Complex sentence: A lack of melatonin could significantly contribute to gallbladder stones, as melatonin both inhibits cholesterol secretion from the gallbladder, enhances the conversion of cholesterol to bile, and is an antioxidant, capable of reducing oxidative stress to the gallbladder.
Split into simpler sentences: A lack of melatonin could significantly contribute to gallbladder stones, as melatonin both inhibits cholesterol secretion from the gallbladder and enhances the conversion of cholesterol to bile. Melatonin is also an antioxidant, capable of reducing oxidative stress to the gallbladder.