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Evaluation of essential Oils extracted from Ocimum gratissimum L. (scent leaf) as organic preservative in comparison with synthetic preservative (dichlorvos) in grains storage

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Ekpo P. B., Abu G. I., Ekpo I. P., Chinyere O.-A., Ogbaji H. O., Job I. E., Achimole C. C.

World News of Natural Sciences

2025

vol. 62

183-197

The use of synthetic preservatives in grain storage has raised concerns about environmental pollution, toxicity to humans and animals, and development of pesticide-resistant pests. This study evaluated the efficacy of essential oils extracted from Ocimum gratissimum (scent leaf) as organic preservatives for grain storage, comparing their effectiveness to the synthetic preservative dichlorvos. The essential oils were extracted using a suitable method and analyzed for their chemical composition. The major constituents of the essential oils were identified as eugenol, linalool, etc. The oils were then tested for their insecticidal properties against common grain pest (Callosobruchus maculatus). Grains were treated with different concentrations of essential oils (of 0.5, 1.0, 1.5 ml) and dichlorvos (concentration of 0.5, 1.0 mL), and stored for a specified period of one month and data was collected within 4 days of application of treatments. The results showed that the essential oils exhibited significant insecticidal properties, reducing pest growth in grains. The efficacy of the essential oils was comparable to dichlorvos, with 85.0 percent mortality of pests. The study suggests that Ocimum gratissimum essential oils could be a viable alternative to synthetic preservatives like dichlorvos for grain storage, offering a safer and more environmentally friendly option for farmers and consumers. The use of these oils could also contribute to sustainable agriculture and food security. Further research is needed to explore the commercial applications of these essential oils and to optimize their use in grain storage.

Fingerprinting Environmental Contaminants in Lemna Dumpsites: A Biomarker-Based Approach for Assessing Ecological Risk in Tropical Regions

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Ekpo P. B., Ekpo I. P., Ogbaji H. O., Unoh F. B., Chinyere O.-A., Onajite E. O.

World News of Natural Sciences

2025

vol. 62

167-182

This study evaluated environmental contamination and biological stress at the Lemna dumpsite in Calabar Municipality, Nigeria, through integrated biochemical and physicochemical analyses. Soil and water samples were assessed for oxidative stress biomarkers, DNA damage, lipid peroxidation, and contaminant levels. Enzymatic activities of catalase (4.82 ± 0.21 U/mg protein), peroxidase (2.91 ± 0.17 U/mg protein), and glutathione S-transferase (5.34 ± 0.22 U/mg protein) were significantly elevated in soil samples compared to water (3.15 ± 0.18, 1.87 ± 0.14, and 3.92 ± 0.19 U/mg protein, respectively), indicating increased oxidative stress in soil microbial communities exposed to heavy metals and organic pollutants. The comet assay revealed pronounced DNA fragmentation in soil microbes, with tail length of 38.6 ± 2.4 µm and 52.4 ± 3.1% DNA in tail, compared to water samples (27.2 ± 2.1 µm and 40.8 ± 2.7%). Lipid peroxidation, measured by malondialdehyde concentration, was also higher in soil samples (8.12 ± 0.31 nmol MDA/g) than in water (5.76 ± 0.29 nmol MDA/g), confirming oxidative membrane damage. Physicochemical analyses showed acidic soil pH (5.4 ± 0.2), elevated total organic carbon (4.3 ± 0.5%), and heavy metal concentrations of lead (62.5 ± 3.2 mg/kg), cadmium (3.1 ± 0.2 mg/kg), and chromium (77.2 ± 4.1 mg/kg), all exceeding WHO permissible limits. Water quality assessment indicated slightly acidic pH (6.2 ± 0.3), high turbidity (22.5 ± 1.7 NTU), and significant microbial pollution with total coliforms at 920 MPN/100 mL and positive E. coli presence, reflecting fecal contamination likely from leachate. These findings demonstrate severe environmental degradation at the dumpsite, with clear biological effects on soil microorganisms and public health risks from contaminated water. The study underscores the urgent need for remediation strategies, improved waste management, and continuous environmental monitoring to mitigate ecological and human health impacts.

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2 World News of Natural Sciences

2 2025

2 Chinyere O.-A.

2 Ekpo I. P.

2 Ekpo P. B.

2 Ogbaji H. O.

1 Abu G. I.

1 Achimole C. C.

1 Job I. E.

1 Onajite E. O.

1 Unoh F. B.

Search results

Evaluation of essential Oils extracted from Ocimum gratissimum L. (scent leaf) as organic preservative in comparison with synthetic preservative (dichlorvos) in grains storage

Fingerprinting Environmental Contaminants in Lemna Dumpsites: A Biomarker-Based Approach for Assessing Ecological Risk in Tropical Regions