Bioadhesive delivery of metformin using prosopis gum with antidiabetic potential. (1/21)

The antidiabetic properties of prosopis gum alone and as a bioadhesive base for the delivery of metformin are presented. The bioadhesive value of the gum was commensurate with those of Carbopol 974-P and sodium carboxymethyl cellulose (NaCMC). The release of the drug was higher from prosopis gum based bioadhesive formulations than from NaCMC and Carbopol 974-P products. This was shown by the shorter time required to reach t(50) (the time required for 50% of the drug to be released) or t(20) (time required for 20% of the drug to be released) for the release of metformin. The gum showed moderate antidiabetic properties when used alone. In combination with metformin in a bioadhesive form, the glucose lowering effect was found to be synergistic. The areas under the plasma drug concentration vs. time curves (AUCs) for the bioadhesive combinations were similar to those of the drugs alone in an aqueous system. This shows that the gum did not interfere with absorption of the incorporated drug. However, the areas under the effect vs. time curves (AUECs) were much higher when combined in a bioadhesive form than with the drug alone. The AUCs obtained with NaCMC based bioadhesive formulations were relatively smaller than those of metformin in an aqueous system and the combinations of metformin and prosopis gum.  (+info)

Growth and architecture of small honey mesquites under jackrabbit browsing: overcoming the disadvantage of being eaten. (2/21)

Browsing is an important mortality factor in seedlings and small plants. However, the induced changes in the architecture of plant survivors may influence subsequent browsing, opening the possibility of compensating for the damage done. How jackrabbit (Lepus californicus) browsing affects the growth and architecture of small individuals of honey mesquite, Prosopis glandulosa var. torreyana, a tree/shrub that produces spines at every node, was explored. Naturally established mesquites of unknown age were selected in one site, and 2-year-old mesquites were transplanted in another site. In both cases, half of them were exposed to jackrabbits and the other half were excluded as controls. After 4 years, shoot production (height, length and number of derived shoots) and plant growth (height and cover) increased 1.4-2.5-fold in naturally established controls relative to exposed plants, depending on the measured variable. In the transplant experiment, the increases were 2.8-7.1-fold in controls relative to exposed plants 2 years after initiation of the experiment. The net loss of biomass in treatment vs. control plants in these experiments suggests a negative response to browsing which has been defined as under-compensation. Alternative architectures in honey mesquites were evident at the end of the exclusion experiments: controls had long branches and an extended crown cover, while exposed plants had short branches and a compact crown cover. Results indicated that mesquites were able to grow under browser pressure by packing many stems in a compact matrix armed with spines and producing one or more shoots tall and wide enough to escape from jackrabbits.  (+info)

Influence of leaf-to-air vapour pressure deficit (VPD) on the biochemistry and physiology of photosynthesis in Prosopis juliflora. (3/21)

The effect of leaf-to-air vapour pressure deficit (VPD) was studied in well-watered, potted, 1-2-year-old plants of the leguminous tree P. juliflora grown outside in northern India. The long-term responses to VPD were analysed from diurnal and seasonal variations in gas exchange parameters measured in two cohorts of leaves produced in February and July, respectively. In general, inhibitory effects of high VPD were visible only when the VPD level exceeded a threshold of >3 kPa. There was a substantial decline in net photosynthesis rate and stomatal conductance at high VPD >4 kPa and transpiration showed a decrease in steady-state rate or feedforward response to VPD. The feedforward responses were visible in all seasons, although the plants were exposed to a wide range of VPD during the year and leaf relative water content was constant. The maximum quantum efficiency of PSII measured predawn was constant (around 0.8) in all seasons except summer. Short-term experiments showed that, although gas exchange was severely affected by high VPD in the leaves of both cohorts, the plant maintained a constant, water use efficiency in different seasons. High VPD also caused reductions in Rubisco activity, affecting carboxylation efficiency, and reductions in sucrose and starch content due to a decrease in the activity of sucrose-phosphate synthase. However, the relative quantum yield of PSII and electron transport rates measured at 1500 micromol m(-2) s(-1) were unaffected by increasing VPD, indicating the presence of a large alternative sink possibly, photorespiration. The overall results showed that P. juliflora can withstand high VPD by reducing metabolic activity and by effective adjustments in the partitioning of electron flow between assimilation and non-assimilation processes, which, in turn, imposed a strong limitation on the potential carbon gain.  (+info)

Osmotic and specific ion effects on the germination of Prosopis strombulifera. (4/21)

BACKGROUND AND AIMS: Salinity can affect germination of seeds either by creating osmotic potentials that prevent water uptake or by toxic effects of specific ions. Most studies have only used monosaline solutions, although these limit the extent to which one can interpret the results or relate them to field conditions. The aim of this work was to evaluate the germination of Prosopis strombulifera seeds under increasing salinity by using the most abundant salts in central Argentina in monosaline or bisaline iso-osmotic solutions, or in solutions of mannitol and polyethylene glycol. METHODS: Seeds were allowed to germinate under controlled conditions in a germination chamber at 30 +/- 1 degrees C and at 80 % r.h. Salinizing agents were KCl, NaCl, Na(2)SO(4), K(2)SO(4), NaCl + Na(2)SO(4) and KCl + K(2)SO(4) and osmotic agents were polyethylene glycol 6000 and mannitol. Treatments for all osmotica consisted of 0.0, -0.4, -0.8, -1.2, -1.5, -1.9 and -2.2 MPa solutions. KEY RESULTS: The percentage of germination decreased as salinity increased. SO(4)(2-) in monosaline solutions, with osmotic potentials -1.2 MPa and lower, was more inhibitory than Cl(-) at iso-osmotic concentrations. This SO(4)(2-) toxicity was alleviated in salt mixtures and was more noticeable in higher concentrations. K(+) was more inhibitory than Na(+) independently of the accompanying anion. CONCLUSIONS: Different responses to different compositions of iso-osmotic salt solutions and to both osmotic agents indicate specific ionic effects. This study demonstrates that the germination of P. strombulifera is strongly influenced by the nature of the ions in the salt solutions and their interactions. Comparative studies of Cl(-) and SO(4)(2-) effects and the interaction between SO(4)(2-) and Cl(-) in salt mixtures indicate that extrapolation of results obtained with monosaline solutions in the laboratory to field conditions can be speculative.  (+info)

Neurohistologic and ultrastructural lesions in cattle experimentally intoxicated with the plant Prosopis juliflora. (5/21)

Intoxication by pods of Prosopis juliflora (mesquite beans) causes an impairment of cranial nerve function in cattle and goats. In goats, vacuolation of neurons in the trigeminal motor nuclei has been reported. To study the lesions in cattle caused by consumption of P. juliflora pods and dry ground pods, eight 6- to 12-month-old male cattle were divided into 4 groups: group 1 was fed a ration containing 50% of pods; groups 2 and 3 received a ration containing 50 and 75% of dry ground pods, respectively; group 4 was the control. After 200 days, all cattle were killed and sampled for histologic evaluation. Samples of the trigeminal motor nucleus were examined by electron microscopy. All cattle from groups 1, 2, and 3 showed clinical signs resulting from impaired function of cranial nerves V, IX, X, and XII, starting 45-75 days after consumption of the plant. The main histologic lesions were vacuolation and loss of neurons in trigeminal motor nuclei and other motor cranial nerve nuclei with Wallerian-like degeneration in the cranial nerves. Mild denervation atrophy was observed in the masseter and other masticatory muscles. On electron microscopy, neurons of the trigeminal nuclei had markedly swollen mitochondria, with the mitochondrial cristae displaced peripherally, disoriented and disintegrating. Intoxication by P. juliflora seems to have a novel pathogenesis, characterized by a selective, primary, chronic, and progressive injury to mitochondria of neurons of the trigeminal and other cranial nerve nuclei. Cranial nerve degeneration and denervation atrophy of the muscles occurs as a consequence of the neuronal lesion.  (+info)

Application of the aza-Achmatowicz oxidative rearrangement for the stereoselective synthesis of the Cassia and Prosopis alkaloid family. (6/21)

cis-2-Methyl-6-substituted piperidin-3-ol alkaloids of the Cassia and Prosopis species are readily prepared by a combination of an aza-Achmatowicz oxidative rearrangement and dihydropyridone reduction followed by a stereoselective allylsilane addition to a N-sulfonyliminium ion. The stereochemical outcome of the reduction reaction can be attributed to steric hindrance between the pseudoaxially oriented 2,6-substituents and the equatorially approaching hydride reagent which explains the exclusive formation of the cis-alcohol by axial approach of the hydride. The unsaturation present in the (E)-methyl-pent-3-enoate side chain was removed by catalytic reduction, and the remaining ester group was converted to the corresponding Weinreb's amide. This key intermediate was utilized for the synthesis of azimic acid, deoxocassine, cassine, and spicigerine. The facile preparation of (S)-N-tosylamidofuran 16 and its conversion to the chiral Achmatowicz oxidation product 18 provide a formal chiral synthesis of these alkaloids.  (+info)

Immunoglobulin E (IgE)-mediated cross-reactivity between mesquite pollen proteins and lima bean, an edible legume. (7/21)

Immunoglobulin E (IgE)-mediated food allergy often develops as a consequence of allergic sensitization to pollen proteins. Mesquite (Prosopis juliflora) tree pollen is reported to be cross-reactive with other pollen species, but little has been reported on its cross-reactivity with plant-derived foods belonging to the same/different families. The present study investigates the in vitro cross-reactivity of mesquite pollen and lima bean (Phaseolus lunatus), an edible seed belonging to the Leguminosae family. Of 110 patients (asthma, rhinitis or both) tested intradermally, 20 showed marked positive reactions with Prosopis pollen extract. Of these, 12 patients showed elevated specific IgE to Prosopis pollen extract alone and four to both Phaseolus and pollen extract. In vitro cross-reactivity was investigated using inhibition assays [enzyme-linked immunosorbent assay (ELISA) inhibition, immunoblot inhibition], histamine release and lymphoproliferation. P. lunatus extract could inhibit IgE binding to P. juliflora in a dose-dependent manner, requiring 400 ng of protein for 50% inhibition in ELISA assay. Immunoblot and immunoblot inhibition demonstrated the presence of 20, 26, 35, 66 and 72 kDa as shared IgE binding components between the two extracts. Histamine release, peripheral blood mononuclear cells proliferation and interleukin (IL)-4 levels also suggested allergenic cross-reactivity. In conclusion, there is humoral and cellular cross-reactivity between Prosopis pollen and Phaseolus seed allergens.  (+info)

Indolizidine, antiinfective and antiparasitic compounds from Prosopis glandulosa var. glandulosa. (8/21)