Three new flavonol galloylglycosides from leaves of Acacia confusa.

Myricetin 3-O-(2"-O-galloyl)-alpha-rhamnopyranoside 7-methyl ether (1), myricetin 3-O-(3"-galloyl)-alpha-rhamnopyranoside 7-methyl ether (2), and myricetin 3-O-(2",3" -di-O-galloyl)-alpha-rhamnopyranoside (3), three new flavonol galloylglycosides, were isolated from leaves of Acacia confusa sampled from Chaoushi in the north of Taiwan. Their structures were established by analysis of spectroscopic data, and the compounds were evaluated for anti-hatch activity against brine shrimp.

Molecular and channel-forming characteristics of gramicidin K's: a family of naturally occurring acylated gramicidins.

The gramicidin K family is a set of naturally occurring acylated linear peptides in which a fatty acid is esterified to the ethanolamine hydroxyl of either gramicidin A or C, and possibly also to gramicidin B (Koeppe, R. E., II, Paczkowski, J. A., & Whaley, W. L. (1985) Biochemistry 24, 2822-2826). These acylated gramicidins form membrane-spanning channels in planar lipid bilayers and therefore constitute a model system with which to study the structural and functional consequences of acylation on membrane proteins. This paper serves to characterize further the channels formed by acylated gramicidins A and C and to demonstrate that these channels are structurally equivalent to the channels formed by the standard gramicidins. We also present additional evidence for the ester linkage in the natural acylated gramicidins A and C and identify the fatty acyl chains.

Devil's-claw (Proboscidea louisianica), essential oil and its components : Potential allelochemical agents on cotton and wheat.

The potential allelopathic activity of devil's-claw [Proboscidea louisianica (Mill.) Thellung] essential oil and a few of the compounds it contains on the elongation of cotton (Gossypium hirsutum L.) and wheat (Triticum aestivum L.) radicles was studied using a Petri dish bioassay. Essential oil was collected by steam distillation using an all-glass-Teflon assembly. Ether extracts of the steam distillates from fresh devil's-claw were inhibitory to cotton and wheat radicle elongation. The following six components of devil's-claw essential oil identified by CGC-MS-DS were inhibitory to cotton and/or wheat at a concentration of 1 mM: vanillin, piperitenone, δ-cadinene,p-cymen-9-ol, α-bisabolol, and phenethyl alcohol.

Allelochemicals in soil from no-tillage versus conventional-tillage wheat (Triticum aestivum) fields.

Putative allelochemicals found in the soil of no-tillage and conventional-tillage wheat plots near Stillwater, Oklahoma, were obtained by a mild alkaline aqueous extraction procedure, bioassayed to determine their biological activity, purified, and analyzed with a capillary gas chromatography-mass spectrometry-data analysis system. The most significant inhibition was found in bioassays of extracts from soil collected immediately after harvest in June, July, and August. No-tillage soils produced significant inhibition during the rest of the year also. Mass spectrometry showed fatty acids as the most abundant compounds. However, when bioassayed authentic samples of the five free fatty acids showed no significant biological activity toward wheat.

Effects of feeding cooked ground beef on plasma lipid and apolipoprotein concentrations in male turkeys.

Two experiments with male turkeys were designed to study the effects of eating cooked ground beef on plasma lipid and lipoprotein levels. In both experiments, cooked ground beef from forage-finished cattle (F-Bf) and grain-finished cattle (G-Bf) were added at an average of 28.1 and 34.5 g of beef per 100 g of ration in order to provide 40% of the protein requirement. The experimental diets formulated to be isocaloric and isonitrogenous were: 1) basal diet (negative control) in which soybean meal and corn oil served as protein and fat sources, respectively; 2) basal plus crystalline cholesterol (positive control) incorporated at 1 and 2% of the diet in trials 1 and 2, respectively; 3) basal plus F-Bf; 4) basal plus G-Bf. The polyunsaturated to saturated fat ratio averaged 3.45 for diets 1 and 2 and 0.17 for diets 3 and 4, respectively. At 16 weeks, consumption of diets 3 and 4 elevated (P less than 0.05) plasma triglyceride levels and phospholipid levels (trial 1). In trial 2, only diet 4 elevated (P less than 0.05) plasma phospholipid levels. In both trials, the beef diets did not significantly elevate plasma cholesterol and high density lipoprotein (HDL) cholesterol levels above the basal diet. However, the major apoprotein in the HDL fraction, apolipoprotein A-I (apoA-I), was increased (P less than 0.05) in the plasma of male turkeys fed the G-Bf diet in both trials and F-Bf diet in trial 1. Plasma apolipoprotein B (apoB), primarily found in low density lipoproteins (LDL), was increased (P less than 0.05) in one of the two trials by the inclusion of beef in the diet. There were no significant differences in plasma cholesterol, HDL-cholesterol, apoA-I and apoB levels between the types of beef (F-Bf vs. G-Bf).

High production of caffeine and related enzyme activities in callus cultures of Coffea arabica L.

Callus tissue culture of Coffea arabica L. cv Hybrido de Timor prepared from apical portions of orthotropic branches produced 49 to 92 times as much caffeine per unit weight of tissue as did the original explant. Cell-free extracts made from 42 to 54-day-old callus cultures in which active biosynthesis was occurring exhibited N-methyl-N (9)-nucleoside hydrolase and N-methyltransferase enzyme activities. Similar cell-free extracts exhibited selective biodegradative activity in forming urea from xanthine. Biosynthetic substrate specificities are similar to those of the enzyme obtained from green coffee fruit and tea leaves, suggesting that callus cultures of C. arabica form caffeine in the same way as the coffee fruit and tea leaves.

Caffeine hazards and their prevention in germinating seeds of coffee (Coffea arabica L.).

The inhibition of growth of seedlings of coffee (Coffea arabica L.) exposed to 10 m M caffeine was found to occur in the rootlet: mitosis and cell plate formation were also inhibited. Since concentrations of endogenous caffeine in the imbibed seed are 40-60 mM, 4-6 times as high as in the seedlings, we conclude that coffee embryos have specific means of avoiding caffeine autotoxicity. Observations indicate that cell divisions in root tips start only after the latter are pushed away from the caffeine-rich endosperm by elongation of the hypocotyl and maintained through cell elongation. Caffeine is introduced into the embryonic cotyledons mostly after cell division is completed there. Thus, coffee seedlings may avoid autotoxic effects of endogenous caffeine by separation between sites where mitosis is occurring and those where caffeine is stored. This is achieved in root tips by separation is space but in the cotyledons by separation in time. Caffeine is liberated from the tree litter in coffee plantations and eventually will produce autotoxic effects, resulting in some degeneration.

Seeds as allelopathic agents.

Inhibitors of germination or of growth, highly diversified chemicals are commonly found in higher plants. They occur in vegetative organs as well as in seeds or other dispersal units. Nonprotein amino acids, when present, are mainly found in seeds where they can occur in extremely high concentrations. Density of seeds, rate of emanation of inhibitors, their amount and effectiveness, all determine allelopathic potential of seeds. To induce allelopathy, rate of emanation of inhibitors must be fast and of sufficient duration. Our observations in coffee seedsCoffea arabica L. indicate that rate of emanation of the inhibitor caffeine is highly enhanced during senescence of seeds, suggesting that when allelopathic potential of seeds is evaluated the presence of both young and old seeds should be considered. In many plants seeds are liberated close to the parent plant, the zone where seed-induced allelopathy may occur. Large numbers of seeds are usually produced in order to ensure establishment; greater number and mass of seeds may also increase allelopathic inhibition of competing vegetation.

Highly potent germination inhibitors in aqueous eluate of fruits of Bishop's weed (Ammi majus L.) and avoidance of autoinhibition.

The aqueous eluate from fruits ofAmmi majus (Bishop's weed, Umbelliferae) remarkably inhibited germination of adjacent seeds ofAnastatica hierochuntica, lettuce, or tomato but had no effect on intact fruits ofAmmi. Similar inhibition was found in dark or in light, except that seeds ofA. hierochuntica were significantly more inhibited in the dark than in the light. Xanthotoxin was isolated, identified, and found to account for about a sixth of the inhibitory activity of the eluate. After fruits ofAmmi were submerged in a large volume of water for 4 days, the fruits still exuded enough inhibitors to prevent germination ofA. hierochuntica, lettuce, or tomato. Data support also the proposal that the phytotoxins are compartmentalized between the inner and the outer fruit envelopes. The inner layer excludes inhibitors from the embryo and autotoxicity is thus avoided, whereas the outer one ensures a gradual liberation of the phytotoxic compounds. This, as well as the high reactivity of the eluate, the high densities ofAmmi fruits in nature, and their relatively limited annual germination, suggest chemical inhibition of neighboring plant species other thanAmmi. Hence, in addition to their chemical protection against predators of either lower or higher organisms, furanocoumarins in fruits ofAmmi majus may contribute to its success as a weed.

Sterols of Delphinium ajacis; production and metabolic relationships in whole plants and callus tissue.

Sterols from whole nonsterile Delphinium ajacis plants and from sterile tissue cultures (callus) were identified and determined quantitatively. The major sterols in the whole plant tissues were sitosterol, campesterol and stigmasterol, whereas those in the callus tissue were stigmastanol, 24-ethylidenelophenol and Delta (7)-stigmastanol. Of the 21 compounds identified in callus tissue, 5 were not present in the whole plant, most notably Delta (7)-stigmastanol. For both sources of tissue, the sterol predominating in one was a minor component in the other (whole plant/tissue cultures: sitosterol 57%/5%; stigmastanol 2%/35%). On a tissue dry-weight basis, the amount of sterols isolated from callus tissue culture was ten to twenty times that obtained from the whole plant. Qualitatively the sterols from both sources fit into a metabolic scheme which proceeds from cycloartenol through 4,4-dimethylsterols and 4-methylsterols to sterols. A proposed metabolic pathway shows the differences in accumulation of sterols in the two types of tissue. The increase in sterol production in cultured cells, especially when favored by growth conditions, has promise for industrial application and in organic synthesis.