Fekadu Fullas

Effect of tannins on screening of plant extracts for enzyme inhibitory activity and techniques for their removal

Ethyl acetate and aqueous extracts of tannin-containing topoisomerase inhibitory plant samples were subjected to one or more of seven tannin removal procedures, and the resulting products were subsequently evaluated for topoisomerase inhibitory activity. In most of the samples investigated, the initial activity was lost after tannin removal. It was concluded that the activity initially observed was primarily due to tannins. Procedures are presented for routinely obtaining tannin-free organic and aqueous fractions.

Gaudichaudiosides A–E, five novel diterpene glycoside constituents from the sweet-tasting plant, Baccharis gaudichaudiana

A new potently sweet labdane diterpene arabinoside, gaudichaudioside A (1), was isolated from the aerial parts of Baccharis gaudichaudiana DC. (Compositae). Also isolated were four other novel labdane arabinosides, gaudichaudiosides B–E (2–5), which although closely related to 1 structurally, were not found to be highly sweet.

A bitter-tasting trihomolabdane arabinoside from Baccharis gaudichaudiana

Abstract Investigation of the aerial parts of Baccharis gaudichaudiana has afforded a new labdane arabinoside with a novel 23-carbon aglycone skeleton. The structure of this compound, to which we have accorded the trivial name, gaudichaudioside F, was established by analysis of its spectroscopic parameters.

Structure-activity relationship of highly sweet natural products

Publisher Summary This chapter focuses on the structure-activity relationship of highly sweet natural products. It may be seen that ongoing research activities on the isolation and characterization of naturally occurring sweet principles have continued to afford many novel molecules in several structural classes. These compounds occur in species representing a taxonomically wide range of plant families. Methodology has been developed in terms of candidate plant selection, dereplication of sugars, polyols and sweet phenylpropanoids, and in other phytochemical procedures, such that significant progress can be made in the elucidation of further highly sweet-tasting molecules with only a modest investment of capital. To being used in an unmodified form as sweeteners, plant-derived sweet-tasting molecules can serve as useful lead molecules for synthetic optimization. Therefore, knowledge of structure-sweetness relationships of plant sweeteners, and their naturally occurring congeners and semi-synthetic analogs is of use in assisting with the rational design of new sweeteners based on natural product leads.