ABSTRACT

Picralima nitida and Cymbopogon citratus, plants traditionally used in West Africa for their health benefits, have attracted attention due to the antioxidant and anti-diabetic properties of Picralima nitida and the anti-inflammatory and antioxidant properties of Cymbopogon citratus. There is a growing need to study their ability to mitigate the harmful effects of benzene-induced haematotoxicity which potentially involves modulation of B-Cell lymphoma 2 (BCL-2) and BCL-2 associated agonist of cell death (BAD) gene expressions. Therefore, the aim of this study is to determine the effects of aqueous leaves extracts of Picralima nitida and Cymbopogon citratus on BCL-2 and BAD gene expression in benzene-induced haematotoxicity in albino Wistar rats. A total of sixty (60) adult male albino Wistar rats were divided into six (6) groups; A, B, C, D, E and F representing control, benzene group, cyclophosphamide group, benzene + 100mg/kg bi-herbal  of Picralima nitida and Cymbopogon citratus aqueous leaf extract, benzene + 200mg/kg bi-herbal of Picralima nitida and Cymbopogon citratus aqueous leaf extract and benzene + 400mg/kg bi-herbal of Picralima nitida and Cymbopogon citratus respectively. The haematological parameters as well as the gene expression levels of BCL-2 and BAD were analyzed using the ERMA haematology autoanalyzer and polymerase chain reaction respectively. Data were statistically analyzed using GraphPad prism software. The comparison of haematological parameters amongst the studied groups show that Total white blood cell count (TWBC ⁹/L) was significantly lower in Group F (5.71±0.33) when compared to groups A (9.93±1.03) and B (8.849±0.51) (p < 0.05). Group C (5.14±0.43) had a significantly lower TWBC count when compared to groups A (9.93±1.03) and B (8.849±0.51) (p < 0.05). Group E (6.14±0.64) had a significantly lower TWBC count when compared to group A (9.93±1.03) (p < 0.05). Group C (26880±4321) had a significantly low platelet count when compared to group B (58070±2859) (p < 0.05). Group E (52710±4449) had a significantly high platelet count when compared to groups A (34320±1822) and C (26880±4321) (p < 0.05). Group C exhibited a significantly lower red blood cell count (RBC) of 4.648±0.134 compared to groups A (5.938±0.21) and B (6.22±0.09), with groups D (6.337±0.07), E (6.316±0.11), and F (6.02±0.11) showing significantly higher RBC counts (p<0.05). Haemoglobin was significantly lower in group C (10.05±0.38) than in group A (14.25±0.33), with groups D (14.65±0.17), E (14.21±0.20), and F (14.21±0.20) having higher haemoglobin levels than group C. Group F had lower haemoglobin levels compared to groups A, B, D, and E (p<0.05). Haematocrit was also lower in group C (27.86±0.80) compared to groups A (39.21±0.50) and B (37.04±0.47), while groups D (37.09±0.64), E (37.88±0.41), and F (34.98±0.40) had higher haematocrit values than group C (p<0.05). MCV was significantly higher in group A (66.67±1.85) compared to all other groups (p<0.05). MCH was highest in group A (24.06±0.45), with group C (21.53±0.27) showing the lowest MCH. Group D had lower MCH than group C, and group F had lower MCH than groups B and D (p<0.05). MCHC was higher in groups B (38.46±0.53) and D (39.47±0.44) than in group A (36.25±0.39), and group C (35.94±0.34) had a lower MCHC than group B (p<0.05). There was a significant increase in the mRNA expression of BCL-2 of groups C and D when compared to group A (p < 0.05). Group C showed significant increase in mRNA expression of BCL-2 in comparison to group B (p < 0.05).There was a significant decrease in the mRNA expression of BAD of groups D, E and F when compared to groups C and B (p < 0.05). In conclusion, administration of benzene and Picralima nitida and Cymbopogon citratus aqueous leaf extract led to dose-dependent effects on various haematological parameters. The mRNA expression of BCL-2 and BAD showed significant dose-dependent responses to the various treatments.