Phenotypical and molecular assessments on the pharmacological effects of curcumin in Drosophila melanogaster

Abstract

Curcumin, a dietary polyphenol derived from turmeric's rhizome, exhibits a range of pharmacological activities, such as antioxidant, analgesic, antipyretic, and anti-inflammatory effects. It has been investigated for its therapeutic potential in chronic obstructive pulmonary disease (COPD) due to its ability to inhibit nuclear factor kappa B (NF-κB), modulate oxidative stress, impact cell viability, and regulate gene expression. However, most studies have been limited to in vitro conditions. To address this gap, we conducted in vivo experiments using the fruit fly Drosophila melanogaster to explore the antioxidant activities and biological significance of curcumin. Several parameters were assessed using different assays, including curcumin toxicity assay, fly survival, locomotor response to curcumin treatment (with or without cigarette smoke), trypan blue staining, larval crawling assays, and gene expression analysis. Our data revealed no significant differences in toxicity and locomotor tests across various curcumin concentrations. D. melanogaster tolerated curcumin at concentrations of 0.5 μM, 5 μM, 50 μM, and 500 μM, suggesting its safety without negatively impacting locomotor. Furthermore, curcumin at 5 μM extended the lifespan of D. melanogaster exposed to cigarette smoke, while reversing the negative effects of smoke exposure on gut cell viability and larval locomotor activity. In conclusion, curcumin administration appeared safe for D. melanogaster, with potential benefits for longevity and locomotory function. These findings support the idea that curcumin possesses in vivo antioxidant properties and may serve as a promising pharmacological agent. However, further study is needed to explore its potential applications in human health and disease management, particularly in the context of COPD.

Keywords: Antioxidant; COPD; D. melanogaster; curcumin; fruit fly.

Figure 1.. Developmental profile of Drosophila melanogaster in the presence or absence of curcumin. D. melanogaster larvae successfully undergo pupation (A) and develop into adult flies (B) regardless of curcumin treatment at different concentrations. The differences observed were found to be non-significant (ns).

Figure 2.. Trypan blue staining on the Drosophila melanogaster larval gut. The gut was unstained with trypan blue (A) but stained as blue upon the introduction of cigarette smoke (B).

Figure 3.. Comparison of larval speed between the untreated control group and the group treated with cigarette smoke. Statistical analysis revealed no significant difference between the two groups. ns, non-significant.

Figure 4.. Survival of Drosophila melanogaster exposed to cigarette smoke and treated with different concentrations of curcumin (500 μM, 50 μM, 5 μM, and 0.5 μM).

Figure 5.. Locomotor activity of Drosophila melanogaster upon treatment with curcumin at different concentrations (A-D). Curcumin treatment at all concentrations did not impair fly locomotion. No significant (ns) differences were observed.

Figure 6.. Expression levels of sod1 (A) and sod2 (B) in Drosophila melanogaster in the presence or absence of curcumin, as determined by RT-qPCR relative to rp49. The results indicate no significant differences in the expression of sod1 and sod2 between the control and treatment groups. ns, non-significant.