Antileishmanial Phenylpropanoids from the Leaves of Hyptis pectinata (L.) Poit.

Hyptis pectinata, popularly known in Brazil as "sambacaitá" or "canudinho," is an aromatic shrub largely grown in the northeast of Brazil. The leaves and bark are used in an infusion for the treatment of throat and skin inflammations, bacterial infections, pain, and cancer. Analogues of rosmarinic acid and flavonoids were obtained from the leaves of Hyptis pectinata and consisted of two new compounds, sambacaitaric acid (1) and 3-O-methyl-sambacaitaric acid (2), and nine known compounds, rosmarinic acid (3), 3-O-methyl-rosmarinic acid (4), ethyl caffeate (5), nepetoidin A (6), nepetoidin B (7), cirsiliol (8), circimaritin (9), 7-O-methylluteolin (10), and genkwanin (11). The structures of these compounds were determined by spectroscopic methods. Compounds 1-5, and 7 were evaluated in vitro against the promastigote form of L. braziliensis, and the ethanol extract. The hexane, ethyl acetate, and methanol-water fractions were also evaluated. The EtOH extract, the hexane extract, EtOAc, MeOH:H2O fractions; and compounds 1, 2 and 4 exhibited antileishmanial activity, and compound 1 was as potent as pentamidine. In contrast, compounds 3, 5, and 7 did not present activity against the promastigote form of L. braziliensis below 100 µM. To our knowledge, compounds 1 and 2 are being described for the first time.