Isolation and synthesis of acmellonate, a new unsaturated long chain 2-ketol ester from Spilanthes acmella.

Paracress (Spilanthes acmella) is commonly used as a spice, e.g., in Madagascar. To get more information about the taste active compounds, Jambu oleoresin produced from Spilanthes acmella and extracts prepared directly from the plant were fractionated and the fractions were analysed and evaluated by tasting. In addition to the long known tingling compounds (2E,6Z,8E)-deca-2,6,8-trienoic acid N-isobutyl amide (spilanthol) and (2E,6Z,8E)-deca-2,6,8-trienoic acid N-(2-methylbutyl) amide, as a minor constituent also the new 2-ketol ester (7Z,9E)-2-oxo-undeca-7,9-dienyl 3-methylbut-2-enoate (acmellonate) was isolated. The structure of the latter compound was verified by total synthesis of the ketol ester via the reaction of tris(trimethylsilyloxy)ethene and (6Z,8E)-deca-6,8-dienoic acid chloride and subsequent classical esterification. Acmellonate shows a weak tingling and numbing effect on the tongue and contributes only to a small extend to the overall flavour of Jambu.

Hydroxy- or methoxy-substituted benzaldoximes and benzaldehyde-O-alkyloximes as tyrosinase inhibitors.

Several benzaldoximes, benzaldehyde-O-ethyloximes, and acetophenonoximes were synthesized and evaluated as tyrosinase inhibitors by an assay based on tyrosinase catalyzed L-DOPA oxidation. Whereas benzaldoxime itself is only a weak inhibitor, its derivatives with one or two hydroxy or methoxy moieties in para and meta positions depress tyrosinase activity. Acetophenonoximes and trisubstituted benzaldoximes show no inhibitory activity. The IC(50) of 3,4-dihydroxybenzaldehyde-O-ethyloxime (0.3 +/- 0.1 micromol L(-1)) is of the same magnitude as tropolone (0.13 +/- 0.08 micromol L(-1)), one of the best tyrosinase inhibitors known so far.

Phenolic acid amides of phenolic benzylamines against UVA-induced oxidative stress in skin.

UVA-radiation is suspected to be a main cause for extrinsic skin ageing in humans. Recent studies showed that topically administered molecular antioxidants are able to protect skin against UVA-generated oxidative stress. Therefore, new phenolic acid amides of phenolic benzylamines were synthesized as potential antioxidants by reaction of (if necessary protected) N-succinimidylesters of ferulic acid, sinapic acid, caffeic acid, 3-(4-hydroxy-3-methoxyphenyl)propanoic acid, 3-(3,4-dihydroxyphenyl)propanoic acid, 2-(4-hydroxy-3-methoxyphenyl)acetic acid and 2-(3,4-dihydroxyphenyl) acetic acid with different phenolic benzylamines in moderate to good yields. The radical scavenging activities of the compounds were determined by the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay and by a superoxide radical anion trapping assay. Antioxidant activities in bulk lipids were tested by accelerated peroxidation with or without test compounds performed in the Rancimat apparatus. Stripped soybean oil and the skin sebum component squalene were used as lipids. The synthesized compounds were found to be efficient radical scavengers and antioxidants, especially the hydroxyphenylacetic amides and the hydroxydihydrocinnamic acid amides of polyhydroxybenzylamines, which are superior to the standards alpha-tocopherol and l-ascorbic acid. A topically applied 0.1% 1,3-butyleneglycol solution of N-(3,4-dihydroxybenzyl)-2-(4-hydroxy-3-methoxyphenyl)acetic acid amide 19 inhibits the UVA-induced sebum peroxidation in human skin significantly, by 39%.

An in vitro comparison of the computerized tomography/CAD-CAM and direct bone impression techniques for subperiosteal implant model generation.

Subperiosteal implants are currently fabricated by using the classic two-stage direct bone impression technique or by the use of the one-stage computer tomography/computer-assisted design-computer-assisted manufacture (CT/CAD-CAM) method. This study compares the accuracy of the two techniques by using cadaver maxillae and mandibles as the models for fabrication of casts. Seven cadaver jaw specimens were collected and subjected to direct bone impressions and to CT scans. Those derived from the direct bone impressions were poured in die stone, while the CT scans were sent for fabrication of CAD-CAM-generated casts. On each of the 14 models so produced, a cast grid was fabricated that was designed as a measuring device. The preciseness of fit of each grid was subjected to analyses that presented levels of accuracy. Statistical evaluation of these levels, reduced to numerical indices, revealed that the direct bone techniques resulted in acceptable castings in seven of seven cases, whereas the CAD-CAM method yielded adequate castings in five of seven cases.

Substrate specificity of the cell envelope-located proteinase of Lactococcus lactis subsp. lactis NCDO 763.

1. The specificity of the cell envelope-located proteinase of Lactococcus lactis subsp. lactis NCDO 763 towards caseins has been submitted to a statistical study. Positive and negative relations have been evidenced between several amino acids and positions P6 to P'2 of the cleaved bonds. 2. Fragment 1-23 of alpha s1 and oxidized B chain of insulin are well cleaved by the proteinase while CMP (fragment 106-169 of kappa-casein) is a poor substrate. 3. Comparison with other cell envelope-located proteinase has been done. The enzyme of the strain 763 hydrolyses alpha s1-casein and fragment 1-23 of alpha s1-casein as the enzyme of the strain Sk11 and beta-casein as the enzyme of the strain Wg2. 4. The specificity of these proteinases and the comparison of their amino acid sequences let us postulate a more complex substrate binding area for these lactococcal proteinases than for the subtilisin.

[Mathematical model on the development of progesterone in the cow: application and proof of differences between breeds]. / Modèle mathématique de l'évolution de progestérone chez la vache: application et mise en évidence de différence entre races.

Peripheral plasma progesterone levels were compared in "Normandy" (6), "Charolais" (6) and French Friesian (6) heifers. The progesterone curves were fitted to mathematical models for the luteal phase (a logistic function) and for the luteolytic phase (an exponential model). 1. Discriminating and multivariate analyses showed a breed difference in luteal phase duration (17.8 +/- 1.1, 16.8 +/- 2.3, 16.1 +/- 1.06 days, respectively, for Normandy, Charolais and French Friesian heifers) and in the rate of progesterone level increase (1.1 +/- 0.4, 1.09 +/- 0.3, 1.3 +/- 0.3 ng/ml/day, respectively) (chi 2 = 22.5; P less than 0.02). 2. Progressive multiple regression showed the duration of the luteal phase was highly correlated to oestrous cycle duration (20.8 +/- 1.7, 20.5 +/- 2.8, 19.2 +/- 1.5 days, respectively) (r = 0.89). It appears that breed differences in bovine oestrous cycle duration are due to differences in luteal phase duration. 3. The rate of progesterone level increase reached a maximum at 7.2 +/- 0.8, 6.9 +/- 1.1 and 6.4 +/- 0.6 days, respectively, concomitant with maximal corpus luteum secretion. 4. The reproducibility of these parameters, summarizing the progesterone pattern during two consecutive oestrous cycles, showed that each animal had an individual secretion pattern.