Phytochemical investigation of the alkaloid extract of the aerial parts of <i>Psychotria nemorosa</i> led to the isolation and characterization of 10 azepine-indole alkaloids, i.e., cimitrypazepine (<b>1</b>), fargesine (<b>2</b>), nemorosines A (<b>3</b>), and B (<b>12</b>), nemorosinosides A-F (<b>4</b>-<b>9</b>), as well as two β-carboline derivatives, 10-hydroxyisodolichantoside (<b>10</b>) and 10-hydroxydolichantoside (<b>11</b>), an isoxazole alkaloid, nemorosinoside G (<b>13</b>), serotonin (<b>14</b>), bufotenine (<b>15</b>), and (<i>S</i>)-gentianol (<b>16</b>). Compounds <b>3</b>-<b>13</b> have not yet been described. These compounds were isolated by semipreparative HPLC, and their structures were determined by means of HRMS, NMR, and ECD measurements. In addition, the monoamine oxidase-A (MAO-A), MAO-B, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) inhibitory activities were evaluated. Alkaloids <b>1</b>-<b>3</b> inhibited the MAO-A activity with IC<sub>50</sub> values of 1.4, 1.4, and 0.9 μM, respectively.