Flavonol glycoside distribution in cultivars and hybrids of Leucaena leucocephala

Abstract

AbstractFlavonol glycosides found in the leaves of Leucaena leucocephala comprised the 3‐arabinosides, 3‐rhamnosides and 3‐glucuronides of quercetin and myricetin, and quercetin‐3‐rhamnosylglucoside, at a total concentration of 3–4%. In cultivars of high productivity (Peru, El Salvador (K28) and Cunningham) all seven compounds occurred with a largely constant pattern of relative concentrations. However in the cosmopolitan form naturalised throughout the tropics the 3‐arabinosides were invariably absent. The same feature which was conspicuous on the high performance liquid chromatography trace, occurred with a low frequency (ca 10%) in Peru and Cunningham. The pattern provides a quick method for identifying the provenance of commercial leucaena leaf meal, and also for detecting blending or adulteration with other leaf meals. The flavonol glycoside distribution of those species associated with ‘leucaena’ leaf meal (Acacia villosa, Calliandra calothyrsus, Manihot utilissima and Sesbania grandiflora) is very different, and all have fewer compounds. All compounds occur in the apical tissue of young leucaena seedlings, enabling identification of cultivar from seed in 10 days. Comparison of leaf flavonol patterns for L. leucocephala, L. pulverulenta their known F1 hybrid, and an entity known locally in Java as ‘L. glabrata’ strongly suggest a hybrid origin for the latter.