Two flavonol diglycosides, tamarixetin 3-O-neohesperidoside, kaempferide 3-
O-neohesperidoside and the known quercetin 3-O-neohesperidoside, together w
ith six other known flavonoids were isolated from the leaves of Costus spic
atus and their structures were elucidated by a combination of spectroscopic
and chemical methods. The flavonol diglycosides were evaluated for inhibit
ory activity of nitric oxide production by activated macrophages (Fig. 1).
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