Effects of amburoside A and isokaempferide, polyphenols from Amburana cearensis, on rodent inflammatory processes and myeloperoxidase activity in human neutrophils

TNF-α Inhibitors from Natural Compounds: An Overview, CADD Approaches, and their Exploration for Anti-inflammatory Agents

Inflammation is a natural process that occurs in the organism in response to harmful external agents. Despite being considered beneficial, exaggerated cases can cause severe problems for the body. The main inflammatory manifestations are pain, increased temperature, edema, decreased mobility, and quality of life for affected individuals. Diseases such as arthritis, cancer, allergies, infections, arteriosclerosis, neurodegenerative diseases, and metabolic problems are mainly characterized by an exaggerated inflammatory response. Inflammation is related to two categories of substances: pro- and anti-inflammatory mediators. Among the pro-inflammatory mediators is Tumor Necrosis Factor-α (TNF-α). It is associated with immune diseases, cancer, and psychiatric disorders which increase its excretion. Thus, it becomes a target widely used in discovering new antiinflammatory drugs. In this context, secondary metabolites biosynthesized by plants have been used for thousands of years and continue to be one of the primary sources of new drug scaffolds against inflammatory diseases. To decrease costs related to the drug discovery process, Computer-Aided Drug Design (CADD) techniques are broadly explored to increase the chances of success. In this review, the main natural compounds derived from alkaloids, flavonoids, terpene, and polyphenols as promising TNF-α inhibitors will be discussed. Finally, we applied a molecular modeling protocol involving all compounds described here, suggesting that their interactions with Tyr⁵⁹, Tyr¹¹⁹, Tyr¹⁵¹, Leu⁵⁷, and Gly¹²¹ residues are essential for the activity. Such findings can be useful for research groups worldwide to design new anti-inflammatory TNF-α inhibitors.

Antineuroinflammatory Effect of Amburana cearensis and Its Molecules Coumarin and Amburoside A by Inhibiting the MAPK Signaling Pathway in LPS-Activated BV-2 Microglial Cells

Microglia plays an important role in the neuroinflammatory response, identified as one of the major factors in the development and progression of neurodegenerative diseases. Amburana cearensis and its bioactive compounds, including coumarin (CM), vanillic acid (VA), and amburoside A (AMB), exert antioxidant, anti-inflammatory, and neuroprotective activities, on 6-OHDA-induced neurotoxicity in rat mesencephalic cells determined by our group. The present study investigated the anti-inflammatory effect of the dry extract from A. cearensis (DEAC), CM, AMB, and VA on lipopolysaccharide- (LPS-) stimulated microglial cells and elucidated the possible molecular mechanism of action. The DEAC was characterized by HPLC-PDA (chemical markers: CM, AMB, and VA). The BV-2 microglial cell line was pretreated with increasing concentrations of DEAC, CM, AMB, or VA in the presence or absence of LPS to evaluate the toxicity and anti-inflammatory activity. The cytotoxicity of DEAC, CM, AMB, or VA on BV-2 cells was evaluated by the MTT test, the free radical scavenging activity of test drugs was investigated, and the nitric oxide (NO) production was determined using the Griess reagent, while cytokine levels were measured by ELISA. The expressions of toll-like receptor 4 (TLR-4), nuclear factor kappa B (NF-κB), MAPK members (JNK and ERK1/2), and iNOS were determined through Western blot analysis. DEAC, CM, AMB, or VA (5-100 μg/mL) did not induce any detectable cytotoxicity in BV-2 cells. All test drugs (100 μg/mL) showed free radical scavenging activity (hydroxyl and superoxide radicals); however, only DEAC, CM, and AMB (5-100 μg/mL) significantly reduced NO production. DEAC (100 μg/mL), as well as CM (50 and 100 μg/mL) and AMB (25 μg/mL), reduced at least 50% of NO produced and markedly decrease the production of TNF-α and IL-6 but they did not significantly affect IL-10 levels. Only DEAC (100 μg/mL) and AMB (25 μg/mL) reduced the expression of iNOS, and they did not affect arginase activity. DEAC (100 μg/mL) suppressed the activation of the MAPKs JNK and ERK1/2 in LPS-activated BV-2 cells but it did not suppress the expression of TLR-4 nor the phosphorylation of NF-κB. In conclusion, DEAC, CM, and AMB exerted anti-inflammatory activity in LPS-activated microglial cells as observed by the reduction in the production of inflammatory mediators and the expression of iNOS. We identified the MAPK signaling pathway as a probable mechanism of action to the anti-inflammatory effects observed.

Phytochemistry and Biological Activities of Amburana cearensis (Allemão) ACSm

Amburana cearensis (Allemão) ACSm. belongs to the Fabaceae family and occurs in the Brazilian semiarid, Argentina, Paraguay, Bolivia, and Peru. Numerous studies that portray its ethnobotany, use in popular medicine, chemical composition, and biological activities exist in the literature. This review aimed to provide an overview of the chemical composition, ethnopharmacology, and biological activities associated with A. cearensis and its isolated constituents. Information was collected from internet searches in the Scopus, Medline, PubMed, Google Scholar, and ScienceDirect databases were performed covering publications from 1997–2020. An ethnopharmacological literature analysis revealed that A. cearensis is used to treat a wide range of respiratory disorders in addition to intestinal, circulatory, and inflammatory problems. Coumarins, flavonoids, phenolic glycosides, phenolic acids, phenylpropanoid derivatives, and triterpenoids, among others, have been reported as active compounds, with High-Performance Liquid Chromatography (HPLC) being the main analytical technique used. The A. cearensis extracts and compounds presented several biological activities, including antimicrobial, antinociceptive, anti-inflammatory, antioxidant, neuroprotective, and myorelaxant activities, among others. This review provides a useful bibliography for future investigations and A. cearensis applications; however, future studies should focus on its toxic effects and the mechanisms of action of its extracts and isolated constituents to guide clinical applications.

Antioxidant and anti-inflammatory action (in vivo and in vitro) from the trunk barks of Cabreúva (Myrocarpus frondosus Allemao, Fabaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Myrocarpus frondosus, known as cabreúva, is a tree whose trunk barks are used in folk medicine as tea, syrup, ointments, and tinctures for the treatment of inflammation. However, there is no scientific evidence demonstrating this activity.

AIM OF THE STUDY

The present investigation was focused on evaluating the antioxidant and anti-inflammatory activities of M. frondosus, using the in vitro model of RAW 264.7 macrophages induced by LPS and the in vivo model of mouse pleurisy induced by carrageenan.

MATERIALS AND METHODS

M. frondosus trunk barks were dried at room temperature for seven days and subjected to exhaustive maceration with ethanol (70%) to obtain its crude extract (CE). CE was subjected to UPLC-HRMS analysis to establish its chemical profile. Its antioxidant activity was evaluated using the DPPH method, reducing power by the iron (III) to iron (II) reduction assay and the β-carotene-linoleic acid bleaching assay. The RAW 264.7 macrophages were pretreated with the CE in a non-cytotoxic concentration and induced by LPS (1 μg/mL). After 24 h, using the supernatant, we evaluated the nitric oxide (NOx) and interleukin-6 (IL-6) levels. The anti-inflammatory effects of CE (at doses of 30, 100 and 300 mg/kg) were evaluated on leukocyte migration (total and differential), exudate concentrations, myeloperoxidase (MPO) and adenosine-deaminase (ADA) activities, NOx, tumor necrosis factor-α (TNF-α), and IL-6 levels, by using a murine model of neutrophilic inflammation.

RESULTS

The UPLC-HRMS of CE revealed the presence of isoflavonones, including biochanin A and formononetin. CE exhibited good antioxidant activity by quenching and decreasing free radicals, as well as reducing pro-oxidant metals. CE did not show cytotoxicity at a concentration below 11 μg/mL and reduced the secretion of the pro-inflammatory NOx in the inflamed macrophages. In vivo assay revealed that CE caused a pronounced inhibition on leukocyte migration, and this inhibition was due to its ability to reduce neutrophil migration. Moreover, CE was also able to reduce the release of critical pro-inflammatory mediators such as MPO, NOx, TNF-α, and IL-6.

CONCLUSIONS

All these findings indicate that M. frondosus exhibited antioxidant activity and anti-inflammatory effect.

Brazilian medicinal plants with corroborated anti-inflammatory activities: a review

CONTEXT

Inflammatory disorders are common in modern life, and medicinal plants provide an interesting source for new compounds bearing anti-inflammatory properties. In this regard, Brazilian medicinal plants are considered to be a promising supply of such compounds due to their great biodiversity.

OBJECTIVES

To undertake a review on Brazilian medicinal plants with corroborated anti-inflammatory activities by selecting data from the literature reporting the efficacy of plants used in folk medicine as anti-inflammatory, including the mechanisms of action of their extracts and isolated compounds.

METHODS

A search in the literature was undertaken by using the following Web tools: Web of Science, SciFinder, Pub-Med and Science Direct. The terms 'anti-inflammatory' and 'Brazilian medicinal plants' were used as keywords in search engine. Tropicos and Reflora websites were used to verify the origin of the plants, and only the native plants of Brazil were included in this review. The publications reporting the use of well-accepted scientific protocols to corroborate the anti-inflammatory activities of Brazilian medicinal plants with anti-inflammatory potential were considered.

RESULTS

We selected 70 Brazilian medicinal plants with anti-inflammatory activity. The plants were grouped according to their anti-inflammatory mechanisms of action. The main mechanisms involved inflammatory mediators, such as interleukins (ILs), nuclear factor kappa B (NF-κB), prostaglandin E2 (PGE2), cyclooxygenase (COX) and reactive oxygen species (ROS).

CONCLUSIONS

The collected data on Brazilian medicinal plants, in the form of crude extract and/or isolated compounds, showed significant anti-inflammatory activities involving different mechanisms of action, indicating Brazilian plants as an important source of anti-inflammatory compounds.

Afrormosin, an Isoflavonoid from Amburana cearensis A. C. Smith, Modulates the Inflammatory Response of Stimulated Human Neutrophils

Isoflavones are phytoestrogens known by their anti-inflammatory, antioxidant and immunomodulatory properties. Presently, there is no information on whether afrormosin, an isoflavone from Amburana cearensis A.C. Smith (Fabaceae), has some effect on the inflammatory response from stimulated human neutrophils. Thus, the aim of this study was to evaluate the anti-inflammatory and antioxidant potentials of afrormosin on human neutrophils. Neutrophils (2.5 × 10(6) cells/mL) were incubated with afrormosin (3.35-335.2 μM) prepared from a product isolated from Amburana cearensis A.C. Smith with a 78.5% degree of purity and stimulated by the addition of cytochalasin B and N-formyl-methionyl-leucyl-phenylalanine (fMLP) or phorbol 12-myristate-13-acetate (PMA). Afrormosin inhibited the neutrophil degranulation induced by fMLP (10.47-335.2 μM) or PMA (0.33-167.6 μM), myeloperoxidase activity (3.3-335.2 μM), TNF-α secretion (16.7-335.2 μM) and the reactive oxygen species (ROS) generation (16.7-335.2 μM). On the other hand, afrormosin did not show any effect either on elastase or as a free radical scavenger. These data suggest that afrormosin modulates intermediary steps of the neutrophil ROS generation process. In addition, the modulatory effect of afrormosin on human neutrophil degranulation seems to be directed towards PMA-induced activation, indicating a potent inhibition of the protein kinase C activity. This study provided evidence, for the first time, to support the anti-inflammatory and antioxidant activities of afrormosin, creating novel insights into the pharmacological actions of this natural isoflavone.

Efficacy and safety of cumaru syrup as complementary therapy in mild persistent asthma: a double-blind, randomized, placebo-controlled study

Amburana cearensis is a medicinal plant known as "cumaru". It is used in Northeast Brazil in the treatment of respiratory diseases. This was a randomized, double-blind, placebo-controlled study, with the aim of evaluating the efficacy and safety of cumaru syrup as complementary therapy in mild persistent asthma. The study consisted of 3 phases, pre-treatment, treatment and post-treatment. The primary efficacy outcome was comparison of the changes reported by patients of the cumaru and placebo groups after treatment, using the "Asthma Quality of Life Questionnaire" (AQLQ). The secondary outcome was the effect of cumaru syrup on lung function based on spirometry. The results showed that in the cumaru group, the proportion of patients who had global improvement in asthma symptoms was significantly greater (61.90%, P=0.0009) than in the placebo group (9.52%). Only the spirometric parameters Forced Vital Capacity (FVC) and Forced Expiratory Volume in 1 second (FEV1) showed significant intergroup differences in post-treatment (P<0.05). The hematological and serum chemistry tests performed in the pre-treatment and post-treatment showed no statistically significant differences (P>0.05). Adverse events were reported by 3 patients (14.29%) in the cumaru group and 3 patients (14.29%) in the placebo group. All adverse events were considered non-serious and mild.

Resilience and adaptation in the use of medicinal plants with suspected anti-inflammatory activity in the Brazilian Northeast

ETHNOPHARMACOLOGICAL RELEVANCE

This study uses the utilitarian redundancy model as a basis to investigate issues related to the preference for plants native to the Caatinga used as anti-inflammatories by respondents from the community of Carão in rural Pernambuco, Brazil.

MATERIALS AND METHODS

For this purpose, 49 respondents and 24 native plants used as anti-inflammatories were selected from a database built by previous studies in this study area. Interviews with respondents were conducted by applying the checklist-interview technique and by presenting photographs of plants, which were ordered according to plant preference for each type of inflammation mentioned. After elaborating each list of preferences, we inquired as to the criteria used for the construction of the lists. A salience index was calculated to determine the most- and least-preferred species, and principal component analysis (PCA) was used to identify the most significant criteria used by the respondents to indicate the preferred plants for anti-inflammatory use.

RESULTS

We identified 37 subcategories or inflammatory conditions, most of which were associated with disorders of the genitourinary (8 conditions), digestive (7) and respiratory (4) systems. Subcategories with the highest level of redundancy include "wound" (79.1% of species), "cut" (66.6%) and "uterus" (66.6%), and five non-redundant conditions were identified (only one species). We obtained approximately 300 lists and 18 choice criteria. PCA analysis showed that seven species were most preferred by the respondents, as they showed the highest salience values, and that the preferred criterion was "treatment effectiveness".

CONCLUSIONS

These results indicate that inflammation is a complex collection of disorders consisting of several subcategories. Furthermore, respondents preferred different treatments for different inflammatory conditions, which pose a challenge for future pharmacological studies that aim to assess the biological activity of anti-inflammatory plants. Preferences were very specific, focused on a small number of species and mainly related to therapeutic effectiveness.

Anti-nociceptive and anti-inflammatory activities of (-)-α-bisabolol in rodents

(-)-α-Bisabolol is an unsaturated, optically active sesquiterpene alcohol obtained by the direct distillation of essential oil from plants such as Vanillosmopsis erythropappa and Matricaria chamomilla. (-)-α-Bisabolol has generated considerable economic interest, as it possesses a delicate floral odour and has been shown to have antiseptic and gastroprotective activities. In this study, (-)-α-bisabolol was tested in standardised rodent models by gavage administration at doses of 100 and 200 mg/kg in the models of inflammation and 25 and 50 mg/kg in the models of nociception. In the inflammatory models of paw oedema induced by carrageenan and dextran, the mice treated with (-)-α-bisabolol showed smaller oedemas compared to animals treated only with the vehicle. (-)-α-Bisabolol was capable of reducing paw oedemas induced by 5-HT but not oedemas induced by histamine. (-)-α-Bisabolol demonstrated anti-nociceptive activity in the models of visceral nociception induced by acetic acid and in the second phase of the nociception test induced by the intraplantar administration of formalin. (-)-α-Bisabolol did not have any effect in a thermal nociception model using a hot plate but was able to diminish mechanical inflammatory hypernociception evoked by carrageenan. These findings suggest that the anti-nociceptive action of (-)-α-bisabolol is not linked to a central mechanism but instead is related to the inflammatory process. (-)-α-Bisabolol was able to decrease leukocyte migration, protein extravasations and the amount of TNF-α to the peritoneal cavity in response to carrageenan. Additionally, (-)-α-bisabolol reduced neutrophil degranulation in response to phorbol-myristate-acetate. We demonstrate, for the first time, the peripheral anti-inflammatory and anti-nociceptive activities of (-)-α-bisabolol.

A comparative chemical and pharmacological study of standardized extracts and vanillic acid from wild and cultivated Amburana cearensis A.C. Smith

The objectives of this work were to carry out a comparative chemical study and to evaluate the antinociceptive and anti-inflammatory activities of ethanol extracts (EtOHE) and vanilic acid (VA) from cultivated and wild Amburana cearensis A.C. Smith (Fabaceae), an endangered species used in Northeast Brazil for the treatment of asthma. The HPLC analysis of EtOHE, showed that coumarin (CM) and VA were the major constituents from the cultivated plant, while in the extract from the wild plant the major constituents were amburoside A (AMB) and CM. Pharmacological tests were performed with male Swiss mice or male Wistar rats acutely administered with 100-400mg/kg, p.o. of EtOHEs or 12.5-50mg/kg, p.o. of VA. EtOHEs from A. cearensis with 4, 7 or 9 months of cultivation significantly inhibited, from 32 to 64%, both phases of the formalin test in mice. Similar results were observed with the EtOHE from the wild species. VA significantly reduced both phases of the formalin test. This effect was partially reversed by naloxone. EtOHE from cultivated or wild A. cearensis inhibited the carrageenan (Cg)-induced mice paw edema. Furthermore, VA inhibited the paw edema and the leukocyte migration in rat peritoneal cavity induced by Cg. On the other hand, it did not inhibit the edema and the increase of vascular permeability induced by dextran in the rat paw. All together, these results indicate that the EtOHE from cultivated A. cearensis exhibit similar chemical and pharmacological profiles, as related to the wild plant. VA is, at least partially, responsible for these pharmacological effects. Its antinociceptive effect occurs by a mechanism partly dependent upon the opioid system, while the anti-inflammatory action was manifested in inflammatory processes dependent on polymorphonuclear cells and are probably related to the VA inhibition of cytokines as observed by others.