G. L. von Poser

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.

Screening for the antidepressant activity of some species of Hypericum from South Brazil.

An Erratum has been published for this article in Phytotherapy Research 14(8) 2000, 661.

Investigation of some Hypericum species native to Southern of Brazil for antiviral activity

Three plant species, Hypericum connatum, Hypericum caprifoliatum, Hypericum polyanthemum (Guttiferae), growing in Southern of Brazil were chemically investigated and tested for their antiviral activity against feline immunodeficiency virus (FIV). The chemical analysis revealed the presence of polyphenolic compounds such as tannins and flavonoids. Hypericin was not detected in these species. The aqueous extract (AE), the aqueous extract with low tannin concentration (LTCAE) and the methanolic extract (ME) were tested for their cytotoxic properties in concentrations of 50-150 microg/ml. AE was toxic to CRFK for the three species in all concentrations. LTCAE and ME varied between different concentrations being not toxic or allowing 80% of cell growth. LTCAE and ME (10-50 microg/ml) were analyzed for antiviral activity by inhibition of CPE and measuring FIV genome from cell culture supernatant. LTCAE of all species in this work did not cause any inhibition of FIV. Although no difference was seen in CPE, a lower number of viral particles in the supernatant was observed when FIV infected cells were treated with ME of H. connatum. These results suggest that some plants of the genus Hypericum from Southern Brazil contain compounds with potential antiviral activity against lentiviruses.

ANTIOXIDANT ACTIVITY OF FLAVONOIDS ISOLATED FROM HYPERICUM TERNUM

In the present work we have studied the scavenging activity of several flavonoids isolated from Hypericum ternum A. St. Hil. The evaluation of the free radical scavenging capacity was based on the 2,2-diphenyl-l-picrylhydrazyl radical (DPPH) consumption elicited by their addition. Also, we have attempted to evaluate their capacity to delay pyrogallol red consumption promoted by peroxyl radicals. The compounds isolated and characterized were 13,118-biapigenin and five quercetin derivatives (quercetin 3-methyl ether, quercetin 3,7-dimethyl ether, hyperoside, isoquercitrin and guaijaverin). All compounds were able to scavenge DPPH radicals. The order in scavenging capacity (from highest to lowest) was: guaijaverin > hyperoside ≈ isoquercitrin > quercetin-3-methyl-ether. No protection of pyrogallol red was evidenced for all flavonoids derivatives at relatively high (100 µM) concentrations. This lack of protection contrasts with the efficient protection afforded by 10 µM quercetin, indicating that substitution at the 3-position in quercetin strongly reduces the capacity of the molecule to scavenge peroxyl radicals

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.

ANTIOXIDANT ACTIVITY IN SOUTHERN BRAZIL HYPERICUM SPECIES

The present study was conducted to assess the antioxidant activity of Hypericum species endemic to South Brazil, H. caprifoliatum, H. carinatum, H. myrianthum and H. polyanthemum. The free radical scavenging properties of plant extracts were evaluated employing different methodologies, including the bleaching of a stable free radical (2,2-diphenyl-1-picrylhydrazyl, DPPH) and the peroxyl reactivity indexes TRAP (Total Reactive Antioxidant Potential) and ORAC-pyrogallol red (Oxygen Radicals Absorbance Capacity). A fair correlation was found between total phenol content determined by Folin-Ciocalteau and DPPH consumption, both in crude methanol and n-hexane extracts. In particular, H. myrianthum and H. caprifoliatum showed the highest TRAP and ORACpyrogallol red values, respectively. This would imply that H. myrianthum contains a larger amount of antioxidants of lower reactivity.

Selective cytotoxicity and apoptosis induction in glioma cell lines by 5-oxygenated-6,7-methylenedioxycoumarins from Pterocaulon species

The coumarins 5-methoxy-6,7-methylenedioxycoumarin 1 5-(3-methyl-2-butenyloxy)-6,7-methylenedioxycoumarin 2 and 5-(2,3-dihydroxy-3-methylbutyloxy)-6,7-methylenedioxycoumarin 3 isolated from Pterocaulon species showed significant cytotoxicity against two glioma cells lines. Compound 1 presented IC(50) values of 34.6 μM and 31.6 μM against human (U138-MG) and rat (C6) glioma cells, respectively, and this compound was at least two times more potent than compounds 2 and 3. This result could be explained by the planar conformation adopted by 1 through a non-classical hydrogen bond between a hydrogen of the methoxy and the oxygen of the methylenedioxy groups. Another important finding was that the cytotoxic effect induced by 1 in glioma cells was not observed in organotypic cultures, indicating a selective cytotoxicity for tumor cells.

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.

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.

Distribution of coumarins in the tribe Plucheeae, genus Pterocaulon

gilsane@farmacia.ufrgs.br; 2) PPG-Botanica, ICBS, 91509-900 Porto Alegre, RS, Brazil, fax (051) 33167670; 3) Grupo Metabolomica, LCQUI/CCT, Universidade Estadual do Norte Fluminense, 28015-620 Campos dos Goytacazes, RJ, Brazil; 4) Faculte de Pharmacie, Universite de Picardie Jules Verne, 80037 Amiens, France. Published in Khimiya Prirodnykh Soedinenii, No. 6, pp. 572-574, November-December, 2007. Original article submitted August 1, 2006.