Comprehensive approaches on the chemical constituents and pharmacological properties of flowers and leaves of American basil (Ocimum americanum L)

Ocimum americanum L. (Lamiaceae) is a common food condiment and also used in traditional medicine in the management of several human diseases. Nonetheless, there has been no effort to delineate the biological and phytochemical profiles of leaves and flowers prepared by different extractive solvents (ethyl acetate, methanol (MeOH), and water). The pharmacological potential of O. americanum extracts on pro-oxidant/pro-inflammatory mediators in rat colon specimens treated with lipopolysaccharide was investigated. In parallel, the inhibitory effects of the extracts on fungal and bacterial strains involved in ulcerative colitis were studied. Qualitative phytochemical analysis showed the presence of phenols, flavonoids, and tannins. Water extracts of flowers and leaves showed strong reducing and radicals scavenging potential. Both MeOH and ethyl acetate extracts of the leaves and flowers were able to inhibit acetylcholinesterase, butyrylcholinesterase, and tyrosinase. All the extracts inhibited the selected bacterial and fungal strains, while only ethyl acetate flower extract displayed antioxidant/anti-inflammatory effects in rat colon. The water and MeOH extracts stimulated colon lactate dehydrogenase (LDH) and serotonin (5-HT) and induced spontaneous migration of HCT116 cells. Future investigations should focus on the biological activity of isolated phytochemicals from the leaves and flowers of O. americanum, in order to clarify the mechanism(s) of action substantiating the observed pharmacological properties.