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A study proposing cyclodextrins as eco-friendly compounds to enhance the physicochemical properties of phthalimide-lactones to produce complexes inducing the germination of parasitic weeds even without using organic co-solvents.

Eight different compounds inspired by benzoxazinones were synthesized in one simple step with easy purification. These compounds have a sulfur atom instead of the oxygen atom present in benzoxazinones. Furthermore, a new derivative obtained by a Rutkauskas–Beresnevicius reaction was synthesized. These compounds were evaluated in vitro to assess their phytotoxicity in plant cells by the elongation of wheat coleoptiles. The novel compounds showed higher inhibition than benzoxazinones and the positive control, especially at higher concentrations (1000 and 300 μM). Benzoxazinones have been described as histidine deacetylase inhibitors and we therefore evaluated the effect of 1.4-benzothiazinones and 1.4-benzoxathianones against HDA6, one of the most important enzymes of the family, in silico by molecular docking and molecular dynamics. In vitro studies against Echinochloa crus-galli, Lolium rigidum and Portulaca oleracea weeds gave interesting results against the growth of the roots for both monocots and dicots. Specifically, the inhibition was more pronounced against dicots, as in the case of common purslane, whose inhibition at a concentration of 1000 μM was similar to that of the classical herbicide employed as a positive control. Higher inhibition was obtained when an aliphatic group was present in the C2 position of 1.4-benzothiazinones.

Aqueous solubility and stability often limit the application of aminophenoxazinones and their sulfur mimics as promising agrochemicals in a sustainable agriculture inspired by allelopathy. This paper presents a solution to the problem using host-guest complexation with cucurbiturils (

C-17-sesquiterpenoids are a group of natural products that have been recently discovered. These compounds have the peculiarity of lacking the alpha,beta-methylene butyrolactone system, which is known to be quite relevant for many of the biological activities reported for sesquiterpene lactones. Unfortunately, the biological interest of C-17-sesquiterpenoids has not been studied in-depth, mainly due to the poor isolation yields in which they can be obtained from natural sources. Therefore, in order to allow a deeper study of these novel molecules, we have worked out a synthetic pathway that provides C-17-sesquiterpenoids in enough quantities from easily accessible sesquiterpene lactones to enable a more thorough investigation of their bioactivities. With this synthesis method, we have successfully synthesized, for the first time, three natural C-17-sesquiterpenoids, pertyolides A, B, and C, with good overall yields. Furthermore, we have also evaluated their phytotoxicity against etiolated wheat coleoptiles and corroborated that pertyolides B and C present strong phytotoxic activity., This research was supported by the Ministerio de Economia, Industria y Competitividad (MINEICO), Spain, AGL2017-88083-R.

Natural products are a promising source for the development of new pesticides with alternative mechanisms of action. In this study, we evaluated the phytotoxic and antifungal activity of a novel family of natural CMany tested compounds exhibited a strong phytotoxic activity. Lappalone and pertyolide B were the most potent molecules from the tested group. Lappalone displayed a strong inhibition profile against selected weed species, reaching a half-maximal inhibitory concentration (ICThe bioassays revealed that frequently the presence of the α-methylene-γ-butyrolactone system is not essential for the bioactivities of sesquiterpene lactones, and suggest that C

Semisynthetic analogs of natural products provide an important approach to obtain safer and more active drugs and they can also have enhanced physicochemical properties such as persistence, cross-membrane processes and bioactivity. Acyl derivatives of different natural product families, from sesquiterpene lactones to benzoxazinoids, have been synthesized and tested in our laboratories. These compounds were evaluated against tumoral and nontumoral cell lines to identify selective derivatives with a reduced negative impact upon application. The mode of action of these compounds was analyzed by anti-caspase-3 assays and molecular dynamics simulations with cell membrane re-creation were also carried out. Aryl derivatives of eudesmanolide stand out from the other compounds and are better than current anticancer drugs such as etoposide in terms of selectivity and activity. Computational studies provide evidence that lipophilicity plays a key role and the 4-fluorobenzoyl derivative can pass easily through the cell membrane.

Strigolactones are natural products that are exuded by plants and stimulate parasitic weed germination. Their use in herbicides is limited since they are produced in small quantities, but the synthesis of bioactive analogues provides an alternative source. In this work, eleven analogues have been synthesized. Among them, nine compounds belong to a novel family named eudesmanestrigolactones. The procedure is short (3-6 steps), the starting materials are isolated on a multigram scale, and global yields are up to 8%, which significantly enhance isolated yields. In bioassay, the compounds germinated high percentages of Phelipanche ramosa, Orobanche cumana, and Orobanche crenata seeds, even at nanogram doses (100 nM). Bioactivity was stereochemistry-dependent, and it was discussed in terms of the presence and geometry of the enol ether, orientation of the butenolide, and unsaturation of ring A. The reported compounds provide a set of readily obtained allelochemicals with potential applications as preventive herbicides.

Weeds have been a major threat in agriculture for several generations as they lead to decreases in productivity and cause significant economic losses. Parasitic plants are a specific type of weed causing losses in crops of great relevance. A new strategy has emerged in the fight against parasitic plants, which is called 'suicidal germination' or the 'honey-pot strategy'. Regarding the problem of weed control from an ecological point of view, it is interesting to investigate new natural compounds with allelopathic activity with the aim of developing new natural herbicides that can inhibit the growth of weeds without damaging the environment. Safflower crops have been affected by parasitic plants and weeds and, as a consequence, the secondary metabolites exuded by safflower roots have been studied. The sesquiterpene lactone dehydrocostuslactone was isolated and characterised, and the structurally related costunolide was identified by UHPLC-MS/MS in safflower root exudates. These sesquiterpene lactones have been shown to stimulate germination of Phelipanche ramosa and Orobanche cumana seeds. In addition, these compounds were phytotoxic on three important weeds in agriculture, namely Lolium perenne, Lolium rigidum and Echinochloa crus-galli. The exudation of the strigolactones solanacol and fabacyl acetate have also been confirmed by UHPLC-MS/MS. The study reported here contributes to our knowledge of the ecological role played by some secondary metabolites. Moreover, this knowledge could help identify new models for the development of future agrochemicals based on natural products.

In this work, the selectivity of different solid catalysts in the alkylation reaction of toluene with hex-1-ene has been studied in order to maximize mono-alkylated products. The reaction has been carried out in a fixed-bed reactor, at 120°C. An industrial alkylation catalyst has been used as a reference along with three commercial acid zeolites with difference structures (faujasite, mordenite and beta). All of catalysts achieved total conversion. Mono-alkyltoluenes selectivity was higher than 95% in all cases and formation of di-alkyltoluenes was less than 4.5%. The main products, mono-alkyltoluenes, were identified by Nuclear Magnetic Resonance spectroscopy. This work analyses the effect of physicochemical and structural properties of solid catalysts on the selectivity to the different alkylation products.

Thapsia garganica L. phytotoxicity was studied on Lactuca sativa L. and associated weeds, by adding powdered dried leaves to soil in amounts of 0.2%, 0.6%, 1% and 2% in pot experiments. The isolation, purification, and identification of the bioactive molecules on L. sativa and on a weed, Lolium perenne L., were carried out using bio-guided tests. In pot experiments, weed development is strongly affected, indeed the dicotyledonous emergence percentage varied between zero and 1%, while that of monocotyledonous was only 6%. For lettuce, the growth of which has been improved at low doses, its shoots, roots, first and last leaves length and weight were reduced by 34%, 58%, 79.66%, 51% and 56.7% respectively, at the highest dose. To identify the bioactive molecules, extracts prepared by extraction of the leaves with organic solvents (hexane, ethyl acetate and methanol extracts) were evaluated in wheat (Triticum aestivum L.) coleoptiles bioassay. Ethyl acetate and methanol extracts were the most toxic. They were used to isolate bioactive molecules. Two flavonoid glycosides, luteolin 7-O-glucoside and apigenin7-O-glucoside and two sesquiterpene lactones, thapsigargin and 10β-acetoxy-8α-butyryloxy-11α-hydroxy-2β-((2-methylbutanoyl) oxy)- 1βH,6αH,7αH,11βH-guaian-3-en-12,6-olide were isolated. The inhibitory activity of T. garganica leaves on lettuce root growth could be due to apigenin7-O-glucoside presence, with an inhibition of the order of 43%, at 1000 µM. 10β-acetoxy-8α-butyryloxy-11α-hydroxy-2β-((2-methylbutanoyl)oxy)- 1βH,6αH,7αH,11βH-guaian-3-en-12,6-olide demonstrated the highest toxicity on root growth and aerial parts of L. perenne and lettuce, with inhibitions of the order of 65%, 56% and 21% respectively, at 500 µM. T. garganica could be a renewable source of molecules for lettuce associated weeds control, acting at very low doses.

Vladimiria souliei is a plant located in China applied in traditional medicine. Recent isolation studies have led to the discover of vlasouliolides, natural sesquiterpene dimers. However, the yield...

Herbicides are a key element in agriculture but they do cause environmental problems and natural alternatives are being sought. In this context, invasive plants could provide an as yet unexplored source for the development of future herbicides. Urochloa humidicola has great invasive potential in Brazilian environments as it hampers the establishment of other plants. The phytotoxicity of U. humidicola root extracts has been evaluated, and the major components have been identified. The phytotoxicity of the extract was assessed in the wheat coleoptile assay on seeds of troublesome weeds and on Anadenanthera colubrina, a tree species used in ecological restoration programs. The ethyl acetate extract showed the highest activity, and the most affected weeds were E. crus-galli, M. maximus, and A. viridis with the latter weed more affected by the extract than by the herbicide Logran. Microscopic ultrastructural analysis of A. colubrina roots indicated possible signals of cell death. Seven compounds were identified in the ethyl acetate extract of which one diterpene and four saponins are new. Six of these compounds were tested in the wheat coleoptile bioassay. The most active were diterpene 1 and saponins 2, 3, and 6. The phytotoxic activity of U. humidicola explains the issues observed in ecological restoration with A. colubrina in the presence of Urochloa species, and its effect on weeds reinforces its potential use in agriculture.

A bifunctional catalyst for selective ring opening (SRO) has been designed using a hierarchical zeolite as support. This material was prepared introducing additional mesoporosity in the microporous structure of a USY zeolite, by surfactant-templating post-synthetic mesostructuring process. Monometallic and bimetallic Pt(x)−Ir(y) catalysts with different metal loadings and Pt/Ir mole ratio have been prepared. In addition, to optimise the acid-metal balance, the acidity of the support has been modulated via ion-exchange process with Na+. The catalytic behaviour of the prepared materials has been evaluated with ethylbenzene hydrogenation and SRO simultaneous reaction in a continuous-flow fixed-bed reactor, at 275°C and 3 MPa. Pt(2)−Ir(1) resulted the most promising metallic combination. The high hydrogenolytic activity of Ir, along with the high hydrogenation activity and cracking limitation of Pt attained a high paraffins production. This behaviour was improved modulating the acidity of the support. Thus, Pt(2)−Ir(1)/Na−FAU−CTAB catalyst maximized the yield to paraffins which improve the cetane number of fuels.

Piptocarpha rotundifolia (Less.) Baker stands out as one of the species with the highest frequency, density, and relative dominance in the Cerrado formations. However, no phytochemical studies have been carried out with this species to date. The aim of this study was to evaluate the phytotoxic activity of P. rotundifolia leaves in the search of new environmentally friendly tools for weed control. Thus, a wheat coleoptile and phytotoxic bioassay, using relevant agricultural weeds, was used to identify the most active extracts and fractions. The subsequent purification process allowed the isolation of 11 compounds, the phytotoxicity of which was evaluated in terms of wheat coleoptile elongation and with the most sensitive weeds. Piptocarphin A was found to be the major compound and the most active. To confirm its phytotoxic potential, the effect on Ipomea grandifolia grown in a hydroponic culture and on metaxylem cells was studied. The results obtained in this study demonstrate that the inhibitory activity displayed by P. rotundifolia leaf extract is mainly due to the presence of piptocarphin A. The phytotoxicity shown by P. rotundifolia leaf extract, and the isolated compounds, on weeds could provide new tools for weed control in agricultural fields., This research was supported by CAPES - Coordination for the Improvement of Higher Education Personnel (Brazil) (Project 88881.119937/2016-01) and "Ministerio de Economia, Industria y Competitividad" (MINEICO), Spain, Project AGL201788-083-R.

11,13-Dehydro seco-guaianolides, a particular type of sesquiterpene lactones, were synthesized from the commercially available α-santonin (11) using a facile strategy involving a high-yielding photochemical reaction. Natural products 10 and 17 from Artemisia gorgonum were synthesized in good yields. Specifically, compound 10 was obtained in five steps with an overall yield of 17%. The sesquiterpene lactones were tested in the etiolated wheat coleoptile bioassay, and the most active compounds were assayed on standard target species. Guaianolide 13 showed the highest phytotoxic activities when compared with the known herbicide Logran.

Natural product anhydrojudaicin (7) is a eudesmanolide that has been synthesized from costunolide (1) in three steps with good yield, simplifying procedures available in the literature. The key step was the efficient oxidation and rearrangement using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). Following the same methodology, 11,13-dehydroanhydrojudaicin (8) was prepared for the first time. All compounds were characterized and tested in three specific bioassays: phytotoxicity bioassays on wheat coleoptile and on weed seeds (Amaranthus viridis, Echinochloa crus-galli and Panicum maximum); as well as bioassay of germination of parasitic weed seeds of broomrape (Orobanchaceae). The final products showed better activity profiles than the starting eudesmanolide in all bioassays. The data allow us to propose compounds 7 and 8 as leads for new natural product-based agrochemicals.

Made available in DSpace on 2019-10-06T15:38:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-06-01 The excessive proliferation of toxin producing cyanobacteria constitutes a significant health risk to the environment and humans. This is due to the contamination of potable water and accumulation of cyanotoxins in plant and animal tissues. As a means of controlling bloom forming cyanobacteria, secondary metabolites with pro-oxidative activities from plants are used to treat water bodies contaminated with cyanobacterial blooms and their associated toxins. The objective of the present study was to evaluate the mechanism of action of extract, fractions and isolated flavonoids of Tridax procumbens L. on Microcystis aeruginosa (Kützing) Kützing. by monitoring changes in growth, oxidative stress, antioxidant response, and cyanatoxin microcystins (MCs) production. The extract, fraction 3 and the isolated flavonoids significantly reduced the cell density of the cyanobacterium. Furthermore, the extract and fraction 3 increased the production of reactive oxygen species, induced lipid peroxidation, and altered antioxidant enzyme activities of M. aeruginosa. The total MCs content of the cyanobacterium was negatively affected by the presence of the extract, fractions and isolated flavonoids. The present study show that T. procumbens has secondary metabolites that are capable of interfering with the physiology and microcystins production of M. aeruginosa. These characteristics are promising for the control of this noxious cyanobacterium in aquatic ecosystems. São Paulo State University (UNESP) School of Sciences Humanities and Languages Assis Department of Biotechnology Laboratory of Herbal Medicine and Natural Products, Avenida Dom Antônio 2100 São Paulo State University (UNESP) Institute of Chemistry, Rua Prof. Francisco Degni 55 Departamento de Ciências Biológicas Escola Superior de Agricultura Luiz de Queiroz Universidade de São Paulo Allelopathy Group Department of Organic Chemistry Institute of Biomolecules (INBIO) School of Science University of Cadiz, Campus de Excelencia Internacional 6 (ceiA3), C/República Saharaui 7 Department of Botany Ahmadu Bello University São Paulo State University (UNESP) School of Sciences Humanities and Languages Assis Department of Biotechnology Laboratory of Herbal Medicine and Natural Products, Avenida Dom Antônio 2100 São Paulo State University (UNESP) Institute of Chemistry, Rua Prof. Francisco Degni 55

Capsaicinoids are reported to have a bunch of promising pharmacological activities, among them antibacterial effects against various strains of bacteria. In this study the effect on efflux pumps of mycobacteria was investigated. The importance of efflux pumps, and the inhibition of these, is rising due to their involvement in antibiotic resistance development. In order to draw structure and activity relationships we tested natural and synthetical capsaicinoids as well as synthetical capsinoids. In an accumulation assay these compounds were evaluated for their ability to accumulate ethidium bromide into mycobacterial cells, a well-known substrate for efflux pumps. Capsaicin and dihydrocapsaicin, the two most abundant capsaicinoids in Capsicum species, proved to be superior efflux pump inhibitors compared to the standard verapamil. A dilution series showed dose dependency of both compounds. The compound class of less pungent capsinoids qualified for further investigation as antibacterials against Mycobacterium smegmatis.

Benzoxazinoids (BXs), alkaloids frequently found in Gramineae species, are natural defensives that can potentially be exploited to the development of novel antimicrobial agents. Here, BXs analogs w...

Six different ortho-disubstituted disulfides were synthesized and evaluated in wheat coleoptiles bioassays. The most active ones were evaluated on seeds of four different plant species (Solanum lycopersicum L., Lolium rigidum Gaudin, Echinochloa crus-galli (L.) Beauvois, and Urochloa decumbens (Stapf) R. D. Webster) to evaluate their effects on the germination and plant growth, presenting, in general, higher activity than the model herbicide Logran. The results shown in this study indicate that these compounds are potential candidates as herbicide leads for weed control in agriculture.

Annona cherimola Mill., or the custard apple, is one of the species belonging to the Annonaceae family, is widely used in traditional medicine, and has been reported to be a valuable source of bioactive compounds. A unique class of secondary metabolites derived from this family are Annonaceous acetogenins, lipophilic polyketides considered to be amongst the most potent antitumor compounds. This review provides an overview of the chemical diversity, isolation procedures, bioactivity, modes of application and synthetic derivatives of acetogenins from A. cherimola Mill., This work was financially supported by the 'Ministerio de Economia y Competitividad' (Project AGL2017-88083-R), Spain. F.J.R.M. thanks Universidad de Cadiz for predoctoral support under grant 2018-009/PU/EPIF-FPI-CT/CP.

Aminophenoxazinones are degradation products resulting from the metabolism of different plant species, which comprise a family of natural products well known for their pharmacological activities. This review provides an overview of the pharmacological properties and applications proved by these compounds and their structural derivatives during 2000–2021. The bibliography was selected according to our purpose from the references obtained in a SciFinder database search for the Phx-3 structure (the base molecule of the aminophenoxazinones). Compounds Phx-1 and Phx-3 are among the most studied, especially as anticancer drugs for the treatment of gastric and colon cancer, glioblastoma and melanoma, among others types of relevant cancers. The main information available in the literature about their mechanisms is also described. Similarly, antibacterial, antifungal, antiviral and antiparasitic activities are presented, including species related directly or indirectly to significant diseases. Therefore, we present diverse compounds based on aminophenoxazinones with high potential as drugs, considering their levels of activity and few adverse effects.

Several strategies have been proposed to control parasitic plants and these include biological control, the use of herbicides, and suicidal germination or trap crops. In the case of sunflower, the most effective solution is genetic resistance. Nevertheless, the use of resistant cultivars is followed by the appearance of new and more virulent races of the parasite that overcome the existing sources of resistance. For this reason, it is necessary to increase our knowledge of the mechanisms involved in the resistant varieties. In this study, the presence of compounds involved in pre-attachment resistance mechanisms in sunflower varieties was analyzed. The production of stimulators of the germination of parasitic plant seeds and the concentration of the haustorial elongation inhibitor, scopoletin, were measured in exudates of resistant and susceptible sunflower varieties. It was found that dehydrocostuslactone and orobanchyl acetate are not involved in the resistance of the sunflower varieties studied. The results demonstrate that costunolide, heliolactone, and scopoletin are related to sunflower resistance. The sunflower varieties studied do not use all available options to fight parasitic plants. This could be one of the reasons that sunflower resistance is rapidly overcome by broomrape.

Strigolactones (SLs) are a prime example of allelochemicals, promoting parasitic plant germination and certain hyphal branching factors associated to the growth of symbiotic arbuscular mycorrhizal fungi (AMF). However, the study of SLs is complex, and various issues have yet to be studied in depth. This review intends to provide an overview of the works that have been conducted on the identification, isolation, and evaluation of the allelopathic activity of natural canonical and non-canonical SLs on parasitic weeds and AMF growth. These topics were related with their application in agriculture through trap crops, suicidal germination or intercropping strategies. The high applicability of SLs in agriculture, for example, as preventing herbicides for parasitic weed control, has increased the interest for these compounds and the number of research articles published. This review updates and discusses the last findings in this field, with special emphasis in the results published since 2015, using tables and graphs to summarize and discuss that information. The promising results and conclusions obtained from the bioassays herein presented provide a good reason to encourage and support further research works on these natural products, which must also consider the disadvantages or current limitations that SLs present., This work was supported by the "Ministerio de Economia, Industria y Competitividad" (MINEICO), Spain, Project AGL2017-88-083-R; and by grants RTI2018-094350-B-C31 from the Spanish National R&D Plan of the Ministry of Science, Innovation and Universities Economy and Competitiveness (MICIU) and the European Regional Development Fund (ERDF).

In Nature, the oldest method of communication between living systems is the chemical language. Plants, due to their lack of mobility, have developed the most sophisticated way of chemical communication. Despite that many examples involve this chemical communication process-allelopathy, there is still a lack of information about specific allelochemicals released into the environment, their purpose, as well as in-depth studies on the chemistry underground. These findings are critical to gain a better understanding of the role of these compounds and open up a wide range of possibilities and applications, especially in agriculture and phytomedicine. The most relevant aspects regarding the chemical language of plants, namely kind of allelochemicals, have been investigated, as well as their releasing mechanisms and their purpose will be described in this chapter.

Annonaceous acetogenins (ACGs) are lipophilic polyketides isolated exclusively from Annonaceae. They are considered to be amongst the most potent antitumor compounds. Nevertheless, their applications are limited by their poor solubility. The isolation of ACGs from Annona cherimola leaves, an agricultural waste, has not been reported to date. Molvizarin (1) cherimolin-1 (2), motrilin (3), annonacin (4) and annonisin (5) are isolated for the first time from A. cherimola deciduous leaves. Annonacin was found to be four- and two-times more potent in tumoral cells (HeLa, 23.6% live cells, IGROV-1, 40.8% live cells for 24 h) than in HEK-293 at 50 &micro, M (24 h, 87.2% live cells). Supramolecular polymer micelles (SMPMs) were synthesized to encapsulate the major ACG isolated, annonacin, in order to improve its solubility in aqueous media. The bioavailability of this compound was increased by a factor of 13 in a simulated human digestive system when compared with free annonacin and an encapsulation efficiency of 35% was achieved. In addition, the cytotoxic activity of SMPMs that hosted annonacin (100 &micro, M, 24 h, 5.8% live cells) was increased compared with free annonacin in water (100 &micro, M, 24 h, 92% live cells). These results highlight the use of by-products of A. cherimola, and their pure compounds, as a promising source of anticancer agents. The use of SMPMs as nanocarriers of ACGs could be an alternative for their application in food field as nutraceutical to enhance the administration and efficacy.

Herbicides are a key element in agriculture but they do cause environmental problems and natural alternatives are being sought. In this context, invasive plants could provide an as yet unexplored source for the development of future herbicides.