Effect of seasonal variation on secondary metabolites and nutritive value of crotalaria aegyptiaca benth

الملخص EN

This study aimed to investigate the effect of seasonal variation on secondary metabolites and the nutritive value of Crotalaria aegyptiaca Benth., family Leguminosae, collected from Wadi Hagul at 15 km from the beginning of the Wadi during winter and summer seasons.

Crotalaria aegyptiaca grows under high degree of aridity.

Na+ ions form the major cations while Cl- ions form the major anions in the soil supporting the plant at Wadi Hagul habitat.

Samples taken from the plant during summer attained the highest of succulence ratio.

The percentages of total available carbohydrates, total ash, total crude fibers, total protein and total fat content reached their maximum values in summer, while reached their minimum values during winter.

The dry matter content of C.

aegyptiaca reached its maximum values during summer season.

Ca++ and Mg++ ions were accumulated in high amounts in summer to counteract the harmful effect of Na+ and Cl- ions.

The plant samples contained fourteen amino acids in winter with various concentrations, glutamic acid was the highest separated one, while plant samples during summer, season contained seventeen separated amino acids, arginine forms the highest one.

Concerning the active constituents of the whole plant (during summer and winter) and seeds, it was found that the percentages of total flavonoids and total akaloids were higher in seeds than in the whole plant and also were higher during winter than summer (for the whole plant).

While the total percentages of saponin content were higher in plant seeds than that of whole plant, and were higher during summer season than winter samples for whole plant.

Meanwhile, the percentages of total tannins were higher in whole plant during summer season.

The nutritive value of C.

aegyptiaca was determined by two methods and indicated high nutritive value during its vegetative stages with no harmful effect to the animals during overgrazing.

However, at the end of seeding stages, the total alkaloids, total flavonoids and total saponin content reached the highest values, so it must be prevented from animal feeding especially during these stages as it would cause animal death.