Quantification of alkaloids, phenols and flavonoids in sunflower (Helianthus annuus L.)

Allelochemicals in leaves, stems and roots of sunflower (cv Hysun 38) were determined using thin layer chromatography (TLC) for alkaloids and spectrophotometry for phenols and flavonoids. In the TLC, the highest Rf value was recorded in leaves, followed by roots and stems, a sequence that held true also for the quantity of phenols and flavonoids. The soil texture, which was sandy loam, was not changed before or after the harvest.   Key words: Allelochemicals, alkaloids, flavonoids, phenols, sunflower, spectrophotometry, thin layer chromatography.