Never a fan of the abuse of the words 'natural' & 'chemical'.  Sucrose (table sugar) is natural.  Dihydrogen Monoxide is a chemical.  Nothing inherently wrong with either.  You'll find Sucrose in pineapple and DHMO in every glass of water you dring regardless of the source.  ;)

In many fruits, such as pineapple and apricot, sucrose is the main sugar. In others, such as grapes and pears, fructose is the main sugar.