Efficacy Of Aqueous Leaf Extracts Research Articles

The efficacy of aqueous leaf extracts of Hyptis suaveolens (L.) Poit and Ocimum basilicum (L.) in the control of Meloidogyne spp infecting Onion, Allium cepa (L.)

The efficacy of aqueous leaf extracts of Hyptis suaveolens and Ocimum basilicum in the control of Meloidogyne spp infecting Allium cepa L (Onion) was investigated using sterile soil that was filled into polythene planting bags. Two varieties of onion (Safari and Belami) and three concentrations (60 mg/ml, 45 mg/ml and 30 mg/ml) each of H. suaveolens and O. basilicum leaf extracts were used. Furadan at 7.7 mg/ml was used as a positive control and the negative control was untreated. Each treatment was replicated three times in a completely randomized design (CRD). Onion raised in steam-sterilized soil were infected with 2000 juveniles of root-knot nematodes four weeks after planting. Two weeks thereafter, the different concentrations of the leaf extracts of the test plants and furadan were applied. The plants were then monitored for growth and yield parameters at harvest. Phytochemical analysis of the aqueous leaves extracts of the two plants were carried out. The result showed that growth and yield data of infected but treated onions were higher than their infected but untreated counterparts. Onions treated with O. basilicum at 60 mg/ml had the highest performance: plant height (39.90 cm), dry bulb weight (16.70 g) among others followed by those treated with H. suaveolens at 60 mg/ml, plant height (36.30 cm), dry bulb weight (13.20 g) then furadan, plant height (36.17 cm), dry bulb weight (14.93 g) while the untreated onions had the least growth and yield data, plant height (24.40 cm), dry bulb weight (8.40 g). Statistical analysis revealed that the various treatments significantly increased plant height, collar girth and leave number (p< 0.05) as compared to the untreated control. Variety Safari generally performed better than variety Belami. Statistical analysis also showed significant difference (p< 0.05) for all parameters. Phytochemical analysis showed presence of some bioactive compounds such as saponins, alkaloid, tannins among others. The study revealed nematicidal efficacy of the aqueous leaves extracts of the test plants, therefore, they can be viable alternatives to synthetic nematicides in nematode management.

Insecticidal Activities of the Leaf Extract of the Invasive Alien Plant, Chromolaena odorata (L.) (Asteraceae) Against Macrotermes species (Termites)

Several studies have demonstrated the biological efficacy of leaf, stem and root powders or extracts of Chromolaena odorata (L.) King and Robinson against insect pests but those that are focused on the biological efficacy of aqueous leaf extracts against Macrotermes species are scanty. Current management of termites with synthetic insecticides is being discouraged due to human and environmental hazards. Therefore, the insecticidal effectiveness of aqueous leaf extract C. odorata against Macrotermes species was investigated. Five concentrations (0, 2.5, 5.0, 7.5 and 10.0% (w/v)) of the aqueous extract of C. odorata plant were evaluated for repellency and toxicity on the worker caste of Macrotermes species following standard procedures. The filter paper impregnation technique was used for the bioassay. Percentage repellency was monitored for 30 minutes and mortality recorded at 12, 24 and 36 hours post exposure. The leaf extract of C. odorata significantly repelled 95% of Macrotermes species at the highest concentration of 10% (w/v) after 30 minutes post treatment exposure. Mortality of Macrotermes species was independent of treatment concentration, but dependent on duration of exposure. All treatment concentrations of aqueous leaf extract of C. odorata caused significant mortality against Macrotermes species ranging between 94% and 98% compared to the control; indicating very great potential for adoption and use in the management of Macrotermes species.

English

Diabetes mellitus is a complex metabolic disorder characterised by impaired glucose tolerance and hyperglycemia, which is caused by either lack of or resistance to insulin in tissues; this disease causes significant morbidity and mortality largely due to its end–organ complications. Traditional treatment of diabetes mellitus has involved the use of several plant extracts; in this study the efficacy of aqueous leaf extract of Vernonia amygdalina (VA) was sought as a treatment module for alloxan induced diabetic rats. The aqueous leaf extract of VA was administered in three (3) different doses (40, 80 and 120 mg/kg) to non-diabetic and alloxan-induced diabetic rats. The body weights of the experimental animals were taken along with blood samples collection at baseline, on 7th, 14th and 21st days, thereafter the blood glucose and serum lipid levels were determined. The aqueous leaf extract of VA showed statistical significant (p< 0.05) reduction of blood glucose, serum triglyceride and cholesterol, as well as body weight in both non-diabetic and alloxan-induced diabetic rats. This study showed that aqueous leaf extract of VA administered at different doses contains anti-hyperglycemic and lipid lowering activities, with 80 mg/kg body weight dosage appearing to be the minimum effective dose; suggesting that aqueous leaf extract of VA is likely to contain actives that could be important in the control of blood glucose and serum lipid levels in diabetics. Key words: Vernonia amygdalina, diabetes mellitus, blood glucose, anti-hyperglycaemic, anti-hyperlipidemic. &nbsp

Potentials of two bio-pesticides in the control of some field insect pests of bambara groundnut in Ilorin

A field experiment was carried out to determine the predominate order of insects associated with Bambara groundnut and to compare the efficacy of aqueous leaf extracts of Jatropha ( Jatropha curcas ) and lemon grass ( Cymbopogon citratu s), used as bio-pesticides in controlling some field insect pests of Bambara groundnut. The experiment was laid out in a Randomized Complete Block Design (RCBD) using four treatments with four replications. The following parameters were recorded and used to evaluate the efficacy of the treatments; flower population, weight of pods (damaged and undamaged pods), number of pods (damaged and undamaged pods), number of holes on damaged pods and number of insects. The results of the experiment showed that insects of seven distinct Orders- Hymenoptera, Coleoptera, Diptera, Hemiptera, Homoptera, Lepidoptera and Orthoptera attack Bambara groundnut with each affecting the plant at different stages of the plant’s development. The bio-pesticides significantly (P <0.05) reduced the effects of attack by insects when compared to the control. Lemon grass was the most effective of the bio-pesticides evaluated and can be used by resource poor farmers in the management of Bambara groundnut on the field. Keywords: Bambara groundnut, bio-pesticide, Cymbopogon citratus , Jatropha curcas

Efficacy of aqueous leaf extracts of negro coffee (&lt;i&gt;Cassia occidentalis&lt;/i&gt;) and lemon grass (&lt;i&gt;Cymbopogon citratus&lt;/i&gt;) in the management of nematode pests of okra (&lt;i&gt;Abelmoschus esculentus&lt;/i&gt; l. Moench)

A two-year rain-fed field trials to evaluate the efficacy of aqueous leaf extracts of Cassia occidentalis and Cymbopogon citratus at different levels in the management of nematode pests of okra was conducted. The levels of treatments used were 25, 50, 75 and 100 %, where 0% served as control. The experimental design was a randomized complete block design (RCBD). Effects of treatments on growth, yield, soil nematode population, root weight and root gall indices were determined. Phytochemical screening and infra-red spectrum to determine the secondary metabolites in the leaf extracts were also carried out. It was observed that the treated plants especially those that received 50% level and above performed significantly better ( p =0.05) than the control with respect to the measured parameters. The phytochemical result revealed the presence of tannin (7.4%), crude alkaloids (2.5%), saponin (0%) and crude oxalates (42.28 mg/g) in cassia while lemon grass contained tannin (4.5%), crude alkaloids (0.52%,), saponin (1.76%) and oxalates (0%). The infra-red spectrum revealed that the two plant extracts contained very strong and broad absorption bands ~3400 -1 cm region, assignable to ~NH stretching mode probably of alkaloid family. The medium absorption bands were due to ~CH bands which are common in natural products. The medium absorption bands are also strong indicators of other compounds in the leaf extracts. The use of botanically derived crude leaf extracts of cassia at 50% and lemon grass at 75% in the management of nematode pests of okra will therefore be of economic benefit, ensuring food security. K ey w o r d s: Nematodes Phytochemical, screening Infra-red spectrum, Secondary metabolites

Efficacy of aqueous leaf extracts and synthetic insecticide on pod-sucking bugs infestation of cowpea (Vigna unguiculata (L.) Walp) in the Guinea Sa-vanna Region of Nigeria

Pod-sucking bugs (PSBs) infestation by Ano-plocnemissp./ Riptortussp./Clavigrallasp./Nezaraviridula( Linnaeus) greatly limits cowpea (Vignaunguiculata (L.) Walp) production throughout sub-Saharan Africa. The efficacy of aqueous leaf extracts (ALEs) (5 percent weight/volume concentration) of three botanicals and one synthetic insecticide against PSBs infestation was thus evaluated. The botanicals tested include Aza- dirachtaindicaA. Juss, Chromolaenaodorata (L.) and Ricinuscommunis (L.), whilst the synthetic insecticide was Uppercot 500 EC ( Lambda cyhalothrin 30 g + Dimethoate 250 g ). The effects of these treatments on the number of PSBs/ pods/seeds, pod/seed weight and grain yield were assessed during 2008 and 2009 rainy seasons in Bayo, Borno State, Guinea Savanna region, Nigeria. The number of PSBs was lower on crops treated with Uppercot 500 EC (0.00 - 0.31). This was followed by crops treated with the ALEs ofA.indica/C.odorata (0.31 - 1.33) and R.communis (0.72 - 3.72) than the untreated (3.06 - 5.64) ones.The number of pods/pod weight per plant, seeds/seed weight per pod and total grain yield were generally higher on cowpea crops treated with Uppercot 500 EC (26/17 g, 14/19 g and 1618 kg). This was followed bycrops treated with the ALEs of A.indica/C.odorata (23 - 25/14 - 15 g, 12 - 13/15 g and 1268 - 1310 kg) and R.communis( 21/13 g, 11/14 g and 972 kg) than the untreated (16/9 g, 7/10 g and 312 kg) ones. Although Uppercot 500 EC was most effective inprotecting cowpea against PSBs attack, theALEs of A.indica and C.odorata appreciably protected treated crops against infestation, giving relatively high total grain yield. Both botanical scan thus serve as alternatives to synthetic insecticides for managing PSBs attack on cowpea.

Antifungal activity of Plumbago species against anthracnose fungus Colletotrichum gloeosporidodes (Penz.) of chilli

The efficacy of aqueous leaf extracts of three Plumbago (Plumbago indica, P. capensis, P. zeylanica) species on anthracnose fungus Colletotrichum gloeosporioides were assessed. Out of the extract of three plants screened, that of Plumbago indica showed the best result both in inhibition of conidial germination up to (98.9%), and radial mycelial growth (98.75%) of the pathogen over the control and in the pectinolytic enzyme studies also P. indica showed a minimum activity of Polymethyl esterase (1.91U), Polymethyl galacturonase (endo PMG-2.77%; exo PMG-0.028U) and Pectin trans eliminate; the least amount of sugar (endo PTE-17.14%; exo PTE-11.11U) was released in P. indica. In cellulolytic enzyme studies, the amount of viscosity loss due to the activity of 1,4-β endoglucanase was remarkably reduced (3.57%) in P. indica compared to the other two species. P. capensis showed moderate results; P. zeylanica showed minimum inhibition of the enzyme activity of the pathogen. Results show that among all three plumbago species tested, Plumbago indica was reported to be an effective plant extract against anthracnose fungus.

The effect of Aloe ferox Mill. in the treatment of loperamide-induced constipation in Wistar rats

BackgroundConstipation is the most common gastrointestinal complaint all over the world and it is a risk factor of colorectal cancer. In this study, the efficacy of aqueous leaf extract of Aloe ferox Mill. was studied against loperamide-induced constipation in Wistar rats.MethodsConstipation was induced by oral administration of loperamide (3 mg/kg body weight) while the control rats received normal saline. The constipated rats were treated with 50, 100 and 200 mg/kg body weight/day of the extract for 7 days during which the feeding characteristics, body weight, fecal properties and gastrointestinal transit ratio were monitored.ResultsThe extract improved intestinal motility, increased fecal volume and normalized body weight in the constipated rats, which are indications of laxative property of the herb with the 200 mg/kg body weight of the extract showing the best efficacy.ConclusionThe effect of the extract compares favourably well with senokot, a standard laxative drug. These findings have therefore, lent scientific credence to the folkloric use of the herb as a laxative agent by the people of the Eastern Cape of South Africa.

Efficacy of aqueous leaf extract of vernonia amygdalina on plasma lipoprotein and oxidative status in diabetic rat models.

Many minor components of foods, such as secondary plant metabolites, have been shown to posses antioxidant activities, improving the effects of oxidative stress on diabetes and other disease conditions. This study evaluates the effect of aqueous extracts from Vernonia amygdalina leaves on lipid profiles and oxidative stress in streptozotocin induced diabetic rats. The results showed that the streptozotocin induced diabetic rats were subjected to oxidative stress as was shown by the extent of lipid peroxidation (high malondialdehyde levels) present in the plasma. The aqueous extract of V. amygdalina leaves possessed antioxidant activity as shown by decreases in malondialdehyde levels. High values of LDL-cholesterol and triglycerides levels, which are typical of the diabetic condition, were also found in streptozotocin induced diabetic rats. The aqueous extract also significantly reduced triglyceride levels and normalized cholesterol concentrations. This shows that the aqueous extract of V. amygdalina leaves have both hypolipidaemic and antioxidant properties.