Coumarins from Rutaceae: Chemical diversity and biological activities.

Rutaceae is a family expressed by approximately 2100 species distributed in 154 genera widespread in tropical and temperate regions of Australasia, America, and South Africa. Substantial species of this family are employed as folk medicines. The literature describes the Rutaceae family as a great source of natural and bioactive compounds like terpenoids, flavonoids, and, especially, coumarins. To data, 655 coumarins were isolated and identified from Rutaceae in the past twelve years and, most of them, showed different biological and pharmacological activities. There are studies with coumarins from Rutaceae indicating that these compounds showed activity against cancer, inflammation, infectious diseases, and in the treatment of endocrinal and gastrointestinal conditions. Although coumarins are considered versatile bioactive molecules, until the present, there is no compiled information about coumarins from the Rutaceae family demonstrating the potency of these compounds in all dimensions and chemical similarities among the genera. The present review covers the relevant studies dealing with isolation of Rutaceae coumarins from 2010 until 2022 and outlines the current data on pharmacological activities these coumpounds. Additionally, the chemical disposition and similarity among Rutaceae genera are also statistically discussed employing PCA and HCA methods.

5-O-methylcneorumchromone K Exerts Antinociceptive Effects in Mice via Interaction with GABAA Receptors.

The proper pharmacological control of pain is a continuous challenge for patients and health care providers. Even the most widely used medications for pain treatment are still ineffective or unsafe for some patients, especially for those who suffer from chronic pain. Substances containing the chromone scaffold have shown a variety of biological activities, including analgesic effects. This work presents for the first time the centrally mediated antinociceptive activity of 5-O-methylcneorumchromone K (5-CK). Cold plate and tail flick tests in mice showed that the 5-CK-induced antinociception was dose-dependent, longer-lasting, and more efficacious than that induced by morphine. The 5-CK-induced antinociception was not reversed by the opioid antagonist naloxone. Topological descriptors (fingerprints) were employed to narrow the antagonist selection to further investigate 5-CK's mechanism of action. Next, based on the results of fingerprints analysis, functional antagonist assays were conducted on nociceptive tests. The effect of 5-CK was completely reversed in both cold plate and tail-flick tests by GABAA receptor antagonist bicuculline, but not by atropine or glibenclamide. Molecular docking studies suggest that 5-CK binds to the orthosteric binding site, with a similar binding profile to that observed for bicuculline and GABA. These results evidence that 5-CK has a centrally mediated antinociceptive effect, probably involving the activation of GABAergic pathways.

Phenylpropanoids from Croton velutinus with cytotoxic, trypanocidal and anti-inflammatory activities.

This current study presents the phytochemical analysis of Croton velutinus, describing phenylpropanoids obtained from this species. The fractionation of the roots hexane extract led to the isolation of four new phenylpropanoids derivatives, velutines A-D (1-4) and three known (5-7). Their structures were established based on spectroscopic (1D-2D NMR; HRMS and IR) analysis. Cytotoxic, trypanocidal and anti-inflammatory activities of compounds 1-7 were evaluated. Only compounds 2 and 5 showed cytotoxic activity against cancer cell lines (B16F10, HL-60, HCT116, MCF-7 and HepG2), with IC50 values ranging from 6.8 to 18.3 µM and 11.1 to 18.3 µM, respectively. Compounds 2 and 5 also showed trypanocidal activity against bloodstream trypomastigotes with EC50 values of 9.0 and 9.58 µM, respectively. Finally, the anti-inflammatory potential of these compounds was evaluated on cultures of activated macrophages. All compounds exhibited concentration-dependent suppressive activity on the production of nitrite and IL-1ß by macrophages stimulated with LPS and IFN-γ. These results indicate phenylpropanoids esters (2 and 5) from C. velutinus as promising cytotoxic, trypanocidal and anti-inflammatory candidates that warrants further studies.

Antinociceptive compounds and LC-DAD-ESIMSn profile from Dictyoloma vandellianum leaves.

Limonoids, quinolone alkaloids and chromones have been reported as constituents of Dictyoloma vandellianum Adr. Juss. (Rutaceae). Although those compounds are known for their biological activities, only the anti-inflammatory activity of chromones isolated from the underground parts has been evaluated. There are no studies of the pharmacological properties of the aerial parts of D. vandellianum. The present study was carried out to determine the phytochemical profile and antinociceptive activity of the methanol extract, fractions and isolated compounds of leaves of D. vandellianum. The phytochemical profile was performed by HLPC-DAD-ESIMSn and pure substances obtained were characterized by MS and NMR spectroscopy. The antinociceptive activity was assessed using the formalin assay in mice, and the motor function in the rotarod test. ME and all the fractions obtained from ME produced antinociceptive effects. Among them, the ethyl ether fraction was the most active. Data from HPLC-DAD-ESIMSn showed that the ethyl ether fraction presented 42 compounds. The major compounds isolated from this fraction-gallic acid, methyl gallate and 1,2,6-tri-O-galloyl-ß-d-glucopyranose-were tested and produced antinociceptive effects. Gallic acid, methyl gallate and 1,2,6-tri-O-galloyl-ß-d-glucopyranose at antinociceptive doses did not affect the motor performance in mice in the rotarod test. This work is the first report of the occurrence of gallotanins in D. vandellianum. In addition, the pharmacological study showed that D. vandellianum leaves present antinociceptive activity, probably induced by gallic acid, methyl gallate and 1,2,6-tri-O-galloyl-ß-d-glucopyranose.

Tri- and Diterpenoids from Stillingia loranthacea as Inhibitors of Zika Virus Replication.

This study represents the first phytochemical analysis of Stillingia loranthacea (S. loranthacea) and describes new terpenoids obtained from the root bark of this species. The fractionation of the hexane extract from the root bark led to the isolation of two new 28-nor-taraxarenes derivatives, loranthones A and B (1 and 2), four new tigliane diterpenes (5-8), three known tigliane diterpenes (9-11), and three known flexibilene diterpenes, tonantzitlolones A-C (12-14). The investigation of these compounds and the use of a molecular networking-based prioritization approach afforded two other new 28-nor-taraxarenes, loranthones C and D (3 and 4). The cytotoxicity of compounds 1, 2, and 5-14 was evaluated against Vero cells, and their 20% cytotoxic concentration (CC20) values varied from 8.7 to 328 µM; antiviral activity was tested against an epidemic Zika virus (ZIKV) strain circulating in Brazil. Six out of 12 compounds (2, 5, 9-11, and 14) exhibited significant antiviral effects against ZIKV. Specifically, compounds 2 and 5 offered the most promise as lead compounds as they had a 1.7 and 1.8 log10 TCID50/mL reduction in ZIKV replication, respectively. Together, the present findings have identified S. loranthacea terpenoids as potent anti-ZIKV inhibitors and pave the way to the development of possible new treatments against this devastating pathogen.

Natural chromones as potential anti-inflammatory agents: Pharmacological properties and related mechanisms.

Chromones are a group of natural substances with a diversity of biological activities. Herein we assessed the pharmacological potential of three chromones (1, 2 and 3) isolated from Dictyoloma vandellianum as anti-inflammatory agents using in vitro and in vivo approaches. During in vitro screening, the production of NO and cytokines by macrophages stimulated with LPS and IFN-γ was inhibited by all chromones at concentrations (5-20 µM) that did not induce cytotoxicity. Analysis of pharmacokinetic parameters (in vitro half-life and intrinsic clearance) using human liver microsomes revealed that 3 has a superior pharmacokinetic profile, compared to 1 and 2. Treatment with 3 (100 mg/kg, ip) did not affect the mice motor performance, while 1 and 2 induced motor deficit. Taking into account the pharmacokinetic profile and absence of motor impairment, 3 was selected for further pharmacological characterization. Corroborating the data from in vitro screening, treatment of cell cultures with 3 (5-20 µM) reduced TNF-α, IL-6 and IL-1ß production by stimulated macrophages. In the complete Freund's adjuvant-induced paw inflammation model in mice, 3 (25 and 50 mg/kg, ip) inhibited mechanical hyperalgesia, edema and cytokine production/release (IL-1ß, IL-6 and TNF-α). 3 (5-20 µM) also reduced the transcriptional activity of NF-κB in stimulated macrophages. Furthermore, treatment with RU486, a glucocorticoid receptor (GR) antagonist, partially prevented the inhibitory effect of 3 on macrophages, indicating that this chromone exerts its anti-inflammatory effects in part through the activation of GR. The results presented herein demonstrate the pharmacological potential of natural chromones, highlighting 3 as a possible candidate for the drug discovery process targeting new anti-inflammatory drugs.

Estrogen and Thyroid Hormone Receptor Activation by Medicinal Plants from Bahia, Brazil.

Background: A number of medicinal plants are traditionally used for metabolic disorders in Bahia state, Brazil. The aim of this study was to evaluate the estrogen receptor (ER) and thyroid receptor (TR) activation of crude extracts prepared from 20 plants. Methods: Species were extracted and assayed for receptor activation through both ER and TR gene-reporter assays, using 17ß-estradiol and triiodothyronine (T3), respectively, as the positive controls. Results: Cajanus cajan (Fabaceae), Abarema cochliacarpus (Fabaceae), and Borreria verticillata (Rubiaceae) were able to activate ER as much as the positive control (17ß-estradiol). These three plant species were also assayed for TR activation. At the concentration of 50 µg/mL, C. cajans exerted the highest positive modulation on TR, causing an activation of 59.9%, while B. verticillata and A. cochliacarpus caused 30.8% and 23.3%, respectively. Conclusions: Our results contribute towards the validation of the traditional use of C. cajans, B. verticillata, and A. cochliacarpus in the treatment of metabolic disorders related to ER and TR functions. The gene-reporter assay was proven effective in screening crude plant extracts for ER/TR activation, endorsing this methodology as an important tool for future bioprospection studies focused on identifying novel starting molecules for the development of estrogen and thyroid agonists.

Solanum paniculatum L. decreases levels of inflammatory cytokines by reducing NFKB, TBET and GATA3 gene expression in vitro.

ETHNOPHARMACOLOGICAL RELEVANCE: Solanum paniculatum L., popularly known as jurubeba, is a common subtropical plant from Brazil, Paraguay, Bolivia and Argentina, that is used in folk medicine for the treatment of anemia, gastrointestinal disorders and inflammatory conditions in general. In addition to that, an ethnobotanical survey in "Todos os Santos" Bay have pointed out S. paniculatum as an herb to treat asthma. Previous publications have shown that S. paniculatum possesses antibiotic, antioxidant and modulatory effects on gastric acid secretion; however, its anti-inflammatory potential remains unexplored. AIM OF THE STUDY: Herein, we analyzed the S. paniculatum fruits hexane extract (SpE) for the presence of stigmasterol and ß-sitosterol and investigated the anti-inflammatory effect of SpE in vitro. MATERIALS AND METHODS: SpE was subjected to high-performance liquid chromatography (HPLC) for standardization and quantification of stigmasterol and ß-sitosterol. Spleen cells from BALB/c mice were cultivated and stimulated with pokeweed mitogen and also exposed to 15, 30 and 60µg/mL of SpE. Following treatment, levels of IFN-γ, IL-4 and IL-10 in the culture supernatants were assessed by ELISA. We also evaluated nitric oxide (NO) production by murine LPS-stimulated peritoneal macrophages using the Griess technique. In addition, the ability of SpE to stabilize membranes was assessed using a model of hemolysis induced by heat on murine erythrocytes. Gene expression of Th1-cell-specific Tbx21 transcription factor (TBET), zinc-finger transcription factor-3 (GATA3), and nuclear factor-κB (NFKB) in murine spleen cells were assessed by quantitative Polymerase Chain Reaction (qRT-PCR). RESULTS: SpE at 15, 30 and 60µg/mL significantly attenuated cell proliferation, decreased IL-4 release, reduced NO production and improved erythrocyte membrane stabilization in a concentration-dependent manner. SpE was also able to decrease the release of IFN-γ without altering IL-10 levels. The mechanism whereby SpE decreased inflammatory markers may be related to the reduction of NFKB, TBET and GATA3 gene expression. CONCLUSIONS: This study is the first to test the anti-inflammatory action of S. paniculatum. Herein, we provided evidence for the popular use of S. paniculatum in inflammatory conditions. Additional studies must be conducted to further explore the anti-inflammatory potential of SpE and to elucidate possible clinical applications.

The anti-inflammatory and immunomodulatory potential of braylin: Pharmacological properties and mechanisms by in silico, in vitro and in vivo approaches.

Braylin belongs to the group of natural coumarins, a group of compounds with a wide range of pharmacological properties. Here we characterized the pharmacological properties of braylin in vitro, in silico and in vivo in models of inflammatory/immune responses. In in vitro assays, braylin exhibited concentration-dependent suppressive activity on activated macrophages. Braylin (10-40 µM) reduced the production of nitrite, IL-1ß, TNF-α and IL-6 by J774 cells or peritoneal exudate macrophages stimulated with LPS and IFN-γ. Molecular docking calculations suggested that braylin present an interaction pose to act as a glucocorticoid receptor ligand. Corroborating this idea, the inhibitory effect of braylin on macrophages was prevented by RU486, a glucocorticoid receptor antagonist. Furthermore, treatment with braylin strongly reduced the NF-κB-dependent transcriptional activity on RAW 264.7 cells. Using the complete Freund's adjuvant (CFA)-induced paw inflammation model in mice, the pharmacological properties of braylin were demonstrated in vivo. Braylin (12.5-100 mg/kg) produced dose-related antinociceptive and antiedematogenic effects on CFA model. Braylin did not produce antinociception on the tail flick and hot plate tests in mice, suggesting that braylin-induced antinociception is not a centrally-mediated action. Braylin exhibited immunomodulatory properties on the CFA model, inhibiting the production of pro-inflammatory cytokines IL-1ß, TNF-α and IL-6, while increased the anti-inflammatory cytokine TGF-ß. Our results show, for the first time, anti-inflammatory, antinociceptive and immunomodulatory effects of braylin, which possibly act through the glucocorticoid receptor activation and by inhibition of the transcriptional activity of NF-κB. Because braylin is a phosphodiesterase-4 inhibitor, this coumarin could represent an ideal prototype of glucocorticoid receptor ligand, able to induce synergic immunomodulatory effects.

The classical photoactivated drug 8-methoxypsoralen and related compounds are effective without UV light irradiation against glioma cells.

Currently, there is no effective therapy for high grade gliomas. 8-Methoxypsoralen (8-MOP) is a compound used in the treatment of skin diseases combined with UV light irradiation. In this work, rat glioma C6 cells, normal astrocytes and human glioblastoma GL-15 cells comprised an in vitro model to evaluate the antitumor activity of 8-MOP. We found that 8-MOP promoted a time- and concentration-dependent reduction of cell viability in tumor, but not in normal cells. This effect was more evident in log-phase growing culture, indicating antiproliferative activity, which was confirmed by colony formation assay. Long-term effect of 8-MOP at low concentration was also attested. The concentrations used in the tests (0.02-0.4 mM) were lower than plasmatic concentration found in patients. Despite the treatment leads to considerable morphological changes and apoptosis when used at high concentrations, 8-MOP did not promote cell cycle arrest, change in migration pattern neither necrosis. In addition, we evaluated the effect of 8-MOP in MDA-MB-231, CT-26 and SCC-3 cell lines, derived from other kind of primary tumors, and found that CT-26 cells did not respond to 8-MOP treatment, indicating that this compound does not act through a generic mechanism. Coumarin derivatives structurally related to 8-MOP were screened for its antitumor potential and presented different patterns of biological activity, and then it was possible to suggest the relevance of 8-MOP molecular structure for antiproliferative action. Therefore, 8-MOP, a drug with an outstanding record of safety, and related coumarins are good prototypes for development of a new class of anti-glioma drugs.

Determination of fexofenadine in Hank's balanced salt solution by high-performance liquid chromatography with ultraviolet detection: application to Caco-2 cell permeability studies.

The drug-transporting proteins can affect the pharmacokinetics and pharmacodymanics of many drugs, resulting in an erratic and unpredictable pharmacological response. The Caco-2 monolayer is routinely applied to investigate the carrier-mediated transport of drugs. Therefore, the selection of a marker compound able to characterize the activity of such transporters is crucial. Fexofenadine (FEX), a P-gp/OATP substrate, can be considered a suitable probe. However, in order to use be used as a marker compound, it is mandatory to develop an analytical method able to quantify this drug during the in vitro permeability assay. An HPLC method with ultraviolet detection was developed; the mobile phase consisted of phosphate buffer (pH 3.2) containing 10 m m of sodium octanosulphonate and acetonitrile (60:40) and the flow rate was set at 1.2 mL/min. Fexofenadine was eluted at 40°C, the retention time was about 4.6 min. The LOD and LOQ values were 1.9 and 6.2 ng/mL, respectively. Verapamil and ketoconazole, the most common P-gp inhibitors, were eluted as distinct peaks of that corresponding to fexofenadine The method was successfully applied to quantify the amount of FEX transported across the Caco-2 monolayer and could be an additional tool for those investigating the role of membrane transporters on drug absorption.

Ocimum gratissimum Linn. and rosmarinic acid, attenuate eosinophilic airway inflammation in an experimental model of respiratory allergy to Blomia tropicalis.

Allergic asthma has emerged as an important public health problem of urban populations in developed countries. Very often herbal medicine is used to treat this widespread disease, due to the lack of efficacy and the important side effects related to the classical drugs in use. Along this line, Ocimum gratissimum (Og) is a plant widely used in Brazilian folk medicine to treat inflammatory disorders, such as asthma. In the present study we evaluated the immunomodulatory effects of Og and rosmarinic acid (RA, a polyphenolic compound) in a murine model of respiratory allergy induced by the Blomia tropicalis (Bt) mite. The respiratory allergy was induced in A/J mice by administration of Bt extract and the treatment was done using 25, 50 or 100mg/kg of an Og methanolic extract or using 2, 20 or 200mg/kg of RA. We then evaluated the changes induced by these drugs on immunological parameters related to the allergic process, which are up-regulated in this allergic model. The treatment of animals with 100mg/Kg Og and 200mg/Kg RA led to a significant reduction in the numbers of leukocytes/eosinophils in bronchoalveolar lavage (BAL); eosinophil peroxidase activity in BAL; presence of mucus in respiratory tract, histopathological changes in the lung, and IL-4 in BAL. These results suggest that the methanolic extract of Og and the polyphenol RA have therapeutic potential in this murine model of respiratory allergy to a clinically relevant human sensitizer allergen.

Cytotoxicity effect of alkaloidal extract from Prosopis juliflora Sw. D.C. (Algaroba) pods on glial cells

Prosopis juliflora is largely used for feeding cattle and humans. Neurological signals have been reported in cattle due to intoxication with this plant. In this study, an alkaloidal fraction (AF) obtained from P. juliflora pods was tested on astrocyte primary cultures. Astrocytes display physiological functions essential to development, homeostasis and detoxification in the central nervous system (CNS). These cells are known for their role on energetic support and immune response in the CNS. Concentrations between 0.03 to 30 µg/ml AF were assayed for 24 - 72 h. The mitochondrial activity, assayed by MTT test, showed cytotoxicity at 30 µg/ml AF after 24 h. At concentrations ranging between 0.3 - 3 µg/ ml, the AF induced an increase on mitochondrial activity, indicating cell reactivity. lmmunocytochemistry assay for GFAP cytoskeletal protein, revealed alterations on cell morphology after treatment with 0.3 - 3 µg/ ml AF for 72 h. This result corroborates with western blot analysis when ceUs treated with 0.3 - 3 I-µg/ml AF for 72 h showed GFAP upregulation. The vimentin expression was not significantly altered in all tested concentrations. These results suggest that alkaloids induce astrocyte reactivity and might be involved in the neurotoxic effects induced by P. juliflora consumption.

A Prosopis juliflora é amplamente utilizada na alimentação humana e de várias espécies animais, especialmente bovinos. Quadros de intoxicação por esta planta, nesta espécie, têm sido relatados, principalmente quando a mesma é oferecida como única fonte alimentar, desencadeando uma doença de sintomatologia nervosa. Neste estudo, objetivou-se avaliar os efeitos in vitro da fração de alcalóides totais (F A) extraída das vagens da Prosopis juliflora utilizando cultura primária de astrócitos obtidos do córtex cerebral de ratos como modelo de estudo. A avaliação da atividade mitocondrial pelo teste do MTT demonstrou a citotoxicidade em 30 µg/ ml da FA após 24 h. As concentrações de 0,3 e 3 µg/ ml da FA induziram um aumento da atividade mitocondrial, indicando reatividade celular. Testes imunocitoquimicos para a GFAP, principal proteína de citoesqueleto de astrócitos, revelaram alterações morfológicas nas células após tratamento com 0,3 e 3 µg/ml da FA por 72 h. Tais resultados são consoantes à análise desta proteína por westernblot, quando as culturas foram tratadas com 0,3 e 3 µg/ml da FA por 72 h, demonstrando interferências na regulação da expressão da GFAP. A expressão de vimentina não foi significativamente alterada em nenhuma das concentrações testadas. Estes resultados sugerem que os alcalóides da P.juliflora induzem a reatividade astrocitária, o que pode estar envolvido nos efeitos neurotóxicos providos pelo consumo desta planta.

Extração com solvente e fluido supercrítico dos constituintes do caule subterrâneo de Spiranthera odoratissima A. St.-Hil. (Rutaceae) / Supercritical fluid and solvent extraction of rhizome from Spiranthera odoratissima A. St.-Hil. (Rutaceae)

O arbusto Spiranthera odoratissima (Rutaceae) foi coletado no município de Mucugê (BA). Seu caule subterrâneo foi submetido a extração com solvente orgânico e fluido supercrítico. A extração com CO2 supercrítico forneceu a 8-prenil-7-geraniloxicumarina. A partir do extrato CH2Cl2 isolou-se a cumarina aurapteno e identificou-se o alcalóide esquimianina. Estas substâncias foram identificadas com base na análise dos seus espectros de RMN 1H e 13C, IV e comparação com dados da literatura.

The shrub S. odoratissima was collected at Mucugê (Chapada Diamantina - Bahia, Brazil). Its rhizome was extracted by maceration with CH2Cl2 and supercritical CO2. The supercritical extraction supplied a coumarin, 8-prenyl-7geranyloxycoumarin. Another coumarin, the auraptene, and an alkaloid, skimmianine, were obtained from the CH2Cl2 extract. The structures of the compounds were elucidated based on spectroscopic studies, and by comparison with literature data.

Estudo fitoquímico de Zanthoxylum stelligerum (Turcz)

The hexanic and methanolic extracts of roots and stem of Zanthoxylum stelligerum (Rutaceae), after chromatographic and phytochemical procedures, yelded the triterpene lupeol, the furanocumarin imperatorin and the benzophenathridine alkaloids dihidrocheleritrine and its probable product of oxidation. The structural determinations of these compounds were performed on basis of spectroscopic analysis as well as comparison with authentic samples.