The leaves of green plants as well as a cyanobacterium, a red alga, and fungi contain insulin-like antigens

Abstract

We report the detection of insulin-like antigens in a large range of species utilizing a modified ELISA plate assay and Western blotting. We tested the leaves or aerial parts of species of Rhodophyta (red alga), Bryophyta (mosses), Psilophyta (whisk ferns), Lycopodophyta (club mosses), Sphenopsida (horsetails), gymnosperms, and angiosperms, including monocots and dicots. We also studied species of fungi and a cyanobacterium, Spirulina maxima. The wide distribution of insulin-like antigens, which in some cases present the same electrophoretic mobility as bovine insulin, together with results recently published by us on the amino acid sequence of an insulin isolated from the seed coat of jack bean (Canavalia ensiformis) and from the developing fruits of cowpea (Vigna unguiculata), suggests that pathways depending on this hormone have been conserved through evolution.

Effect of an aqueous extract of Scoparia dulcis on blood glucose, plasma insulin and some polyol pathway enzymes in experimental rat diabetes

“…The maximum reduction in glucose levels was observed in groups receiving 200 mg/kg of the extract. Although the mechanism of action of the SPEt extract is unknown, a number of other plants have been reported to have antihyperglycemic and insulin releasestimulating effects (30,31) or to contain insulin (32,33).…”

Isolation and intracellular localization of insulin-like proteins from leaves of Bauhinia variegata

“…In addition, materials resembling insulin were described in spinach, rye and Lemna gibba, which were recognized by broad spectrum anti-pork and anti-chicken insulin antibodies and had molecular weights, chromatographic properties and biological activities similar to those of vertebrate insulins (7). Insulin-like antigens were also detected in a wide range of green plants, algae, fungi, and a cyanobacterium by an ELISA assay and Western blotting (8). Bioactive and immunoactive insulins were detected in the unicellular eukaryotes Neurospora crassa and Aspergillus fumigatus, which are fungi, in Tetrahymena pyriformis, a ciliated protozoon (9), and in the prokaryote Escherichia coli (10).…”

Insulin or insulin-like studies on unicellular organisms: a review

“…Specific effects of human insulin on oxidative and non-oxidative glucose metabolism in yeast were also observed (Müller, 2000). Silva et al (2002) showed insulin-like antigens in extracts of Saccharomyces cerevisiae at the same position as bovine insulin on a Western blots band.…”

“…The purified material was found to have an immunoactivity to the anti-insulin antibody and similarity was demonstrated between the unicellular material and vertebrate insulins. More recently, Silva et al (2002) Köhidai et al (1992) verified that 1) the number of insulin binding sites decrease in the control conditions as a function of time. The down regulation of binding sites lasts approximately 48h and only low insulin concentration can induce a binding site elevation over the long term; 2) hormonal imprinting could be present in Amoeba.…”