Resumen Antecedentes. La primera monografía del género Viguiera fue publicada en 1918 por Blake, incluyendo alrededor de 141 especies. Schilling & Panero en sus estudios sobre la Subtribu Helianthinae (Tribu Heliantheae) basados en secuencias moleculares de los Espaciadores nucleares Transcritos Interno y Externos, así como de cpDNA, proponen reclasificar al género reubicando sus especies en al menos otros nueve géneros. Pregunta: ¿Es posible identificar patrones distintivos entre las especies de la nueva clasificación de Viguiera s. l. y los resultados obtenidos de los estudios químicos reportados? Especies consideradas: Sesenta y siete especies en la circunscripción amplia de Viguiera con estudios químicos y actividades biológicas informados. Resultados: Las especies del género Viguiera s.l. sintetizan terpenoides, representados principalmente por lactonas sesquiterpénicas y diterpenos, aunque también se reportan triterpenos, poliacetilenos, terpenoides volátiles y flavonoides. En todas las especies estudiadas se obtuvieron los principales tipos de metabolitos, siendo algunos más frecuentes que otros en ciertos clados. Conclusión: Los principales constituyentes del género Viguiera s l. son germacrólidas, heliangólidas, furanoheliangólidas, diterpenos tetracíclicos y flavonoides. Se notan algunas relaciones quimiotaxonómicas interesantes. No obstante, no se observaron patrones distintivos claros entre los clados y grupos químicos de los géneros segregados. Estos resultados son probablemente consecuencia de la diversidad de objetivos y metodologías de los estudios químicos reportados.

Abstract Background: The first monograph of the genus Viguiera was published in 1918 by Blake, including about 141 species. Schilling & Panero based on studies of molecular sequences of nuclear Internal Transcribed Spacer and External Transcribed Spacer, as well as cpDNA, proposed to reclassify the genus, relocating its species in at least other nine genera. Question: Is it possible to identify distinctive patterns between the species of the new classification of Viguiera s. l. and the results of the chemical studies reported? Species considered: Sixty-seven species within the wide Viguiera circumscription with chemical studies and biological activities reported. Results: The species of the genus Viguiera synthesize terpenoids represented mainly by sesquiterpene lactones and diterpenes, with triterpenes, polyacetylenes, volatile terpenoids and flavonoids also present. The main types of secondary metabolites were present in the studied species, although some compounds were more frequent than others in some clades. Conclusion: Germacrolides, heliangolides, furanoheliangolides, tetracyclic diterpenes and flavonoids are the main constituents of Viguiera and segregated genera. Some interesting chemotaxonomic relationships are noted. Nevertheless, nondistinctive clear patterns were observed between clades and chemical groups. These results are likely a consequence of the diversity of objectives and methodologies of the reported chemical studies on Viguiera.

Species of genus Sida are used around the world for a large amount of therapeutic treatments, including hyperglycemia. α-Glucosidase inhibitors are recognized as valuable tools for reducing postprandial hyperglycemia by retarding absorption of glucose. The effect of extracts and isolated compounds of S. acuta and S. rhombifolia on inhibition of α-glucosidase as primary screening of anti-hyperglycemic activity was tested using yeast and mammalian α-glucosidases. When yeast α-glucosidase was used the acetone extracts of S. acuta and S. rhombifolia showed IC50 values of 8.49 ± 0.66 and 8.10 ± 0.34 µg mL-1, respectively, and the most active compound was p-hydroxyphenethyl trans-ferulate (IC50 19.24 ± 1.73 µmol L-1) followed by β-sitosteryl glucopyranoside (IC5032.70 ± 1.35 µmol L-1). However, the activity of extracts and isolated compounds decreased significantly when mammalian α-glucosidase was used, indicating that substrates affinity is higher for type 1 enzymes. The antioxidant and anti-inflammatory activities of extracts and isolates were also tested since many diabetic complications are associated to the oxidative stress and inflammatory immune responses. Acetone extracts were the most active in all evaluations. p-Hydroxyphenethyl trans-ferulate, could be associated to these activities, since it was active in the three evaluations. This effect could be related to its phenolic character.

The chemical study of Roldana platanifolia led to the isolation of β-caryophyllene, five eremophilanolides, chlorogenic acid, and a mixture of β-sitosterol-stigmasterol, β-sitosteryl glucopyranoside, and sucrose. The anti-inflammatory activities of the extracts and isolated products were tested using the 12-O-tetradecanoylphorbol-13-acetate (TPA) model of induced acute inflammation. The acetone and methanol extracts showed dose dependent activities (ID50 0.21 and 0.32 mg/ear, respectively), while none of the isolated compounds exhibited relevant edema inhibition. The active extracts were also evaluated with the myeloperoxidase assay technique (MPO) to determine their ability to prevent neutrophil infiltration. Results showed that the anti-inflammatory activity was related to the compound’s ability to inhibit pro-inflammatory mediators such as neutrophils.

The chemical study of two species of the tribe Senecioneae afforded two eremophilanes and two pyrrolizidine alkaloids from Senecio subauriculatus and four modified eremophilanes from Roldana oaxacana. The chemistry of these species is in accord with that reported for species of Senecio and Roldana studied so far, and therefore, with the already described for the tribe Senecioneae.

El estudio químico de dos especies de la tribu Senecioneae permitió obtener dos eremofilanos y dos alcaloides pirrolizidínicos de Senecio subauriculatus y cuatro eremofilanos modificados de Roldana oaxacana. Los metabolitos obtenidos de estas especies concuerdan con el tipo de metabolitos aislados de especies de Senecio y Roldana estudiadas hasta ahora, y en consecuencia, concuerdan con lo descrito para la tribu Senecioneae.

O estudo químico da Villasenoria orcuttii, a única espécie do gênero Villasenoria, levou ao isolamento de três diterpenos acíclicos, dois deles descritos pela primeira vez. Dois alcaloides pirrolizidínicos, florosenina e floridanina, entre outros compostos já conhecidos, também foram isolados. A configuração absoluta da floridanina foi determinada por análise de raios X usando dispersão anômala com radiação Cu Kα e seus dados de ressonância magnética nuclear (RMN) de¹ H e de13 C foram corrigidos.

The chemical study of Villasenoria orcuttii, the only species of the genus Villasenoria, afforded three acyclic diterpenes, two of them described for the first time. Two pyrrolizidine alkaloids, florosenine and floridanine, among other known compounds were also isolated. The absolute configuration of floridanine was determined by X-ray analysis using anomalous dispersion with Cu Kαradiation, and its¹ H and13 C nuclear magnetic resonance (NMR) data were corrected.

The chemical study of Roldana reticulate led to the isolation of two 9-oxo-furanoeremophilanes (1, 2), together with senecrassidiol, tyrosol, icariside D2, and rutin; no pyrrolizidine alkaloids were detected, in agreement with the chemistry of the genus reported so far. The anti-inflammatory activity of extracts and isolated products was tested using the TPA model of induced acute inflammation.

De Roldana reticulata se aislaron dos 9-oxo-furanoeremofilanos (1, 2), además de senecrassidiol, tirosol, icarisida D2 y rutina; no se detectaron alcaloides pirrolizidínicos, coincidiendo con el patrón químico del género reportado hasta ahora. La actividad anti-inflamatoria de los extractos y productos aislados fue evaluada en el modelo de edema de inflamación aguda inducido con TPA.

Quatro novos eremofilanos modificados, juntamente com dez derivados conhecidos de cacalol, dois cariofilenos, um aromadendreno e um flavonoide foram purificados a partir de Psacalium cirsiifolium. As estruturas destes compostos foram elucidadas por análise espectroscópica. A atividade anti-inflamatória dos extratos e de sete dos compostos isolados foi avaliada no modelo de 12-O-tetradecanoilforbol-13-acetato (TPA) de inflamação aguda induzida. O composto inédito 2α -hidroxiadenostin B (4) mostrou uma atividade dependente da dose (IC50 0,41 µmol por orelha) e um efeito de inibição de neutrófilos medido pelo teste de mieloperoxidase (MPO) semelhante ao efeito da indometacina, 0,31 e 1,0 µmol por orelha.

Four new modified eremophilanes, together with ten known cacalol derivatives, two caryophyllenes, one aromadendrene and one flavonoid were isolated from Psacalium cirsiifolium. The structures of these compounds were elucidated by spectroscopic analysis. The anti-inflammatory activity of extracts and of seven of the isolated compounds was evaluated on 12-O-tetradecanoylphorbol-13-acetate (TPA) model of induced acute inflammation. The new compound 2α -hydroxyadenostin B (4) showed a dose dependent activity (IC50 0.41 µmol per ear) and a neutrophil inhibition effect as measured by the myeloperoxidase (MPO) assay similar to that of indomethacin at 0.31 and 1.0 µmol per ear.

A chemical study of Psacalium sinuatum afforded the furanoeremophilane decompostine, the modified eremophilanes: cacalol, cacalol acetate, dehydrocacalol, maturinin, cacalohastin, dehydroca-calohastin, adenostin B, cacalone-epi-cacalone mixture, dimaturin, adenostylide, radulifolin F, and epi-radulifolin F, in addition to hyperin, sucrose and a mixture of sitosterol-stigmasterol. Extracts and isolated compounds were tested for anti-inflammmatory activity. The hexanic extract of root showed a dose dependent activity (IC50 0.20 mg/ear).

Por medio de un estudio químico de Psacalium sinuatum se aislaron el furanoeremofilano decompostina, los eremofilanos modificados: cacalol, acetato de cacalol, deshidrocacalol, maturinina, cacalohastina, deshidrocacalohastina, adenostina B, mezcla de cacalona-epi-cacalona, dimaturina, adenostilida, radulifolina F, y epi-radulifolina F, además de hiperina, sacarosa y mezcla de sitosterol-estigmasterol. Los extractos y los compuestos aislados fueron sometidos a pruebas de actividad anti-inflamatoria. El extracto hexánico de raíz presentó actividad dependiente de la dosis (IC50 0.20 mg/oreja).

A revision of the Mexican species belonging to the tribe Senecioneae chemically studied so far, shows that the genera Senecio and Packera (subtribe Senecioninae), and the genera Barkleyanthus, Pittocaulon, Psacalium, and Telanthophora (subtribe Tussilagininae) contain pyrrolizidine alkaloids (PAs) and eremophilane derivatives as their main secondary metabolites. However, from Roldana and Robinsonecio (subtribe Tussilagininae) no PAs have been isolated. A special case is the genus Pseudogynoxys in which neither PAs nor eremophilanes are reported.

Una revisión de las especies mexicanas de la tribu Senecioneae estudiadas químicamente hasta el momento, muestra que los géneros Senecio y Packera (subtribu Senecioninae), y los géneros Barkleyanthus, Pittocaulon, Psacalium y Telanthophora (subtribu Tussilagininae) contienen alcaloides pirrolizidínicos (APs) y derivados de eremofilano como sus metabolitos secundarios principales. Sin embargo, de Roldana y Robinsonecio (subtribu Tussilagininae) no se han aislado APs. Un caso especial es el género Pseudogynoxys para el cual no se han reportado ni APs ni eremofilanos.

Two new seco-eremophilanolides, roldehrenbergins C and D, were isolated from Roldana ehrenbergiana. Structural elucidation was achieved by spectroscopic methods and confirmed by X-ray crystallographic analysis.

Dos seco-eremofilanólidas, roldehrenberginas C y D, fueron aisladas de Roldana ehrenbergiana. La elucidación estructural se llevó a cabo por métodos espectroscópicos y confirmada por análisis cristalográfico de rayos-X.

A chemical study of Senecio procumbens afforded the 12-membered macrocyclic diester pyrrolizidine alkaloids senecionine (1), senecivernine (2), retrorsine (3) and their N-oxides, together with 13²-hydroxyphaeophytin a (4), caffeic acid methyl ester (5), and cacticin (6). The identification of these compounds was accomplished by comparison of their spectral features with those reported in literature. The structures of compounds 1, and those of the N-oxides of 1 and 3 were confirmed by comparison with authentic samples. In addition, the ¹H and 13C NMR spectroscopies of 2 N-oxide are reported since they were not available in the literature.

De un estudio químico de Senecio procumbens se aislaron los alcaloides pirrolizidínicos diésteres macrocíclicos de 12 miembros: senecionina (1), senecivernina (2), retrorsina (3) y sus N-óxidos, junto con 13²-hidroxifeofitina a (4), cafeato de metilo (5) y cacticina (6). Estos metabolitos fueron identificados por comparación de sus datos espectroscópicos con los descritos. La estructura de 1, y de los N-óxidos de 1 y 3 fue confirmada por comparación con muestras auténticas. Adicionalmente se incluyen los datos de RMN de ¹H y 13C del N-óxido de 2, los cuales no han sido descritos.

The phytochemical study of Psacalium beamanii afforded the phenylethanoid 1, three sterols, the furanoeremophilane derivatives 2-10, and maturone acetate (12), which was isolated as a natural product for the first time. Its structure was established by means of spectroscopic data and confirmed by chemical correlation. The optical rotation of decompostin (4) was corrected and its identity was corroborated by the X ray analysis of its 2S-bromo derivative (11).

El estudio fitoquímico de Psacalium beamanii permitió el aislamiento del feniletanoide 1, tres esteroles, los furanoeremofilanos 2-10, y el acetato de maturona (12), el cual fue aislado por primera vez como producto natural. Su estructura se estableció por medio de sus datos espectroscópicos y se confirmó por correlación química. La rotación óptica de la decompostina (4) se corrigió y su identidad se corroboró por el análisis de rayos X de su derivado 2S-bromo (11).