What is the definition of chemical components?

Chemical components is the chemical makeup which is naturally found in the herb.

For example:  If we were to talk about a fruit, let's say an orange.  
The chemical components of the orange would be:
Vitamin C, essential oils, flavoniods, esters, etc.

If we look at an herb, say Yu Xing Cao.
The chemical components would be Decanoylacetaldehyde, Myrcene, α- Pinene, Linalool, Quercetin.

These are all naturally occurring components, and are not something which has been added to the product.

Other names for Chemical Components are: 
Chemical Makeup
Chemical Composition
Chemical Analysis
List of Compounds