP generation, as well as inhibition of autophagy, cell proliferation, invasion, and metastasis. In fact, these anticancer mechanisms are considered the most targeted for new chemotherapeutic agents' development. In the light of all these data, α-hederin could be a very interesting candidate as an anticancer drug for chemotherapy, as well as it could be used in combination with other molecules already validated or possibly investigated as an agent sensitizing tumor cells to chemotherapeutic treatments.

Desmodinosides A-E: New Flavonoid C-glycosides from Desmodium heterocarpon var. stigosum with hepatoprotective and antifungal activity

Five new flavonoid C-glycosides named desmodinosides A-E (1-5) and one known compound, apigenin 6-C-β-d-xylopyranosyl-2''-O-β-D-glucopyranoside (6) have been isolated from the methanol extract of the aerial parts of Desmodium heterocarpon var. stigosum. These compounds were determined by 1D and 2D-NMR and HR-MS spectroscopies. The methanol extract of this plant, in particular, demonstrated hepatoprotection and antifungal inhibition. This extract has a remarkable hepatoprotection and activity-dose response with an EC50 of 43.07 μg/mL. The hepatoprotective effect on human liver hepatoma cells (HepG2) of the isolated flavonoid C-glycosides 1-6 was observed. Desmodinosides A-C (1-3) were found to exhibit moderate hepatoprotective activity on HepG2 cells. Of these, compound 2 showed the best hepatoprotective activity with an EC50 value of 74.12 μg/mL. While compounds 1 and 3 displayed EC50 values of 271.21 and 211.99 μg/mL, respectively. Quercetin, a positive control, also caused an EC50 value of 36.42 μg/mL. In addition to having hepatoprotective effect, the methanol extract had an inhibitory effect on the growth of oomycete; it inhibited Phytophthora infestans with IC50 of 13.3 μg/mL and IC90 of 78.7 μg/mL. The oomycete inhibition was directly attributed to compounds 5 and 6, which significantly inhibited P. infestans with IC50 values of 27.4 and 24.7 μg/mL, respectively. Both 5 and 6 and methanol extract were active against P. infestanse in a dose-dependent manner. Our study demonstrated for the first time the new flavonoid C-glycosides from D. heterocarpon var. stigosum and their novel pharmacological properties. The study findings also suggest the plant extract and its metabolites could be used as a new botanical source of bioactive compounds.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2017-2018

This review is the tenth update of the original article published in 1999 on the application of matrix-assisted laser desorption/ionization mass spectrometry (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2018. Also included are papers that describe methods appropriate to glycan and glycoprotein analysis by MALDI, such as sample preparation techniques, even though the ionization method is not MALDI. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, new methods, matrices, derivatization, MALDI imaging, fragmentation and the use of arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly-saccharides, glycoproteins, glycolipids, glycosides, and biopharmaceuticals. Most of the applications are presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions, and applications to chemical synthesis. The reported work shows increasing use of combined new techniques such as ion mobility and highlights the impact that MALDI imaging is having across a range of diciplines. MALDI is still an ideal technique for carbohydrate analysis and advancements in the technique and the range of applications continue steady progress.

Phenyl Ethers from the Marine-Derived Fungus Aspergillus tabacinus and Their Antimicrobial Activity Against Plant Pathogenic Fungi and Bacteria

Marine fungi produce various secondary metabolites with unique chemical structures and diverse biological activities. In the continuing search for new antifungal agents from fungi isolated from marine environments, the culture filtrate of a fungus Aspergillus tabacinus SFC20160407-M11 exhibited the potential to control plant diseases caused by fungi. From the culture filtrate of A. tabacinus SFC20160407-M11, a total of seven compounds were isolated and identified by activity-guided column chromatography and spectroscopic analysis: violaceol I (1), violaceol II (2), diorcinol (3), versinol (4), orcinol (5), orsellinic acid (6), and sydowiol C (7). Based on in vitro bioassays against 17 plant pathogenic fungi and bacteria, violaceols and diorcinol (1-3) showed a broad spectrum of antimicrobial activity with minimum inhibitory concentration values in the range of 6.3-200 μg mL^-1. These compounds also effectively reduced the development of rice blast, tomato late blight, and pepper anthracnose caused by plant pathogenic fungi in a dose-dependent manner. Our results suggest that A. tabacinus SFC20160407-M11 and its phenyl ether compounds could be used for developing new antimicrobial agents to protect crops from plant pathogens.

Association of Bitter Metabolites and Flavonoid Synthesis Pathway in Jujube Fruit

Jujube is rich in nutrients and can be eaten fresh or made into dried fruit, candied fruit, and preserved fruit. Its slightly bitter peel affects nutritional value and commercial value, but the mechanism of the formation of bitter substances is still unclear. We dynamically analyzed the biosynthesis of jujube peel bitterness and related nutrient metabolites through the transcriptome and metabolome. The results demonstrated that flavonoids were the main bitter substances in 'Junzao' jujube fruit skins and a total of 11,106 differentially expressed genes and 94 differentially abundant flavonoid metabolites were identified. Expression patterns of genes in the flavonoid synthesis pathway showed that flavonol synthase (FLS) expression was significantly correlated with quercetin content. Transient overexpression and virus induced gene silencing (VIGS) of ZjFLS1 and ZjFLS2 in jujube fruits and sour jujube seedlings significantly affected flavonol accumulation, especially the content of quercetin-3-O-rutinoside. Moreover, in vitro enzymatic reactions showed that ZjFLS1 and ZjFLS2 could catalyze the formation of quercetin from dihydroquercetin. These findings indicate that ZjFLS gene is the key gene in the biosynthesis of bitter substances in jujube fruit skins and provide basis for the research on the development of functional nutrients in jujube and the synthesis mechanism of bitter compounds.

Characterization of Alternaria porri causing onion purple blotch and its antifungal compound magnolol identified from Caryodaphnopsis baviensis

Alternaria porri (Ellis) Clf. causes purple blotch disease on Allium plants which results in the reduction of crop yields and quality. In this study, to efficiently find natural antifungal compounds against A. porri, we optimized the culture condition for the spore production of A. porri and the disease development condition for an in vivo antifungal assay. From tested plant materials, the methanol extracts derived from ten plant species belonging to the families Cupressaceae, Fabaceae, Dipterocarpaceae, Apocynaceae, Lauraceae, and Melastomataceae were selected as potent antifungal agents against A. porri. In particular, the methanol extract of Caryodaphnopsis baviensis (Lec.) A.-Shaw completely inhibited the growth of A. porri at a concentration of 111 μg/ml. Based on chromatographic and spectroscopic analyses, a neolignan compound magnolol was identified as the antifungal compound of the C. baviensis methanol extract. Magnolol showed a significant inhibitory activity against the spore germination and mycelial growth of A. porri with IC₅₀ values of 4.5 and 5.4 μg/ml, respectively. Furthermore, when magnolol was sprayed onto onion plants at a concentration of 500 μg/ml, it showed more than an 80% disease control efficacy for the purple blotch diseases. In terms of the antifungal mechanism of magnolol, we explored the in vitro inhibitory activity on individual oxidative phosphorylation complexes I–V, and the results showed that magnolol acts as multiple inhibitors of complexes I–V. Taken together, our results provide new insight into the potential of magnolol as an active ingredient with antifungal inhibitory action to control purple blotch on onions.

Synthesis, Fungitoxic Activity against Botrytis cinerea and Phytotoxicity of Alkoxyclovanols and Alkoxyisocaryolanols

Clovane and isocaryolane derivatives have been proven to show several levels of activity against the phytopathogenic fungus Botrytis cinerea. Both classes of sesquiterpenes are reminiscent of biosynthetic intermediates of botrydial, a virulence factor of B. cinerea. Further development of both classes of antifungal agent requires exploration of the structure–activity relationships for the antifungal effects on B. cinerea and phytotoxic effects on a model crop. In this paper, we report on the preparation of a series of alkoxy-clovane and -isocaryolane derivatives, some of them described here for the first time (2b, 2d, 2f–2h, and 4c–4e); the evaluation of their antifungal properties against B. cinerea, and their phytotoxic activites on the germination of seeds and the growth of radicles and shoots of Lactuca sativa (lettuce). Both classes of compound show a correlation of antifungal activity with the nature of side chains, with the best activity against B. cinerea for 2d, 2h, 4c and 4d. In general terms, while 2-alkoxyclovan-9-ols (2a–2e) exert a general phytotoxic effect, this is not the case for 2-arylalkoxyclovan-9-ols (2f–2i) and 8-alkoxyisocaryolan-9-ols (4a–4d), where stimulating effects would make them suitable candidates for application to plants.

Rapid Identification of the Chemical Components of Ilex rotunda Thunb Using UPLC-Q-TOF-MS/MS

Ilicis Rotundae Cortex (IRC) consists of the bark of Ilex rotunda Thunb, and its chemical constituents mainly include flavonoid glycosides, phenols, and triterpenoid saponins. In this study, a preliminary analysis was performed to identify and obtain the chemical components from IRC to better control the quality of the medicinal materials and provide a chemical basis for the study of the efficacy of the active components. Simple and efficient sample pretreatment and ultrasonic-assisted extraction methods were used to analyze the mass spectrum fragments and fracture modes in the anion mode by UPLC-Q-TOF-MS/MS. Using a two-step strategy, the neutral loss, diagnostic ions, and characteristic fragments were studied to screen diverse skeletons and substitutions, and the possible compounds were identified by comparison with databases. The representative compounds were compared with the standard, and the mass spectrogram was found to match perfectly. Thus, our findings reveal that this method is feasible and reliable and can be used to analyze the chemical components of IRC. We identified 105 compounds, including 22 triterpenoid saponins, 15 chlorogenic acids, 33 phenylpropanoids and phenylpropanosides, 3 iridoids, 1 flavonoid, 10 lignans, 12 glycosides, and 9 other compounds. This method lays the foundation for further elucidating the pharmacodynamics of IRC and provides a practical method for the identification of IRC.

Clerodane Diterpenoids Identified from Polyalthia longifolia Showing Antifungal Activity against Plant Pathogens

In the search for new natural resources showing plant disease control effects, we found that the methanol extract of Polyalthia longifolia suppressed fungal disease development in plants. To identify the bioactive substances, the methanol extract of P. longifolia was extracted by organic solvents, and consequently, four new 2-oxo-clerodane diterpenes (1-4), a new 4(3 → 2)-abeo-clerodane diterpene (5), together with ten known compounds (6-16) were isolated and identified from the extracts. Of the new compounds, compound 2 showed a broad spectrum of antifungal activity with moderated minimum inhibitory concentration (MIC) values in a range of 50-100 μg/mL against tested fungal pathogens. Considering with the known compounds, compound 6 showed the most potent antifungal activity with an MIC value in the range of 6.3-12.5 μg/mL. When compound 6 was evaluated for an in vivo antifungal activity against rice blast, tomato late blight, and pepper anthracnose, compound 6 reduced the plant disease by at least 60% compared to the untreated control at concentrations of 250 and 500 μg/mL. Together, our results suggested that the methanol extract of twigs and leaves of P. longifolia and its major compound 6 could be used as a source for the development of eco-friendly plant protection agents.

Endophytes of Brazilian Medicinal Plants With Activity Against Phytopathogens

Plant diseases caused by phytopathogens are responsible for significant crop losses worldwide. Resistance induction and biological control have been exploited in agriculture due to their enormous potential. In this study, we investigated the antimicrobial potential of endophytic fungi of leaves and petioles of medicinal plants Vochysia divergens and Stryphnodendron adstringens located in two regions of high diversity in Brazil, Pantanal, and Cerrado, respectively. We recovered 1,304 fungal isolates and based on the characteristics of the culture, were assigned to 159 phenotypes. One isolate was selected as representative of each phenotype and studied for antimicrobial activity against phytopathogens. Isolates with better biological activities were identified based on DNA sequences and phylogenetic analyzes. Among the 159 representative isolates, extracts from 12 endophytes that inhibited the mycelial growth (IG) of Colletotrichum abscissum (≥40%) were selected to expand the antimicrobial analysis. The minimum inhibitory concentrations (MIC) of the extracts were determined against citrus pathogens, C. abscissum, Phyllosticta citricarpa and Xanthomonas citri subsp. citri and the maize pathogen Fusarium graminearum. The highest activity against C. abscissum were from extracts of Pseudofusicoccum stromaticum CMRP4328 (IG: 83% and MIC: 40 μg/mL) and Diaporthe vochysiae CMRP4322 (IG: 75% and MIC: 1 μg/mL), both extracts also inhibited the development of post-bloom fruit drop symptoms in citrus flowers. The extracts were promising in inhibiting the mycelial growth of P. citricarpa and reducing the production of pycnidia in citrus leaves. Among the isolates that showed activity, the genus Diaporthe was the most common, including the new species D. cerradensis described in this study. In addition, high performance liquid chromatography, UV detection, and mass spectrometry and thin layer chromatography analyzes of extracts produced by endophytes that showed high activity, indicated D. vochysiae CMRP4322 and P. stromaticum CMRP4328 as promising strains that produce new bioactive natural products. We report here the capacity of endophytic fungi of medicinal plants to produce secondary metabolites with biological activities against phytopathogenic fungi and bacteria. The description of the new species D. cerradensis, reinforces the ability of medicinal plants found in Brazil to host a diverse group of fungi with biotechnological potential.

Anti-phytopathogen terpenoid glycosides from the root bark of Chytranthus macrobotrys and Radlkofera calodendron

Chytranthus macrobotrys and Radlkofera calodendron are two Sapindaceae characterized by a lack of phytochemical data. Both root barks from the two Sapindaceae species were processed by ethanol extraction followed by the isolation of their primary constituents by liquid chromatography. This process yielded four previously undescribed terpenoid glycosides together with eight known analogues. Extracts and isolated compounds from C. macrobotrys and R. calodendron were then screened for antimicrobial activity against fifteen phytopathogens. The biological screening also involved extracts and pure compounds from Blighia unijugata and Blighia welwitschii, two Sapindaceae previously studied by our group. Phytopathogens were chosen based on their economic impact on agriculture worldwide. The selection was composed primarily of fungal species including; Pyricularia oryzae, Gaeumannomyces graminis var. tritici, Zymoseptoria tritici, Fusarium oxysporum, Botrytis cinerea, Pythium spp., Trichoderma spp. and Rhizoctonia solani. Furthermore, pure terpenoid glycosides were tested for the first time against wood-inhabiting phytopathogens such as; Phaeomoniella chlamydospora, Phaeoacremonium minimum, Fomitiporia mediterranea, Eutype lata and Xylella fastidiosa. Raw extracts exhibited different levels of activity dependent on the organism. Some pure compounds, including 3-O-α-L-arabinopyranosyl-(1 → 4)-β-D-xylopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranosylhederagenin, 3-O-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranosylhederagenin (α-hederin), 3-O-β-D-glucopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranosylhederagenin (macranthoside A) and 3-O-α-L-arabinopyranosyl-(1 → 3)-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranosylhederagenin (clemontanoside C), exhibited significant growth inhibitions on Pyricularia oryzae, Gaeumannomyces graminis var. tritici, Fomitiporia mediterranea and Zymoseptoria tritici. Monodesmoside triterpene saponins, in particular, exhibited MIC (IC₁₀₀) values as low as 25 μg/ml and IC₅₀ values as low as 10 μg/ml against these phytopathogens. Structure-activity relationships, as well as plant-microbe interactions, were discussed.

Plant Disease Control Efficacy of Platycladus orientalis and Its Antifungal Compounds

Plants contain a number of bioactive compounds that exhibit antimicrobial activity, which can be recognized as an important source of agrochemicals for plant disease control. In searching for natural alternatives to synthetic fungicides, we found that a methanol extract of the plant species Platycladus orientalis suppressed the disease development of rice blast caused by Magnaporthe oryzae. Through a series of chromatography procedures in combination with activity-guided fractionation, we isolated and identified a total of eleven compounds including four labdane-type diterpenes (1-4), six isopimarane-type diterpenes (5-10), and one sesquiterpene (11). Of the identified compounds, the MIC values of compounds 1, 2, 5 & 6 mixture, 9, and 11 ranged from 100 to 200 μg/mL against M. oryzae, whereas the other compounds were over 200 μg/mL. When rice plants were treated with the antifungal compounds, compounds 1, 2, and 9 effectively suppressed the development of rice blast at all concentrations tested by over 75% compared to the non-treatment control. In addition, a mixture of compounds 5 & 6 that constituted 66% of the P. orientalis ethyl acetate fraction also exhibited a moderate disease control efficacy. Together, our data suggest that the methanol extract of P. orientalis including terpenoid compounds has potential as a crop protection agent.

Biological and biorational management of blast diseases in cereals caused by Magnaporthe oryzae

Blast diseases, caused by the fungal pathogen Magnaporthe oryzae, are among the most destructive diseases that occur on at least 50 species of grasses, including cultivated cereals wheat, and rice. Although fungicidal control of blast diseases has widely been researched, development of resistance of the pathogen against commercially available products makes this approach unreliable. Novel approaches such as the application of biopesticides against the blast fungus are needed for sustainable management of this economically important disease. Antagonistic microorganisms, such as fungi and probiotic bacteria from diverse taxonomic genera were found to suppress blast fungi both in vitro and in vivo. Various classes of secondary metabolites, such as alkaloids, phenolics, and terpenoids of plant and microbial origin significantly inhibit fungal growth and may also be effective in managing blast diseases. Common modes of action of microbial biocontrol agents include: antibiosis, production of lytic enzymes, induction of systemic resistance in host plant, and competition for nutrients or space. However, the precise mechanism of biocontrol of the blast fungus by antagonistic microorganisms and/or their bioactive secondary metabolites is not well understood. Commercial formulations of biocontrol agents and bioactive natural products could be cost-effective and sustainable but their availability at this time is extremely limited. This review updates our knowledge on the infection pathway of the wheat blast fungus, catalogs naturally occurring biocontrol agents that may be effective against blast diseases, and discusses their role in sustainable management of the disease.

Spirulina platensis, Punica granatum peel, and moringa leaves extracts in cosmetic formulations: an integrated approach of in vitro biological activities and acceptability studies

The selection of suitable natural raw materials in the cosmetic research and development is a key point, in order not only to obtain the expected results but also to avoid undesirable side effects. In this study, spirulina platensis, pomegranate (Punica granatum) peel, and moringa leaves alone were evaluated for anti-oxidant and antimicrobial properties. The chemical composition (moisture, dry matter, protein, lipid, and ash) and total polyphenols, flavonoids, and carotenoids content were evaluated in the three extracts. Total antioxidant capacity and ferric reducing activity power of extracts were also studied. Using agar diffusion method, the anti-Micrococcus luteus, Staphylococcus aureus, E. coli, Listeria monocytogenes, Salmonella typhimurium, and Enterococus faecalis activities were measured. Interestingly, after combinations, pomegranate peel/spirulina (A), and moringa/spirulina (B): 25%/75% and 50%/50%, we have found that pomegranate peel can be incorporated into cosmetic formulations as an excellent preservative due to its exceptionally amount of phenolic compounds, powerful antioxidant activity, and its antibacterial activity against pathogenic strains.

Fungicidal and antistress properties of the preparation based on triterpene acids on spring barley

The most effective concentration range of the studied preparation synthesized on the basis of triterpene acids is in the range of 0.01-0.005 %. In the conditions of water-salt stress, the studied preparation increased laboratory germination of seeds, length of seedling and root of spring barley compared with the control variant. At a concentration of 0.01-0.005 %, the preparation reduced the intensity of the pathogenic complex development on the seed material of spring barley, but was significantly inferior in effectiveness to the synthetic protectant. At the same time, unlike a fungicide, the preparation did not have a depressing effect on the development of barley in the initial stages of ontogenesis.

Strawberry fatty acyl glycosides enhance disease protection, have antibiotic activity and stimulate plant growth

An increasing interest in the development of products of natural origin for crop disease and pest control has emerged in the last decade. Here we introduce a new family of strawberry acyl glycosides (SAGs) formed by a trisaccharide (GalNAc-GalNAc-Glc) and a monounsaturated fatty acid of 6 to 12 carbon atoms linked to the glucose unit. Application of SAGs to Arabidopsis thaliana (hereafter Arabidopsis) plants triggered a transient oxidative burst, callose deposition and defense gene expression, accompanied by increased protection against two phytopathogens, Pseudomonas viridiflava and Botrytis cinerea. SAGs-induced disease protection was also demonstrated in soybean infected with the causal agent of target spot, Corynespora cassiicola. SAGs were shown to exhibit important antimicrobial activity against a wide-range of bacterial and fungal phytopathogens, most probably through membrane destabilization, and the potential use of SAGs as a biofungicide for postharvest disease protection was demonstrated on lemon fruits infected with Penicillium digitatum. Plant growth promotion by application of SAGs was shown by augmented primary root elongation, secondary roots development and increased siliques formation in Arabidopsis, whereas a significant increment in number of seed pods was demonstrated in soybean. Stimulation of radicle development and the induction of an auxin-responsive reporter system (DR5::GUS) in transgenic Arabidopsis plants, suggested that SAGs-stimulated growth at least partly acts through the auxin response pathway. These results indicate that strawberry fatty acid glycosides are promising candidates for the development of environmental-friendly products for disease management in soybean and lemon.

Potential Use of L-arabinose for the Control of Tomato Bacterial Wilt

The present study aimed to investigate the potential of simple sugars for use as protection agents in the control of tomato bacterial wilt caused by Ralstonia pseudosolanacearum. Based on the sugar assimilation patterns of the pathogen, four unassimilable sugars (L-arabinose, maltose, D-raffinose, and D-ribose) were selected from 10 representative sugars present in tomato root exudates. These sugars were evaluated for their effects on bacterial wilt using a tomato seedling bioassay. The application of 0.25% L-arabinose significantly reduced disease severity and was, thus, selected as a candidate for further evaluations in a pot experiment under glasshouse conditions. The results obtained showed that the disease suppressive effects of L-arabinose slightly increased at higher concentrations; drench treatments at 0.1, 0.25, and 0.5% reduced disease severity by ca. 48, 70, and 87%, respectively. The drench treatment with 0.5% L-arabinose significantly reduced the pathogen population in the rhizosphere and stem tissues of tomato plants without any antibacterial activity. Real-time reverse-transcription PCR revealed that the expression of salicylic acid-dependent and ethylene-dependent defense genes was significantly enhanced in the stem tissues of L-arabinose-treated tomato plants following the pathogen inoculation. These results suggest that soil drenching with L-arabinose effectively suppresses tomato bacterial wilt by preventing pathogen proliferation in the rhizosphere and stem tissues of tomato plants. This is the first study to report the potential of L-arabinose as a safe, eco-friendly, and cost-effective plant protection agent for the control of tomato bacterial wilt.

Combined Effect of Spirulina Platensis and Punica Granatum Peel Extacts: Phytochemical Content and Antiphytophatogenic Activity

Biological control is one of the effective methods for managing plant diseases in food production and quality. In fact, there is a growing trend to find new bio-sources, such as marine algae and vegetal by-products. In this study, pomegranate (Punica granatum) peel (S1) and Spirulina platensis (S2) alone and in combinations, pomegranate peel/Spirulina: 25%/75% (S3) and 50%/50% (S4) were evaluated for antimycotoxigenic and antiphytopathogenic fungal properties. The chemical composition (moisture, dry matter, protein, lipid and ash) as well as total polyphenols, flavonoids and anthocyanins content were evaluated in the four extracts. Using agar diffusion and broth microdilution methods, the anti Fusarium oxysporum, Fusarium culmorum, Fusarium graminearum, Aspergillus niger and Alternaria alternata activities were measured and their correlations with phytochemical content were evaluated. Interestingly, combinations between Spirulina at 75% and pomegranate peel at 25% (S3) have a significant impact (p < 0.05) on the antifungal activity compared to S1, S2 and S4. These findings underlie the effectiveness of biocontrols over standard fungicides and imply that existing methods can be further improved by synergistic effects while maintaining food safety in an eco-friendly manner.

New lupane-type and ursane-type triterpene saponins from the leaves of Trevesia palmata

Three new triterpene saponins including two lupane-types and an ursane-type were isolated from the leaves of Trevesia palmata. Their structures were determined as 2α,3β,23-trihydroxylup-20(29)-en-28-oic acid 3-O-α-L-arabinopyranoside (1), 2α,3β,23-trihydroxylup-20(29)-en-28-oic acid 3-O-[α-L-arabinopyranoside]-28-O-[β-D-glucopyranosyl] ester (2), and 2α,3β,23-trihydroxyurs-12-en-28-oic acid 3-O-[α-L-arabinopyranoside]-28-O-[β-D-glucopyranosyl(1→2)-β-D-glucopyranosyl] ester (3) by analysis of their HR-ESI-MS, 1D and 2D NMR spectra. The 2α,3β,23-trioxygenated pentacyclic triterpenes were uncommonly found in the nature. At concentration of 100 µM, compounds 1-3 inhibited NO production in LPS activated BV2 cells with inhibitory rates of 17.4 ± 1.8%, 33.1 ± 1.2%, and 11.7 ± 2.2%, respectively. But, they did not significantly inhibit yeast α-glucosidase activity.

Discovery of New Triterpenoid Saponins Isolated from Maesa japonica with Antifungal Activity against Rice Blast Fungus Magnaporthe oryzae

While searching for new antifungal compounds, we revealed that a methanol extract of plant species Maesa japonica has a potent antifungal activity in vivo against rice blast fungus Magnaporthe oryzae. To identify the antifungal substances, the methanol extract of M. japonica was extracted by organic solvents, and consequently, six active compounds were isolated from the n-butanol layer. The isolated compounds were five new acylated triterpenoid saponins including maejaposide I (1), maejaposides C-1, C-2, and C-3 (2-4), and maejaposide A-1 (5), along with a known one, maejaposide A (6). These chemical structures were determined by NMR and a comparison of their NMR and MS data with those reported in the literature. Based on the in vitro antifungal bioassay, the five compounds (2-6) exhibited strong antifungal activity against M. oryzae with MIC values ranging from 4 to 32 μg/mL, except for maejaposide I (1) (MIC > 250 μg/mL). When the compounds were evaluated at concentrations of 125, 250, and 500 μg/mL for an in vivo antifungal activity against rice blast, compounds 2-6 strongly reduced the development of blast by at least 85% to 98% compared to the untreated control. However, compound 1 did not show any in vivo antifungal activity up to a concentration of 500 μg/mL. Taken together, our results suggest that the methanol extract of M. japonica and the new acylated triterpenoid saponins can be used as a source for the development of natural fungicides.

Diphenyl Ethers from a Marine-Derived Aspergillus sydowii

Six new diphenyl ethers (1⁻6) along with eleven known analogs were isolated from the ethyl acetate extract of a marine-derived Aspergillus sydowii guided by LC-UV-MS. Their structures were unambiguously characterized by HRESIMS, NMR, as well as chemical derivatization. Compounds 1 and 2 are rare diphenyl ether glycosides containing d-ribose. The absolute configuration of the sugar moieties in compounds 1⁻3 was determined by a LC-MS method. All the compounds were evaluated for their cytotoxicities against eight cancer cell lines, including 4T1, U937, PC3, HL-60, HT-29, A549, NCI-H460, and K562, and compounds 1, 5, 6, and 8⁻11 were found to exhibit selective cytotoxicity against different cancer cell lines.