Abstract Phytochemical studies of Cespedesia spathulata (Ochnaceae) leaves using 1H, 13C NMR, and GC-MS have led to the isolation of some metabolites identified for the first time in these species such as cathechin, epicatechin, vitexin, orientin, 6’’-O-acetyl-vitexin, sitosterol, stigmasterol, phytol, 4,5-dihydrovomifoliol and a mixture of aliphatic methyl esters, together with ochnaflavone, which was previously isolated from this plant. The modulating activity of some fractions and compounds from Cespedesia spathulata towards tyrosinase enzyme was assayed by spectroscopic and theoretical means/experiments. The dichloromethane fraction (133 μg mL-1) and ochnaflavone (333 μM) inhibited tyrosinase activity by 20 % and 2.0 %, respectively, whereas the ethyl acetate fraction (666 μg mL-1) and ±catechins (catechin and epicatechin - 800 μM) activated it by 104 % and 384 %, respectively. Quantum chemical calculations suggested that catechin and epicatechin are better activators than L-DOPA by interacting with Cu (II) ions. Molecular docking results suggested that hydrogen bonding and hydrophobic interactions are the main binding forces between each tyrosinase activator and the amino acid residues inside the active protein binding pocket.

Abstract: This study aims to identify phenolic compounds in dichloromethane and methanolic extracts of the rhizome of Renealmia nicolaioides collected in the North Region of Brazil. Two known diarylheptanoids, 1,7-bis(4-hydroxyphenyl)-(1E)-1-hepten-3-one (1), and 5R-1,7-bis(4-hydroxyphenyl)-1E-hepten-5-ol (2), and a new one (1R,2S,5S)-2-hydroxy-1,7(p-hydroxyphenyl)-centrolobine (3), as well as one flavonoid, 3-metoxi-quercetin (4) were isolated by chromatographic procedure and identified by spectroscopic techniques (1H and13C NMR, HRMS and CD). The acetyl derivative of 2 was used to confirm its structure. All four compounds are reported for the first time for this genus, and this is the first occurrence of compound 1 as a natural metabolite. The results reported here are unprecedented for the genus Renealmia.

ABSTRACT This study aims to identify special metabolites in polar extracts from Urochloa humidicola (synonym Brachiaria humidicola) that have allelopathic effects and induce secondary photosensitization in ruminants. The compounds were isolated and identified via chromatographic and spectroscopic techniques. The compounds 4-hydroxy-3-methoxy-benzoic acid, trans-4-hydroxycinnamic acid, and p-hydroxy-benzoic acid; the flavonols isorhamnetin-3-O-β-d-glucopyranoside and methyl quercetin-3-O-β-d-glucuronate; and kaempferitrin, quercetin-3-O-α-l-rhamnopyranoside, and tricin were identified in the extract from the leaves of Urochloa humidicola. Two furostanic saponins, namely, dioscin and 3-O-α-l-rhamnopyranosyl-(1-4)-[α-l-rhamnopyranosyl-(1-2)]-β-d-glucopyranosyl-penogenin, as well as catechin-7-O-β-d-glucopyranoside were identified in the methanolic extract obtained from the roots of this plant. This species features a range of metabolites that may be toxic for animals if used in food and may interfere with the growth medium, thereby inhibiting the development of other species.

The aim of this study was to identify the composition of the essential oil from leaves of Lippia sidoides (EOLS), a typical shrub commonly found in the dry northeast of Brazil, popularly known as “alecrim-pimenta”. Additionally, we investigated the nymphicidal, ovicidal, phagoinhibitory and excretion effects of EOLS, its major constituent thymol and its isomer carvacrol, on fourth instar nymphs and eggs of Rhodnius prolixus, the Chagas’ disease vector. The nymphicidal and ovicidal activity of thymol, carvacrol, and EOLS was assessed by tests using impregnated Petri dishes. The lethal concentration values (LC50) for EOLS, carvacrol, and thymol were 54.48, 32.98, and 9.38 mg/cm2, respectively. The ovicidal test showed that both carvacrol and thymol (50 mg/cm2) inhibited hatching (50% and 23.3%, respectively), while treatments with 10 mg/cm2 or 50 mg/cm2 EOLS did not affect the hatching rate at all (80% and 90%, respectively). We observed an anti-feeding effect in insects fed with blood containing natural products at the higher concentrations (100 µg/mL). Finally, excretion rate was affected by EOLS and carvacrol, but not by thymol. These findings offer novel insights into basic physiological processes that make the tested natural compounds interesting candidates for new types of insecticides.

The phytochemical investigation of Clusia lanceolata leaves yielded fourteen compounds including six flavones, vitexin, isovitexin, isovitexin-2"-O-α-L-rhamnopyranoside, vitexin-2"-O-α-L-rhamnopyranoside, orientin and isoorientin, two phaeophytins [132-hydroxy-(132-S-)-phaeophytin a and 132-hydroxy-(132-R)-phaeophytin a], two triterpenes, α- and β-amyrin, and four steroids, β-sitosterol, stigmasterol, sitosterone and stigmasterone. Their structures were assigned based on spectroscopic analysis, including two-dimensional NMR techniques and comparison with literature data. The antioxidant capacity in vivo of vitexin and mixing isovitexin-2"-O-α-L-rhamnopyranoside and vitexin-2"-O-α-L-rhamnopyranoside was evaluated using the yeast Saccharomyces cerevisiae as the biological system model and hydrogen peroxide as a stressor agent. The results showed that the tested flavonoids were able to protect the yeast cell against the oxidative damage caused by H2O2.

Abstract The aim of the current study is to evaluate the effect of Acmella oleracea (L.) R.K. Jansen, Asteraceae, methanolic extract, hexane (84.28% spilanthol) and dichloromethane (approximately 100% spilanthol) fractions on the tyrosinase enzyme. The dehydrated jambu extract was obtained through maceration using methanol. The extract residue was solubilized in MeOH/H2O (8:2) and subjected to liq.–liq. partition in organic solvents. Both the extraction and the partition procedures were conducted with three replicates. The analyses were performed using GC–MS, 1H and 13C NMR. The hexane fraction provided samples containing 84.28, 82.91 and 62.83% spilanthol in repetitions 1, 2 and 3, respectively. The dichloromethane fraction showed 88.55% spilanthol in repetition 1, and approximately 100% spilanthol in repetitions 2 and 3. The jambu extract as well as the hexane fraction (84.28% spilanthol) were able to activate the oxidizing activity of the tyrosinase enzyme for L-DOPA. The dichloromethane fraction (approximately 100% spilanthol) showed stronger inhibition effect on the tyrosinase enzyme in the first 10 min. The results raise the interest in study in spilanthol formulations for topical use, since it may prevent and/or slow skin hyperpigmentation or depigmentation processes. Furthermore, spilanthol may be used to control the enzymatic browning in fruits and vegetables.

Abstract Spilanthol (C14H23NO, 221.339 g/mol) is a bioactive compound that is found in many different plants that are used as traditional remedies throughout the world. It is present in Heliopsis longipes and several species in the genus Acmella, including A. oleracea L., also known as paracress and jambu. Its leaves and flowers have sensory properties (pungency, tingling, numbing, mouth-watering) that make it a popular spice and ingredient in several Brazilian dishes. Spilanthol can exert a variety of biological and pharmacological effects including analgesic, neuroprotective, antioxidant, antimutagenic, anti-cancer, anti-inflammatory, antimicrobial, antilarvicidal and insecticidal activities. So, the aim of this review is to present a literature review on the spilanthol that describes its occurrence, chemistry, extraction and biological activities.

Essential oils of galled and non-galled leaves of Clusia lanceolataCambess., Clusiaceae, were obtained by hydrodistillation and analyzed by GC and GC/MS. The chemical composition of both oils was similar, with a predominance of sesquiterpene caryophyllenes. The extracts from the leaves were evaluated regarding total phenols, flavonoids and proanthocyanidins. Galled leaves showed higher levels of phenolics and proanthocyanidins, since the content of flavonoids was higher in non-galled leaves. The chromatographic profiles of extracts were obtained by using HPLC/DAD and LC-ESI-MS. Electrospray ionisation (ESI) in positive and negative ion mode was used to identify four flavones C-glycosides in both extracts. The study constitutes a first report on the chemical research of C. lanceolata.The extract from galled leaves had a higher antioxidant activity.

A new triterpene, 1-epi-castanopsol, besides eleven known compounds: sitosterol, stigmasterol, campesterol, lupeol, lupenone, simirane B, syringaresinol, scopoletin, isofraxidin, 6,7,8-trimethoxycoumarin and harman, were isolated from the wood of Simira glaziovii. The structures of the known compounds were defined by 1D, 2D ¹H, 13C NMR spectra data analyses and comparison with literature data. The detailed spectral data analyses allowed the definition of the structure of the new 1-epi isomer of castanopsol and performance of ¹H and 13C NMR chemical shift assignments.

The phytochemical investigation of the roots of Piptadenia rigida Benth., Fabaceae, known as "angico", afforded sitosterol, lupeol, betuline, the chalcone isoliquiritigenin, the flavonoids, 7,4'-dihydroxyflavone, 7,3',4'-trihydroxyflavone, 7,8,3',4'-tetrahydroxyflavanone, 4-hydroxy-3,5-dimethoxybenzaldehyde and methyl-3,4-dihydroxy-benzoate. Both flavones were also isolated from the branches of this plant. Five derivatives of the aldehyde were obtained by diazomethane treatment. The structures of compounds were identified by IR, NMR and mass spectral data analysis of natural compounds and some derivatives, and by comparison with literature data.

O estudo fitoquímico de Solanum crinitum Lam forneceu quatro flavonóides: tilirosídeo (1), astragalina (2), kaempferol (3) e biochanina A-7-O-β-D-apiofuranosil-(1→5)-β-D-apiofuranosil-(1→6)-β-D-glucopiranosideo (7), ácido 4-hidroxibenzoico (12), e quatro derivados do ácido cinâmico: cis- e trans- cumárico (10 e 11), cis- e trans- cumarato de etila (8 e 9), isolados de tricomas do fruto. Do extrato metanólico de frutos verdes foram isolados três alcalóides esteroidais glicosilados: solamargina (13), 20-epi-solamargina (14) e solasonina (16). Os derivados 3,5,7,4'-tetra-O-metil-kaempferol (4), 3,7,4'-tri-O-metil-kaempferol (5), 3,7,4'-tri-O-metil-5-O-acetil-kaempferol (6), peracetil-epi-solamargina (15) e peracetil-solasonina (17) foram sintetizados e estão sendo registrados pela primeira vez na literatura. As estruturas foram definidas através de análise de dados espectrométricos.

The phytochemical investigation of Solanum crinitum Lam led to the isolation from the fruit trichomes of four flavonoids, tiliroside (1), astragalin (2), kaempferol (3), biochanin A-7-O-β-D-apiofuranosyl-(1→5)-β-D-apiofuranosyl-(1→6)-β-D-glucopyranoside (7), along with 4-hydroxybenzoic acid (12), and four cinnamic acid derivatives, cis- and trans- coumaric acids (10 and 11) and cis- and trans- ethyl coumarate (8 and 9). Three tri-glycosyl-steroidal alkaloids, solamargine (13), 20-epi-solamargine (14) and solasonine (16) were isolated from the methanolic extract of the green fruits. The derivatives 3,5,7,4'-tretra-O-methyl-kaempferol (4), 3,7,4'-tri-O-methyl-kaempferol (5), 3,7,4'-tri-O-methyl-5-O-acetyl-kaempferol (6), the peracetyl-epi-solamargine (15) and peracetyl-solasonine (17) were prepared. The structures were established through the analysis of their spectral data. The complete ¹H and 13C NMR data assignments of the new peracetyl derivatives of the alkaloids were made.

O estudo fitoquímico de galhos de Piptadenia gonoacantha (Mart.) J.F. Macbr. (Leguminosae-Mimosoideae), comumente conhecida como "pau jacaré", forneceu sitosterol, estigmasterol, o éster N-benzoilfenilalaninato de 2-N-benzoil-3-fenilpropila, conhecido como asperfenamato, 3-O-β-D-glicopiranosil-sitosterol, além de três flavonóides, apigenina (5,7,4'-triidroxiflavona), apigenina-5-O-metil éter e 7,4'-dihidroxi-3' , 5-dimetoxiflavona. Das folhas isolaram-se galato de metila e dois flavonóides, 8-C-glicopiranosil-5,7,4' -trihidroxiflavona e 6-C-glicopiranosil-5,7,4'-trihidroxiflavona, conhecidas como vitexina e isovitexina. Das cascas desta planta isolaram-se uma mistura de sitosterol, campesterol e estigmasterol; mistura de cicloartenona, cicloartan-25,26-en-3-ona e 24-metileno-cicloartanona, além dos triterpenos, 24-metilenocicloartenol, fridelina, lupeol e lupenona. As estruturas foram estabelecidas através de análise de espectros de IV, RMN ¹H e 13C e massas, além de análise com CG-EM para identificar os componentes das misturas de cicloartanos e esteróides. O éster conhecido como asperfenamato, os flavonóides e os cicloartanos estão sendo registrados pela primeira vez em Piptadenia.

The phytochemical investigation of Piptadenia gonoacantha (Mart.) J.F. Macbr. (Leguminosae-Mimosoideae), commonly known as "pau jacaré" (alligator stick), afforded sitosterol, campesterol, stigmasterol, the N-benzoylphenylalanine-2-benzoylamide-3-phenylpropyl ester, known as asperphenamate, sitosterol-3-O-β-D-glucopyranoside, besides three flavonoids, apigenin, 5-O-methylapigenin and 7,4'-dihydroxy-3',5-dimethoxyflavone from its branches. From its leaves, the methyl gallate and two flavonoids, vitexin and isovitexin, were isolated. From its bark, a mixture of sitosterol, campesterol, and stigmasterol, besides a mixture of cycloartenone, cycloartan-25-en-3-one, and 24-methylene-cycloartenone, and the pure triterpenes 24-methylenecycloartanol, friedelin, lupeol and lupenone, were isolated. Their structures were established on the basis of spectral analysis, comparison with literature data and GC-MS analysis of the mixtures. The ester, flavonoids and the cycloartanes are been identified for first time in the genus Piptadenia.

O presente trabalho trata da investigação química das folhas e caule da espécie Ouratea castaneifolia (DC.) Engl., sobre a qual não há registros de estudos químicos ou farmacológicos anteriores. O estudo fitoquímico clássico dos extratos orgânicos do caule e das folhas de O. castaneifolia foi aliado à técnica da cromatografia líquida de alta eficiência (CLAE) e resultou na identificação de dezessete metabólitos: sete triperpenos (friedelina, 3β-friedelinol, α-amirina, β-amirina, lupeol, taraxerol e germanicol), quatro esteróides (sitosterol, estigmasterol e os glucosídeos sitosteril 3-O-β-D-glicopiranosídeo e estigmasteril 3-O-β-D-glicopiranosídeo), uma isoflavona (5,7,4´-trimetoxiisoflavona), uma flavona (5,4´-diidroxi-7,3´,5´-trimetoxiflavona), quatro biflavonas (amentoflavona, 7,7"-O-dimetil-amentoflavona, heveaflavona e tetrametilamentoflavona). A identificação das substâncias foi feita com base na análise de espectros de RMN de ¹H, 13C e técnicas bidimensionais. As classes dos metabólitos identificados estão de acordo com aquelas citadas em estudos químicos do gênero Ouratea.

This paper presents the chemical investigation of the leaves and stems of Ouratea castaneifolia (DC.) Engl.. There are no chemical or pharmacological studies with this species. Classic phytochemical investigation of the organic extracts together with high pressure liquid chromatography (HPLC) procedures lead to the identification of seventeen metabolites: seven triterpenes (friedelin, 3β-friedelinol, α-amyrin, β-amyrin, lupeol, germanicol and taraxerol), four steroids (sitosterol, stigmasterol and the glycosides sitosteryl 3-O-β-D-glucopyranoside and stigmasteryl 3-O-β-D-glucopyranoside), one isoflavone (5,7,4'-trimethoxyisoflavone), one flavone (5,4'-dihydroxy-7,3',5'-trimethoxyflavone) and four biflavones (amenthoflavone, 7,7"-O-dimethylamenthoflavone, heveaflavone and tetramethylamenthoflavone). The structures of the compounds were established by the analysis of ¹H, 13C NMR spectra including bidimensional techniques. The classes of the identified metabolites are in agreement with previous studies of the Ouratea genus.

O ácido flavona-6-sulfônico, 4'-O-metil-5,7-diidroxi-flavona-6-sulfonato, conhecido como niruriflavona, e a saponina, ácido 3-O-[6'-O-4-hidroxibenzoil]-²-D-galactopiranosil-ursa-12-en-28-óico, foram isolados, respectivamente, de madeira e folhas de Licania arianeae. As estruturas foram estabelecidas através da análise de espectros de massas e RMN incluindo experimentos bidimensionais.

The flavone-6-sulfonic acid, 4'-metil-5,7-dihydroxy-flavone-6-sulfonic acid, known as niruriflavone, and the saponin 3-O-[6'-O-4-hydroxybenzoyl]-²-D-galactopyranosyl-ursa-12-en-28-oic acid were isolated, respectively, from wood and leaves of Licania arianeae. The structures were established from the NMR and mass spectra data analysis including two-dimensional NMR experiments.

A reação do flavonol 3,7,3',4'-tetra-O-metilquercetina (1) e da isoflavona 7,4'-di-O-metilgenisteina (2) com iodo/KOH em metanol forneceu como produto quatro derivados iodados: 8-iodo-5-hidroxi-3,7,3',4'-tetrametoxiflavona (1a) e 6-iodo-5-hidroxi-3,7,3',4'-tetrametoxiflavona (1b) a partir da iodação de 1; a partir de 2 foi obtida uma mistura racêmica composta de (±)-trans-5-hidroxi-2,3,7,4'-tetrametoxi-8-iodo-isoflavanona (2a) e (±)-trans-5-hidroxi-2,3,7,4'-tetrametoxi-6,8-diiodo-isoflavanona (2b). A formação destes diferentes produtos revela a significante diferença envolvendo a interação química entre o sitio reativo de cetonas α, β-insaturadas de flavonol e de isoflavonas nas condições experimentais testadas (usando I2/KOH/MeOH). Além disso, ressalta-se a estereosseletividade trans na adição de metanol ao sistema α, β-insaturado da isoflavona. As estruturas foram identificadas com análise nos dados espectrométricos de RMN 1D e 2D e massas.

The reaction of the flavonol 3,7,3', 4'-tetra-O-methylquercetin (1) and of the isoflavone 7,4'-di-O-methylgenistein (2) with alkaline iodine in methanol afforded four new iodine derivatives: 8-iodo-5-hydroxy-3,7,3', 4'-tetramethoxy- flavone (1a) and 6-iodo-5-hydroxy-3,7,3', 4'-tetramethoxyflavone (1b) from 1; 2 afforded a mixture of two compounds, identified as a racemic mixture of (±)-trans-5-hydroxy-2,3,7,4'-tetramethoxy-8-iodo-isoflavanone (2a) and (±)-trans-5-hydroxy-2,3,7,4'-tetramethoxy-6,8-diiodo-isoflavanone (2b). The formation of these different products reveals a significant difference involving the chemical interaction between the reactive site of α, β-unsaturated ketones of flavonol and isoflavone under the tested reaction conditions (using I2/KOH/MeOH). Furthermore, the trans stereo selectivity is noteworthy in the nucleophylic addition of methanol at the isoflavone α, β-unsaturated system. The structures were identified on the basis of spectral data, mainly 1D and 2D NMR and mass spectra.