Phytochemical Composition of Oleogum Resins and Their Cytotoxicity against Skin Cancer Cells.

Oleogum resins of the genus have been used in traditional medicines for centuries. More than 200 species exhibit highly variable phytochemical compositions. A novel highly selective, sensitive, accurate HPLC-MS/MS method was developed and validated to quantify five characteristic phytosteroids and furanosesquiterpenoids, namely ()-guggulsterone, ()-guggulsterone, curzerenone, furanoeudesma-1,3-diene, and myrrhone. The resulting contents and additionally GC analysis were used to classify and differentiate oleogum resins of the species , , , , , and , as well as unspecified resins. Interestingly, a sample from Ogaden, Ethiopia, comprised 446 ng/mg guggulsterones presumed to be unique to from the Indian subcontinent. However, from Ogaden differed considerably from in respect to guggulsterones isomer's ratio. Moreover, the cytotoxicity of extracts, essential oils, botanical drugs containing , and pure compounds against the epidermoid carcinoma A431, malignant melanoma RPMI-7951 and SK-MEL-28 cells was investigated in vitro. Thereby, especially extract and essential oil exhibited high cytotoxicity against skin cancer cells with IC of 2.9-10.9 µg/mL, but were less toxic to normal keratinocytes. In summary, oleogum resins and its phytochemicals warrant further investigation aiming at chemotaxonomical classification as well as application in skin cancer treatment.