Melatonin as a multifunctional modulator: emerging insights into its role in health, reproductive efficiency, and productive performance in livestock

The effect of melatonin on sleep quality and daytime sleepiness in Parkinson's disease: A systematic review and meta-analysis of randomized placebo-controlled trials

BACKGROUND

Sleep disturbances are common in Parkinson's disease (PD), significantly impacting quality of life. Melatonin may help, but evidence regarding dosage, formulation, and treatment duration remains inconclusive.

OBJECTIVE

To quantitatively analyze the effect of melatonin on sleep quality and daytime sleepiness in patients with PD.

METHODS

We comprehensively searched multiple databases up to February 2025, selecting relevant randomized controlled trials (RCTs). RevMan software was used for analysis. Subgroup analyses included treatment duration (4 weeks vs. 8-12 weeks), dose (≤4 mg vs. >4 mg), and formulation (immediate-release vs. prolonged-release).

RESULTS

Five RCTs (206 patients) were included. Doses ≤4 mg showed no significant improvement in total Pittsburgh Sleep Quality Index (PSQI) scores (MD = -1.26, 95 % CI: -2.72 to 0.20). Doses >4 mg demonstrated a stronger effect (MD = -2.90, 95 % CI: -4.02 to -1.78). Short-term use (4 weeks) significantly improved PSQI scores (MD = -2.43, 95 % CI: -3.98 to -0.88), whereas longer treatment (8-12 weeks) showed a non-significant effect (MD = -1.24, 95 % CI: -3.15 to 0.67). Immediate-release formulations significantly improved PSQI scores (MD = -2.20, 95 % CI: -3.32 to -1.08), while prolonged-release formulations showed no significant effect (MD = -0.61, 95 % CI: -4.15 to 2.93). Melatonin modestly reduced excessive daytime sleepiness measured by the Epworth Sleepiness Scale (ESS) (MD: -0.97, 95 % CI: -1.81, -0.14).

CONCLUSION

Melatonin may improve sleep quality and reduce daytime sleepiness in PD patients, particularly with short-term use of immediate-release formulations.

Melatonin augments anti-tumor activity and alleviates nephrotoxicity of gemcitabine in a pancreatic cancer xenograft model targeting P62/Keap1 pathway

Although gemcitabine is a primary chemotherapy for pancreatic cancer, its effectiveness is limited by chemoresistance and nephrotoxicity, posing significant clinical challenges. Therefore, the development of novel therapeutic approaches to prevent pancreatic malignancy remains crucial. This study aimed to investigate the potential of melatonin in enhancing gemcitabine's anticancer efficacy while mitigating its nephrotoxic effects through modulation of the Keap1/p62 pathway. A pancreatic cancer xenograft model was established in rats, which received either gemcitabine (50 mg/kg, I.P.), melatonin (50 mg/kg, I.P.), or their combination three times per week for 2 weeks. Our findings demonstrate that melatonin potentiates gemcitabine's cancer-suppressing effects via modulation of the Kelch-like-ECH associated protein-1 (Keap1)/p62 pathway, resulting in reduced fibrosis, oxidative stress, and inflammatory markers. Additionally, melatonin significantly mitigated gemcitabine-induced nephrotoxicity. These results suggest that melatonin may serve as an adjuvant therapy in pancreatic cancer treatment, enhancing chemotherapy efficacy while reducing its adverse effects.

Melatonin from Plants: Going Beyond Traditional Central Nervous System Targeting-A Comprehensive Review of Its Unusual Health Benefits

Melatonin is indispensable for the homeostasis of plants and animals. In humans, it can help prevent or be an adjuvant treatment for several diseases mainly related to the immune system, inflammation, and oxidative stress. Moreover, a melatonin-rich diet is linked to several health benefits, such as regulation of circadian rhythm, regulation of the immunological system, epilepsy control, delaying the aging process, and diminishing hormones related to cancer. This review aimed to show the effects of melatonin in diseases beyond its traditional use. The results showed it can present scavenging of free radicals, reducing inflammatory cytokines, and modulating the immune system. Moreover, it can improve insulin resistance, blood pressure, LDL-c, adipose tissue mass, adhesion molecules, endothelial impairment, and plaque formation. These effects result in neuro- and cardioprotection, improvement of liver diseases, rheumatoid arthritis, dermatitis, COVID-19, polycystic ovaries, and sepsis. We conclude that plant melatonin can benefit patients with many diseases besides sleep problems and neurodegeneration. Plant melatonin may be more cost-effective and present fewer adverse events than synthetic. However, more clinical trials should be performed to show adequate doses, formulation, and treatment time.