Paulete Romoff

Constituíntes fenólicos polares de Schinus terebinthifolius Raddi (Anacardiaceae)

The EtOH extract from the leaves of Schinus terebinthifolius showed anti-radicalar potential in the DPPH test. It was partitioned between n-BuOH:H2O (1:1) and these two phases were also evaluated for anti-radicalar activity. The active n-BuOH phase was partitioned between EtOAc:H2O (1:1) and the active EtOAc phase was submitted to chromatographic procedures to afford five active phenolic compounds: ethyl gallate, methyl gallate, quercitrin, myricetrin and myricetin. The structures of these compounds were established by NMR spectral data analysis.

Flavonoids as chemotaxonomic markers for Asteraceae.

Flavonoids have been shown to be good taxonomic markers for Asteraceae. More than 800 compounds comprising 4700 flavonoid occurrences were included in a computational system specially made for chemotaxonomic purposes. Some implications of flavonols, flavones and other types as well as structural features of them are discussed for tribes and subtribes of Asteraceae.

Jacaranone induces apoptosis in melanoma cells via ROS-mediated downregulation of Akt and p38 MAPK activation and displays antitumor activity in vivo.

Background Malignant melanoma is a deadly type of metastatic skin cancer with increased incidence over the past 30 years. Despite the advanced knowledge on the biology, immunobiology and molecular genetics of melanoma, the alternatives of treatment are limited with poor prognosis. On clinical trials, natural products and among them redox-active quinones have been tested in the attempt to control the growth of cancer cells. Recently, we isolated jacaranone from Pentacalia desiderabilis, a benzoquinone derivative that showed a broad antitumor activity and protective anti-melanoma effect in a syngeneic model. The purified substance is active at micromolar concentrations, is not hemolytic, and is not toxic in naïve mice. Methodology/Principal Findings The jacaranone antitumor activity was shown against several human cancer cell lines in vitro. Moreover, the induction of apoptosis in murine melanoma cells and jacaranone antitumor activity in vivo, in a melanoma experimental model, were also shown. Jacaranone renders antiproliferative and proapoptotic responses in tumor cells, by acting on Akt and p38 MAPK signaling pathways through generation of reactive oxygen species (ROS). The free radical scavenger N-acetyl-cysteine (NAC) was able to completely suppress cell death induced by jacaranone as it blocked Akt downregulation, p38 MAPK activation as well as upregulation of proapoptotic Bax. Notably, treatment of melanoma growing subcutaneously in mice with jacaranone significantly extended the mean survival times in a dose-dependent manner. Conclusions/Significance The results provide evidence for the mechanisms of action of jacaranone and emphasize the potential use of this quinone for the treatment of melanoma.

Isolation of an antileishmanial and antitrypanosomal flavanone from the leaves of Baccharis retusa DC. (Asteraceae).

In the course of selection of new bioactive compounds from Brazilian flora, the crude MeOH extract from the leaves of Baccharis retusa DC. (Asteraceae) showed potential against Leishmania sp. and Trypanosoma cruzi. Chromatographic fractionation of the dichloromethane phase from MeOH extract yielded great amounts of the bioactive derivative, which was characterized as 5,6,7-trihydroxy-4′-methoxyflavanone. The structure of this compound was established on the basis of spectroscopic data analysis, mainly nuclear magnetic resonance and mass spectrometry.

Anti-leishmanial effects of purified compounds from aerial parts of Baccharis uncinella C. DC. (Asteraceae)

Species of Baccharis exhibit antibiotic, antiseptic, wound-healing, and anti-protozoal properties, and have been used in the traditional medicine of South America for the treatment of several diseases. In the present work, the fractionation of EtOH extract from aerial parts of Baccharis uncinella indicated that the isolated compounds caffeic acid and pectolinaringenin showed inhibitory activity against Leishmania (L.) amazonensis and Leishmania (V.) braziliensis promastigotes, respectively. Moreover, amastigote forms of both species were highly sensible to the fraction composed by oleanolic + ursolic acids and pectolinaringenin. Caffeic acid also inhibited amastigote forms of L. (L.) amazonensis, but this effect was weak in L. (V.) braziliensis amastigotes. The treatment of infected macrophages with these compounds did not alter the levels of nitrates, indicating a direct effect of the compounds on amastigote stages. The results presented herein suggest that the active components from B. uncinella can be important to the design of new drugs against American tegumentar leishmaniases.

Microclimatic factors and phenology influences in the chemical composition of the essential oils from Pittosporum undulatum Vent. leaves

The essential oil from leaves of a Brazilian specimen of Pittosporum undulatum Vent. was analyzed by means of gas chromatography-mass spectrometry (GC-MS) and NMR analysis after chromatographic separation. The leaves of P. undulatum were collected during one year (January, March, May, July, September and November, 2004) and the obtained essential oils were analyzed. The oil is rich in hydrocarbon monoterpenes and sesquiterpenes, being (+)-limonene the main constituent. It was observed a significant variation on the relative amount of (+)-limonene in these collections, which could be associated to microclimatic parameters (temperature and pluviometric index) despite of phenology of the studied species.

Chemical composition and anti-inflammatory evaluation of essential oils from leaves and stem barks from Drimys brasiliensis Miers (Winteraceae)

The essential oils from leaves and stem barks from Drimys brasiliensis Miers (Winteraceae) were individually obtained by hydrodistillation and their compounds characterized by use of GC/FID and GC/MS. The main identified derivatives were monoterpenes (leaves 4.31% and stem barks 90.02%) and sesquiterpenes (leaves 52.31% and stem barks 6.35%). Additionally, the sesquiterpene polygodial was isolated from hexane extract from stem barks of D. brasiliensis after chromatographic steps and characterized by spectroscopic means, mainly NMR. Aiming the evaluation of anti-inflammatory potential, the crude essential oils and the sesquiterpene polygodial were subjected to bioassays to evaluate the acute toxicity of these compounds as well as the anti-inflammatory and antinociceptive activities induced by carrageenan and formalin in mices. Ours results showed that essential oil obtained from the stem barks significantly reduced the oedema induced by carrageenan. The anti-inflammatory effect induced by stem barks oil (at 200 mg kg-1) was similar to observed for indomethacin (at 10 mg kg-1) and superior for polygodial (at 200 mg kg-1) in 30 and 60 min after the administration of essential oils. The inflammatory response induced by formalin was effective to the stem barks oil (62.5%) in comparison to polygodial (50.0%).

Toxicity of apolar and polar Lantana camara L. crude extracts in mice

Lantana camara L, widely used in folk medicine, presents toxicity for farm animals. The acute poisoning effects of the apolar and polar L. camara L. extracts in mice were done. The percentage of death during 7 days after treatment, the acute signs of toxicity as well as the general activity observed in open field were assessed. The extracts were administered by i.p. route at 1.5, 3.0 and 5.0 g/kg. Animals were evaluated during the first 2 h after the treatments to assess the acute signs of toxicity and daily observations were done for the presence of death. In the end of the experiment, at day 7, or immediately after death the animals had their organs removed, weighted and observed for macroscopic alterations. (1)H NMR and TLC analysis suggest the presence of triterpenoids in the apolar phase but not in the polar phase. Results showed also that both extracts produced similar percentage of death, mainly after 2 days of treatment; only the apolar extract presented a dose-dependent increased lethality. At necropsy, mice treated by both apolar and polar extracts were severely icteric, dehydrated and constipated, with hepatosis, showed congested heart and lung, and nephrosis; no skin lesions were shown. The main signs of toxicity revealed a decreased spontaneous general activity. In addition, it was observed a decreased duration of locomotion and animal rearing parallel to an increased immobility in the open field. The similarity of the signs related to the acute toxicity for both apolar and polar extracts suggested that the extracts have some of the active toxic principles in common. Data from open field behavior and spontaneous signs of toxicity suggest that the toxic principles have depressive properties on central nervous system.

Evaluation of anti-inflammatory activity of derivatives from aerial parts of Baccharis uncinella.

Context: Species of Baccharis exhibit antibiotic, antiseptic, and wound-healing properties, and have been used in the traditional medicine of South America for the treatment of inflammation, headaches, diabetes, and hepatobiliary disorders. Objective: To investigate the anti-inflammatory activity of organic phases from EtOH extract of the aerial parts of Baccharis uncinella DC (Asteraceae). Materials and methods: The crude EtOH extract from the aerial parts of B. uncinella was subjected to partition procedures and the corresponding CH2Cl2 and EtOAc phases were subjected to several chromatographic separation procedures. Thus, these phases and their purified compounds were assayed for evaluation of anti-inflammatory activity. Results: The CH2Cl2 phase from EtOH extract from B. uncinella contained two triterpenoids (oleanolic and ursolic acids) and one flavonoid (pectolinaringenin), whereas the respective EtOAc phase showed to be composed mainly by two phenylpropanoid derivatives (caffeic and ferulic acids). The CH2Cl2 and EtOAc phases as well as their isolated compounds exhibited anti-inflammatory effects against inflammatory reactions induced by phospholipase A2 (from Crotalus durissus terrificus venom) and by carrageenan. Discussion and conclusion: The results suggested that the components obtained from partition phases of EtOH extract of B. uncinella could represent lead molecules for the development of anti-inflammatory agents. Additionally, the results confirmed the use of Baccharis genus in the traditional medicine of South America for the treatment of inflammation and other heath disorders. To date, the present work describes for the first time the anti-inflammatory effects of compounds isolated from B. uncinella.

A Trinuclear Oxo-Chromium(III) Complex Containing the Natural Flavonoid Primuletin: Synthesis, Characterization, and Antiradical Properties

A new trinuclear oxo-centered chromium(III) complex with formula [Cr3O(CH3CO2)6(L)(H2O)2] (L = 5-hydroxyflavone, known as primuletin) was synthetized and characterized by ESI mass spectrometry, thermogravimetry, and 1H-NMR, UV-Vis, and FTIR spectroscopies. In agreement with the experimental results, DFT calculations indicated that the flavonoid ligand is coordinated to one of the three Cr(III) centers in an O,O-bidentate mode through the 5-hydroxy/4-keto groups. In a comparative study involving the uncoordinated primuletin and its corresponding complex, systematic reactions with the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) showed that antiradical activity increases upon complexation.