Water is a great solvent. It’s neutral and doesn’t provide any strong positive or negative effects. It just helps components to mix better and to transport active components.
Vitamin C is known for its strong antioxidant activity. It helps to slow down aging processes. The other positive effect of this ingredient is that it helps to make skin tone even. It's a great ingredient to counter dark areas and uneven skin tone. It's well-researched and considered safe. But it's acid and can irritate the skin if used too often.
Pentylene Glycol is a great replacement for Propylene Glycol. It has very similar characteristics but it’s derived from plants (usually from corn). Natural cosmetics lovers will find this component very useful. It enhances the moisturizing effect of cosmetic products, improves the efficiency of preservatives and it’s an effective emulsifier. It’s approved by ECOCERT and COSMOS so it’s considered to be 100% safe and can be used in vegan products.