ABSTRACT
Piper guineense, commonly known as West African black pepper, is a plant traditionally used for its medicinal and therapeutic properties due to its rich content of bioactive compounds, including alkaloids, flavonoids, and essential oils. The PTEN gene plays a crucial role in regulating cell growth, apoptosis, and oxidative stress responses, while Glutathione-STransferase (GST) activity is critical for cellular detoxification and antioxidant defense. This study aims to evaluate the effects of Piper guineense leaf extract on PTEN gene expression, GST activity, survival, and locomotor performance in Drosophila melanogaster.A total of 1020 Drosophila melanogaster were used for survival studies, negative geotaxis performance, gene expression, and biochemical analysis. The groups were designated as the Control Group, with Group A, Group B, and Group C representing 500 mg/kg, 250 mg/kg, and 125 mg/kg of Piper guineense extract, respectively. mRNA expression of PTEN was determined using polymerase chain reaction (PCR), while GST activity was measured using a colorimetric assay. Data generated were analyzed using GraphPad Prism (version 8.02, California, USA).The results showed a dose-dependent effect of Piper guineense on survival and locomotor performance. The control group had the highest survival rate (90.5%), while Group B (250 mg/kg) exhibited the lowest (46.6%). Negative geotaxis performance was highest in Group C (125 mg/kg), with 66.7% of D. melanogaster climbing the 6 cm mark within six seconds. GST activity was significantly elevated in Group C (0.15 ± 0.01) compared to the control (0.03 ± 0.01, p<0.001). PTEN expression was significantly upregulated in Group A (500 mg/kg, 3.15 ± 0.05, p<0.01), compared to the control (2.3 ± 0.1).In conclusion, this study revealed that Piper guineense leaf extract modulates PTEN gene expression and GST activity in a dose-dependent manner. While low to moderate doses enhanced antioxidant activity and neuromuscular function, higher doses promoted PTEN expression, suggesting its potential role in cellular protection. However, intermediate doses caused adverse effects, underscoring the importance of dose optimization.
