Brassinosteroids

Assessment of natural products in the Drosophila melanogaster BII cell bioassay for ecdysteroid agonist and antagonist activities

“…The apparent similarity of certain structural features between the ecdysteroids and brassinosteroids has been put forward as the basis of these activities. However, where effects are observed, they occur only at high concentrations ( \ 10 − 5 M) and almost certainly play no role in insectplant relationships because brassinosteroids occur in plants in only minute quantities [17]. In the B II assay, none of a significant number of brassinosteroids (19 -28) possessed either specific agonist or antagonist activity, although some did show cytotoxicity at high concentrations ( \ 10 − 4 M).…”

“…Veratridine (16), one of the insecticidal steroidal alkaloid components of sabadilla [prepared from the seeds of Schoenocaulon officinale (Liliaceae)], did not possess ecdysteroid (ant)agonistic activity. Two other steroidal alkaloids, chaconine (5) and solanine (12), were also inactive, as were the nonsteroidal alkaloids atropine (2), nicotine (9), strychnine (14), caulerpin (17) and yohimine (18). Brassinosteroids.…”

Steroids: Cholesterol and Other Phytosterols

“…Brassinosteroids represent a new class of phytohormones and its first member named brassinolide 1 has been isolated in extremely small yield (4 mg from 40 kg bee collected pollens) of rape seed plant (Brassica napus, Cruciferae/ Brassicaceae) [35,36]. Isolation of brassinolide confirms the role of steroids as hormones in plants and demonstrates an evolutionary conservation between plants and animals.…”

“…The challenging stereostructures of brassinosteroids have attracted the attention of synthetic chemists and a number of syntheses have been reported. The first synthesis of brassinolide has been reported in 1980 by two groups of workers [41,42] The structure of brassinolide was completely established by its X-ray crystallographic analysis [35,36]. [43,44] 11.4.1.1 Introduction.…”

“…Till 1991, more than 60 brassinosteroids have been isolated from a wide variety of plants [37,38]. A few representatives of brassinosteroid family are shown to possess the following structural characteristics [36,39,40] (Fig. 11.20).…”