The phytochemical investigation of the hexane and methanol extracts from the bark of Duguetia pycnastera Sandwith (Annonaceae) afforded seven known compounds, two asarone-derived phenylpropanoids and five isoquinoline-derived alkaloids. The asarones, γ-asarone (1-allyl-2,4,5-trimethoxybenzene) and 2,4,5-trimethoxy-styrene were isolated of the hexane extract while the aporphine alkaloids, O-methylmoschatoline, lysicamine, nornuciferidine, and guatterine N-oxide, and the benzyltetrahydroisoquinoline alkaloid, (S)-reticuline were isolated of the alkaloid fraction of the methanol extract. This is the first report of these compounds in D. pycnastera. γ-Asarone is being reported for the first time in the Annonaceae. Nornuciferidine is described for the second time in the Annonaceae while guatterine N-oxide is the third register. The structures of the isolated compounds were established by extensive analyses using 1D and 2D NMR spectroscopy in combination with MS. The cytotoxic activity of the isolated compounds (except for nornuciferidine) was evaluated against cancer and non-cancerous cell lines, in which lysicamine was the most active compound, mainly against HL-60, HepG2, and K562 with IC50 values of 24.40, 28.86 and 38.75 µmol L-1, respectively.

The phytochemical investigation of the hexane extract which was obtained from the leaves of Xylopia laevigata (Annonaceae) produced six terpenes. Among these, five diterpenes named abieta-7,13-dien-3-one, ent-7β-acetoxy-16β-hydroxy-kaurane, 4-epi-cupressic acid, powerol, and labdorffianic acid B, and one oxygenated sesquiterpene, spathulenol. This is the first time these isolated diterpenes from X. laevigata have been described. The different structures belong to the abietane, kaurane, and labdane diterpenoids, and are indicative of the chemical diversity found in X. laevigata. Moreover, the diterpene ent-7β-acetoxy-16β-hydroxy-kaurane is reported herein for the first time as a natural product, and 4-epi-cupressic acid, powerol, and labdorffianic acid B are reported for the first time in the Annonaceae family. The structures of the isolated compounds were established by extensive analyses using 1D and 2D NMR spectroscopy in combination with MS. The cytotoxic activities of compounds abieta-7,13-dien-3-one, spathulenol, 4-epi-cupressic acid, and powerol were evaluated against tumor and non-tumor cell lines, in which spathulenol was found to be the most active, mainly against K562 with an IC50 value of 17.20 μmol L-1.

Onychopetalum is an Amazonian botanical genus close-related with Bocageopsis and Unonopsis, whose species are used in traditional medicine. Although these genera are widely investigated from the phytochemical viewpoint, the knowledge about Onychopetalum remains almost unexplored. In order to perform a comprehensive characterization of isoquinoline-derived alkaloids from Onychopetalum amazonicum, an integrative approach based on the alkaloid profile analysis by leaf spray mass spectrometry (LS-MS), followed by a robust dereplication through high-performance liquid chromatography coupled with diode array detector and atmospheric pressure chemical ionization tandem mass spectrometry, (HPLC-DAD-APCI-MS/MS) and nuclear magnetic resonance (NMR) analysis was adopted. LS-MS allowed the tentative identification of reticuline, norjuziphine, nornuciferine, O-methylisopiline, nuciferine, N-methyl-O-methylisopiline, anonaine, and N-methylanonaine. HPLC-DAD-MS/MS analysis supported the tentative identification of N-methylasimilobine, asimilobine, norushinsunine, N-methylisopiline, isopiline, liriodenine, and lysicamine. Moreover, the integration of MS and NMR data allowed the additional identification of stepholidine and isocorypalmine. The applied integrative approach proposed herein enabled a comprehensive analysis of the alkaloid content from the O. amazonicum, showing to be a useful strategy for the dereplication of isoquinoline-derived alkaloids.

BACKGROUND Since the World Health Organization (WHO) declared Coronavirus disease 2019 (COVID-19) to be a pandemic infection, important severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) non-structural proteins (nsp) have been analysed as promising targets in virtual screening approaches. Among these proteins, 3-chymotrypsin-like cysteine protease (3CLpro), also named main protease, and the RNA-dependent RNA polymerase (RdRp), have been identified as fundamental targets due to its importance in the viral replication stages. OBJECTIVES To investigate, in silico, two of the most abundant flavonoid glycosides from Dysphania ambrosioides; a medicinal plant found in many regions of the world, along with some of the putative derivatives of these flavonoid glycosides in the human organism as potential inhibitors of the SARS-CoV-2 3CLpro and RdRp. METHODS Using a molecular docking approach, the interactions and the binding affinity with SARS-CoV-2 3CLpro and RdRp were predicted for quercetin-3-O-rutinoside (rutin), kaempferol-3-O-rutinoside (nicotiflorin) and some of their glucuronide and sulfate derivatives. FINDINGS Docking analysis, based on the crystal structure of 3CLpro and RdRp, indicated rutin, nicotiflorin, and their glucuronide and sulfate derivatives as potential inhibitors for both proteins. Also, the importance of the hydrogen bond and π-based interactions was evidenced for the presumed active sites. MAIN CONCLUSIONS Overall, these results suggest that both flavonoid glycosides and their putative human metabolites can play a key role as inhibitors of the SARS-CoV-2 3CLpro and RdRp. Obviously, further researches, mainly in vitro and in vivo experiments, are necessary to certify the docking results reported here, as well as the adequate application of these substances. Furthermore, it is necessary to investigate the risks of D. ambrosioides as a phytomedicine for use against COVID-19.

A investigação fitoquímica das folhas de Guatteria friesiana (Annonaceae) levou à obtenção de três novos alcaloides isoquinolínicos, 13-hidroxi-discretinina, 6,6a-desidroguateriopsiscina e 9-desidroxi-1-metoxi-diidroguattouregidina, juntamente com oito alcaloides conhecidos, 13-hidroxi-2,3,9,10-tetrametoxiprotoberberina, guateriopsiscina, lisicamina, liriodenina, aterospermidina, lanuginosina, 7,8-diidro-8-hidroxipalmatina e palmatina. 13-Hidroxi-2,3,9,10-tetrametoxiprotoberberina, obtido somente através de síntese, é relatada pela primeira vez como produto natural. As estruturas dos alcaloides isolados foram elucidadas por extensivas análises de ressonância magnética nuclear (RMN 1D e 2D), espectrometria de massas (MS) e comparação com os dados descritos na literatura. A atividade citotóxica in vitro dos alcaloides majoritários foi avaliada frente a linhagens de células tumorais e não tumorais. Considerando a atividade média, de acordo com os critérios do National Cancer Institute (NCI/EUA), todos os alcaloides avaliados foram inativos. Entretanto, o alcaloide palmatina apresentou efeito citostático para as linhagens MCF-7 (mama) e U251 (glioma) com valores de GI50 abaixo de 20,0 µmol L-1 (10,5 e 16,2 µmol L-1, respectivamente), sugerindo uma ação citotóxica seletiva.

Phytochemical investigation of the leaves of Guatteria friesiana (Annonaceae) afforded three new isoquinoline alkaloids, 13-hydroxy-discretinine, 6,6a-dehydroguatteriopsiscine and 9-dehydroxy-1-methoxy-dihydroguattouregidine. Eight known alkaloids were also isolated, 13-hydroxy-2,3,9,10-tetramethoxyprotoberberine, guatteriopsiscine, lysicamine, liriodenine, atherospermidine, lanuginosine, 7,8-dihydro-8-hydroxypalmatine and palmatine. 13-Hydroxy-2,3,9,10-tetramethoxyprotoberberine was only obtained by synthesis and is being reported as a natural product for the first time. The structures of the isolated alkaloids were established by extensive analysis of 1D and 2D nuclear magnetic resonance (NMR) and mass spectrometric (MS) data, as well as by comparison with data reported in the literature. The in vitro cytotoxic activity of the major alkaloids was evaluated against tumor and non-tumor cell lines. All of the alkaloids evaluated were determined to be inactive based on National Cancer Institute (NCI/USA) criteria. However, the alkaloid palmatine exhibited a cytostatic effect on MCF-7 (breast) and U251 (glioma) human tumor cell lines, with GI50 values lower than 20.0 µmol L-1 (10.5 and 16.2 µmol L-1, respectively), suggesting a selective cytotoxic action.

Se evalúan productos de origen vegetal en busca de sustancias bioactivas que tengan la capacidad de reducir la dependencia de insecticidas organofosforados y piretroides, a los que las poblaciones de insectos se han vuelto resistentes. Por esta razón el objetivo de este estudio fue evaluar si los aceites esenciales de Guatteria hispida, G. blepharophylla y G. friesiana presentan efecto insecticida contra A. aegypti bajo condiciones de laboratorio. Los aceites esenciales se extrajeron a través de hidrodestilación por medio de un aparato tipo Clevenger, analizados por Cromatografía Gaseosa acoplada a Espectrometría de Masas (CG-EM) y Resonancia Magnética Nuclear (RMN). Los bioensa-yos se analizaron de acuerdo con el modelo Probit. Los análisis de (CG-EM) y (RMN) confrmaron que las hojas de G. blepharophylla presentan óxido de cariofileno como el principal componente; en G. friesiana fue a-, b- y g-eudesmol, y en G. hispida a- y b-pineno y (E)-cariofileno fueron los compuestos predominantes. La concentraciones letales CL50, CL95 y CL99 fueron respectivamente 85,74, 199,35 y 282,76ppm para G. hispida; 58.72, 107.6 y 138.37 ppm para G. blepharophylla; 52,6, 94,37 y 120,22ppm para G. friesiana. El aceite extraído de G. friesiana presentó el mejor efecto insecticida.

the products of vegetal origin were assessed for bioactive substances to reduce reliance on organophosphate and pyrethroid insecticides, to which insect populations have become resistant. For this reason the aim of this study was to assess whether the essential oils of Guatteria hispida, G. blepharophylla and G. friesiana have insecticidal effect against A. aegypti under laboratory conditions. Essential oils were extracted through hydrodistillation using a modifed Clevenger apparatus and analyzed by Gas Chromatography (CG-FID), Gas Chromatography coupled to Mass Spec-trometry (GC-MS), and Nuclear Magnetic Resonance (NMR). the bioassays were analyzed according to the Probit model. The GC-MS and NMR analyses confrmed that the leaves of G. blepharophylla have the caryophyllene oxide as their main component; in G. friesiana the a-,b- and g-eudesmols prevail, and in G. hispida a- and b-pinene, and (E)-caryophyllene are the predominant compounds. the lethal concentrations LC50, LC95 and LC99, were respectively 85.74, 199.35 and 282.76ppm for G. hispida; 58.72, 107.6 and 138.37ppm for G. blepharophylla; and 52.6, 94.37 and 120.22ppm for G. friesiana. the oil extracted from G. friesiana presented the best insecticidal effect.

O estudo fitoquímico das cascas de Guatteria blepharophylla (Mart.) Mart. forneceu 12 compostos, sendo dois sesquiterpenos, óxido de cariofileno (1) e espatulenol (3), uma xantona, liquexantona (2), uma mistura de esteróides, β-sitosterol (4) e estigmasterol (5), e sete alcalóides isoquinolínicos, O-metilmoschatolina (6), lysicamina (7), nornuciferina (8), liriodenina (9), isocoreximina (10), subsessilina (11) e isomoschatolina (12). Suas estruturas foram determinadas através de métodos espectroscópicos. Os compostos 1-6, 11 e 12 são reportados pela primeira vez nesta espécie. Os dados de RMN 13C (ressonância magnética nuclear) para os compostos 11 e 12 são descritos pela primeira vez na literatura. As atividades antiproliferativa em linhagens de células tumorais humanas e antimicrobiana foram investigadas para os compostos majoritários. O composto 9 mostrou significativa atividade contra linhagens de células de mama (MCF-7, Michigan Cancer Foundation-7), superior ao controle positivo doxorrubicina. O composto 12 apresentou atividade antifúngica similar ao controle positivo nistatina contra Candida albicans

Phytochemical study of the bark of Guatteria blepharophylla (Mart.) Mart. afforded twelve compounds, namely two sesquiterpenes, caryophyllene oxide (1) and spathulenol (3), one xanthone, lichexanthone (2), a mixture of steroids, β-sitosterol (4), and stigmasterol (5), and seven isoquinoline alkaloids, O-methylmoschatoline (6), lysicamine (7), nornuciferine (8), liriodenine (9), isocoreximine (10), subsessiline (11), and isomoschatoline (12). Their structures were established on the basis of spectroscopic methods. Compounds 1-6, 11 and 12 were reported for the first time in this species. The 13C NMR (nuclear magnetic resonance) data for the compounds 11 and 12 are described for the first time in the literature. The antiproliferative activity against human tumour cell lines and antimicrobial activities were investigated for the major compounds. Compound 9 showed significant activity against cell lines of breast (MCF-7, Michigan Cancer Foundation-7), superior to the positive control doxorubicin. Compound 12 presented antifungal activity similar to the positive control nystatin against Candida albicans.

O presente trabalho descreve o isolamento, a partir do caule de Annona amazonica, do ácido acantóico, um diterpeno do tipo pimaradieno que possui várias e importantes atividades biológicas descritas na literatura. Neste estudo foi verificado que este composto apresenta significante atividade tripanocida contra as formas epimastigotas de Trypanosoma cruzi. Também foi constatado que este diterpeno é o constituinte majoritário da planta, encontrado em cerca de 65% do extrato hexânico, demonstrando que A. amazonica é uma nova fonte natural renovável desta substância. Além do ácido acantóico, a investigação química resultou no isolamento dos alcalóides liriodenina e cassiticina, entre outros compostos, tais como terpenos, esteróides e ácidos graxos. Adicionalmente, é descrita a completa e inequívoca atribuição dos deslocamentos químicos de RMN de ¹H e 13C da cassiticina.

The present work reports the isolation of acanthoic acid, a promising pimaradiene-type diterpene with several important biological activities described in the literature, from the stems of Annona amazonica. We found that acanthoic acid has significant trypanocidal activity against the epimastigote forms of Trypanosoma cruzi. This diterpene is the major constituent of the plant, comprising at least 65% of the hexane extract, demonstrating that A. amazonica is a new renewable natural source for this compound. The chemical investigation also resulted in the isolation of the alkaloids liriodenine and cassythicine, and other compounds including terpenes, sterols, and fatty acids. Additionally, the complete and unequivocal ¹H and 13C NMR chemical shift assignments for cassythicine are provided.

The present communication reports the isolation and identification of three lignans from metanolic root extracts of Strychnos guianensis (Aublet) Mart.: olivil (1), cycloolivil (2) and the unknown derivative cycloolivil carbonate (3). From hexane extracts was identified a long chain fatty acid mixture and the triterpene lupeol. The analyses were based on chromatographic and spectroscopy techniques (IR, MS, GC/MS, ¹H-NMR and 13C-NMR, 1D (BB, DEPT 135) and 2D (¹H, ¹ H-COSY, ¹H, 13C-COSY, ¹H, 13C-COSY-LR, HMQC, HMBC and NOESY) and comparison with literature data.