http://hdl.handle.net/123456789/23 Science 2026-04-20T03:31:52Z http://hdl.handle.net/123456789/2423 CHEMICAL CONSTITUENTS AND BIOLOGICAL ACTIVITIES OF ESSENTIAL OILS FROM SELECTED NIGERIAN MEDICINAL PLANTS ALADE, Adekemi Temitope Oxidative stress and microbial infections are major threats to humans. Toxicity, side effects and resistance to the existing drugs necessitate the need for alternatives. Essential Oils (EOs) of plants, which are complex mixtures of terpenes and terpenoids, have demonstrated multiple pharmacological activities. However, there is dearth of information on the EOs of most plants used as antioxidant and in the treatment of microbial infections. Therefore, this study was designed to determine the chemical constituents and biological activities of EOs from selected medicinal plants in Nigeria. Tecoma stans (TS) (FHI 112524), Plumeria acuminata (PA) (FHI 112495), Plumeria rubra (PR) (FHI 112567), Delonix regia (DRe) (FHI 112523), Gliricidia sepium (GS) (FHI 112496), Duranta repens (DR) (FHI 112525), Zanthoxylum zanthoxyloides (ZZ) (FHI 112982), Ceiba pentandra (CP) (FHI 112962) and Annona muricata (AM) (FHI 112526) were collected within University of Ibadan and authenticated at Forest Research Institute of Nigeria. Different plant parts (leaves, stem, stembark, fruits, twig, seeds, flowers, heartwood, root) were air-dried, pulverised and subjected to hydrodistillation. The EOs were analysed for their chemical constituents using gas chromatographymass spectrometry. Antioxidant properties and cytotoxicity of the oils were respectively determined using 2,2-diphenyl-1-picryhydrazyl radical-scavenging and brine shrimp lethality assays, with reference to the standards. Antimicrobial activities were also determined using agar-diffusion method against selected fungi (Candida albicans, Aspergillus niger, Fusarium solani) and bacteria (Staphylococcus aureus, Escherichia coli, Salmonella typhi, Leclericia adecarboxylata, Morganella morganii, Citrobacter freundii, Klebsiella pneumoniae) using Ketoconazole and Gentamycin as reference drugs. Data were analysed using descriptive statistics. The yields of the EOs ranged from 0.06 to 0.62 % (w/w). Dominant terpenes in the EOs were linalool (11.4%, stem), α-terpineol (11.7%, seed) in TS; linalool (16.1%, leaf), β-eudesmol (43.0%, root) in PA; spathulenol (34.7%), carryophyllene (17.8%) in PR stem; phytol (12.7%) in DRe root; humulene epoxide II (17.5%) in GS stem; geranyl acetone (4.3%) in DR leaf. Others were α-pinene (38.5%, stembark), caryophyllene oxide (27.0%, leaf) in ZZ; β-elemene (18.5%, stem) α-eudesmol (21.1%, heartwood), β-caryophyllene (28.7%, stembark) in CP; E-caryophyllene (28.2%) in AM leaf. Prominent non-terpenes were pentadecanal (51.2%) in PR leaf; (9Z)-docosenamide (51.6%) in DRe twig; palmitic acid (55.7%, root), styrene (52.5%, fruit) in DR. Thus, the chemical constituents were established for Tecoma stans, Delonix regia and Ceiba pentandra essential oils. The EOs of TS (seed, stem), DR (fruit, stem) and AM (leaf) displayed higher antioxidant activities (IC50 6.44 - 43.22 µg/mL) than control (IC50: BHA- 45.11 µg/mL, α-tocopherol-81.58µg/mL). Cytotoxicities of all the EOs were high (LC50 5.8992-89.8190 ppm) compared with standard values. The EOs exhibited antifungal activities (7.8±0.4 - 22.1±0.1 mm) compared with Ketoconazole (10.3±0.4 – 21.0±1.4 mm). However, only EOs of PA exhibited antibacterial activities (7.9±0.0 - 12.1±0.1 mm) comparable with Gentamycin (8.0±0.0 - 12.5±0.1 mm). The essential oils of selected plants had antioxidant properties, were cytotoxic and possessed antimicrobial activities. Essential oils of Tecoma stans (stem, seed), Duranta repens (fruit, stem) and Annona muricata (leaf) could be alternative sources of antioxidants, while Plumeria acuminata (leaf, root, flower) oils could act as a natural antimicrobial agent. 2022-01-01T00:00:00Z http://hdl.handle.net/123456789/2298 MEASUREMENT OF SOIL-GAS RADON CONCENTRATION AND GEOGENIC RADON POTENTIAL MODELLING FOR SOUTHWEST NIGERIA FAJEMIROYE, Joseph Adesoji Ademola Radon-222 is a radioactive gas in the natural decay series of Uranium-238. It easily emanates from the soil to constitute radiological hazard and is the leading cause of lung cancer apart from smoking. High indoor radon buildup could occur in buildings sited over high radon-bearing bedrocks. Radon hazard, expressed as Geogenic Radon Potential (GRP), is due to a combination of soil-gas radon concentration ( ) and soil-air permeability ( ), both of which depend on bedrocks. Data on these two quantities over different bedrock formations and soil types in Southwest (SW) of Nigeria are very scarce resulting in limited knowledge on radon hazard and lack of requisite radon control guidelines. This study was designed to measure , determine GRP and model the distribution of GRP over different bedrocks of SW Nigeria. Measurements of were made using a calibrated real-time semiconductor radon monitor at a depth of 0.80 – 1.00 m in 150 randomly selected locations across 20 bedrocks in the six states of SW Nigeria. Saturated hydraulic conductivities of undisturbed soil samples taken from these locations were measured with a constanthead permeameter in order to determine . The GRP for each location was calculated from and and categorised using Neznal classification for radon hazard ratings. A Levenberg-Marquardt feed-forward-back-propagation artificial neural network was employed to develop a predictive model for . Data was randomly split in 70:15:15 for training, testing and validation, respectively, for six different architectures and the best was chosen following standard procedure. Goodness-of-Prediction (G), Average Validation Error , Mean Bias Error and Root Mean Square Error were used to determine performance and validation of the model. The and GRP maps were generated on existing geological map for SW region. The measured ranged . The ranged , while ranged . The GRP ranged . Sedimentary formation had highest of , while granitic bedrocks had highest and GRP of and , respectively. Radon hazard classification showed that , and of the sites were of low, medium and high radon hazard rating, respectively. Out of the 13 sites with high radon hazard rating, granitic and metamorphic bedrocks presented more sites (84.6%). The best performing architecture was 2 x 8 x 1. Performance indices of the model, yielded G of 73.5%, of 0.073, of 0.42 and of 4.62 kBqm-3. Validation indices yielded G of 86 , of , of and of 1 , indicating good model performance. Values of measured and GRP were used to generate maps which showed spatial distribution of low, medium and high radon hazard ratings. The values of measured soil-gas radon concentration and determined geogenic radon potential were highest in granitic bedrocks. The performance indices of the developed neural network model showed good reliability in predicting geogenic radon potential for southwest Nigeria. 2023-11-01T00:00:00Z http://hdl.handle.net/123456789/2252 RESPONSES OF WOROWO [Senecio biafrae (Oliv. & Hiern.) S. Moore] TO COMPOSTS ENRICHED WITH ORGANIC NITROGEN SOURCES ADEYEMI, FOLASADE OLUWAFISAYO Worowo (Senecio biafrae) is a semi-wild, indigenous and nutritious vegetable. Demand for worowo is increasing due to its nutritional values, thus necessitating its domestication for increased production. However, there is limited information on soil fertility requirements of worowo and the use of inorganic fertilisers for its production could be expensive and detrimental to environment. Composts are more environmentfriendly and effective in improving soil fertility but their use are constrained by low nitrogen contents, thereby necessitating enrichment with various nitrogen sources. Therefore, responses of worowo to organically nitrogen-enriched composts were investigated. Composts from Cattle Dung+Sawdust-CDS at 1:1 (w/w) and Poultry Droppings+Sawdust-PDS at 1:1 (w/w) were enriched to 15, 30, 45 and 60 g N/kg with meals from dried bone-BnM, blood-BM, hoof-HM, and horn-HnM, neem-Nm and Tithonia leaves-TM. Compost treatments obtained were: CDS and PDS (no enrichment added), CDSBnM, CDSBM, CDSHM, CDSHnM, CDSNM and CDSTM; PDSBnM, PDSBM, PDSHM, PDSHnM, PDSNM and PDSTM. Compost treatments (30 t/ha) in 2.0 kg soils and control (soil alone) were incubated for 16 weeks for nitrogen analysis. Worowo was raised in pots with CDS, PDS and 60 g N/kg enriched composts at 30 t/ha and control (soil alone), compared with 60 kg N/ha NPK 15-15-15 in a completely randomised design with three replicates. Edible Shoot Yield (ESY) of worowo (t/ha) was measured at 180 Days After Planting (DAP). On the field, effects of CDSNM (60 g N/kg) at 0, 10, 20, 30 and 40 t/ha were compared with NPK 15-15-15 at 60 kg N/ha on the ESY of worowo at 180 DAP, using randomised complete block design with four replicates, in two raining seasons. Samples of worowo edible shoots at harvest at the two seasons were analysed for Crude Fibre-CF (%). Data were analysed using descriptive statistics and ANOVA at α0.05. Highest and least N (g N/kg) contents (9.2 and 0.4) from soils incubated with compost treatments were from CDSNM at 60 g N/kg (16 weeks) and control (8 weeks), respectively. In pots, ESY (t/ha) of 60 g N/kg CDSNM (54.93±1.91) was significantly higher than NPK (36.53±1.27) and others but similar to CDS (50.93±1.77) while pots treated with PDS were lowest (8.00±0.28). At first season on the field (180 DAP), CDSNM at 40 t/ha had the highest ESY (8.66±1.24) which significantly differed from other treatments except CDSNM at 30 (6.30±0.90) and 20 (5.53±0.79) t/ha while control gave lowest (3.00±0.43). The ESY (180 DAP) from CDSNM at 40 t/ha (10.55±1.95) was highest in the second season and differed significantly from other treatments but comparable to CDSNM at 30 t/ha (7.30±1.35). Lowest ESY (1.41±0.26) was from plots allotted to NPK. At first season, CF contents of 60 g N/kg CDSNM treatments, NPK 15-15-15 and control were in the order: 40 t/ha-12.00±0.59> NPK-11.20±0.59> 30 t/ha-11.00±0.59> 20 t/ha-10.62±0.59>Control- 10.50±0.59> 10 t/ha-10.45±0.59, which followed the same order at the second season. Cattle dung-sawdust compost enriched with neem to 60 g N/kg applied at 30 t/ha improved edible shoot yield and crude fibre of worowo, hence could be adopted for its production. 2022-03-01T00:00:00Z http://hdl.handle.net/123456789/2161 PERFORMANCE OF POST-HARVEST STORAGE BAGS AND DIATOMACEOUS EARTH FOR THE PROTECTION OF STORED MAIZE AGAINST INSECT PEST INFESTATIONS ASIWAJU-BELLO, Shekinat Kehinde Maize is an important staple crop widely used in domestic and industrial processes. It is usually stored in Polypropylene (PP) bags, where it is prone to heavy insect infestations, resulting in high economic losses. A number of recent interventions to prevent insect infestations during grain storage include Diatomaceous Earth (DE) and novel bags such as ZeroFly (ZF) and Purdue Improved Crop Storage (PICS). However, there is paucity of data on their effectiveness and optimal use in insect pest management. Therefore, this study was conducted to determine the effectiveness of different storage bags and DE against stored-insect pests of maize. The study was conducted between February, 2017 and January, 2018 in a storehouse at Arisekola Market, Bodija, Ibadan. Pristine 50 kg SWAN 2 maize variety was stored using eight different bag treatments comprising: PP (control) and ZF, DE admixed in PP and ZF (PPDE and ZFDE), single and double hermetic liners in PP (PP1L and PICS), single and double hermetic liners in ZF (ZF1L and ZF2L). A stack of three replicates for each treatment was placed on separate pallet and arranged one meter apart. In addition, for each ZF1L, ZF2L, PP1L and PICS, two sets comprising 3 replicates/set were stored for destructive sampling every four-months using standard procedure. Maize in ZF, PP, ZFDE and PPDE were sampled monthly. Insect population count, insect damaged kernel, maize weight loss and insect perforation on bags were determined through standard procedures. Maize quality was determined through standard seed germination method, maize Moisture Content (MC) was measured by MC meter and aflatoxin level by Thin-Layer Chromatography. Data were analysed using descriptive statistics and ANOVA at α0.05. Total insect population of 5,945 in all treatment bags comprised predominantly Sitophilus zeamais (2,593), followed by Tribolium castaneum (1,298), Liposcelis spp. (1,193) and the least occurring Cryptolestes ferrugineus (861). Percentage of insect species per bag: ZF2L (0.2) and ZF1L (0.3) were significantly lower than the population in ZFDE (3.2) and PPDE (7.9), but higher in ZF (51.8) and PP (35.4). Insect damaged kernel was significantly low in ZF2L (0.4±0.0%), ZF1L (0.5±0.0%) and ZFDE (0.8±0.3%) compared to ZF (16.9±1.6%) and PP (5.4±0.9%). The maize weight loss was significantly low in ZF2L (0.1±0.0%), PICS (0.2±0.0%) and ZFDE (0.2±0.1%) compared to ZF (6.7±0.8%). The number of insect perforations on ZF2L (0.0±0.0), PICS (1.3±0.4) and ZF (17.0±3.1) were significantly lower compared with the control, PP (51.5±5.7). Seed germination rate (97.5±0.6%) in ZF2L and PICS were significantly higher than PP (78.3±0.1%) and ZF (66.0±2.3%). The initial MC of the maize in treatment bags was 11.4±0.1%, but the final MC in ZF2L (12.2±0.1%) was significantly lower than in PP (13.5±0.1%). Aflatoxin levels in maize in all treatment bags were within the recommended limits (4 µg/kg) of Standards Organisation of Nigeria, except the PP (5.0 µg/kg). Hermetic storage bags and diatomaceous earth were effective at controlling insect infestations and preserved stored maize quality. Therefore, they could be used in postharvest storage interventions. 2023-06-01T00:00:00Z