Gossypol and related terpenoids : 1-toxicity and fertility effects

Abstract EN

Gossypol and related terpends are present throughout the cotton plan؛ in glands of foliage, floral organs, and bolls as well as the roots.

Gossypol ; a polyphenolic binaphthalene-dialdehyde; and other terpenoids (generally tefetTed as a terpenoid aldehydes) from cottonseed produce both general toxic and antifertility effects ; mammals and insects.

A^^cholinesterase is the target site for organophosphates and carbamate Insecticides and Its role in cholinergic synapses is essential for life.

In vitro Inhibition, o / £art؛ally purified AChE from Torpedo electric organ, kinetic parameters were 6.

2 ^ 10 M for Kn, and 13.

33OD X , n2nm mg'1 protein, min'1 for the maximum activity (Vmax) when gossypol was incubated with AChE for 5 min at 5 X 10 ; and 7.5 X 10 'M.

Km value was found to be the same for the AChE activity in the absence of terpenoid, while the velocity of the enzyme reaction was depressed.

The maximum velocity in the presence of terpenoid was found to be 11.11 and 6.89 OD ^ i2nm• mg protein, min * at 5X10 and 7.5X10 '؛ M terpenoid respectively.

These data indicate that gossypol is a non competitive Inhibitor for Torpedo AChE with a K, value of 50.

Purified terpenoid increased Spodoptera AChE activity, in vitro, up to 1^ 10 M.

By increasing concentrations a slight inhibitory effect was show up at 5X10' M.

The concept of such differences on the enzyme activities and inhibitions from two different sources (vertebrate vs.

invertebrate) may play an Important role in Insecticide selectivity.

However, the effect of purified terpenoid on percent eggs laid and % hatchability in treated pupae, adults and larvae of littoralis for three consecutive generations showed a significantly reduction of the number of egg laid and also the % hatchability.