Alexandre Ferraz

Antimicrobial activity of some Hypericum species

The crude methanolic extracts of six species of Hypericum [H. caprifoliatum Cham. & Schlecht., H. carinatum Griseb., H. connatum Lam., H. ternum A. St. Hil., H. myrianthum Cham. & Schlecht. and H. polyanthemum Klotzsch ex Reichardt] growing in southern Brazil were analyzed for antimicrobial activity against several microorganisms (bacteria and fungi). The most active plant was H. caprifoliatum, which showed activity against Staphylococcus aureus. Only H. polyanthemum and H. ternum extracts were active against Bacillus subtilis. None of the crude methanolic extracts showed activity against S. epidermidis, Escherichia coli or Saccharomyces cerevisiae. Extracts from these species were evaluated chemically and tannin, flavonoid and phenolic acids were the prominent compounds. The plants contained quercitrin, hyperoside (except H. connatum) and, less frequently, isoquercitrin and chlorogenic acid. In contrast to H. perforatum, which has high concentrations of rutin, these species do not produce this flavonoid or it appears as traces. The tannin concentration varied between 5.1 and 16.7% in H. myrianthum and H. ternum, respectively.

The antidepressant-like effect of Hypericum caprifoliatum Cham & Schlecht (Guttiferae) on forced swimming test results from an inhibition of neuronal monoamine uptake

A crude (ECH) and a purified cyclohexane extract (HCP) of Hypericum caprifoliatum and their main phloroglucinol derivative (HC1) were evaluated regarding their action on monoaminergic systems, more precisely on dopamine. In rats and mice forced swimming test, ECH and HCP dose-dependently reduced the immobility time. The effect of the highest dose was prevented by a prior administration of either sulpiride or SCH 23390 (D(2) and D(1) dopamine receptor antagonist, respectively). HCP (360 mg/kg) decreased the locomotor activity of mice. ECH (90 mg/kg) caused hypothermia and potentiated apomorphine-induced (16 mg/kg) hypothermia in mice. HCP and HC1 inhibited, in a concentration-dependent and monophasic manner, the [(3)H]-DA, [(3)H]-NA and [(3)H]-5HT synaptosomal uptakes, but did not prevent the binding of specific ligands to the monoamine transporters. Moreover, when tested at the concentrations corresponding to its IC(50) on [(3)H]-DA uptake, HC1 did not induce a significant [(3)H]-DA release, while at a higher concentration (200 ng/ml) it enhanced significantly (by 12%) the synaptosomal DA release. These data suggest that the antidepressant-like effect of H. caprifoliatum on the forced swimming test is due to an increase in monoaminergic transmission, resulting from monoamine uptake inhibition, more potently of dopamine, which may be related to their phloroglucinol contents.

Monoamine oxidase inhibitory activity of some Hypericum species native to South Brazil.

The total methanol crude extracts and petroleum ether, chloroform, and methanol fractions obtained from Hypericum species, H. caprifoliatum, H. carinatum, H. connatum, H. cordatum, H. myrianthum, H. piriai, H. polyanthemum and H. brasiliense, all native to South Brazil, were assayed for monoamine oxidase A (MAO A) and MAO B inhibitory activity in rat brain mitochondrial preparations at concentrations ranging from 1 to 20 μg mL−1. Three benzo‐pyrans, HP1 (6‐isobutyryl‐5,7‐dimethoxy‐2,2‐dimethylbenzopyran), HP2 (7‐hydroxy‐6‐iso‐butyryl‐5‐methoxy‐2,2‐dimethylbenzopyran) and HP3 (5‐hydroxy‐6‐isobutyryl‐7‐methoxy‐2,2‐dimethylbenzopyran) isolated from H. polyanthemum were also tested at maximal concentrations of 150, 150 and 75 μ, respectively. The lipophilic extracts of H. polyanthemum, H. caprifoliatum and H. piriai displayed MAO A inhibitory activity greater than 50%. Among the benzopyrans, only HP3 showed significant activity, with an IC50 value of 22 μ. The total methanol crude extracts of aerial parts from H. carinatum, H. connatum, H. cordatum, H. polyanthemum and H. piriai were evaluated for antidepressant activity in the Porsolts forced swimming test in Wistar rats (270 mg kg−1 day−1; i.p); however, none of them showed activity.

Benzopyrans from Hypericum polyanthemum

From the aerial parts of Hypericum polyanthemum Klotzsch ex Reichardt (Guttiferae), three chromenes, 6-isobutyryl-5,7-dimethoxy-2,2-dimethyl-benzopyran; 7-hydroxy-6-isobutyryl-5-methoxy-2,2-dimethyl-benzopyran and 5-hydroxy-6-isobutyryl-7-methoxy-2,2-dimethyl-benzopyran were isolated. Their structures were determined by NMR spectroscopic analyses.

Botanical (morphological, micrographic), chemical and pharmacological characteristics of Pfaffia species (Amaranthaceae) native to South Brazil

Some parameters for the quality control of P. glomerata and P. paniculata roots using their botanical and chemical characteristics are presented. It was also carried out an in vitro pharmacological screening to evaluate some biological properties of P. glomerata that could be related to its popular use as tonic. Relating to biological assays, ethanolic extract from P. glomerata roots did not present antiviral, antiproliferative, antifungal or MAO inhibitory activities. The cytotoxicity evaluation of P. glomerata determined that IC50 is >2,000 µg/mL. The main morphological and micrographic characteristics of P. glomerata and P. paniculata roots are described in this paper in order to aid in their unequivocal identification.