[1] Julian was the first person to synthesize the natural product physostigmine, and a pioneer in industrial large-scale chemical synthesis of the human hormones progesterone and testosterone from plant sterols such as stigmasterol and sitosterol.

His work laid the foundation for the steroid drug industry's production of cortisone, other corticosteroids, and artificial hormones that led to birth control pills.

His father, James was employed as a clerk in the Railway Service of the United States Post Office, and his mother Elizabeth was a schoolteacher.

[citation needed] After graduating from DePauw, Julian wanted to obtain his doctorate in chemistry, but learned it would be difficult for an African American to do so.

However, worried that white students would resent being taught by an African American, Harvard withdrew Julian's teaching assistantship, making it impossible for him to complete his Ph.D. there.

At Howard, in part due to his position as a department head, Julian became caught up in university politics, setting off a chain of scandals.

At university president Mordecai Wyatt Johnson's request,[16] he goaded white professor of chemistry Jacob Shohan (Ph.D., Harvard[17]), into resigning.

"[18] In the letters, he spoke with familiarity, and some derision, of members of the Howard University faculty, calling one well-known dean an "ass (also known as a donkey)".

[23] At the lowest point in Julian's career, his former mentor, William Martin Blanchard, a professor of chemistry at DePauw, threw him a much-needed lifeline.

[5] Julian also extracted stigmasterol, which took its name from Physostigma venenosum, the west African calabar bean that he hoped could serve as raw material for the synthesis of human steroidal hormones.

At about this time, in 1934, Butenandt and Fernholz, in Germany,[24][25] had shown that stigmasterol, isolated from soybean oil, could be converted to progesterone by synthetic organic chemistry.

DuPont offered a job to Pikl, but declined to hire Julian, despite his superlative qualifications as an organic chemist, apologizing that they were "unaware he was black".

Isolated soy protein could replace the more expensive milk casein in industrial applications such as coating and sizing of paper, glue for making Douglas fir plywood, and in the manufacture of water-based paints.

At the start of World War II, Glidden sent a sample of Julian's isolated soy protein to National Foam System Inc. (today a unit of Kidde Fire Fighting), which used it to develop Aer-O-Foam,[27][28] the U.S. Navy's firefighting "bean soup."

When a hydrolyzate of isolated soy protein was fed into a water stream, the mixture was converted into a foam by means of an aerating nozzle.

[29] Percy's research at Glidden changed direction in 1940 when he began work on synthesizing progesterone, estrogen, and testosterone from the plant sterols stigmasterol and sitosterol, isolated from soybean oil by a foam technique he invented and patented.

Julian and his co-workers obtained patents for Glidden on key processes for the preparation of progesterone and testosterone from soybean plant sterols.

Product patents held by a former cartel of European pharmaceutical companies had prevented a significant reduction in wholesale and retail prices for clinical use of these hormones in the 1940s.

Julian also announced the synthesis, starting with the cheap and readily available pregnenolone (synthesized from the soybean oil sterol stigmasterol) of the steroid cortexolone (also known as Reichstein's Substance S, and most often referred as 11-Deoxycortisol[41]), a molecule that differed from cortisone by a single missing oxygen atom; and possibly 17α-hydroxyprogesterone and pregnenetriolone, which he hoped might also be effective in treating rheumatoid arthritis,[37][38][39][40][42] but unfortunately they were not.

[40] On April 5, 1952, biochemist Durey Peterson and microbiologist Herbert Murray at Upjohn published the first report of a fermentation process for the microbial 11α-oxygenation of steroids in a single step (by common molds of the order Mucorales).

[43] After two years, Glidden abandoned production of cortisone to concentrate on Substance S. Julian developed a multistep process for conversion of pregnenolone, available in abundance from soybean oil sterols, to cortexolone.

In 1952, Glidden, which had been producing progesterone and other steroids from soybean oil, shut down its own production and began importing them from Mexico through an arrangement with Diosynth (a small Mexican company founded in 1947 by Russell Marker after leaving Syntex).

Julian used his own money and borrowed from friends to build a processing plant in Mexico, but he could not get a permit from the government to harvest the yams.

Abraham Zlotnik, a former Jewish University of Vienna classmate whom Julian had helped escape from the Holocaust, led a search to find a new yam source in Guatemala for the company.

In July 1956, Julian and executives of two other American companies trying to enter the Mexican steroid intermediates market appeared before a U.S. Senate subcommittee.

[54] Ruben Santiago-Hudson portrayed Percy Julian in the Public Broadcasting Service Nova documentary about his life, called "Forgotten Genius".

It was presented on the PBS network on February 6, 2007, sponsored by the Camille and Henry Dreyfus Foundation with further funding by the National Endowment for the Humanities.