A new lupine alkaloid, (-)-Δ⁵-dehydromultiflorine [1], was isolated from the viable seeds of Lupinus termis. The unusual lupine alkaloids (-)-multiflorine [2], (+)-angustifoline and (±)-lupanine N-oxide were also isolated, together with (±)-lupanine and (+)-13-hydroxylupanine. The structure of 1 was determined by spectroscopic methods. As a result of screening plants belonging to the Leguminosae for lupine alkaloids (14), a novel lupine alkaloid, (-)-Δ⁵-dehydromultiflorine [1], was isolated from the viable seeds of the Egyptian lupine, Lupinus termis Forsk. L. termis is an annual herb which is cultivated in the countries of the Mediterranean region for its edible seeds (5). Previous work on the basic constituents in the seeds of L. termis has demonstrated the presence of (±)-lupanine and (+)-13-hydroxylupanine (6-8). In further investigations, the basic components in the viable seeds of the Egyptian lupine yielded the new lupine alkaloid 1 together with the five known lupine alkaloids (±)-lupanine, (-)-multiflorine [2], (+)-angustifoline, (+)-13-hydroxylupanine, and (±)-lupanine N-oxide. This is the first isolation of (±)-lupanine N-oxide from natural sources, while (+)-lupanine N-oxide has already been isolated from Thermopsis lupinoides (1). The structure of 1 was confirmed by ¹H- and ¹³C-nuclear magnetic resonance (NMR) spectroscopy, including correlation spectroscopy (COSY), high-resolution electron impact mass spectrometry (HR-EI-MS), infrared (IR), and ultraviolet (UV) spectroscopy. These results indicated that the configuration of rings C and D in the molecule of 1 is a chair-chair cis system. Compound 1 has been previously reported as an unexpected intermediate in a catalytic hydrogenation (PtO₂ in H₂O) of (-)-multiflorine [2] (9), and its structure has been confirmed by X-ray analysis (15). However, this is the first report of the isolation and full characterization of 1 from a natural source.