Six new compounds, globunones A-F (<b>1</b>-<b>6</b>), and two new flavonoids (<b>7</b> and <b>8</b>) together with nine known compounds (<b>9</b>-<b>17</b>) were isolated from the stems of <i>Knema globularia.</i> The chemical structures of <b>1</b>-<b>8</b> were elucidated by an analysis of their NMR and high-resolution electrospray ionization mass spectrometry data as well as by comparison with literature values. The absolute configurations were determined using time-dependent density functional theory electronic circular dichroism (TD-DFT-ECD). Globunones A-E (<b>1</b>-<b>5</b>) represent the initial combined structures of a flavan-3-ol core and a 1,4-benzoquinone core. Globunone F (<b>6</b>) is the first flavanone-type compound bearing a 2-(2,4-dihydroxyphenyl)-2-oxoethyl group found to date in Nature. Compounds <b>1</b>-<b>3</b> and <b>6</b>-<b>17</b> were tested for their yeast α-glucosidase inhibitory activity. All compounds tested (except for <b>13</b> and <b>14</b>) showed potent inhibition toward α-glucosidase with IC<sub>50</sub> values in the range 0.4-26.6 μM. Calodenin A (<b>15</b>) was the most active compound with an IC<sub>50</sub> value of 0.4 μM (the positive control, acarbose, IC<sub>50</sub> 93.6 μM). A kinetic analysis of <b>15</b> revealed that it is a noncompetitive inhibitor with a <i>K</i><sub>i</sub> value of 3.4 μM.