The first organ to emerge from germinating seeds is the root. The roots perform the vital function of absorbing water and nutrients (iron, calcium, vitamins, hormones and amino acids) deposited by decaying matter.
In addition, roots anchor plants in the soil and permit them to remain in position to collect the sunlight needed to carry out photosynthesis.
Plant stems provide a framework for branches and leaves to obtain maximal exposure to the sun. Stems of herbs are covered by a thin epidermis and are not protected by a woody bark.
Rhizomes are a network of underground stems.
Leaves are the sites of photosynthesis and the production of unique compounds that provide humankind with natural medicine.
Plant Derived Medicines
Fatty acids, volatile oils, alkaloids and saponins are important plant constituents. Since their contribution to a plant’s medicinal potential is based on reaching the target receptor sites in the body, their solubility within membranes is essential. Membrane permeability, solubility and absorption from the gastrointestinal tract are determined by the chemical structure of the plant compound.
Saponins or plant steroids are among the most commonly encountered medicinal agents found in plants.
These compounds when attached to sugar molecules are termed glycosides. Glycosides are usually the pharmacologically active form of the medicinal compound.