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1.
J Agric Food Chem ; 2024 Jun 05.
Article in English | MEDLINE | ID: mdl-38838244

ABSTRACT

The good phytotoxicity and selectivity against weeds versus tomato or cress make saponin-rich fractions from Agave macroacantha, A. colorata, A. parryi, and A. parrasana attractive candidates as bioherbicides. The saponin contents have only previously been reported for A. macroacantha, and as a consequence, simultaneous dereplication has been performed on saponin-rich fractions from the other plants by mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy. This strategy enables the identification of a total of 26 saponins, 14 of which have been described previously and 12 of which are proposed as new saponins. They include isomers and a new sugar chain with a ß-d-apiofuranose unit. The method is corroborated by the isolation of eight dereplicated saponins from A. colorata.

2.
Toxins (Basel) ; 15(5)2023 05 20.
Article in English | MEDLINE | ID: mdl-37235382

ABSTRACT

Naphthoquinones are a valuable source of secondary metabolites that are well known for their dye properties since ancient times. A wide range of biological activities have been described highlighting their cytotoxic activity, gaining the attention of researchers in recent years. In addition, it is also worth mentioning that many anticancer drugs possess a naphthoquinone backbone in their structure. Considering this background, the work described herein reports the evaluation of the cytotoxicity of different acyl and alkyl derivatives from juglone and lawsone that showed the best activity results from a etiolated wheat coleoptile bioassay. This bioassay is rapid, highly sensitive to a wide spectrum of activities, and is a powerful tool for detecting biologically active natural products. A preliminary cell viability bioassay was performed on cervix carcinoma (HeLa) cells for 24 h. The most promising compounds were further tested for apoptosis on different tumoral (IGROV-1 and SK-MEL-28) and non-tumoral (HEK-293) cell lines by flow cytometry. Results reveal that derivatives from lawsone (particularly derivative 4) were more cytotoxic on tumoral than in non-tumoral cells, showing similar results to those obtained with of etoposide, which is used as a positive control for apoptotic cell death. These findings encourage further studies on the development of new anticancer drugs for more directed therapies and reduced side effects with naphthoquinone skeleton.


Subject(s)
Antineoplastic Agents , Naphthoquinones , Female , Humans , HEK293 Cells , Naphthoquinones/pharmacology , Naphthoquinones/metabolism , Antineoplastic Agents/pharmacology , Antineoplastic Agents/chemistry , Etoposide , Cell Line, Tumor
3.
Plants (Basel) ; 11(23)2022 Dec 05.
Article in English | MEDLINE | ID: mdl-36501417

ABSTRACT

Plant growth-stimulation bioactivity of triterpenoid saponins is well known, especially for oleanane-type compounds. Nevertheless, a few phytotoxicity bioassays performed on some steroidal saponins have shown hormesis profiles and growth stimulation on Lactuca sativa roots. The focus of the work described here was on the use of the wheat coleoptile bioassay to evaluate plant growth stimulation, and on the search for a commercially available source of active saponins by bio-guided fractionation strategy. Selected saponins were tested and a cluster analysis showed that those saponins with a sugar chain of more than five units had a hormesis profile, while saponins with growth enhancement had fewer sugar residues. Two saponins showed similar activity to the positive control, namely the phytohormone indole-3-butyric acid (IBA). As a potential source of these metabolites, a commercial extract of Yucca schidigera used as a fertilizer was selected. Bio-guided fractionation led to the identification of two fractions of defined composition and these showed stimulation values similar to the positive control. It was observed that the presence of a carbonyl group at C-12 on the aglycone skeleton led to improved activity. A saponin-rich fraction from Y. schidigera could be proposed to enhance crop quality and production.

4.
Phytochemistry ; 203: 113350, 2022 Nov.
Article in English | MEDLINE | ID: mdl-35973612

ABSTRACT

Defense-related metabolome traits in pine species after infestation by Sirex noctilio are largely unknown, despite, in most cases, trees being overwhelmed. Using LC-MS-based untargeted metabolomics, we revealed the systemic metabolic changes induced by this insect in 14-year-old Pinus radiata trees, the most affected species worldwide. An immediate metabolome alteration was expressed in needles after infestation, including the up-regulation of flavonols, flavan-3-ols, oxyneolignans, auxins, proline, and tryptophan, among others. The flavan-3-ols (catechin and procyanidin B1) suggested a rapidly induced photoprotection mechanism aided by diverting proline as an alternative substrate for respiration to compensate for the progressive chlorosis that degrades photosystems. Meanwhile, glutathione, glutamate, and ascorbate levels significantly dropped in needles, which may indicate the critical oxidative stress that trees had to face since the onset of the infestation. They were not fully replenished after long-term infestation, and redox homeostasis was probably not achieved, compromising tree survival. Nevertheless, a huge auxins overexpression detected in needles throughout the infestation may reflect tolerance against the premature senescence caused by the woodwasp venom. In contrast, the metabolome of wood tissues remained initially unchanged, although it seems to collapse after three months. Overall, the metabolomics strategy adopted in this work evidenced its usefulness in uncovering the fundamental roles of plants' chemical defense that govern interactions with specific stressors.


Subject(s)
Catechin , Hymenoptera , Pinus , Animals , Flavonols , Glutamates , Glutathione , Hymenoptera/physiology , Indoleacetic Acids , Proline , Trees , Tryptophan
5.
J Nat Prod ; 84(11): 2904-2913, 2021 11 26.
Article in English | MEDLINE | ID: mdl-34670365

ABSTRACT

A dereplication strategy using UPLC-QTOF/MSE, the HMAI method, and NMR spectroscopy led to the identification of five main steroidal saponins (1-5), including three previously unknown compounds named macroacanthosides A-C (3-5), in a bioactive fraction of Agave macroacantha. The major saponins were isolated, and some of them together with the saponin-rich fraction were then evaluated for phytotoxicity on a standard target species, Lactuca sativa. The inhibition values exhibited by the pure compounds were confirmed to be in agreement with the phytotoxicity of the saponin-rich fraction, which suggests that the saponin fraction could be applied successfully as an agrochemical without undergoing any further costly and/or time-consuming purification processes. The NMR data of the pure compounds as well as of those corresponding to the same compounds in the fraction were comparable, which indicated that the main saponins could be identified by means of this replication workflow and that no standards are required.


Subject(s)
Agave/chemistry , Saponins/isolation & purification , Lactuca/drug effects , Lactuca/growth & development , Magnetic Resonance Spectroscopy , Saponins/chemistry , Saponins/toxicity
6.
Molecules ; 26(17)2021 Aug 30.
Article in English | MEDLINE | ID: mdl-34500685

ABSTRACT

Yucca is one of the main sources of steroidal saponins, hence different extracts are commercialized for use as surfactant additives by beverage, animal feed, cosmetics or agricultural products. For a deeper understanding of the potential of the saponins that can be found in this genus, an exhaustive review of the structural characteristics, bioactivities and analytical methods that can be used with these compounds has been carried out, since there are no recent reviews on the matter. Thus, a total of 108 saponins from eight species of the genus Yucca have been described. Out of these, the bioactivity of 68 saponins derived from the isolation of Yucca or other genera has been evaluated. Regarding the evaluation and quality control of the saponins from this genus LC-MS technique is the most often used. Nevertheless, the development of methods for their routine analysis in commercial preparations are needed. Moreover, most of the studies found in the literature have been carried out on Y. schidigera extract, since is the most often used for commercial purposes. Only eight of the 50 species that belong to this genus have been studied, which clearly indicates that the identification of saponins present in Yucca genus is still an unresolved question.


Subject(s)
Saponins/chemistry , Yucca/chemistry , Glycosides/chemistry
7.
Phytochem Anal ; 32(1): 38-61, 2021 Jan.
Article in English | MEDLINE | ID: mdl-32515107

ABSTRACT

INTRODUCTION: The analysis and detection of steroidal saponins is mainly performed using chromatographic techniques coupled with mass spectrometry. However, nuclear magnetic resonance (NMR) spectroscopy is a potential tool that can be combined with these techniques to obtain unambiguous structural characterisation. OBJECTIVE: This work provides a review of the carbon-13 (13 C)- and proton (1 H)-NMR spectroscopic data of aglycones from Agave saponins reported in the literature and also the development of an easy identification method for these natural products. METHODS: The database Scifinder was used for spectroscopic data collection in addition to data obtained from the Cadiz Allelopathy research group. The keywords used were Agave, spirostanic, furostanic, and saponin. RESULTS: The shielding variations produced by functional groups on the aglycone core and the structural features of the most representative aglycones from Agave species are described. The effects are additive for up to four long-range connectivities. A method for the identification of aglycones (HMAI) is proposed to classify aglycones from Agave spp. through the use of 1 H-NMR and heteronuclear multiple bond correlation (HMBC) experiments. CONCLUSIONS: The HMBC spectrum is representative of the structural features of aglycones from Agave spp. The HMBC method for aglycone identification (HMAI) method allowed the identification of pure saponins or mixtures thereof and this method can be used in combination with chromatographic techniques coupled with mass spectrometry to provide a more thorough analysis of Agave samples that contain aglycones.


Subject(s)
Agave , Saponins , Magnetic Resonance Spectroscopy , Plant Extracts
8.
J Nat Prod ; 82(6): 1496-1502, 2019 Jun 28.
Article in English | MEDLINE | ID: mdl-31244146

ABSTRACT

A bioassay-guided phytochemical study of a Mimosa caesalpiniifolia leaf extract with antifungal activity permitted the identification of 28 compounds, including the new 6-(ß-boivinopyranosyl)apigenin (1), 8-(ß-oliopyranosyl)apigenin (2), (E)-6-(2-carboxyethenyl)apigenin (3), (E)-8-(2-carboxyethenyl)apigenin (4), and 7,5″-anhydro-6-(α-2,6-dideoxy-5-hydroxyarabinohexopyranosyl)apigenin (5). The structures of the new compounds were determined by comprehensive spectroscopic analysis, including 1D and 2D NMR techniques, and by mass spectrometry. Compound 3 showed promising activity and selectivity against Candida krusei (IC50 44 nM), which exhibits resistance to azoles. The association of the major components 3-ß-d-glucopyranosyloxysitosterol (8) and ethyl gallate (10) was synergistic against C. krusei, especially the IC values of compound 10, which were reduced by more than 100-fold.

9.
J Nat Prod ; 79(11): 2903-2911, 2016 11 23.
Article in English | MEDLINE | ID: mdl-27797203

ABSTRACT

Four new steroidal saponins (1-4) along with 13 known saponins were isolated from the leaves of Furcraea hexapetala. The new compounds were identified as (20R,22R,25R)-3ß-hydroxy-5α-spirostan-12-one 3-O-{α-l-rhamnopyranosyl-(1→4)-O-ß-d-glucopyranosyl-(1→3)-O-[ß-d-glucopyranosyl-(1→3)-O-ß-d-glucopyranosyl-(1→2)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (1), (25R)-3ß-hydroxy-5α-spirost-20(21)-en-12-one 3-O-{α-l-rhamnopyranosyl-(1→4)-O-ß-d-glucopyranosyl-(1→3)-O-[ß-d-glucopyranosyl-(1→3)-O-ß-d-glucopyranosyl-(1→2)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (2), (25R)-5α-spirostan-3ß-ol 3-O-{ß-d-glucopyranosyl-(1→2)-O-ß-d-glucopyranosyl-(1→2)-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (3), and (25R)-5ß-spirostan-3ß-ol 3-O-{ß-d-glucopyranosyl-(1→6)-O-ß-d-galactopyranoside} (4) by spectroscopic analysis, including one- and two-dimensional NMR techniques, mass spectrometry, and chemical methods. The phytotoxicity of the isolated compounds against the standard target species Lactuca sativa was evaluated. Structure-activity relationships for these compounds with respect to phytotoxic effects are discussed.


Subject(s)
Alkaloids/isolation & purification , Alkaloids/pharmacology , Asparagaceae/chemistry , Phytosterols/isolation & purification , Phytosterols/pharmacology , Plant Leaves/chemistry , Saponins/isolation & purification , Saponins/pharmacology , Alkaloids/chemistry , Cuba , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Phytosterols/chemistry , Saponins/chemistry , Stereoisomerism , Structure-Activity Relationship
10.
J Nat Prod ; 78(1): 77-84, 2015 Jan 23.
Article in English | MEDLINE | ID: mdl-25517504

ABSTRACT

A phytochemical study of a Serjania marginata leaf extract with antiulcer activity afforded 15 compounds, including the new 3-O-α-l-arabinopyranosyl(1→3)-α-l-rhamnopyranosyl(1→2)[ß-d-glucopyranosyl(1→4)]-α-l-arabinopyranosyloleanolic acid (1) and 7,5″-anhydroapigenin 8-C-α-(2,6-dideoxy-5-hydroxy-ribo-hexopyranosyl)-4'-O-ß-d-glucopyranoside (4). The structures of the new compounds were determined by spectroscopic analysis, including 1D and 2D NMR techniques, mass spectrometry, and chemical methods. Compound 4 is a C-hexopyranosylapigenin with an unusual cyclic ether linkage between C-5″ and C-7 of apigenin. The isolated proanthocyanidins have high antioxidant activities, and these compounds are probably responsible for the gastroprotective effect of the extract.


Subject(s)
Anti-Ulcer Agents/chemistry , Apigenin/chemistry , Glycosides/isolation & purification , Oleanolic Acid/isolation & purification , Sapindaceae/chemistry , Anti-Ulcer Agents/isolation & purification , Anti-Ulcer Agents/pharmacology , Apigenin/isolation & purification , Apigenin/pharmacology , Brazil , Glycosides/chemistry , Glycosides/pharmacology , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Oleanolic Acid/chemistry , Oleanolic Acid/pharmacology , Plant Leaves/chemistry , Saponins/chemistry , Triterpenes/chemistry
11.
Phytochemistry ; 105: 92-100, 2014 Sep.
Article in English | MEDLINE | ID: mdl-24939800

ABSTRACT

A bioassay-guided fractionation of Agave offoyana leaves led to the isolation of five steroidal saponins (1-5) along with six known saponins (6-11). The compounds were identified as (25R)-spirost-5-en-2α,3ß-diol-12-one 3-O-{α-l-rhamnopyranosyl-(1→3)-O-ß-d-glucopyranosyl-(1→2)-O-[ß-d-xylopyranosyl-(1→3)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (1), (25R)-spirost-5-en-3ß-ol-12-one 3-O-{α-l-rhamnopyranosyl-(1→3)-O-ß-d-glucopyranosyl-(1→2)-O-[ß-d-xylopyranosyl-(1→3)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (2), (25R)-spirost-5-en-3ß-ol-12-one 3-O-{ß-d-xylopyranosyl-(1→3)-O-ß-d-glucopyranosyl-(1→2)-O-[ß-d-xylopyranosyl-(1→3)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (3), (25R)-26-O-ß-d-glucopyranosylfurost-5-en-3ß,22α,26-triol-12-one 3-O-{α-l-rhamnopyranosyl-(1→3)-O-ß-d-glucopyranosyl-(1→2)-O-[ß-d-xylopyranosyl-(1→3)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (4) and (25R)-26-O-ß-d-glucopyranosylfurost-5-en-3ß,22α,26-triol-12-one 3-O-{ß-d-xylopyranosyl-(1→3)-O-ß-d-glucopyranosyl-(1→2)-O-[ß-d-xylopyranosyl-(1→3)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (5) by comprehensive spectroscopic analysis, including one- and two-dimensional NMR techniques, mass spectrometry and chemical methods. The phytotoxicity of the isolated compounds on the standard target species Lactuca sativa was evaluated.


Subject(s)
Agave/chemistry , Phytosterols/isolation & purification , Phytosterols/pharmacology , Saponins/isolation & purification , Saponins/pharmacology , Nuclear Magnetic Resonance, Biomolecular , Phytosterols/chemistry , Plant Leaves/chemistry , Saponins/chemistry , Stereoisomerism , Structure-Activity Relationship
12.
J Agric Food Chem ; 61(41): 9789-96, 2013 Oct 16.
Article in English | MEDLINE | ID: mdl-24098957

ABSTRACT

Seven previously unreported triterpene glycosides (1-7) were isolated from methanol extract of the aerial parts of Trifolium medium var. sarosiense (zigzag clover). Their structures were established by the extensive use of 1D and 2D NMR experiments along with ESI-MS and HRMS analyses. Compounds 1-7 are oleanane derivatives characterized by the presence of a keto group at C-22 of an aglycone and a primary alcoholic function at C-24 and differing functions at C-30. Among these, compounds 1-3 and 6 showed a secondary alcoholic function at C-11, which is methoxylated in compounds 4 and 7. Compound 5 was shown to possess a known aglycone, wistariasapogenol A; however, it is described here for the first time as a saponin constituent of the Trifolium genus. Some aspects of taxonomic classification of zigzag clover are also discussed.


Subject(s)
Plant Extracts/chemistry , Saponins/chemistry , Trifolium/chemistry , Triterpenes/chemistry , Molecular Structure , Plant Extracts/isolation & purification , Plant Leaves/chemistry , Plant Stems/chemistry , Saponins/isolation & purification , Triterpenes/isolation & purification
13.
Phytochemistry ; 95: 298-307, 2013 Nov.
Article in English | MEDLINE | ID: mdl-23859261

ABSTRACT

Bioguided studies of flowers of Agave offoyana allowed the isolation of five steroidal saponins never described previously, Magueyosides A-E (1-5), along with six known steroidal saponins (6-11). The structures of compounds were determined as (25R)-spirost-5-en-2α,3ß-diol-12-one 3-O-{ß-d-xylopyranosyl-(1→3)-O-ß-d-glucopyranosyl-(1→2)-O-[ß-d-xylopyranosyl-(1→3)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (1), (25R)-spirost-5-en-2α,3ß-diol-12-one 3-O-{ß-d-glucopyranosyl-(1→2)-O-[ß-d-xylopyranosyl-(1→3)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (2), (25R)-spirost-5-en-2α,3ß,12ß-triol 3-O-{ß-d-glucopyranosyl-(1→2)-O-[ß-d-xylopyranosyl-(1→3)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (3), (25R)-5α-spirostan-2α,3ß-diol-12-one 3-O-{ß-d-xylopyranosyl-(1→3)-O-ß-d-glucopyranosyl-(1→2)-O-[ß-d-xylopyranosyl-(1→3)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (4), and (25R)-5α-spirostan-2α,3ß-diol-9(11)-en-12-one 3-O-{ß-d-xylopyranosyl-(1→3)-O-ß-d-glucopyranosyl-(1→2)-O-[ß-d-xylopyranosyl-(1→3)]-O-ß-d-glucopyranosyl-(1→4)-O-ß-d-galactopyranoside} (5), by comprehensive spectroscopic analysis, including one- and two-dimensional NMR techniques, mass spectrometry and chemical methods. The bioactivities of the isolated compounds on the standard target species Lactuca sativa were evaluated. A dose-dependent phytotoxicity and low dose stimulation were observed.


Subject(s)
Agave/chemistry , Plant Extracts/pharmacology , Saponins/pharmacology , Flowers/chemistry , Lactuca/drug effects , Molecular Structure , Plant Extracts/chemistry , Saponins/chemistry , Saponins/isolation & purification
14.
J Agric Food Chem ; 61(11): 2631-7, 2013 Mar 20.
Article in English | MEDLINE | ID: mdl-23438309

ABSTRACT

Five azukisapogenol glycosides (1-5) have been isolated from the aerial parts of alsike clover (Trifolium hybridum L.), and their structures were elucidated by combined spectroscopic, spectrometric (1D and 2D NMR; HRESIMS, ESI-MS/MS), and chemical methods. Three of them are new compounds and were identified as 3-O-[-α-L-arabinopyranosyl(1→2)]-ß-D-glucuronopyranosyl azukisapogenol (1), 3-O-[-ß-D-glucuronopyranosyl(1→2)-ß-D-glucuronopyranosyl]-29-O-ß-D-glucopyranosyl azukisapogenol (2), and 3-O-[-α-L-arabinopyranosyl(1→2)-ß-D-glucuronopyranosyl]-29-O-ß-D-glucopyranosyl azukisapogenol (3). The remaining two (4, 5) are known compounds but have not been previously described as saponins constituents of the genus Trifolium . Also, azukisapogenol is reported here as a triterpenoid aglycone for the first time in this genus. Finally, the main chemotaxonomic features that may be recognized as specific of Trifolium species were discussed.


Subject(s)
Glycosides/chemistry , Plant Components, Aerial/chemistry , Plant Extracts/chemistry , Trifolium/chemistry , Triterpenes/chemistry , Glycosides/isolation & purification , Molecular Structure , Plant Extracts/isolation & purification , Triterpenes/isolation & purification
15.
Nat Prod Commun ; 8(12): 1687-90, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24555273

ABSTRACT

Three new triterpenoid saponins (1-3), along with nine known saponins, were isolated from the roots of Saponaria officinalis L. Two of them: vaccaroside D (4) and dianchinenoside B (5) are known, but not previously reported for S. officinalis, and seven others: saponarioside C (6), D (7), F (8), G (9), I (10), K (11), and L (12) have been previously isolated from this plant. The structures of the new saponins were established as 3-O-beta-D-xylopyranosyl-16alpha-hydroxygypsogenic acid-28-O-[beta-D-glucopyranosyl-(1 -->6)-beta-D-glucopyranoside (1), 3-O-beta-D-xylopyranosyl-16alpha-hydroxygypsogenic acid-28-O-[beta-D-glucopyranosyl-(1-->3)]-[alpha-D-galactopyranosyl-(1-->6)-alpha-D-galactopyranosyl-(1-->6)-beta-D-glucopyranosyl-(1-->6)]-beta-D-glucopyranoside (2) and 3-O-beta-D-xylopyranosyl-gypsogenic acid-28-O-[beta-D-glucopyranosyl-(1-->3)]-[6-O-(3-hydroxy-3-methylglutaryl)-beta-D-glucopyranosyl-(1-->6)]-beta-D-glucopyranoside (3). Their structures were elucidated by extensive spectroscopic methods, including 1D- (1H, 13C) and 2D-NMR (D QF-COSY, TOCSY, ROESY, HSQC and HMBC) experiments, as well as high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), ESI-MS/MS and acid hydrolysis.


Subject(s)
Saponaria/chemistry , Triterpenes/isolation & purification , Molecular Structure , Plant Roots/chemistry , Triterpenes/chemistry
16.
Magn Reson Chem ; 48(5): 350-5, 2010 May.
Article in English | MEDLINE | ID: mdl-20391439

ABSTRACT

A careful NMR analysis, especially by 1D TOCSY and 1D ROESY, of a refined saponin fraction allowed us to determine the structure of three saponins from a polar extract of Agave brittoniana Trel. spp. Brachypus leaves. The use of 1D DOSY for the suppression of the solvent signal was useful to obtain the chemical shifts of anomeric signals. A full assignment of the (1)H and (13)C spectral data for the new saponins, agabrittonosides E-F (1-2) and the well-known Karatavioside C (3) and their methoxyl derivatives, is reported. The structures were established using a combination of 1D and 2D ((1)H, (1)H-COSY, TOCSY, ROESY, g-HSQC, g-HMBC and g-HSQC-TOCSY) NMR techniques and ESI-MS. In addition, the methoxylation of these furostane saponins in the presence of MeOH was studied.


Subject(s)
Agave/chemistry , Magnetic Resonance Spectroscopy/methods , Saponins/chemistry , Chromatography, High Pressure Liquid , Models, Molecular , Molecular Structure
17.
J Chem Ecol ; 35(1): 39-49, 2009 Jan.
Article in English | MEDLINE | ID: mdl-19151929

ABSTRACT

The new bioactive sesquiterpenoid (3R,6E)-2,6,10-trimethyl-3-(3-p-hydroxyphenylpropanoyloxy)-dodeca-6,11-diene-2,10-diol, named megalanthine, was isolated from the resinous exudates of Heliotropium megalanthum. The degradation products of this compound were identified. Several plant-defensive properties (insecticidal, antifungal, and phytotoxic) were evaluated after obtaining positive results in a preliminary etiolated wheat coleoptile bioassay. This bioassay showed the need to have both the phenolic and sesquiterpene moieties of the natural product present to achieve a biological effect. This result was confirmed in phytotoxicity bioassays. Megalanthine was ruled out as a significant plant-plant defense agent because of its lack of stability. The positive results recorded in the antifungal and antifeedant tests suggest, however, that this chemical is relevant in several ecological interactions involving H. megalanthum.


Subject(s)
Antifungal Agents/isolation & purification , Heliotropium/chemistry , Insecticides/isolation & purification , Phenylpropionates/isolation & purification , Phenylpropionates/pharmacology , Animals , Antifungal Agents/metabolism , Antifungal Agents/pharmacology , Biological Assay , CHO Cells , Cells, Cultured , Cotyledon/drug effects , Cotyledon/growth & development , Cricetinae , Cricetulus , Fungi/drug effects , Fungi/growth & development , Insecticides/metabolism , Insecticides/pharmacology , Lactuca/drug effects , Lactuca/growth & development , Solanum lycopersicum/drug effects , Solanum lycopersicum/growth & development , Microbial Sensitivity Tests , Onions/drug effects , Onions/growth & development , Phenylpropionates/metabolism , Plant Roots/drug effects , Plant Roots/growth & development , Seeds/drug effects , Seeds/growth & development , Triticum/drug effects , Triticum/growth & development
18.
Magn Reson Chem ; 45(7): 615-20, 2007 Jul.
Article in English | MEDLINE | ID: mdl-17516586

ABSTRACT

A careful NMR analysis, especially 1D TOCSY and 1D ROESY, of two refined saponin fractions allowed us to determine the structures of four new saponins from a polar extract of the Agave brittoniana Trel. spp. Brachypus leaves. A full assignment of the 1H and 13C spectral data for these new saponins, agabrittonosides A-D (1-4), and one previously known saponin, karatavioside A (5) is reported. Their structures were established using a combination of 1D and 2D (1H, 1H-COSY, TOCSY, ROESY, g-HSQC, g-HMBC and g-HSQC-TOCSY) NMR techniques and ESI-MS. Moreover, the work represents a new approach to structural elucidation of saponins in refined fractions by NMR investigations.


Subject(s)
Magnetic Resonance Spectroscopy/methods , Saponins/chemistry , Spirostans/chemistry , Agave/chemistry , Molecular Structure , Plant Extracts/chemistry , Plants, Medicinal/chemistry , Saponins/isolation & purification , Spirostans/isolation & purification
19.
J Agric Food Chem ; 54(4): 991-1000, 2006 Feb 22.
Article in English | MEDLINE | ID: mdl-16478208

ABSTRACT

Compounds with a (2H)-1,4-benzoxazin-3(4H)-one skeleton have attracted the attention of phytochemistry researchers since 2,4-dihydroxy-(2H)-1,4-benzoxazin-3(4H)-one (DIBOA) and 2,4-dihydroxy-7-methoxy-(2H)-1,4-benzoxazin-3(4H)-one (DIMBOA) were isolated from plants belonging to the Poaceae family. These compounds exhibit interesting biological properties, such as phytotoxic, antimicrobial, antifeedant, antifungal, and insecticidal properties. These chemicals, in addition to a wide variety of related compounds involved in their metabolism, detoxification mechanisms, and degradation on crop soils and other systems, have high interest and in some cases potential agronomic utility. This paper presents a complete review of the methods employed for their synthetic obtention in addition to some of the authors' own contributions to their chemistry. The degradation and phytotoxicity experiments carried out in ongoing research into the potential agronomic utility of these compounds required large amounts of them, which were obtained from natural sources. This paper presents a modified methodology to access DIMBOA from Zea mays cv. Apache and to obtain 2-O-beta-D-glucopyranosyl-2,4-dihydroxy-(2H)-1,4-benzoxazin-3(4H)-one (DIBOA-Glc) and DIBOA from Secale cereale L. New synthetic methodologies were employed for the obtention of the lactams 2-hydroxy-(2H)-1,4-benzoxazin-3(4H)-one and 2-hydroxy-7-methoxy-(2H)-1,4-benzoxazin-3(4H)-one and the malonamic acids N-(2-hydroxyphenyl)malonamic acid and N-(2-hydroxy-7-methoxyphenyl)malonamic acid. The aminophenoxazines 2-amino-7-methoxyphenoxazin-3-one and 2-acetamido-7-methoxyphenoxazin-3-one have been synthesized in the authors' laboratory by novel procedures. All of the methodologies employed allowed the desired compounds to be obtained in high yield and in an easy-to-scale manner.


Subject(s)
Oxazines/isolation & purification , Pheromones/isolation & purification , Poaceae/chemistry , Benzoxazines , Glycosides/isolation & purification , Oxazines/chemical synthesis , Pheromones/chemical synthesis , Secale/chemistry , Zea mays/chemistry
20.
J Agric Food Chem ; 54(4): 1040-8, 2006 Feb 22.
Article in English | MEDLINE | ID: mdl-16478215

ABSTRACT

Avena fatua L. (wild oat) and Lolium rigidum Gaud. (rigid ryegrass) are highly problematic weeds affecting a wide variety of cereal crops worldwide. The fact that both of these weeds have developed resistance to several herbicide groups made them optimal candidates as target organisms for ongoing research about the potential application of allelochemicals and analogue compounds as natural herbicide models. Benzoxazinones, a family of natural allelochemicals present in corn, wheat, and rye, including 2,4-dihydroxy-(2H)-1,4-benzoxazin-3(4H)-one and 2,4-dihydroxy-7-methoxy-(2H)-1,4-benzoxazin-3(4H)-one, together with some degradation products, found in crop soils as well as in other systems, and some synthetic analogues of them were tested on wild oat and rigid ryegrass seeds; the results were statistically treated, and some structure-activity relationships, useful in further development of natural herbicide models, were elucidated. The most active compounds were the synthetic benzoxazinone 2-acetoxy-(2H)-1,4-benzoxazin-3(4H)-one and the degradation product 2-aminophenoxazin-3-one, with highly significant inhibition on the development of both weeds. The ecological role of these compounds is discussed by considering both degradability and phytotoxicity. The bioactivity of aminophenoxazines has been correlated by their aqueous solubility-lipophilicity predicted by means of computational methods.


Subject(s)
Lolium/drug effects , Methylurea Compounds/pharmacology , Oxazines/chemistry , Oxazines/pharmacology , Poaceae/drug effects , Benzoxazines , Pheromones/chemistry , Pheromones/pharmacology , Structure-Activity Relationship
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