Browsing by Author "Senanayake S P"

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    A comparative chemosystematical study of the genus Shorea in Sri Lanka
    (Proceedings of the sixth Round Table Conference on Dipterocarps, Bangalore, India, 1999) Perera N I S; Senanayake S P
    The genus Shorea of the Dipterocarpaceae family is represented by 15 species in Sri Lanka, of which 13 are endemic. Because of the existence of different classification systems for this genus, proposed by several authors (Trimen 1974, Ashton 1980, Kostermann 1992), the aim of this study was to determine the taxonomic position of the genus Shorea using flavonoid composition. Flavonoid composition of the leaves of 11 species was studied using chromatographic techniques and UV visible spectroscopy. It was revealed that 48% flavonols, 36% flavones, 63% proanthocyanidins and 13% deoxy compounds were present in the leaves. In this study, a comparison of the flavonoid glycoside distribution patterns of Shorea stipularis and S. hulanidda suggested that the two species should be treated as different entities. However, several authors treat the taxonomic positions of these two species differently.
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    Leaf flavonoid aglycone patterns in the species of Dipterocarpaceae in Sri Lanka
    (Biochemical Systematics and Ecology, 2004) Joshia K; Seneviratne G I; Senanayake S P
    A flavonoid aglycone survey was carried out on 46 taxa of the family Dipterocarpaceae belonging to the genera Cotylelobium, Dipterocarpus, Hopea, Shorea, Stemonoporus, Vateria and Vatica. After acid hydrolysis the main aglycones found were the flavonols quercetin and kaempferol, and the flavone apigenin. The flavone luteolin was present in all the species of the genus Shorea and was absent in the rest of the species of the family, giving a chemotaxonomic significance to its presence. The flavonol myricetin was detected in only three species of Shorea, S. affinis, S. trapezifolia, and S. gardneri. Proanthocyanidins were only found in 13 species of Shorea and two species of Dipterocarpus. These two genera can be regarded as the most primitive with respect to the flavonoid patterns and the other five genera have more advanced patterns, recognizing Stemonoporus as the most advanced. The aglycone results do not completely agree with the existing classifications, and suggests the need for a revision of the species and sectional levels in the family Dipterocarpaceae in Sri Lanka.