Volume 45, 2015, Pages 121–145
Chapter 5 – Ecdysteroids in Plants and their Pharmacological Effects in Vertebrates and Humans
Abstract
Ecdysteroids,
the molting hormones of arthropods, have been found in many plant
species. Phytoecdysteroids belong to a large family of ecdysteroids that
comprises more than 250 representatives. To date, ecdysteroids or
ecdysteroid-like compounds have been found in gymnosperms, angiosperms,
fungi, algae, and certain marine organisms. Ecdysteroids accumulate in
various plant organs, including fruits, seeds, flowers, anthers, leaves,
and roots, during various phases of their growth. Ecdysteroid
concentrations in plants may be very large, i.e., several orders of
magnitude higher than in most arthropods. The chemical structure of
phytoecdysteroids is very varied. Plants may contain C27, C28, or C29 type of ecdysteroids either in the free form or as various polar or apolar conjugates. They may also contain C24, C21, or C19
compounds resulting from various side chain cleavage reactions. The
presence of ecdysteroids and their conjugates in plants is suggested to
be a factor which may alter development of nonphytoecdysteroid-adapted
insect species. Phytoecdysteroids induce abnormal molting in many
arthropods with lethal effect. Hence these compounds may potentially
prove useful to control insect herbivory on agriculturally important
plants. However, many functions of ecdysteroids in plants are still
unknown.
At present, our knowledge of the effects
of phytoecdysteroids in animals or human is still rather fragmentary.
Phytoecdysteroids from Ajuga decumbens showed strong inhibitory
effect on early induction and potent antitumor-promoting activities of
Epstein–Barr virus on a mouse skin. It suggests that A. decumbens
may be valuable as a source of potential cancer chemopreventive agent.
Phytoecdysteroids have an antifungal and antibacterial activity. They
are apparently nontoxic to mammal ecdysteroids. A very low toxicity (LD50 > 6 g/kg)
of ecdysteroids in vertebrates is observed. The wide range of
beneficial pharmacological (adaptogenic, anabolic, antidiabetic,
hepatoprotective, immunoprotective, wound-healing, anti-inflammatory,
and perhaps even antitumor) activities is claimed for ecdysteroids. In
particular, this has led to a large (and unregulated) market for
ecdysteroid-containing preparations for bodybuilders, sportsmen, and
pets, among others. Ecdysteroids are also being considered as
nutraceutical additives to food products. They have antioxidative and
antifree-radical properties.
Keywords
- Application;
- Chemical structures;
- Ecdysteroids;
- Medical consequences
Copyright © 2015 Elsevier B.V. All rights reserved.
