ofLeucaena Leucocephala Research Articles

Leucaena leucocephala fruit aqueous extract stimulates adipogenesis, lipolysis, and glucose uptake in primary rat adipocytes.

Leucaena leucocephala had been traditionally used to treat diabetes. The present study was designed to evaluate in vitro “insulin-like” activities of Leucaena leucocephala (Lam.) deWit. aqueous fruit extract on lipid and glucose metabolisms. The ability of the extract to stimulate adipogenesis, inhibit lipolysis, and activate radio-labeled glucose uptake was assessed using primary rat adipocytes. Quantitative Real-Time RT-PCR was performed to investigate effects of the extract on expression levels of genes (protein kinases B, AKT; glucose transporter 4, GLUT4; hormone sensitive lipase, HSL; phosphatidylinositol-3-kinases, PI3KA; sterol regulatory element binding factor 1, Srebp1) involved in insulin-induced signaling pathways. L. leucocephala aqueous fruit extract stimulated moderate adipogenesis and glucose uptake into adipocytes when compared to insulin. Generally, the extract exerted a considerable level of lipolytic effect at lower concentration but decreased gradually at higher concentration. The findings concurred with RT-PCR analysis. The expressions of GLUT4 and HSL genes were upregulated by twofold and onefold, respectively, whereas AKT, PI3KA, and Srebp1 genes were downregulated. The L. leucocephala aqueous fruit extract may be potentially used as an adjuvant in the treatment of Type 2 diabetes mellitus and weight management due to its enhanced glucose uptake and balanced adipogenesis and lipolysis properties.

Determination of Mimosine and 2,3-Dihydroxypyridine in <i>Leucaena leucocephala</i> by Reversed Phase High-Performance Liquid Chromatography

A reversed high performance liquid chromatography method was developed for the quantitative determination of mimosine and 2,3-DHP in leaves ofLeucaena Leucocephala. Mimosine and 2,3DHP were extracted using 0.1N HCl.The chromatograph conditions were investigated and optimized. The optimal HPLC conditions as follows: Agilent HC-C18 column （4.6×150mm,5μm） was used at 30°C. The method used a variable wavelength UV detector at 280nm, the mobile phase consisted of 0.2 % (w/v) orthophosphoric acid and methanol, the gradient elution was adopted. The injection volume was 10μL. The linearity is favorable in the range of 1.0 to 50μg mL-1with a correlation coefficient of 0.99998 for mimosine and 0.99902 for 2,3DHP. Under the optimal conditions, the method limit of detection (LOD) of mimosine and 2,3DHP were 0.40mg/kg and 0.55mg/kg respectively. The recovery of mimosine was 87.00-94.70% with the RSD (n=5) of 2.75-3.81% in the spiked levels 0,1, 5, 20mg/g. At the same time, the recovery of 2,3DHP was 88-95.4% with the RSD (n=5) of 2.24-4.90%. The method was found to be simple, sensitive, fast and accurate, and has been applied successfully for the quantitative detection of mimosine and 2,3-DHP in leaves ofLeucaena Leucocephala, plasma and excretion of ruminant.

Systematic position ofPyloetis mimosae(Stainton) (Lepidoptera: Tineidae), with redescriptions of the adults and immature stages

AbstractMorphological characters of adults and immature stages ofPyloetis mimosae(Stainton 1859) are redescribed mainly on the basis of material collected from seed pods ofLeucaena leucocephala(Lem.) in the Ryukyus, Japan. Although the systematic position of this species in the family Tineidae has been problematic, we conclude that it should be placed in the subfamily Erechthiinae based on morphological characters.Pyloetis mimosaeis newly recorded from Japan.

Bioactivity studies on the alkaloid extracts from seeds ofLeucaena leucocephala

The chloroform soluble (CS) and ethyl acetate (ES) soluble alkaloidal extracts from the seeds of Leucaena leucocephala Lam. (de Witt) were tested for their analgesic, anthelminthic, mutagenic, antimutagenic and pharmacological activities. The CS alkaloidal extract is analgesic at a dose of 5 mg/20 g mouse as it showed a comparable result to mefenamic acid using the acetic acid-induced writhing method. An in vitro test for anthelminthic activity using Ascaris suum showed that the CS alkaloidal extract gave a comparable result to mebendazole (Antiox) at a concentration of 5 mg/mL. Results of the micronucleus test, an in vivo method, showed that both the CS and ES alkaloidal extracts were not mutagenic but instead exhibited antimutagenic activities at 0.5 mg/20 g mouse. The CS- and ES-soluble alkaloidal extracts reduced the number of micronucleated polychromatic erythrocytes induced by tetracycline, a known mutagen, by 67.0% and 71.2%, respectively. Preliminary pharmacological screening showed that both extracts caused a relative depression in the central nervous system as evidenced by a decrease in respiratory rate and depth and a decrease in motor activity. © 1997 John Wiley & Sons, Ltd.

Genetic estimates of dispersal ability in the leucaena psyllid predatorCurinus coeruleus(Coleoptera: Coccinellidae): implications for biological control

AbstractThe leucaena psyllid,Heteropsylla cubanaCrawford, can devastate plantings ofLeucaena leucocephala(Leguminosae), an economically important tree species in the Pacific Islands, Southeast Asia, Australia, India, Africa, and elsewhere. The predatory beetle,Curinus coeruleusMulsant (Coleoptera: Coccinellidae), has been introduced into many of these areas from Hawaii for biological control of the psyllid. In this study, collections ofC. coeruleuswere made from 11 populations on four islands in the Hawaiian archipelago to determine population structure and estimate levels of gene flow. Over all populations, a measure of population subdivision, θ was 0.095, and the estimate ofNem, the average migration rate, was 2.4. θ values for the individual islands were 0.02, 0.12, 0.24 and 0.05 for Kauai, Hawaii, Maui, and Oahu, respectively. Estimated levels of gene flow between populations were not correlated with geographic distance, therefore isolation by distance does not appear to be an important process structuringC. coeruleuspopulations. Gene flow estimates can be used to characterize dispersal capabilities in insects or other organisms released for biological control. In this case, the inferior dispersal ability ofC. coeruleuslikely limits its rapid widespread establishment during release programmes.

Effect of intercropping maize and closely spacedLeucaena hedgerows on soil conservation and maize yield on a steep slope at Ntcheu, Malawi

A six-year soil conservation trial was conducted on a steep slope, 44%, with a subhumid climate, based on very closely spaced (90 cm) hedgerows, using three intraspecific hybrids ofLeucaena leucocephala. Soil loss averaged 2.0 t/ha per year on theLeucaena plots compared with an initial 80 t/ha per year on the unprotected control plot, falling to 27 t/ha per year after the top soil had been eroded. After 6 years, micro terraces of 35 cm high and 81 cm wide had developed on the intercropped plots, with substantially improved soil properties. Maize yield (unfertilized) were maintained at 1.5–2.0 t/ha on the protected plots, compared with a progressive fall from 0.8 to 0.5 t/ha on the sole maize control.

Efficacy of root litter as a biofertiliser

The efficacy ofLeucaena leucocephala root litter as a natural biological fertiliser was assessed usingZea mays as a test plant. Up to 8% of the fine roots of the plants constituted root litter. This fine root litter was better than that ofTrigonella foenum-graecum at increasing the growth and productivity ofZea mays. The root litter increased the growth of maize shoots more than the growth of roots. This appears to be a general phenomenon when plant nutrients are insufficient, as in the present study.

Charcoal and fuel value of agroforestry tree crops

Charcoal was produced from short rotation tropical species ofLeucaena leucocephala andTectona grandis. The combustion-related properties, moisture content, specific gravity and percentage element composition of carbon, hydrogen, oxygen, nitrogen, sulphur and ash in wood and charcoal from the two species were determined. The gross heat of combustion of wood and charcoal was also determined. There were significant differences in the moisture content, specific gravity and percentage element composition between wood and charcoal from the two species. The carbon and ash content of charcoal were higher than those of wood. The average heat of combustion of charcoal 25.25 MJKg−1 was higher than that of wood 13.75 MJKg−1.

Crop-tree interactions in alley cropping systems on alluvial soils of the Upper Amazon Basin

A crop/hedgerow interface design was used to test three leguminous species,Inga edulis, Leucaena leucocephala andErythrina sp., for their potential use for alley cropping on alluvial soils in the upper Amazon Basin. Prunings were applied as mulch at three rates 0, 3.3 and 6.7 Mg dry matter/ha/crop. Competition, crop yields, nutrient budgets, and weed control were monitored for three consecutive crops of upland rice. Crop yield reductions were evident up to 1.5 m from each of the hedgerow species, but were more pronounced withLeucaena hedgerows. Additional mulch was able to compensate for these reduced yields close to the hedges inLeucaena leucocephala andErythrina but not inInga edulis systems. In general rice yields were higher withLeucaena leucocephala andErythrina mulch as compared toInga mulch, perhaps because of higher levels of available N provided by the rapidly decomposing leaves ofLeucaena leucocephala andErythrina sp. as compared toInga. Weed control was greater, however, with the slowly decomposingInga mulch. For all three hedgerow/crop systems there was a net export of P from the system which was exhibited by declining soil P levels and decreasing crop yields.

Intake and digestion in swamp buffaloes and cattle. 1. The digestion of rice straw (Oryza sativa)

SUMMARYFour swamp buffaloes (Bubalus bubalis) and four crossbredBos indicusxB. tauruscattle, fistulated at the rumen and abomasum or duodenum, were offered rice straw with mineral supplements in two experiments. In Expt 1, the straw was supplemented with 5% of leaf ofLeucaena leucocephala, and in Expt 2 with either urea or urea with sunflower meal and rice grain. Intake of supplements of urea or urea/sunflower/rice respectively was 935 and 681 g/kg offered in buffaloes and 566 and 789 in cattle.Buffaloes ruminated longer than cattle (Expt 1, 635v. 452 min/day; Expt 2, 626v. 466 min/day,P< 0·01). In Expt 1, voluntary intake and frequency of ‘A’ sequence forestomach contractions of both species was not affected by species, but buffaloes had a greater (P< 0·05) contraction force in the rumen and omasum, lower rate of ‘B’ sequence rumen contractions, and faster (P< 0·001) rate of gastrointestinal passage than cattle. In Expt 2, voluntary intake of both species was similar, and addition of concentrates did not affect voluntary roughage consumption, norin siturate of digestion of rice straw. Rate and predicted extent of digestion of dietary materials did not differ between species in Expt 1, despite lower concentrations of ammonia in rumen fluid in cattle than buffaloes; however in Expt 2, the rate of digestion of rice straw was higher (p< 0·05) and predicted extent of digestion was 14–20% (P< 0·05) lower in buffaloes. Digestibility of cell wall constituents was lower (P< 0·05) in buffaloes than in cattle in both experiments, but in Expt 2, provision of concentrates reduced (P< 0·01) the proportion of digestible cell wall constituents digested in the forestomach of buffaloes, but not of cattle.

Interactive metabolic regulations during biomethanation ofLeucaena leucocephala

Biomethanation of leaves of the legumeL. leucocephala operated in batch reactors at different input volatile solids (12–18 g/L) proceeded in distinct metabolic phases. An initial cellulolytic phase of 4 d was followed by an early and active methanogenic phases (5–21 d) and a terminal phase of low-rate methanogenesis. Hydrolysis of cellulose was concentration-dependent and resulted in increased volatile acid levels. The trend of changes showed some variations at different input volatile solids. The changes in the levels of volatile acids followed an oscillatory pattern. The controlled rate of cellulose hydrolysis, levels of volatile acids, and steady-state levels of soluble carbohydrates and reducing sugars observed during active methanogenesis are indicative of interactive metabolic regulations.

Response ofLeucaena leucocephala to vesicular-arbuscular mycorrhizal colonization and rock phosphate fertilization in an Oxisol

Response ofLeucaena leucocephala (Lam) de Wit to rock phosphate application and inoculation with the vesicular-arbuscular mycorrhizal (VAM) fungusGlomus aggregatum (Schenck and Smith emend Koske) was evaluated in a pot experiment. VAM colonization increased as rock phosphate application increased. Using phosphorus concentration in pinnules as an indicator of VAM activity, significant VAM activity occurred at 25 days after planting at the lower levels of rock phosphate application (0, 0.34 and 0.68 g P kg−1). The time required for significant VAM activity was shortened by 5 days at the higher P levels (1.36, 2.72 and 5.44 g P kg−1). The highest VAM activity was associated with the highest rate of rock phosphate application.

Nodulation and growth ofLeucaena leucocephala (Lam.) de Wit as affected by inoculation and N fertilizer

Leonard jar, pot and field experiments examined the effects of inoculation and the influence of nitrogen fertilizer on nodulation, nitrogen fixation and growth ofLeucaena leucocephala (Lam.) de Wit at IITA, Ibadan, Nigeria. Leucaena responded to both inoculation and/or nitrogen application. Shoot growth and total N and P of inoculated plants were comparable to those of the highest N treatment, and the values were about 55% greater than those of uninoculated ones. Field data indicated that toal N yields of inoculated leucaena were increased by 50% with 40 or 80 kg ha−1 of N fertilizer. However, N fertilizer depressed N fixation by 56% as was expected from nodule mass data. N-fixation was delayed for about 8 weeks in the plots without N. Application of small amounts of N starter (20 ppm) proved to be beneficial to satisfy the plant need during the early stage of leucaena growth. The rhizobial strains IRc 1045 and IRc 1050 were effective, competitive and survived well in the field one year after their establishment.

Response of Leucaena/Rhizobium symbiosis to mineral nutrients in Southwestern Nigeria

Pot and field experiments carried out at the International Institute of Tropical Agriculture (IITA) and at Fashola, Southwestern Nigeria, examined the effect of inoculation and N, P and micronutrients on nodulation and growth ofLeucaena leucocephala (Lam.) de Wit. In pot studies all parameters measured, except the percentage of nitrogen in shoots, were improved by inoculation, nitrogen and phosphorus. Micronutrients increased only nitrogen and allantoin contents. Interactions between inoculation and P, N and micronutrients on nodulation and growth of leucaena were observed. The effect of inoculation and fertilization with phosphorus or micronutrients was further investigated in field experiments. Establishment of uninoculated and unfertilized leucaena was poor at both locations due to low soil fertility and the presence of only a few native leucaena rhizobia. At one site, only inoculated plants were nodulated, while at the other, all plants produced nodules. Shoot dry weight, total nitrogen and phosphorus of inoculated plants were statistically equal to nitrogen-fertilized plants. Uninoculated plants were stunted. Generally, micronutrients did not influence nodulation, total nitrogen or growth of leucaena. They had only a positive effect on nitrogenase activity. Phosphorus increased total nitrogen and phosphorus uptake and plant growth. A 75% increase in shoot dry weight was obtained when 80 kg P ha−1 was applied to inoculated leucaena with Rhizobium strain IRc 1045. Inoculated plants contained more allantoins than uninoculated ones but no significant correlation was found between these compounds and other parameters of N fixation.

Effect of liming and phosphorus application on performance ofLeucaena leucocephala in acid soils

Pot experiments were conducted to assess the lime and phosphorus requirements ofLeucaena leucocephala (LAM.) De Wit grown on three acid soils (Ultisols) from southeastern Nigeria. Liming and phosphorus application significantly enhanced growth ofL. leucocephala. Ammakama soil showed best effect to phosphorus application, while acidity problems were more pronounced on Onne and Isienu soils. High lime rate (2000 ppm) reduced plant growth in Isienu soil probably due to nutrient imbalance. Potassium, manganese and zinc levels in the plants were reduced with increasing lime rates. On Onne and Isienu soils plant tops correlated better with total acidity and extractable Al+3 level than with soil pH-H2O.

Leaf dry matter productivity of three selected perennial leguminous species in humid tropical Ivory Coast

Leaf dry matter productivity has been measured at the end of regrowth cycles of 3 months for stands ofleucaena leucocephala, Gliricidia sepium andFlemingia macrophylla, all three species belonging to the Leguminosae. The effective period of observation was minimally 24 months, or 8 regrowth cycles, after a period of establishment of slightly more than a year. Using systematic trial designs, originally developed by NELDER, yield figures have been acquired for a broad range of plant densities. At a plant density of 10,000 trees per hectare the average yearly leaf DM productivity amounted to 15.4 ton forLeucaena leucocephala, 12.4 ton forFlemingia macrophylla and 10.5 ton forGliricidia sepium. Productivity figures and leaf area indices are compared with those of relevant cropping systems.

Effects of CaSO4 and NaCl on growth and nitrogen fixation ofLeucaena leucocephala

Effects and interactions of varying CaSO4 and NaCl levels on growth and nitrogen fixation ofLeucaena leucocephala K8 were examined. Leucaena was grown in nutrient solution at four levels of CaSO4 (0.5, 1.0, 2.5 and 5.0 mM) and NaCl (1, 25, 50 and 100 mM) in randomized blocks with five replications. While NaCl significantly reduced plant growth, additions of CaSO4 increased plant height, leaf number, and biomass of salt treated plants. For the nonsaline treatments, high CaSO4 levels slightly depressed growth, which contradicts suggestions that Leucaena has a high calcium requirement. A significant calcium/sodium interaction was not seen for nodule number or weight. Nodule number was significantly depressed by 100 mM NaCl and nodule weight of the salt stressed plants significantly increased as CaSO4 concentration increased from 0.5 to 2.5 mM. Effects of NaCl and CaSO4 on nitrogen content of plant parts were inconclusive. The promotion of Leucaena salinity tolerance by addition of CaSO4 may be attributed to the effect of calcium in maintaing the selective permeability of membranes.

Effect of CaSO4 and NaCl on mineral content ofLeucaena leucocephala

The effects of varying CaSO4 and NaCl levels on the nutrient content ofLeucaena leucocephala were established by examining the concentrations of Na, Ca, Cl, K and Mg in leucaena roots, stems and leaves. Leucaena was grown in nutrient solution at four levels of CaSO4 (0.5, 1.0, 2.5 and 5.0 mM) and NaCl (1, 25, 50 and 100 mM), in randomized blocks with five replications. Leucaena excluded sodium from stems and leaves when NaCl concentration was 50 mM or less. Sodium uptake decreased as CaSO4 concentration increased. Calcium uptake was affected by NaCl concentration when substrate CaSO4 concentration was 0.5 mM. At this level, 100 mM NaCl caused a marked decrease in leaf calcium and a marked increase in leaf Cl. In all other treatments, Cl uptake was not affected by CaSO4 concentration. Potassium uptake was strongly depressed as NaCl concentration increased at low Ca concentration, but this effect was offset at high Ca. Magnesium uptake decreased as CaSO4 levels increased.

The performance of the leaf mulches ofLeucaena leucocephala, Flemingia macrophylla andGliricidia sepium in weed control

The performance of the leaf mulches ofLeucaena leucocephala, Gliricidia sepium andFlemingia macrophylla in weed control has been tested in two trials. The length of the period during which a mulch layer yields significantly less weedbiomass compared to the control plots is called the ‘effective life-span’ of the mulch.

The effects of pH and calcium on the growth ofLeucaena leucocephala in an oxisol and ultisol soil

Leucaena was grown for eleven weeks in a pH and calcium amended oxisol and ultisol to determine whether poor growth in acid soils is related to calcium deficiency or low pH induced effects, such as aluminium toxicity. Soil pH was ameliorated by the addition of either CaCO3, or SrCO3, while CaCO3 or Ca(NO3)2 were used to modify calcium supply. In both soils, CaCO3, and SrCO3 application resulted in an increase in pH and a reduction in exchangeable aluminium although the response of leucaena to the applied amendment varied between the two soils. In the oxisol there was little effect of increased pH on growth, but a marked response to Ca application. In the ultisol, growth was improved by increasing pH but there was no response to increased calcium. The effects of liming on these soils are discussed in relation to alternative strategies available for utilising leucaena and other tree legumes.