An extract of Lannea microcarpa: composition, activity and evaluation of cutaneous irritation in cell cultures and reconstituted human epidermis

Lannea microcarpa (Anacardiaceae) is a tropical tree used in African folk medicine and commercial dermopharmaceutical formulations. Fractionation and analysis of its polar extract allowed the identification of 4′‐methoxy‐myricetin 3‐O‐α‐l‐rhamnopyranoside, myricetin 3‐O‐α‐l‐rhamnopyranoside, myricetin 3‐O‐β‐d‐glucopyranoside, vitexin, isovitexin, gallic acid and epi‐catechin, as the major constituents. In‐vivo assay (the croton oil ear test in mice) showed that the extract had significant anti‐inflammatory effect (ID50 = 900 μg cm2) but ten times lower than that of indometacin (ID50 = 93 μg cm2), the non‐steroidal anti‐inflammatory drug used as reference. Cytotoxicity and cutaneous irritation of the extract and its constituents were investigated. The crude extract and its major components did not affect cell viability in‐vitro either in three different cultures (J774.A1, WEHI‐164 and HEK‐293) of cells grown in monolayers or in the reconstituted human epidermis (RHE, 3D model), nor did they cause release of pro‐inflammatory mediators (IL‐1α) or histomorphological modification of RHE.