Gilvandete Maria Pinheiro Santiago

Antibacterial and Antioxidant Activities of Ursolic Acid and Derivatives

Ursolic acid, an important bioactive compound, was isolated from ethanol extract of aerial parts of Sambucus australis. In order to develop bioactive ursolic acid derivatives, two semi-synthetic compounds were obtained through modification at C-3. The antibacterial activity of the ursolic acid and its derivatives was investigated. The microdilution method was used for determination of the minimal inhibitory concentration (MIC), against twelve bacterial strains. The influence of ursolic acid and its derivatives on the susceptibility of some bacterial pathogens to the aminoglycosides antibiotics neomycin, amikacin, kanamycin and gentamicin was evaluated. The most representative synergistic effect was observed by 3β-formyloxy-urs-12-en-28-oic acid at the concentration of 64 μg/mL in combination with kanamycin against Escherichia coli (27), a multidrug-resistant clinical isolate from sputum, with reduction of MIC value from 128 μg/mL to 8 μg/mL. Ursolic acid and its derivatives were examined for their radical scavenger activity using the DPPH assay, and showed significant activity.

Study of technical CNSL and its main components as new green larvicides

Larvicidal activities against Aedes aegypti of technical cashew (Anarcadium Occidentale L.) nut shell liquid (CNSL) and its main constituents, cardanol, cardol and their products of hydrogenation were evaluated. In addition, the structure-activity relationship is also discussed.

Larvicidal and Nematicidal Activities of the Leaf Essential Oil of Croton regelianus

The chemical composition of the leaf essential oil of Croton regelianus collected from wild plants growing in two different sites at Ceará State (Brazil) was analyzed by GC/MS and GC‐FID. Twenty monoterpenoids, representing more than 96% of the chemical composition of the oils, were identified and quantified. The oils showed similar chemical composition but considerable variation in the levels of each constituent. Ascaridole (33.9–17.0%), p‐cymene (22.3–21.6%), and camphor (13.0–3.1%) were the predominant constituents. The monoterpene ascaridole was isolated and characterized by spectroscopic data. The essential oils and the isolated compounds were tested against Aedes aegypti and Artemia sp. larvae, and the root knot nematode Meloidogyne incognita. The bioassay results show that the essential oil of C. regelianus and ascaridole were moderately active against the M. incognita, but strongly effective against both A. aegypti and Artemia sp. larvae.

Chemical Composition and Larvicidal Activity of the Essential Oils of Cordia leucomalloides and Cordia curassavica from the Northeast of Brazil

Os oleos essenciais das folhas de Cordia leucomalloides e Cordia curassavica foram obtidos por hidrodestilacao e suas composicoes quimicas determinadas por uma combinacao de CG-EM e CG-DIC. Como resultado, vinte e tres componentes foram identificados em ambos os oleos, representando 98,6 e 91,2% da composicao volatil. O oleo essencial de C. leucomalloides foi caracterizado por uma alta percentagem de sesquiterpenos (90,6%), sendo d-cadineno (17,4%), (E)-cariofileno (15,7%), biciclogermacreno (12,5%) e germacreno D (11,2%) os majoritarios. Por outro lado, o oleo de C. curassavica mostrou proporcoes similares de monoterpenos (47,3%) e sesquitepenos (43,9%), entre os quais a-pineno (20,5%), b-pineno (13,1%), (E)-cariofileno (12,4%) e biciclogermacreno (13,8%) foram os compostos predominantes. O potencial larvicida dos dois oleos foi avaliado contra larvas no terceiro estagio do mosquito Aedes aegypti. Os resultados mostraram que ambos os oleos apresentaram atividade biologica significativa, particularmente o oleo essencial de C. leucomalloides, o qual foi capaz de matar 98,7% das larvas numa concentracao de 100 ppm.

Estudo fitoquímico e avaliação da atividade larvicida de Pterodon polygalaeflorus Benth (Leguminosae) sobre Aedes aegypti

Chemical investigation of the hexane and methanol extracts of the fruits of Pterodon polygalaeflorus (Leguminosae) resulted in the isolation and identification of furanic diterpenes: 6-a-acetoxivouacapane, 6-a-hidroxyvouacapane and vouacapane, which is related by the first time as a natural product. The structures of these compounds were established by spectroscopic analysis, including 2D NMR experiments. The 6-a-acetoxivouacapane, the hexane and methanol extracts, and the essential oil were evaluated on 3rd instar larvae of Aedes aegypti and only the hexane extract showed good larvicidal activity with LC50 23.99 ± 0.75 µg/mL.

Nematicidal and larvicidal activities of the essential oils from aerial parts of Pectis oligocephala and Pectis apodocephala Baker

The chemical composition of the essential oils from aerial parts of Pectis apodocephala and Pectis oligocephala were analyzed by GC-MS. The essential oils of these species were predominantly constituted by monoterpenes. Geranial (42.9-44.5%), neral (32.2-34.2%) and alpha-pinene (10.7-11.4%) were the main constituents in the oil of P. apodocephala, while p-cymene (50.3-70.9%) and thymol (24.4-44.7%), were the prevalent compounds in the oil of P. oligocephala. The essential oils were tested against the root knot nematode Meloidogyne incognita and Aedes aegypti larvae survival. The results obtained show that both essential oils exhibited significant activity and could be considered as potent natural namaticidal and larvicidal agents.

Atividades larvicida e anticolinesterásica de plantas do gênero Kalanchoe

Acetylcholine esterase inhibitors are successfully used to treat the symptoms of Alzheimers disease. Extracts of three Kalanchoe species (K. brasiliensis, K. pinnata and K. gastonis-bornieri) showed acetylcholine esterase inhibitory effects and a toxic effect on Aedes aegypti larvae. Here we describe the bioassay guided fractionation of extracts of the most active extracts (K. brasiliensis) which resulted in the isolation of an active mixture of three flavonoids: 8-methoxyquercetin, 3,7-di-O-rhamnopyranoside and 8-methoxykaempferol-3,7-di-O-rhamnopyranoside. On TLC these flavonoids showed an acetylcholine esterase inhibitory effect.

Estudo químico e biológico de Tephrosia toxicaria Pers.

The ethanol extracts from leaves, stems, pods and roots were assayed against the 3rd instar Aedes aegypti larvae and the highest activity was observed in the roots extracts (LC50 47.86 ppm). This extract was submitted to partition with hexane, chloroform, ethyl acetate and methanol. The respective fractions were bioassayed and the best larvicidal activities were identified in the hexane (LC50 23.99 ppm) and chloroform (LC50 13.80 ppm) fractions. Antioxidant activity (DDPH method) was observed in the ethanol extract (IC50 276 µg/mL) from roots of T. toxicaria. Fractions from this extract were also tested and the highest antioxidant activity (IC50 89 µg/mL) was found in the methanol fraction. The flavonoids iso-obovatin (1), obovatin (2), 6a,12a-dehydro-β-toxicarol (3), 6a,12a-dehydro-α-toxicarol (4) and α-toxicarol (5) were isolated and bioassayed against A. aegypti. The flavonoid 5 showed the best larvicidal activity (LC50 24.55 ppm). The antioxidant activity of 2 was investigated and showed IC50 3.370 µg/mL. The antioxidant and larvicidal activities of Tephrosia toxicaria are reported for the first time.

Phytochemical study guided by the myorelaxant activity of the crude extract, fractions and constituent from stem bark of Hymenaea courbaril L.

ETHNOPHARMACOLOGICAL RELEVANCE Hymenaea courbaril L. (Caesalpinoideae) is used in Brazilian folk medicine to treat anemia, kidney problems, sore throat and other dysfunctions of the respiratory system, such as bronchitis and asthma, although such properties are yet to be scientifically validated. AIM OF THE STUDY In order to give a scientific basis to support the traditional use of Hymenaea courbaril, this study was designed to evaluate antioxidant, myorelaxant and anti-inflammatory properties of the ethanol extract from stem bark and its fractions. The myorelaxant effect of astilbin, a flavonoid isolated from the bioactive ethyl acetate fraction (EAF), has also been evaluated. MATERIAL AND METHODS In the present study ethanol extract from stem bark (EEHC) and fractions were analyzed using bioassay-guided fractionation. The following activities were investigated: antioxidant by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, myorelaxant on rat tracheal smooth muscle, and anti-inflammatory using ovalbumin-induced leukocytosis and airway hyperresponsiveness in rats. RESULTS The results of the present investigation show that the whole extract of Hymenaea courbaril and some of its fractions strongly scavenged DPPH radical. The extract showed myorelaxant activity on rat trachea, being EAF its highest efficient fraction. Bio-guided study allowed the isolation of astilbin, a well-known flavonoid. The activity induced by this compound indicates that it may be partly responsible for the myorelaxant effect of EAF. EAF reduced contractions that depended on divalent cation inflow through voltage-operated Ca(2+) channels (VOCCs) or receptor-operated Ca(2+) channels (ROCCs), but it was more potent to inhibit VOCC- than ROCC-dependent contraction induced by Ca(2+) addition in ACh-enriched Ca(2+)-free medium. Oral pretreatment of antigen-challenged animals with EAF prevented airway hyperresponsiveness on KCl-induced contraction and reduced the number of total white cells, particularly eosinophils and neutrophils in bronchoalveolar lavage. CONCLUSIONS This study provided scientific basis that Hymenaea courbaril presents potential antioxidant, myorelaxant and anti-inflammatory actions, which support its use in folk medicine to treat inflammatory airway diseases.

Effects of Myrcia ovata Cambess. essential oil on planktonic growth of gastrointestinal microorganisms and biofilm formation of Enterococcus faecalis

The essential oil from the leaves of Myrcia ovata Cambess., commonly used in Brazil for the treatment of gastric illnesses, was screened for antimicrobial activity and action in the formation of microbial biofilms by Enterococcus faecalis. The oil was obtained by hydrodistillation using a clevenger-type system. Its chemical composition was analyzed using GC and GC-MS. Both MIC and MBC of the essential oil were determined by broth microdilution techniques and agar dilution method. The essential oil showed antimicrobial activity against E. faecalis, Escherichia coli, Pseudomonas aeruginosa, Salmonella choleraesuis, Staphylococcus aureus, Streptococcus pneumoniae and Candida parapsilosis. The results showed that the essential oil of M. ovata Cambess. was effective against the formation of biofilm by E. faecalis when compared with the control. Four volatile compounds, representing 92.1 % of the oil, were identified and geranial was the major component (50.4 %). At the best of our knowledge, this is the first report of the chemical composition and antimicrobial activity of the essential oil from leaves of M. ovata.