Some helpful notes about Calendula

Calendula officinalis otherwise commonly known as the Marigold flower.  The main constituents of this flower are; essential oil, saponins, carotenoids, bitter principle, sterols, flavonoids, mucilage. 

And why do we use calendula:

Marigold is one of the best herbs for treating local skin problems. It may be used safely wherever there is an inflammation on the skin whether due to infection or physical damage. [1] (Hoffman, The Holistic Herbal, 1983.)

Preparation of the drug inhibit inflammation and promote the formation of granulation tissue*. They are used ... externally in the form of infusions, tinctures & ointments as a wound healing remedy ... for poorly healing wounds, bruises, boils and rashes. [2] (Grainger Bisset & Wichtl, Herbal Drugs and Phytopharmaceuticals, 2001.)

*Granulation tissue is new connective tissue and microscopic blood vessels that form on the surfaces of a wound during the healing process [3] Wikepedia, https://en.wikipedia.org/wiki/Granulation_tissue.

Extracts from the German Commission E. monograph (BAnz no 50 13.03.1986) "... promotes wound healing, anti-inflammatory and granulation-promoting effects on topical application ..."