Peter Rüedi

PHENYLPROPANOID GLYCOSIDES FROM MARRUBIUM ALYSSON

From the aerial parts of Marrubium alysson a new phenylpropanoid glycoside, alyssonoside, and five known glycosides, verbascoside (= acteoside), leucosceptoside A, martynoside, forsythoside B and leucosceptoside B were isolated. On the basis of spectral data, the structure of the new compound was elucidated as beta-(3,4-dihydroxyphenyl)ethyl-O-[alpha-L-rhamnopyranosyl-(1-->3)]-O- [beta-D-apiopyranosyl-(1-->6)]-4-O-feruloyl-beta-D-glucopyra noside.

1H-Indole-3 acetonitrile glycosides from Capparis spinosa fruits

Abstract Two new glucose-containing 1 H -indole-3-acetonitrile compounds, capparilosides A and B, were isolated from mature fruits of Capparis spinosa . On the basis of spectral and chemical evidence, they were shown to be 1 H -indole-3-acetonitrile 4- O - β -glucopyranoside and 1 H -indole-3-acetonitrile 4- O - β - (6′- O - β -glucopyranosyl)-glucopyranoside, respectively.

Sorbitol and sucrose partitioning in the growing apple fruit

Summary Growing apple fruit is supplied with the C-assimilates sorbitol and sucrose produced in leaf photosynthesis. These C-sources enter fruit metabolism and accumulate as fructose, sucrose, malic acid, and starch. In the present study, the contribution of sucrose and sorbitol in carbon partitioning was investigated. After incorporation of [ 14 C] sorbitol and [ 14 C] sucrose, labeled either in the glucosyl or the fructosyl part of the molecule, into discs of parenchyma tissue, the distribution of the label among the metabolic products was compared. With [Glc- 14 C] sucrose as the C-source, starch and other major metabolic products contained 2–3 times more radioactivity than when [Fru-l4C] sucrose was used. When [ 14 C] sorbitol was fed, fructose was preferentially labeled, but incorporation into starch and other metabolites was less compared with [Fru- 14 C] sucrose. The results show that glucose derived from sucrose more readily enters into the hexose phosphate pool than fructose derived either from sucrose or sorbitol. The selective utilization of glucose is therefore dependent on the cleavage of sucrose by sucrose synthase. This reaction favors diversion of glucose to starch while fructose is accumulated in the vacuole of the parenchyma cell. The hexose phosphates produced in the sucrose synthase pathway are more liable to be used as precursors for starch synthesis than triose phosphates. This conclusion is reached from experiments in which [1- 13 C] glucose and [6- 13 C] glucose were incorporated into starch of excised tissue discs. After hydrolysis of labeled starch, redistribution of 13 C between carbon C1 and carbon C6 of glucose was measured by nuclear magnetic resonance (NMR). The extent of redistribution was 15–31 %, indicating that a hexose or hexose monophosphate is incorporated into starch without substantial previous cleavage to triose phosphates. The partitioning of sucrose between soluble sugars and starch was also dependent on the cell turgor. In the presence of increasing external mannitol concentrations, which reduced cell turgor, asymmetrically labeled sucrose was metabolized in excised tissue discs in such a way that the glucose moiety was preferentially partitioned into starch, while fructose was favored for accumulation.

Two phenylpropanoid glycosides fromLeonurus glaucescens

Two new phenylpropanoid glycosides, leonosides A and B, and two known glycosides lavandulifolioside and verbascoside, were isolated from the aerial parts of Leonurus glaucescens. On the basis of chemical and spectral evidence, leonosides A and B were shown to be beta-(3,4-dihydroxyphenyl)-ethyl-O-alpha-L-arabinopyranosyl-(1---- 2)-alpha-L- rhamnopyranosyl-(1----3)-4-O-feruloyl-beta-D-glucopyranoside and beta-(3-hydroxy, 4-methoxyphenyl)-ethyl-O-alpha-L-arabinopyranosyl-(1----2)- alpha-L-rhamnopyranosyl-(1----3)-4-O-feruloyl-beta-D-glucopyranosi de, respectively.

Phlinosides A, B and C, three phenylpropanoid glycosides from Phlomis linearis.

Three new phenylpropanoid glycosides, phlinosides A, B and C were isolated from a methanolic extract of the aerial parts of Phlomis linearis. On the basis of chemical and spectral evidence their structures were determined as 3,4-dihydroxy-beta-phenylethoxy-O-beta-D-glucopyranosyl-(1----2)-a lpha-L- rhamnopyranosyl-(1----3)-4-O-caffeoyl-beta-D-glucopyranoside, 3,4 dihydroxy-beta-phenylethoxy-O-beta-D-xylopyranosyl-(1----2)-alpha- L- rhamnopyranosyl-(1----3)-4-O-caffeoyl-beta-D-glucopyranoside and 3,4-dihydroxy-beta-phenylethoxy-O-alpha-L-rhamnopyranosyl-(1----2) -alpha- L-rhamnopyranosyl-(1----3)-4-O-caffeoyl-beta-D-glucopyranoside, respectively.

Scent marking in wild banded mongooses: 1. Sex-specific scents and overmarking

Overmarking occurs when one individual places its scent mark directly on top of the scent mark of another individual. Although it is almost ubiquitous among terrestrial mammals, we know little about the function of overmarking and detailed field observations are rare. We investigated the chemical composition of scents and patterns of overmarking by wild banded mongooses, Mungos mungo. Chemical analyses of anal gland secretions showed that scents were sexually dimorphic. Both male and female adults were more likely to overmark the scents of same-sex individuals. An analysis of responses to two scents on the same site suggested that the sex of the top or most recent scent was more important than that of the bottom or original scent in determining overmarking response. Juveniles also overmarked scents at high rates, but did not respond to scents in a sex-specific way. Same-sex-specific patterns within groups have not been described in any other species, and may reflect a social system with intense intrasexual competition for reproduction within both sexes. Banded mongooses live in large mixed-sex groups, with intense competition between males for females, owing to the heavily male-biased adult sex ratio and highly synchronized oestrous cycles. Oestrous synchronization may also promote intrasexual competition for males within females, as females compete simultaneously for high-quality males. Female competition for males may also be enhanced by the rewards of male-biased parental care. This investigation highlights the need for detailed studies of overmarking in the natural context, to confirm and expand upon laboratory findings.

3-Fluoro-2,4-dioxa-3-phosphadecalins as Inhibitors of Acetylcholinesterase. A Reappraisal of Kinetic Mechanisms and Diagnostic Methods

A systematic survey of the acetylcholine-mimetic 2,4-dioxa-3-phosphadecalins as irreversible inhibitors of acetylcholinesterase revealed hitherto overlooked properties as far as the kinetic mechanisms of interaction are concerned. As a support to past and future work in this field, we describe the kinetics of eight reaction schemes that may be found in irreversible enzyme modification and compare them with two mechanism of reversible, slow-binding inhibition. The relevant kinetic equations and their associated graphical representations are given for all mechanisms, and concrete examples illustrate their practical use. Since irreversible inhibition is a time-dependent phenomenon, kinetic analysis is greatly facilitated by fitting the appropriate integrated rate equations to reaction-progress curves by nonlinear regression. This primary scrutiny provides kinetic parameters that are indispensable tools for diagnosing the kinetic mechanism and for calculating inhibition constants. Numerical integration of sets of differential equations is an additional useful investigation tool in critical situations, e.g., when inhibitors are unstable and/or act as irreversible modifiers only temporarily.

Phlinosides D and E, phenylpropanoid glycosides, and iridoids from Phlomis linearis

Two new phenylpropanoid glycosides, phlinosides D and E were isolated from the methanolic extract of the aerial parts of Phlomis linearis, along with the known iridoid glucosides, lamiide, ipolamiide and auroside (= 5-hydroxy-8-epiloganin). On the basis of chemical and spectral evidence the structures of phlinosides D and E were determined as 3,4-dihydroxy-beta-phenylethoxy-O-beta-D-xylopyranosyl-(1----2)-al pha-L-rhamnopyranosyl-(1----3)-4-O-feruloyl-beta-D-glucopyranoside and 3,4-dihydroxy-beta-phenylethoxy-O-alpha-L-rhamnopyranosyl-(1----2) -alpha-L- rhamnopyranosyl-(1----3)-4-O-feruloyl-beta-D-glucopyranoside, respectively.

Scent marking in wild banded mongooses: 3. Intrasexual overmarking in females

In contrast to numerous studies of scent marking in male mammals, studies of female scent marking are relatively rare. We have previously shown that communally breeding female banded mongooses, Mungos mungo, are more likely to overmark the scent of other females. Here we describe female overmarking patterns in more detail, and discuss these results in relation to hypotheses potentially explaining such ‘female intrasexual overmarking’. To our knowledge, this is the first study to investigate female overmarking in any wild mammal. First, although we found some evidence of individually distinctive scent marks in females, we found no evidence to suggest that female intrasexual overmarking was related to competition for food, as feeding competition was infrequent, and unrelated to overmarking scores. We also found no evidence to suggest that intrasexual overmarking in females was involved in reproductive suppression. Females with the highest and lowest overmarking scores in each group were mate-guarded by males for similar durations. Finally, we found little evidence to suggest that female intrasexual overmarking was involved in competition for males. Although the female with the highest overmarking score in each group tended to be mate-guarded by males in better condition than the female with the lowest overmarking score, a female’s overmarking score affected neither the amount of harassment she received from males nor the frequency of mating attempts received. These results are discussed in light of these and other untested hypotheses for female overmarking.

Evaluation of Biological Activity of Turkish Plants. Rapid Screening for the Antimicrobial, Antioxidant, and Acetylcholinesterase Inhibitory Potential by TLC Bioautographic Methods

Using thin-layer chromatography (TLC) bioautography, a total of 58 extracts from various organs (aerial parts, leaves, flowers, fruits, roots) of 16 Turkish plants were tested for their antibacterial, antifungal, acetylcholinesterase inhibitory, antioxidant, and radical scavenging activities. The hexane, CHCl3/CH2Cl2, water, and total MeOH extracts were used. No activity was observed against two Gram-negative bacteria (Escherichia coli and Pseudomonas aureginosa) and the yeast Candida albicans. However, 23 plant extracts, mostly the CHCl3/CH2Cl2 and H2O-solubles, inhibited the growth of all five Gram-positive bacteria tested, Micrococcus luteus, Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, and Staphylococcus epidermidis. Of the active extracts, the CHCl3-soluble of the roots of Putoria calabrica (L. fil) DC (Rubiaceae) displayed the highest antibacterial potential. The majority of the CHCl3/CH2Cl2 crude extracts also appeared to inhibit acetylcholinesterase on TLC plates at 100 µg/spot concentration. Particularly active samples were the middle polarity extracts (CHCl3/CH2Cl2) of the leaves of Rhododendron smirnovii Trautv., R. ponticum L., and R. ungernii Trautv. (Ericaceae). β-Carotene, β-carotene/linoleic acid mixture, and 2,2-diphenyl-l-pieryhydrazyl (DPPH) solutions sprayed onto TLC plates were used for detecting antioxidant and radical scavenging properties of the crude extracts. Antioxidant and radical scavenging activities were found to be predominant in highly polar extracts. The water-solubles of all Rhododendron (Ericaceae) and Phlomis (Lamiaceae) species presented the most significant activity.