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Biomedical subjects

G Schmeda-Hirschmann

Publications and source records attributed to G Schmeda-Hirschmann.

12 recordsLinked to original sources
PubMed2003

Free-radical scavengers and antioxidants from Peumus boldus Mol. ("Boldo").

The dry leaves of Peumus boldus (Monimiaceae) are used in infusion or decoction as a digestive and to improve hepatic complains. Preliminary assays showed free-radical scavenging activity in hot water extracts of boldo leaves, measured by the decoloration of a methanolic solution of the 1,1-diphenyl-2-picryl-hydrazyl radical (DPPH). Assay-guided isolation led to the active compounds. Catechin proved to be the main free-radical scavenger of the extracts. Lipid peroxidation in erythrocytes was inhibited by boldo extracts and fractions at 500 microg/ml with higher effect for the ethyl acetate soluble and alkaloid fractions. The IC50 for catechin and boldine in the lipid peroxidation test were 75.6 and 12.5 microg/ml, respectively. On the basis of dry starting material the catechin content in the crude drug was 2.25% while the total alkaloid calculated as boldine was 0.06%. The activity of boldine was six times higher than catechin in the lipid peroxidation assay. However, the mean catechin:total alkaloid content ratio was 37:1. The relative concentration of alkaloids and phenolics in boldo leaves and their activity suggest that free-radical scavenging effect is mainly due to catechin and flavonoids and that antioxidant effect is mainly related with the catechin content The high catechin content of boldo leaves and its bioactivity suggest that quality control of Boldo folium has to combine the analysis of catechin as well as their characteristic aporphine alkaloids.

Antioxidants↗
PubMed2001

Immunomodulatory activity of Chilean Cyttaria species in mice with L5178Y lymphoma.

The immunomodulatory effect of hydrosoluble extracts of four Chilean Cyttaria species (Discomycetes, Fungi) was assessed in mice with L5178Y lymphoma. Oral administration of 100 mg extract per day for 7 days enhanced the percentual phagocytosis and phagocytosis index in animals receiving Cyttaria berteroi, Cyttaria darwinii, Cyttaria espinosae and Cyttaria harioti extracts. Differences in the digestion index were observed in mice treated with C. darwinii and C. berteroi. In the delayed-type hypersensitivity model, only C. harioti was able to modify the immune response. The results suggest that intake of Cyttaria can improve the immune system of consumers.

Adjuvants, Immunologic↗
PubMed2001

Cryptofolione derivatives from Cryptocarya alba fruits.

Cryptofolione (1) and the new cryptofolione derivative 6-(4,6-dimethoxy-8-phenyl-octa-1,7-dienyl)-4-hydroxy-tetrahydro-pyran-2-one (2) were isolated from the fruits of Cryptocarya alba. The structures were elucidated by spectroscopic methods. Cryptofolione showed activity towards Trypanosoma cruzi trypomastigotes, reducing their number by 77% at 250 microg mL(-1). Cryptofolione showed moderate cytotoxicity in both macrophages and T. cruzi amastigotes. It also displayed a mild inhibitory effect on the promastigote form of Leishmania spp. As both cytotoxic and trypanocidal effects are similar, the compound presented little selectivity in our assay models.

Animals↗
PubMed2000

Biologically active alkaloids and a free radical scavenger from Prosopis species.

The biological activity of extracts from the aerial parts of five Argentinian Prosopis species and the exudate of P. flexuosa were assessed for DNA binding, beta-glucosidase inhibition and free radical scavenging effect using the DPPH decoloration assay. DNA binding effect was found mainly in the basic fraction. The alkaloids tryptamine as well as piperidine and phenethylamine derivatives were isolated from the basic extracts. At 0.50 mg/ml, DNA binding activities ranged from 28% for tryptamine to 0-27% for the phenethylamine and 47-54% for the piperidine derivatives. Tryptamine and 2-beta-methyl-3-beta-hydroxy-6-beta-piperidinedodecanol showed a moderate inhibition (27-32%) of the enzyme beta-glucosidase at 100 microg/ml. The exudate of P. flexuosa displayed a strong free radical scavenger effect in the DPPH decoloration assay. The main active constituent was identified as catechin.

Alkaloids↗
PubMed2000

Free radical scavenging activity of Lafoensia pacari.

The methanolic extract of the stem bark of Lafoensia pacari (Lythraceae) showed free radical scavenging activity in the diphenyl picryl hydrazyl radical (DPPH) decoloration assay and inhibited the enzyme xanthine oxidase 'in vitro'. Bioassay-guided isolation led to ellagic acid (EA) as the main active compound of Brazilian and Paraguayan collections of the plant.

Alcohols↗
PubMed1999

Free radical scavengers from Mutisia friesiana (Asteraceae) and Sanicula graveolens (Apiaceae).

The water-soluble extract of Sanicula graveolens (Apiaceae) and Mutisia friesiana (Asteraceae) showed radical scavenging activity in the DPPH decoloration assay. Bioassay-guided isolation led to caffeic acid derivatives and flavonoids as the main active compounds of both species. After hydrolysis, caffeic acid and quercetin proved to be the bioactive principles of both plants.

Antioxidants↗
PubMed1993

Magic and medicinal plants of the Ayoreos of the Chaco Boreal (Paraguay).

The Ayoreo is a hunter-gatherer tribe of Amerindians which occupy the central-northern part of the Paraguayan Chaco. The whole Ayoreo culture cannot be disassociated from religious beliefs. Disease is considered of supernatural origin and as the result of breaking or disobeying the tabu which regulates existence. A description of the shamanic practices is given to understand better the position of health practices in the Ayoreo culture, particularly the use of medicinal and hallucinogenic plants. Fragments of the Asojna ritual and the methods for becoming shaman; the initiation of the last living shaman, as well as references to the magic powers of the shaman are presented. Diagnosis and treatment included invocations to plant and animal spirits and the use of a few medicinal plants. The plants used as medicine or invoked for healing are presented for the first time. Of particular interest is the identification of two Euphorbiaceae as ritual plants by the Ayoreo.

Female↗
PubMed1993

Prevalence of Chagas' disease in Ayoreo communities of the Paraguayan Chaco.

The prevalence of Chagas' disease in Ayoreo amerindians living in their traditional habitat of the Paraguayan Chaco was assessed by ELISA and indirect immunofluorescence techniques. The Ayoreo is the last hunther-gatherer tribe of the Paraguayan Chaco and was "pacified" between 1965 and 1975. They still maintain a seminomadic way of life. Chagas' disease prevalence in the Ayoreo communities probably represents their natural prevalence in Chaco Amerindians before settlement. Triatoma sordida was identified as the insect vector in the settlements of Gesudi and Chovoreca, while the highly domiciliary Triatoma infestans was found in Campo Loro. The prevalence of Chagas' disease in Gesudi and Chovoreca, based on our serological surveys was 12-13%. Other authors reported a 72.9% of Chagas' disease prevalence in amerindians settled in the Chaco since 1930-1940.

Adolescent↗
PubMed1991

Xanthine oxidase inhibitory activity of Chilean Myrtaceae.

Twenty-one Myrtaceae collections belonging to 10 species, 5 of which are used in Chilean folk medicine, were assayed for inhibitory activity towards the enzyme xanthine oxidase. Most leaf and stem extracts were devoid of activity or showed a weak inhibitory effect. Chilean ethnobotanical data on the species are linked to the astringent properties of Myrtaceae and their use for treating wounds and diarrhea. The results show the advantage of using proper plant selection criteria when searching for new drugs to treat human gout.

Chile↗
PubMed1990

Paraguayan medicinal compositae.

A survey of the Compositae used in traditional medicine and as economic plants by Paraguayan country people was undertaken to identify the components of crude drugs traded by herbalists. Forty-five medicinal and economic species have been identified through field work in the rural areas and enquiries in the markets, as well as by examination of the literature in the Spanish language. Some crude drugs are shown to be mixtures of several closely-related species. The role of indigenous plant remedies within the local health care system is also discussed.

Humans↗
PubMed1987

Preliminary pharmacological studies on Eugenia uniflora leaves: xanthine oxidase inhibitory activity.

Eugenia uniflora is widely used in Paraguayan folk medicine. A hydroalcoholic extract of the leaves showed some central nervous system activity in hippocratic screening when given intraperitoneally, but little to no acute or subacute toxicity in doses up to 4200 mg/kg orally in BALB c mice. The LD50 of the extract was 220 mg/kg i.p. in mice. A decoction or infusion of the leaves is recommended for treating gout by native herbalists. The known flavonoids quercitrin, quercetin, myricitrin and myricetin were found to be responsible for the xanthine oxidase inhibitory action of the plant extract.

Administration, Oral↗