A penicillium strain having the ability to produce several indole alkaloids in surface and submerged cultures was isolated from the soil of the surrounding of laboratory. By close investigations into morphological characteristics, this strain was identified as Penicillium roqueforti Thom. By the routine procedures using alumina column chromatography, four indole alkaloids, “X-1,” “X-2,” “X-3” and “Y,” were isolated in crystalline form from the surface cultures of mold mentioned in the yields of 230, 15, 16 and 28mg, respectively, when a selected strain was grown at 22°C for 15 days in 200 Roux flasks (1 liter capacity), containing each 150ml of the medium composed of mannitol (30g), glucose (10g), succinic acid (10g), KH2PO4 (1.0g), MgSO4•7 H2O (0.3g), NH4OH (to pH 5.6) and tap water (1 liter). “X-1” crystallized from methanol as colorless needles; C18H22N2O2, mp 182°C (decomp.), [α]15D-130° (c=0.56, pyr.). On hydrolysis with alkali, it yielded a deacetyl derivative; C16H20N2O, colorless needles from methanol, sp 222~224°C (760 mmHg), [α]15D-148° (c=0.55, pyr.). This derivative as well as “X-1” gave a purple color with Allport and Cocking's reagent. “X-2” crystallized from methanol as colorless long needles; C16H20N2, mp 238~239°C (decomp.), [α]15D-108° (c=0.3, pyr.). “X-3” crystallized from methanol as colorless needles; C16H20N2O, sp 222~225°C (760 mmHg), [α]15D-147° (c=0.50, pyr.). On acetylation with acetic anhydride in pyridine, it yielded the alkaloid “X-1” mentioned above. “X-2” and “X-3” were just identical with festuclavine and the above deacetyl derivative of “X-1,” respectively, not only in the said properties but also in color reactions, chromatographic behavior, and UV- and IR-spectra. “Y” crystallized from methanol as colorless needles; C22H23N5O2, mp 225~228°C (decomp.), [α]15D-764° (c=0.50, pyr.). It gave a green color turning gradually into a purple color with Allport and Cocking's reagent. “X-1,” “X-3” and “Y” were undoubtedly new indole alkaloids, for which the authors proposed the names roquefortine A, B and C, respectively. From the data mentioned and from the physico- and spectro-chemical properties, roquefortine A and B were considered to be the new ergoline alkaloids having the structure of 6, 9-dimethyl-7-O-acetyl ergoline and 6, 9-dimethyl-7-hydroxyl ergoline, respectively. The main alkaloid, roquefortine A, exhibited a variety of weak pharmacological actions, such as muscle relaxant, antidepressant, local anesthetic, etc., in experimental animals. Its LD50 (mg/kg, IP) in mice was 340. It has been found certainly with roquefortine B and other also in various roquefort-type cheeses on the market at the insignificant rate of 0.2~3.6mg roquefortine A per 1kg cheese. © 1975, Japan Society for Bioscience, Biotechnology, and Agrochemistry. All rights reserved.