Trehalose is an enigmatic compound that accumulates in Saccharomyces cerevisiae and has been implicated in survival under various stress conditions by acting as membrane protectant, as a supplementary compatible solute or as a reserve carbohydrate that may be mobilized during stress. In this study, specific mutants in trehalose metabolism were used to evaluate whether trehalose contributes to survival under severe osmotic stress and generates the compatible solute glycerol under moderate osmotic stress. The survival under severe osmotic stress (0866 a , NaCl or sorbitol) of mutants was compared to that of the wild-type strain when cultivated to either the midexponential or the stationary growth phase on glucose, galactose or ethanol. Stationary-phase cells survived better than exponential-phase cells. The death rates of ethanol-grown cells were lower than those of galactose-grown cells, which in turn survived better than glucose-grown cells. There was a strong relationship between intracellular trehalose levels and resistance to osmotic stress. The mutant strains unable to produce trehalose (tpslA tps2A and tpslA hxk2A) were more sensitive to severe osmotic stress (0866 aw) than the isogenic wild-type strain, confirming a role for trehalose in survival. Hyperaccumulation of trehalose found in the nthlA and the nthlA gpdlA mutant strains, however, did not improve survival rates compared to the wildtype strain. When wild-type, nthlA and nthlA gpdlA cells were exposed to moderate osmotic stress (098 and 097 a , NaCI), which permits growth, glycerol production did not appear to be related to the intracellular trehalose levels although glycerol levels increased more rapidly in nthlA cells than in wild-type cells during the initial response to osmotic stress. These data indicate that trehalose does not act as a reserve compound for glycerol synthesis under these conditions. No evidence was found for solutes other than glycerol and trehalose being significant for the survival of or growth by 5. cerevisiae under osmotic stress conditions.

An acetone/water extract of the fodder legume Onobrychis viciifolia afforded arbutin, kaempferol, quercetin, rutin, afzelin, the branched quercetin-3-(2(G)-rhamnosylrutinoside), the amino acid L-tryptophan, the inositol (+)-pinitol, and relatively high concentrations of sucrose (ca. 35% of extractable material). Acid-catalyzed cleavage of the condensed tannins with phloroglucinol afforded catechin, epicatechin and gallocatechin as the terminal and extender units, but epigallocatechin was only present in extender units. The condensed tannins in O. viciifolia presumably consist of hetero- and homopolymers containing both procyanidin and prodelphinidin units. Comparison of data from the present study and the literature suggests that sainfoin tannins have a highly variable composition with cis:trans ratios ranging from 47:53 to 90:10 and delphinidin:cyanidin ratios from 36:64 to 93:7. The composition of terminal and extender units in sainfoin tannins seems to be cultivar specific.

The fermented leaves and stems of Cyclopia intermedia are used to brew Honeybush tea, a herbal tea indigenous to South Africa. The plant is also used to manufacture a sweet herbal infusion used for restorative properties such as soothing coughs and alleviating bronchial complaints including tuberculosis, pneumonia, and catarrh. It is claimed to have a low tannin content and no caffeine and contains various antioxidants. Continued investigations into the phenolic content of the leaves and stems of C. intermedia yielded tyrosol and a methoxy analogue, 2-[4-[O-alpha-apiofuranosyl-(1' '-->6')-beta-d-glucopyranosyloxy]phenyl]ethanol, 4-[O-alpha-apiofuranosyl-(1' '-->2')-beta-d-glucopyranosyloxy]benzaldehyde, five glycosylated flavonols, two isoflavones, four flavanones, two isoflavones, and two flavones. Structure elucidation was done by NMR, CD, and MS methods. Because flavonoids are presumed to contribute significantly toward the scavenging effects of active oxygen species, our results indicate that the tentative claimed health-promoting properties may be attributed to the presence of these and other phenolics in C. intermedia.