Ascorbic acid conjugates isolated from the phloem of Cucurbitaceae

A series of l-ascorbic acid analogues were isolated from phloem exudates of Cucurbitaceae fruit. The most abundant analogue from Cucurbita pepo was a 6-glucosyl conjugate. The potential role of ascorbate glycosides in long-distance transport is discussed in relation to the polymer trap theory of phloem loading.