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BY:MUHAMMAD KAMRAN SIAL
SERIAL# 16
SUBMITTED TO:DR. MUHAMMAD ANJUM AQUEEL
o Heterogeneous class of natural products
o Their basic substances contain one or more nitrogen atoms
o They interfere with key components in acetylcholine transmission in nervous system
o Most common in plants
o 20% of species of flowering plants, show their specific alkaloid pattern
o Numerous alkaloids are toxic and deterrent to insects
Pyridine
o Before the advent of synthetic insecticides Nicotine and Nor-nicotine were popular as botanical insecticides
o A great number of structurally unrelated alkaloids are feeding deterrent to many insects such as:
o A potent inhibitore of alpha-glucosidase from insects
o Prensent in Derris and Lanchocarpus.
o At 0.03 per cent DMDP killed seed beetle, Callosobruchusmaculatus (Evans et al., 1985)
o DMDP also acts as feeding deterrent in young nymphs of Locusta migratorianb at 0.001 per cent concentration
DMDP
Derris scandens
Lonchocarpus sericeus
Callosobruchus maculatus
Locusta migratorianb
o A small group of about 100 sulphur or nitrogen containing distinctive secondary compounds
o Act as precursors of mustard oils
o Glucosinolate appear to contribute to effective chemical defences against a majority of non-adapted phytophagousinsects
o Capparales,Cruciferae are good examples
Cruciferae
o A small minority of adapted (crucifer-feeding) insects are able to utilize glucosinolates in host seeking and host recognition behavior.
o Specific cocentrations of different glucosinolates also stimulate larval feeding by adapted species.
o Damage by herbivorous insects tend to decline as the concentration of glucosinolates increase.
o Furthermore, the occurrence of species of adapted insects decline as total glucosinolates concentration increased.
o volatile hydrolysis products, are also used as cues by parasitoids of crucifer-feeding insects.
