Extracellular hydrolytic enzymes produced by yeasts from Antarctic lichens.

In the Antarctic environment, yeasts are versatile eukaryotes that have shown wide dispersion in different substrates, producing active enzymes in extreme conditions, but their relevance in biotechnological applications is largely unknown. The aim of this study was to evaluate the production of extracellular hydrolases by yeasts isolated from Antarctic lichens and molecularly identify these isolates. From a total of 144 isolates on the screening, 109 (76%) produced at least one of the hydrolases tested, with most activities for proteases 59 (41%), cellulases 58 (40%), esterases 57 (39%), lipases 29 (20%), amylases 23 (16%) and pectinases 20 (14%). Among these isolates, 76 were identified, most belonged to the phylum Basidiomycota (n=73) with the dominance of Vishniacozyma victoriae (n=27), Cystobasidium alpinum (n=3), Mrakia niccombsii (n=3), Cystobasidium laryngis (n=2), Bannozyma yamatoana (n=2), Holtermanniella nyarrowii (n=2), and Glaciozyma martinii (n=2). This study is the first one reporting extracellular enzyme production by yeasts isolated from thallus of the species of Antarctic lichens Lecania brialmontii, Polycauliona candelaria, Usnea capillacea, Cladonia metacorallifera, and Polycauliona regalis. With these data, it's possible to confirm lichens as a source of hydrolase-producing yeasts, reinforcing the potential of these microorganisms in bioprospecting studies of catalytic molecules from polar regions that may be useful in promising biotechnological applications.

Flavonoids induce cell death in Leishmania amazonensis: in vitro characterization by flow cytometry and Raman spectroscopy.

Leishmaniasis comprises a group of infectious diseases with worldwide distribution, of which both the visceral and cutaneous forms are caused by Leishmania parasites. In the absence of vaccines, efficacious chemotherapy remains the basis for leishmaniasis control. The available drugs are expensive and associated with several secondary adverse effects. Due to these limitations, the development of new antileishmanial compounds is imperative, and plants offer various perspectives in this regard. The present study evaluated the in vitro leishmanicidal activity of flavonoids isolated from Solanum paludosum Moric. and investigated the mechanisms of cell death induced by them. These compounds were evaluated in vitro for their antileishmanial activity against Leishmania amazonensis promastigotes and they showed prominent leishmanicidal activity. The EtOAc fraction, gossypetin 3,7,8,4'-tetra-O-methyl ether (1), and kaempferol 3,7-di-O-methyl ether (3) were selected to be used in an in vitro assay against L. amazonensis amastigotes and cell death assays. The flavonoids (1) and (3) presented significant activity against L. amazonensis amastigotes, exhibiting the IC50 values of 23.3 ± 4.5 µM, 34.0 ± 9.6 µM, and 10.5 ± 2.5 µM for the EtOAc fraction, (1), and (3), respectively, without toxic effects to the host cells. Moreover, (1) and (3) induced blocked cell cycle progression at the G1/S transition, ultimately leading to G1/G0 arrest. Flavonoid (3) also induced autophagy. Using Raman spectroscopy in conjunction with principal component analysis, the biochemical changes in the cellular components induced by flavonoids (1) and (3) were presented. The obtained results indicated that the mechanisms of action of (1) and (3) occurred through different routes. The results support that the flavonoids derived from S. paludosum can become lead molecules for the design of antileishmanial prototypes.

Chemical constituents from Sidastrum paniculatum and evaluation of their leishmanicidal activity

AbstractSidastrum paniculatum (L.) Fryxell, Malvaceae, is popularly known in Brazil as “malva-roxa” or “malvavisco”. The species is found mainly in Northeast region where it is used by locals to treat spider bites and bee stings. Aiming to identify the chemical compounds from S. paniculatum secondary metabolism and to contribute to the chemotaxonomic knowledge of Malvaceae family, a phytochemical study of S. paniculatum was carried out. Besides that, the isolated compounds were evaluated for antileishmanial activity against promastigotes of Leishmania braziliensis. By using chromatographic techniques the study resulted the isolation of eight compounds: 3-oxo-21β-H-hop-22(29)-ene; sebiferic acid; sitosterol 3-O-β-d-glucopyranoside/stigmasterol 3-O-β-d-glucopyranoside; phaeophytin a; 132(S)-hydroxyphaeophytin a; 132(S)-hydroxy-(173)-ethoxyphaeophorbide a and 7,4′-di-O-methylisoescutellarein. The structure of all isolated compounds was elucidated by spectroscopic analysis, including two-dimensional NMR techniques. In addition, the isolated compounds phaeophytin a; 132(S)-hydroxyphaeophytin a; 132(S)-hydroxy-(173)-ethoxyphaeophorbide a and 7,4′-di-O-methylisoescutellarein exhibited antileishmanial activity against promastigotes of L. braziliensis.

Antileishmanial Phenylpropanoids from the Leaves of Hyptis pectinata (L.) Poit.

Hyptis pectinata, popularly known in Brazil as "sambacaitá" or "canudinho," is an aromatic shrub largely grown in the northeast of Brazil. The leaves and bark are used in an infusion for the treatment of throat and skin inflammations, bacterial infections, pain, and cancer. Analogues of rosmarinic acid and flavonoids were obtained from the leaves of Hyptis pectinata and consisted of two new compounds, sambacaitaric acid (1) and 3-O-methyl-sambacaitaric acid (2), and nine known compounds, rosmarinic acid (3), 3-O-methyl-rosmarinic acid (4), ethyl caffeate (5), nepetoidin A (6), nepetoidin B (7), cirsiliol (8), circimaritin (9), 7-O-methylluteolin (10), and genkwanin (11). The structures of these compounds were determined by spectroscopic methods. Compounds 1-5, and 7 were evaluated in vitro against the promastigote form of L. braziliensis, and the ethanol extract. The hexane, ethyl acetate, and methanol-water fractions were also evaluated. The EtOH extract, the hexane extract, EtOAc, MeOH:H2O fractions; and compounds 1, 2 and 4 exhibited antileishmanial activity, and compound 1 was as potent as pentamidine. In contrast, compounds 3, 5, and 7 did not present activity against the promastigote form of L. braziliensis below 100 µM. To our knowledge, compounds 1 and 2 are being described for the first time.

Antinociceptive activities of crude methanolic extract and phases, n-butanolic, chloroformic and ethyl acetate from Caulerpa racemosa (Caulerpaceae) / Atividade antinociceptiva do extrato metanólico bruto e das fases n-butanólica, clorofórmica e acetato de etila de Caulerpa recemosa (Caulerpaceae)

In this study, we attempted to identify the possible antinociceptive actions of n-butanolic phase, chloroformic phase, ethyl acetate phase and crude methanolic extract obtained from Caulerpa racemosa. This seaweed is cosmopolitan in world, mainly in tropical regions. The n-butanolic, chloroformic, ethyl acetate phases and crude methanolic extract, all administered orally in the concentration of 100 mg/kg, reduced the nociception produced by acetic acid by 47.39 percent, 70.51 percent, 76.11 percent and 72.24 percent, respectively. In the hotplate test the chloroformic and ethyl acetate phase were activite in this models. In the neurogenic phase on formalin test, were observed that crude methanolic extract (51.77 percent), n-butanolic phase (35.12 percent), chloroformic phase (32.70 percent) and indomethacin (32.06 percent) were effective in inhibit the nociceptive response. In the inflammatory phase, only the ethyl acetate phase (75.43 percent) and indomethacin (47.83 percent) inhibited significantly the nociceptive response. Based on these data, we can infer that the ethyl acetate phase shows a significant anti-inflammatory profile, whose power has not yet been determined. However, pharmacological and chemical studies are continuing in order to characterize the mechanism(s) responsible for the antinociceptive action and also to identify other active principles present in Caulerpa racemosa.

Neste estudo, tentamos identificar a atividade antinociceptiva do extrato metanólico bruto e das fases n-butanólica, clorofórmica e acetato de etila provenientes da alga Caulerpa racemosa. Esta alga é cosmopolita no mundo, principalmente em regiões tropicais. O extrato metanólico bruto e as fases n-butanólica, clorofórmica e acetato de etila foram administrados por via oral, na concentração de 100 mg/kg. Estes foram capazes de reduzir a nocicepção produzida pelo ácido acético, sendo 47,39 por cento, 70,51 por cento, 76,11 por cento e 72,24 por cento, respectivamente. No ensaio da placa quente as fases clorofórmica e acetato de etila foram ativas neste modelo. Na fase neurogênica do teste de formalina, foi observado que o extrato metanólico bruto (51,77 por cento), fase n-butanólica (35,12 por cento), fase clorofórmica (32,70 por cento) e indometacina (32,06 por cento) foram eficazes em inibir a resposta nociceptiva. Na fase inflamatória, apenas a fase acetato de etila (75,43 por cento) e indometacina (47,83 por cento) foram capazes de inibir significativamente a resposta nociceptiva. Com base nestes dados, podemos sugerir que o a fase acetato de etila apresenta um significativo efeito anti-inflamatório, cuja potência ainda não foi determinada. No entanto, estudos farmacológicos e químicos serão necessários, a fim de caracterizar o mecanismo responsável pela ação antinociceptiva e também para identificar outros princípios ativos presentes na alga Caulerpa racemosa.