Patience N Ugwu1,
Eleje O Okonta1 
,
Vincent O Chukwube1,
Nonhlangabezo Mabuba2,
Edith O Diovu1,
Uchenna E Odoh1,
Esther C Godwin3,
Charles O Nnadi4, 5,
Christopher O Ezugwu1
For correspondence:- Eleje Okonta Email: eleje.okonta@unn.edu.ng Tel:+234-806840 5223
Received: 27 February 2025 Accepted: 13 June 2025 Published: 03 July 2025
Citation: Ugwu PN, Okonta EO, Chukwube VO, Mabuba N, Diovu EO, Odoh UE, et al. Environmental impact of crude oil on the phytochemical constituents of some selected medicinal plants in Nigeria. Trop J Pharm Res 2025; 24(6):819-828 doi: https://dx.doi.org/10.4314/tjpr.v24i6.9
© 2025 The authors.
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Purpose: To investigate the effect of crude oil exploration on secondary metabolites of Magnifera
indica, Ficus exasperata, Mallotus oppositifolius, Millettia aboensis and Newbouldia leavis.
Methods: The leaves of the plants were collected from Ogoni (oil-producing area) referred to as test
samples, and Awka (non-oil-producing area) referred to as control, in Nigeria. Methanol and
dichloromethane extracts of the leaves of the plants, harvested from both regions, were subjected to
phytochemical analyses and gas chromatography/mass spectrometry (GC-MS) analysis. Quantification
of the phytochemicals was done spectrophotometrically and expressed as equivalent to their respective
standards.
Results: Extraction yield ranged from 4.4 to 10.4 %w/w. Phytochemical analysis showed that all the test
phytochemicals, except cyanogenic compounds, were detected in both test and control samples.
Steroids and alkaloids were significantly higher in test samples compared to control samples (p < 0.05).
Furthermore, terpenoid was significantly lower (p < 0.05) in test samples (F. exasperate and M.
oppositifolius) than in control samples. The GC-MS analysis revealed that only M. indica contained 1,3-
diazocane-2-thione and 5-methyl-1,2-oxazol-3-amine were present in both the test and control samples,
while the other samples contained diverse alkaloidal chemotypes.
Conclusion: The multifactorial nature of oil exploration may affect plant phytochemicals via chemical
transformation, depletion or accumulation. This provides valuable insights into the need for
environmental conservation
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