Homoisoflavonoids and cardenolides from cultivated Ornithogalum species: Ornithogalum dubium Houtt. and Ornithogalum ponticum ‘Sochi’
Resource type
Journal article
Creator (person)
Langat, L
Langat, Moses K.
Mulholland, D
Date published
May 24, 2019
Abstract
Three new homoisoflavonoids, (3R)-3,5-dihydroxy-7-methoxy-3-(4′-hydroxybenzyl)-4-chromanone, 4, and its 5-O-β-D-glucopyranoside and 5-O-β-D-gentiobiose derivatives, 5 and 6, along with the known homoisoflavonoids, (3S)-5-hydroxy-7-methoxy-3-(4-methoxybenzyl)-4-chromanone, 1, (3R)-5-hydroxy-7-methoxy-3-(4-methoxybenzyl)-4-chromanone (2) and (3S)-5-hydroxy-7-methoxy-3-(4-hydroxybenzyl)-4-chromanone, 3, were isolated from the bulbs of Ornithogalum dubium Houtt. In addition, three known cardenolides, 3β-(O-α-L-rhamnoside)-5β,14β-dihydroxy-19-oxocardenolide 7, 3β-(O-α-L-rhamnoside)-5β,11α,14β-trihydroxy-19-oxocardenolide, 8 and 3β-(O-α-L-rhamnoside)-5β,11α,14β,19-tetrahydroxycard-20(22)-enolide, 9, were isolated from Ornithogalum ponticum ‘Sochi’. Yields of homoisoflavonoids were low (0.0002%–0.0003%) so stereospecific synthetic methodology needs further refinement to produce antiangiogenic (3R)-3-benzylchromanones and (3S)-3-hydroxyhomoisoflavonoid analogues for further evaluation. This work confirms that, apart from producing cardenolides, the absolute configuration at C-3 of homoisoflavonoids produced by Ornithogalum is 3R (H-3β) for the 3-benzylchromanones and 3S (3-OH β) for the 3-hydroxy benzylchromanones, in agreement with our earlier reports.
Journal title
South African Journal of Botany
ISSN
0254-6299
Rights statement
In Copyright