DRI is an umbrella term for groups of values including RDA's, that specify recommended dosages proposed by the Food and Nutrition Board. For herbals, you should ask at the health food store, your pharmacist or a health care practitioner. They are also used to ensure compatibility among various ingredients for tableting, to make sure the tablet adheres together. It is nearly impossible to manufacture a supplement tablet without these inactive ingredients. Here is a question that follows the previous question about daily values.
Many spices used in cooking also have a therapeutic effect as a medicinal herb.
Take for example, ginger. It is used widely in Asian cookery and is used medicinally for digestion and upset stomach. There are many herbs that are very bitter and would not be good used as a flavoring or spice. Elemental weight refers to the actual weight of the available mineral. Compound weight refers to the entire weight of the mineral plus an organic material it has been combined with.