Antidermatophytic triterpenoids from Syzygium jambos (L.) Alston (Myrtaceae)

Chemical investigation of the EtOAc extract of the stem bark of Syzygium jambos (L.) Alston (Myrtaceae) afforded a number of known triterpenes such as friedelin, beta-amyrin acetate, betulinic acid and lupeol. Friedelin was submitted to a Baeyer-Villiger oxidation, and was also reduced with LiAlH(4) to give the known friedelolactone and friedelanol, respectively. These compounds were identified by comparison of NMR spectral data with those from the literature. The EtOAc extract and the isolated compounds were tested for their antidermatophytic activity against three dermatophyte species: Microsporum audouinii, Trichophyton mentagrophytes and Trichophyton soudanense, commonly found in Cameroon. Betulinic acid and friedelolactone were the most active compounds, and the most sensitive fungi were Trichophyton soudanense and Trichophyton mentagrophytes.