Both ginger and turmeric are generally considered safe and without significant side effects, and both are available as capsules from health-food stores. However, each may interact with certain prescription medications, and neither should be taken if you are pregnant. Do not self-treat with either ginger or turmeric.
Think of the leather in your car as skin that needs to be cleaned, conditioned, and protected to maintain a healthy appearance. Similar to our skin, if we do not take care of leather, it will dry, crack, and eventually break over time. Wrinkles in leather are caused by environmental stress, heat, or damage from regular wear and tear.
Don't... wait for a layer of crud to accumulate before washing. Dead bugs, bird droppings, and chemicals from the atmosphere all leach acids that can strip away wax and eventually eat into your car's paint. If left too long, they can cause damage that requires sanding and repainting the area to correct.