A.T. Henriques

Ervatamia coronaria: chemical constituents and some pharmacological activities.

A new bisindole alkaloid, 19,20-dihydroervahanine A was isolated from the stems of Ervatamia coronaria grown in Brazil, together with five known alkaloids: coronaridine, heyneanine, voacristine, voacamine, descarbomethoxyvoacamine and five phenolic acids: vanillic, gentisic, syringic, 4-hydroxybenzoic and salicylic acid. The aqueous and alcoholic extracts, when administered p.o. or i.p. to rats 1 h before subplantar injection of carrageenin had a significant anti-inflammatory effect. The alcoholic extract also had an analgesic effect and increased the pentobarbital induced sleeping time.

Inhibition of cytochrome P450-dependent monooxygenases by an alkaloid fraction from Helietta apiculata markedly potentiate the hypnotic action of pentobarbital

Crude alkaloid fraction (CAF) isolated from the leaves of Helietta apiculata showed the presence of furoquinolines. The extract was investigated to determine if it can enhance the sensitivity of the central nervous system (CNS) to the hypnotic action of pentobarbital. Administration of CAF to mice in a dose range of 300-500 mg/kg prior to an injection of pentobarbital (40 mg/kg, i.p.) was associated with a statistically significant decrease of sleep latency and prolongation of pentobarbital-induced sleeping time. Pretreatment of rats with the same alkaloid extract (150 mg/kg, i.p. for 4 days) prior to administration of pentobarbital (40 mg/kg, i.p.) caused not only significant reduction of the levels of microsomal proteins, total cytochrome P450 enzymes and a decrease of aminopyrin-N-demethylation and 3,4-benz(a)pyrene hydroxylation but also changed the pattern of cytochrome P450. It is concluded that the CAF isolated from H. apiculata can potentiate the CNS depressant effect of pentobarbital due to alteration of barbiturate metabolism through inhibition, mainly, of cytochrome P450-dependent enzymes.

Screening for cytotoxic activity of extracts and isolated alkaloids from bulbs of Hippeastrum vittatum

The dichloromethane and n-butanol extracts obtained from fresh bulbs of Hippeastrum vittatum (Amaryllidaceae), collected in Southern Brazil, were evaluated for their cytotoxic activity in vitro against five human cell lines (HT29 colon adenocarcinoma, H460 non-small cell lung carcinoma, RXF393 renal cell carcinoma, MCF7 breast cancer, and OVCAR3 epithelial ovarian cancer), using the sulphorhodamine B assay. Both extracts showed potential antiproliferative activity. From CH(2)Cl(2) fraction, three alkaloids were isolated: lycorine, vittatine and montanine. The two last compounds were submitted to the antiproliferative assay and the highest level of cytotoxicity was found for the alkaloid montanine.

Biological Activities and Essential Oil Composition of Leaves of Blepharocalyx salicifolius

Infusions obtained from dried and fresh leaves of Blepharocalyx salicifolius were assessed in antibacterial (with S. aureus and E. coli), antiinflammatory, antinociceptive, antispasmodic and intestinal transit models. All samples analyzed showed significant antibacterial activity against Gram-positive and Gram-negative bacteria. The highest activity was observed with the dried leaves against E. coli. An infusion from fresh leaves inhibited the stimulating action of acetylcholine on intestinal musculature (average inhibition 45%). Other biological assays gave no significant results with doses up to 300 and 600 mg/kg for dried and fresh material, respectively. The essential oil obtained from fresh leaves by hydrodistillation (0.9%) was analyzed by GC and GC/MS, where 42 components were identified. The main components were 1,8-cineole (25.2%), linalool (20.4%) and ß-caryophyllene (22.9%).

Aromatic Plants from Brazil. III. The Chemical Composition of Piper gaudichaudianum Kunth and P. mikanianum (Kunth) Steudel Essential Oils

ABSTRACT Essential oils from fresh leaves of Piper gaudichaudianum and P. mikanianum, collected in South Brazil, which were obtained by hydrodistillation, were analyzed by GC and GC/MS. Forty-one compounds representing 94.4–95.1% of the oils were identified. P. gaudichaudianum showed small amounts of monoterpenes: among them, β-pinene and linalool were the most abundant. Considerable amounts of sesquiterpenes were present, particularly α-humulene (37.5%) and β-caryophyllene (17.4%). P. mikanianum showed a higher diversity of constituents, of which limonene (14.8%), bicyclogermacrene (14.3%) and β-caryophyllene (10.5%) were the major components.

Strictosidinic acid, isolated from Psychotria myriantha Mull. Arg. (Rubiaceae), decreases serotonin levels in rat hippocampus

Psychotria is a complex genus whose neotropical species are known by the presence of glucosidic monoterpene indole alkaloids. These compounds are able to display a large range of effects on the central nervous system, such as anxiolytic, antidepressant, analgesic, and impairment of learning and memory acquisition. The aims of this study were to investigate the effects displayed by strictosidinic acid, isolated from Psychotria myriantha Mull. Arg. (Rubiaceae) leaves, on monoamine levels in rat hippocampus and on monoamine oxidase activity. A significance (p<0.01) of 83.5% reduction in 5-HT levels was observed after intra-hippocampal injection (20 μg/μl). After treatment by intraperitoneal route (10 mg/kg), a 63.4% reduction in 5-HT levels and a 67.4% reduction in DOPAC values were observed. The results indicate that strictosidinic acid seems to act on 5-HT system in rat hippocampus, possibly inhibiting precursor enzymes of 5-HT biosynthesis. The decrease verified in DOPAC levels suggests a role of strictosidinic acid in the dopaminergic transmission, probably due to an inhibition of monoamine oxidase activity, confirmed by the enzymatic assay, which demonstrated an inhibitory effect on MAO A in rat brain mitochondria.

Cytostatic, cytotoxic and mutagenic effects of voacristine, an indole alkaloid in wild-type and repair-deficient yeasts

Voacristine, an indole alkaloid isolated from the leaves of Ervatamia coronaria (Stapf.) (Apocynaceae) has dose-dependent cytostatic and cytotoxic effects on cultures of Saccharomyces cerevisiae. These inhibitory effects take place only in growing cells. Among the different repair-deficient mutants examined, a mutant defective in excision-resynthesis repair pathway (rad3-e5) was found to be the most sensitive to such a toxic effect. The mutant rad52-1 blocked in the DNA strand break repair pathway showed an intermediary sensitivity to the lethal effect induced by this indole alkaloid, whereas the mutant defective in the mutagenic repair pathway (rad6-1) demonstrated practically the same sensitivity as the wild-type strain. The nuclear reversion mutation for the locus lysl-1 was induced by voacristine, whereas the mitochondrial petite mutation was not induced by this alkaloid. These results indicate that the lesions induced by voacristine in vivo are likely to be of the adducts type; such damage is repairable in the wild-type; the DNA strand break repair pathway plays a minor role in the repair of voacristine-induced lesions.

Genotoxic effect of alkaloids

Because of the increased use of alkaloids in general medical practice in recent years, it is of interest to determine genotoxic, mutagenic and recombinogenic response to different groups of alkaloids in prokaryotic and eucaryotic organisms. Reserpine, boldine and chelerythrine did not show genotoxicity response in the SOS-Chromotest whereas skimmianine showed genotoxicity in the presence of a metabolic activation mixture. Voacristine isolated from the leaves of Ervatamia coronaria shows in vivo cytostatic and mutagenic effects in Saccharomyces cerevisiae hapioids cells. The Rauwolfia alkaloid (reserpine) was not able to induce reverse mutation and recombinational mitotic events (crossing-over and gene conversion) in yeast diploid strain XS2316.

Monoamine levels in rat striatum after acute intraperitoneal injection of strictosidinic acid isolated from Psychotria myriantha Mull. Arg. (Rubiaceae)

Strictosidinic acid 10mg/kg, isolated from Psychotria myriantha leaves, were administered intraperitoneally to Wistar male rats (n=5-6). After 60 minutes, striatum was dissected, homogenized and injected onto HPLC-ED chromatographic system. It was observed a 28.7% reduction in the 5-HT levels followed up by an increase of 5-HIAA levels (29.4%). Furthermore there was a decrease of 8.0% in DA levels and an increase in the levels of metabolites DOPAC (21.5%) and HVA (52.5%). The results indicate that strictosidinic acid has a promising effect in the central nervous system, justifying more studies about the central actions of Psychotria compounds.

Chemical Constituents and Antitumour Acitivity of Nectandra grandiflora

AbstractThe Trunk Bark Of Nectandra Grandiflora, Of Southern Brazil, Contains Four Aporphine Alkaloids, Laurolitsine, Laurotetanine, Boldine and Isoboldine, In Addition To The Sesquiterpene Costic Acid. Preliminary Studies With An Alcohol Extract Of The Bark Revealed Antitumour Activity Against The Sarcoma 180 and Ehrlichs Carcinoma Models.