Henning Adsersen

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.

Research on Islands: Classic, Recent, and Prospective Approaches

In classic studies of island biota three main approaches may be identified: description of strange plants and animals as phenomena at the species level; examination of the mechanisms behind evolutionary and distributional patterns recognized at the population and community level; and quantitative and comparative evaluation of the diversity of entire island biota.

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

Introduction-Why Focus on Islands?

Research on islands has long played a fundamental part in developing our basic understanding of ecology and evolution. Both Darwin’s and Wallace’s insight into evolution and speciation were shaped by studies on islands (Darwin 1859; Wallace 1881); it is no coincidence that Darwin felt close to “that great fact — that mystery of mysteries — the first appearance of new beings on this earth” in the Galapagos (Darwin 1845). Even today, the Hawaiian drosophilids provide a primary standard for analyses of speciation (Carson et al. 1970; Kaneshiro, Chap. 3). More recently, ecology has been enriched by analyses of competition and character displacement (Lack 1947; Brown and Wilson 1956) and by island biogeography theory (MacArthur and Wilson 1967), which were developed and tested on islands but applied much more widely.