Cellular toxicity and DNA damage induced by Newbouldia laevis used for male infertility treatment in prokaryotic and eukaryotic models.

Leaves of Newbouldia laevis have been extensively used in solving problems associated with infertility and childbirth in many African countries. Yet, information is very limited on the DNA damaging potential of this plant. This study evaluated the cytogenotoxic effect of the aqueous extract of N. laevis leaf using prokaryotic models (Ames Salmonella fluctuation test using TA100 and TA98 strains of Salmonella typhimurium and SOS Chromotest with Escherichia coli PQ37) and eukaryotic model (Allium cepa root cells). Identification of the volatile organic compounds (VOCs) and phytochemical screening of the plant extract were also performed. Onion bulbs were grown on each concentration (1 to 50%; v/v, extract/tap water) of the extract for chromosomal aberrations and root growth analyses. Results of the Ames test indicated that the extract is mutagenic while the SOS Chromotest results showed good complementation to the Ames test results, although the E. coli PQ37 system showed slightly higher sensitivity in the detection of mutagenicity and genotoxicity of the extract. The plant extract was cytotoxic when compared to the control, inducing a significant (p < 0.05) concentration-dependent inhibition of root growth from 5 to 50% concentrations. At 50% concentration, the extract completely inhibited cell division in the A. cepa. Also, chromosomal aberration increased significantly (p < 0.05) in exposed onions from 5 to 20% concentrations. The mutagenicity and cytogenotoxicity recorded in this report were believed to be caused by the presence of VOCs such as 1,2,3-benzene-triol, 1,2-benzenediol, and 5-hydroxymethylfurfural, and alkaloids in the extract an indication of the cytogenotoxicity of the aqueous extract of N. laevis leaf even at low concentration.

Comparative chemical analysis, mutagenicity, and genotoxicity of Petroleum refinery wastewater and its contaminated river using prokaryotic and eukaryotic assays.

Concern on the toxicity of final wastewater generated by the petroleum refining industry has increased in recent years due to the potential health threats associated with their release into the waterways. This study determined the mutagenic and genotoxic potential of petroleum refinery wastewater and a receiving river using the Ames fluctuation test on Salmonella typhimurium strains TA100 and TA98, SOS chromotest on Escherichia coli PQ37, and piscine peripheral micronucleus (MN) assay. Analyses of the physicochemical parameters, heavy metal, and organic contents of the samples were also performed. Ames test result showed that the two tested samples were mutagenic with TA100 strain as the more responsive strain for both the refinery wastewater and the river sample in terms of the calculated mutagenic index. A similar result was obtained in the SOS chromotest; however, the E. coli PQ37 system recorded a slightly higher sensitivity for detecting genotoxins than the Salmonella assay in the two samples. MN data showed induction of a concentration-dependent significant (p < 0.05) increase in the frequency of MN by both samples when compared with the negative control. Generally, the refinery wastewater induced the highest mutagenicity and genotoxicity compared to the river sample in the three assays used. Haemoglobin, platelets, red blood cells, mean corpuscular volume, total white blood cells, heterophils, haematocrit, and eosinophils reduced significantly with increased lymphocytes, basophils, mean corpuscular haemoglobin, and mean corpuscular haemoglobin concentration in fishes exposed to both samples. Total petroleum hydrocarbon, benzene, toluene, phenol index, polycyclic aromatic hydrocarbons, cadmium, mercury, nickel, lead, and vanadium contents analysed in the samples were believed to be responsible for the observed genotoxicity and mutagenicity. The findings of this study revealed that petroleum refinery wastewater is a potential mutagenic and genotoxic risk to the environment.

Comparative study of the reproductive toxicity and modulation of enzyme activities by crude oil-contaminated soil before and after bioremediation.

Contamination of soil with crude oil is a serious ecological problem with potential adverse public health effects. This study assessed the germ cell toxicity of simulated leachates from crude oil-contaminated soil before and after bioremediation using the murine sperm abnormality assay, sperm count, and testes histopathology. The levels of Total Testosterone (TT), Follicle Stimulating Hormone (FSH), and Luteinizing Hormone (LH); and activities of catalase (CAT), alkaline phosphatase (ALP), superoxide dismutase (SOD), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were determined. The physicochemical, Total Petroleum Hydrocarbon (TPH), and heavy metal analyses of the leachates were also carried out. Male mice were exposed to 50, 25, 10, 5, and 1% (v/v; leachate:distilled water) of the leachate samples for five consecutive days, and were sacrificed after 35 days. The result showed a statistically significant (p < 0.05), concentration-dependent increase in abnormal sperm cells in exposed mice, with aberrations such as folded sperm, amorphous head, wrong tail attachment, distal droplet, no hook, and looped tail. Data further showed a concentration-dependent significant reduction in mean sperm count in the exposed mice. Alterations of seminiferous tubules with different lesions and activities of ALT, AST, ALP, FSH, LH, and TT were also recorded. The high level of selected heavy metals (As, Cr, Cd, Cu, and Pb) and TPH was believed to contribute to the observed reproductive toxicity and modulated enzyme activities in the treated mice. It is therefore concluded that the microbial remediation of the crude oil contaminated soil produced a reduction in the levels of heavy metals and TPH in the soil, reduced reproductive toxicity, and modulation of enzyme activities. However, the induced reproductive toxicity by the bioremediated soil is still significant, hence, further work could be done to employ a consortium of bacteria and extend the period of the bioremediation process to ensure complete removal of the contaminants.

Cytogenotoxicity of the aqueous extract of Parquetina nigrescens leaf using Allium cepa assay.

Parquetina nigrescens has been used for decades in ethnomedicine for its antioxidant, antimicrobial, anti-inflammatory, analgesic, and aphrodisiac properties. In this study, the cytotoxic and genotoxic effect of aqueous crude leaf extracts of P. nigrescens on the root meristematic cells of Allium cepa was examined. Volatile organic compounds (VOCs) present in the plant extract were also identified using gas chromatography-mass spectrometry (GC-MS). The extract was prepared with tap water as is locally practised by many Nigerians. Onion bulbs were exposed to 1, 5, 10, 20, and 50% concentrations of the extract for the analysis of root growth inhibition and chromosomal aberration. Lead nitrate (10 ppm) and tap water were used as the positive and negative controls, respectively. The result showed cytotoxicity which was observed as statistically significant (p