Anne Adsersen

Antimicrobial screening of selected medicinal plants from India.

From the Indian traditional medicines 78 plants were selected on the basis of their use in the treatment of infectious diseases. Different concentrations of 80% ethanol extracts were tested, using the agar dilution method, against four bacteria: Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa and, using the agar-well diffusion method, against two fungi: Candida albicans and Aspergillus niger. In the lowest tested concentration of 1.6 mg/ml, 10% of the plant extracts were active; 44% in a concentration of 6.25 mg/ml and 90% of the plant extracts were active against at least two bacteria in a concentration of 25 mg/ml. Only 13% of the plant extracts were active against at least one fungus in a concentration of 50 mg/ml.

In vitro screening of traditional medicines for anti-hypertensive effect based on inhibition of the angiotensin converting enzyme (ACE)

Traditional medicines reported to be used as anti-hypertensives or diuretics from different regions in the world (China, India and South America) have been investigated. The bioassay is based on inhibition of ACE, as measured from the enzymatic cleavage of the chromophore-fluorophore-labelled substrate dansyltriglycine into dansylglycine and diglycine. In total, 31 species have been investigated and the crude extracts from seven species inhibit the enzyme by more than 50%.

Isolation of an Angiotensin Converting Enzyme (ACE) inhibitor from Olea europaea and Olea lancea

The aqueous extract of the leaves of Olea europaea and Olea lancea both inhibited Angiotensin Converting Enzyme (ACE) in vitro. A bioassay-directed fractionation resulted in the isolation of a strong ACE-inhibitor namely the secoiridoid 2-(3,4-dihydroxyphenyl)ethyl 4-formyl-3-(2-oxoethyl)-4 E-hexenoate (oleacein) (IC(50) = 26 μM). Five secoiridoid glycosides (oleuropein, ligstroside, excelcioside, oleoside 11-methyl ester, oleoside) isolated from Oleaceous plants showed no significant ACE-inhibition whereas, after enzymatic hydrolysis, the ACE-inhibition at 0.33 mg/ml was between 64% to 95%. Secoiridoids have not been described previously in the literature as inhibitors of ACE. Oleacein showed a low toxicity in the brine shrimp (Artemia satina) lethality test (LC(50) (24 h) = 969 ppm).

Plants from Réunion Island with alleged antihypertensive and diuretic effects--an experimental and ethnobotanical evaluation.

Eighty species of vascular plants were collected on Reunion Island and tested for their ability to inhibit the angiotensin converting enzyme (ACE), which plays an important role in the regulation of blood pressure and diuresis. Of these species, 26 serve as antihypertensive remedies in traditional medicine, and 38 as diuretics-10 of the 64 species have both alleged antihypertensive and diuretic effects. Of the species examined, 26 have not been reported to have any of these effects. Plant material was extracted with both acetone, ethanol and water, and samples were considered active if ACE inhibition was 50% or more in one of the extracts. Of the species with alleged antihypertensive or diuretic effect, 44% proved active. Of the species with no report of such effects, 31% proved active. There were no overall differences in the range of inhibition of the three extracts, but amongst the species considered active there was a strong negative correlation between inhibition of acetone and water extracts. A statistical analysis of the results demonstrated clear differences between plants with alleged antihypertensive effects, diuretic effects, and no alleged use with respect to inhibition of the three extracts.

Antimicrobial evaluation of Huilliche plant medicine used to treat wounds

ETHNOPHARMACOLOGICAL RELEVANCE The traditional use of 40 plant species used for treatment of wounds and associated infections by the Huilliche people of Chile was evaluated against bacterial and fungal human pathogens, especially including wound pathogens. MATERIALS AND METHODS The extracts were tested against the fungi Penicillium expansum, Candida albicans and the bacteria Bacillus subtilis, Pseudomonas aeruginosa (four different strains), Staphylococcus aureus, Escherichia coli (four different strains), Streptococcus pneumoniae (four different strains with one being resistance to streptomycin). RESULTS Thirteen of the plant species have interesting antimicrobial activities, with that of Acaena argentea, Aristotelia chilensis, Blechnum chilense, Francoa appendiculta, Gevuina avellana and Laureliopsis philippiana being the most noteworthy. CONCLUSIONS The findings in the manuscript support the traditional use by the Huilliche people, and allow enhanced economical benefit and use by the locals. The results obtained on Acaena argentea, Aristotelia chilensis, Blechnum chilense, Francoa appendiculta, Gevuina avellana and Laureliopsis philippiana are of specific scientific interest, and further studies is needed in order to establish the active constituents of the species.

Cyanogenic constituents in plants from the Galápagos Islands

Abstract A screening for cyanogenic constituents in leaves of 475 specimens of plants from the Galapagos Islands, both fresh material tested on the Islands and herbarium material tested in Copenhagen show that of the 97 species tested on fresh material, 24 proved to contain cyanogenic constituents at a level corresponding to 10 mg of HCN per kg material, while 27 species were slightly positive, i.e. released between 2.5 and 10 mg HCN per kg. In total for analyses of fresh and dried material, 33 genera are reported for the first time to contain cyanogenic species, and 92 species hitherto not reported cyanogenic showed positive reaction to some extent. The importance of these findings in relation to herbivory is discussed

Cyanogenesis of Passiflora colinvauxii, a species endemic to the galápagos islands

Abstract Passibiflorin, (1 S ,4 R )-1-(β- d -glucopyranosyloxy)-4-(6-deoxy-β- d -gulopyranosyloxy)-2-cyclopentene-1-carbonitrile, was isolated from Passiflora colinvauxii endemic to the Galapagos Islands; the plant is only the second known source of passibiflorin. The glycoside was identified by spectroscopic methods. Some preparations of the plant material contained the corresponding amide, the structure of which was inferred from spectroscopic data and confirmed by chemical correlation with passibiflorin. Chemotaxonomic implications of the occurrence of bisglycosidic cyclopentanoids in Passiflora are briefly discussed.

Methoxyflavones from Melicope borbonica and M. obscura (Rutaceae)

Leaves of Melicope borbonica (Bory) T.G. Hartley (syn. Euodia borbonica var. borbonica (Bory) Engl.) were collected in July 1998 at Plaine d’Affouches, Reunion Island. Leaves of Melicope obscura (Cordem.) T.G. Hartley (syn. Euodia obscura Cordem.) were collected in February 2000 at Plaine de Palmiste, Reunion Island. Voucher specimens (DFHAA3 and DFHAA4) were deposited in Herbarium C (Botanical Museum, University of Copenhagen, Copenhagen, Denmark).

Cyanogenic plants in the Galapagos Islands: ecological and evolutionary aspects

A representative part (65%) of the indigenous Galapagos flora was screened for contents of cyanogenic compounds by incubation of fresh crushed leaf material with β-glucuronidase and by analysis of released HCN. Most species with HCN development (cyanogenic species) were subsequently incubated with pure water to test for contents of glycosidases in the leaf. Plants with positive reaction were termed cyanophoric. The endemic part of the flora proved to have a higher percentage of cyanogenic and cyanophoric plants than the native part. The absence of mammalian leaf herbivores in the herbivore regime made us assume that cyanogenic compounds would be redundant

Benzoquinones from Embelia angustifolia

Three new 2,5-dihydroxy-3-alkyl-1,4-benzoquinones, (Z)-2,5-dihydroxy-3-(pentadec-8-enyl)-1,4-benzoquinone, (Z,Z)-2,5-dihydroxy-3-(heptadeca-8,11-dienyl)-1,4-benzoquinone and (Z)-2,5-dihydroxy-3-(heptadec-8-enyl)-1,4-benzoquinone and the known 2,5-dihydroxy-3-pentadecyl-1,4-benzoquinone were isolated from the leaves of Embelia angustifolia. Their structures have been established on the basis of spectral analysis and by chemical methods.