Amburana cearensis: Pharmacological and Neuroprotective Effects of Its Compounds.

Amburana cearensis A.C. Smith is an endemic tree from Northeastern Brazil used in folk medicine as teas, decocts and syrups for the treatment of various respiratory and inflammatory diseases, since therapeutic properties have been attributed to compounds from its stem bark and seeds. Numerous pharmacological properties of semi-purified extracts and isolated compounds from A. cearensis have been described in several biological systems, ranging from antimicrobial to anti-inflammatory effects. Some of these activities are attributed to coumarins and phenolic compounds, the major compounds present in A. cearensis seed extracts. Multiple lines of research demonstrate these compounds reduce oxidative stress, inflammation and neuronal death induced by glutamate excitotoxicity, events central to most neuropathologies, including Alzheimer's disease (AD) and Parkinson's Disease (PD). This review focuses on the botanical aspects, folk medicine use, biological effects and pharmacological activities of A. cearensis compounds and their potential as novel non-toxic drugs for the treatment of neurodegenerative diseases.

Apigenin from Croton betulaster Müll restores the immune profile of microglia against glioma cells.

The flavonoid apigenin, extracted from the Brazilian plant Croton betulaster Müll. has demonstrated the ability to inhibit proliferation, induce differentiation, and modify the inflammatory profile of glioma cells. The aim of the present study was to evaluate the effect of apigenin on chemotaxis and regulation of inflammatory cytokines of microglia cells and these impacts on glioma cell growth. In cultures of isolated rat microglia, it was observed that apigenin induced changes in Iba1-positive cells to an ameboid phenotype, associated to an increase in the expression of the activated M1 profile marker OX-42 and iNOS and a reduction in the expression of the M2 profile marker CD206. Besides, apigenin modulated the tumor necrosis factor and IL-10 release by microglia. Treatment of C6 glioma cells with conditioned medium of microglia treated with apigenin-induced reduction of tumor migration and viability, associated with significant reduction in IL-6 levels. On the other hand, treatment of C6 cells with apigenin-induced microglia chemotaxis to glioma in vitro. Moreover, apigenin treatment of microglia/C6 co-cultures induced preferentially reduction in the viability of C6 cells and increased microglia-activated phenotype, associated with a change in the balance of TNF/IL-10 levels. Together, these results demonstrated that the flavonoid apigenin restores the immune profile of microglia against glioma cells.

Amburana cearensis seed extract protects brain mitochondria from oxidative stress and cerebellar cells from excitotoxicity induced by glutamate.

ETHNOPHARMACOLOGICAL RELEVANCE: Amburana cearensis (Allemao) A.C.Sm. is a medicinal plant of the Brazilian Caatinga reported to present antioxidant and anti-inflammatory activity. This study aimed to evaluate the neuroprotective effect of the extracts obtained from the seeds of A. cearensis in primary cultures of cerebellar cells subjected to excitotoxicity induced by glutamate and brain mitochondria submitted to oxidative stress. MATERIALS: and methods: Primary cultures of cerebellar cells were treated with the ethanol (ETAC), hexane (EHAC), dichloromethane (EDAC) and ethyl acetate (EAAC) extracts of the seeds of A.cearensis and subjected to excitotoxicity induced by glutamate (10µM). Mitochondria isolated from rat brains were submitted to oxidative stress and treated with ETAC. RESULTS: Only the EHAC extract reduced cell viability by 30% after 72h of treatment. Morphological analyses by Immunofluorescence showed positive staining for glutamine synthetase, ß-III tubulin, GFAP and IBA1 similar to control cultures, indicating a better preservation of astrocytes, neurons and microglia, after excitotoxic damage induced by glutamate in cerebellar cultures treated with the extracts. The ETAC extract also protected mitochondria isolated from rat brains from oxidative stress, reducing the swelling, dissipation of the membrane potential, ROS production and calcium influx. CONCLUSION: Thus, this study suggests that the seed extracts from A. Cearensis exhibit neuroprotective potential against oxidative stress and excitotoxicity induced by glutamate and can be considered a potential therapeutic agent in the treatment of neurodegenerative diseases.

Amburana cearensis seed extracts protect PC-12 cells against toxicity induced by glutamate

ABSTRACT Amburana cearensis (Allemão) A.C. Sm., Fabaceae, has been widely studied for its medicinal activities. Many neurodegenerative disorders are caused by oxidative stress, mitochondrial dysfunction, excitotoxicity induced by glutamate and ultimately cell death. This study describes the chemical profile of the ethanolic, hexane, dichloromethane, and ethyl acetate extracts obtained from seeds of A. cearensis. The objective of this study was to investigate the chemical profile of extracts obtained from seeds of A. cearensis, as well as their cytotoxicity and neuroprotective effects in cultures of neural PC12 cells. Metabolite profile was performed by GC–MS. PC12 cells were treated with increasing concentrations of the extracts (0.01–2000 µg/ml) and the cell viability was analyzed after 24 and 72 h using an MTT test. For the excitotoxicity assay, PC12 cells were pre-treated with glutamate (1 mM) for 6 h and treated with increasing concentrations (0.1–1000 µg/ml) of the extracts. The chromatographic analysis of the extracts detected various compounds with antioxidant properties, with the majority of peaks corresponding to the isoflavone coumarin. Only the hexane extract showed toxicity after 72 h exposure at the highest concentration (1000 µg/ml). By contrast, all extracts increased the cellular viability of PC12 cells against the toxicity caused by glutamate. Therefore, the extracts from the seeds of A. cearensis showed no toxicity and have neuroprotective potential against neuronal damage induced by glutamate, which may be related to their antioxidant properties.

The flavonoid apigenin from Croton betulaster Mull inhibits proliferation, induces differentiation and regulates the inflammatory profile of glioma cells.

This study aimed to investigate the antitumor and immunomodulatory properties of the flavonoid apigenin (5,7,4'-trihydroxyflavone), which was extracted from Croton betulaster Mull, in glioma cell culture using the high-proliferative rat C6 glioma cell line as a model. Apigenin was found to have the ability to reduce the viability and proliferation of C6 cells in a time-dependent and dose-dependent manner, with an IC50 of 22.8 µmol/l, 40 times lower than that of temozolomide (1000 µmol/l), after 72 h of apigenin treatment. Even after C6 cells were treated with apigenin for 48 h, high proportions of C6 cells entered apoptosis (39.56%) and autophagy (22%) as shown by flow cytometry using annexin V/propidium iodide and acridine orange staining, respectively. In addition, the flavonoid apigenin induced cell accumulation in the G0/G1 phase of the cell cycle and inhibited glioma cell migration efficiently. Moreover, apigenin induced astroglial differentiation and morphological changes in C6 cells, characterized by increased expression of glial fibrillary acidic protein and decreased expression of nestin protein, a typical marker of neuronal precursors. The immunomodulating effects of apigenin were also characterized by a change in the inflammatory profile as evidenced by a significant decrease in interleukin-10 and tumor necrosis factor production and increased nitric oxide levels. Because apigenin can induce differentiation, apoptosis, and autophagy, can alter the profile of cytokines involved in regulating the immune response, and can reduce the survival, growth, proliferation, and migration of C6 cells, this flavonoid may be considered a potential antitumor drug for the adjuvant treatment of malignant gliomas.

Flavonoids modulate the proliferation of Neospora caninum in glial cell primary cultures.

Neospora caninum (Apicomplexa; Sarcocystidae) is a protozoan that causes abortion in cattle, horses, sheep, and dogs as well as neurological and dermatological diseases in dogs. In the central nervous system of dogs infected with N. caninum, cysts were detected that exhibited gliosis and meningitis. Flavonoids are polyphenolic compounds that exhibit antibacterial, antiparasitic, antifungal, and antiviral properties. In this study, we investigated the effects of flavonoids in a well-established in vitro model of N. caninum infection in glial cell cultures. Glial cells were treated individually with 10 different flavonoids, and a subset of cultures was also infected with the NC-1 strain of N. caninum. All of the flavonoids tested induced an increase in the metabolism of glial cells and many of them increased nitrite levels in cultures infected with NC-1 compared to controls and uninfected cultures. Among the flavonoids tested, 3',4'-dihydroxyflavone, 3',4',5,7-tetrahydroxyflavone (luteolin), and 3,3',4',5,6-pentahydroxyflavone (quercetin), also inhibited parasitophorous vacuole formation. Taken together, our findings show that flavonoids modulate glial cell responses, increase NO secretion, and interfere with N. caninum infection and proliferation.

Temporal and spatial regulation of chondroitin sulfate, radial glial cells, growing commissural axons, and other hippocampal efferents in developing hamsters.

We investigated the time and space relationship between growth of hippocampal efferents, particularly those forming the hippocampal commissure, and expression of extracellular matrix components related to radial glial cells. Developing hamster brains from embryonic day (E) 13 to postnatal day (P) 7 had 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) crystals implanted into the hippocampus or were processed for fluorescent immunohistochemistry against chondroitin sulfate (CS) glycosaminoglycans and glial fibrillary acidic protein (GFAP). The first, pioneer fibers from the hippocampus were seen crossing the midline at E15 and arriving at the contralateral hippocampus 24-48 hours later (P1), followed closely by a thick front of growing fibers. Before E15, CS expression was preceded by septal fusion and was concomitant with formation of the commissural tract. On E15, CS expression formed a U-shaped border below the fimbria. From E15 to P3, CS became expressed between the hippocampal commissure and the third ventricle and at the caudal borders of the fornix columns. As the hippocampal commissure expanded, CS expression became gradually lighter to virtually disappear by P7. On E15 and P1, GFAP-positive radial glial cells were present caudal (but not rostral) to the commissure at the midline, partially overlapping CS expression. Similar cells were present dorsal to the fimbria, extending their processes perpendicularly over the growing axons. The data reveal that CS and radial glial cells form a tunnel surrounding the developing fimbria and a border at the midline caudal to the hippocampal commissure. It is suggested that these cellular and molecular borders play a role in guidance of hippocampal efferents.