The line, "sophisticated rhetorician intoxicated with the exuberance of your own verbosity" that is spoken by Anthony when he emerges from the Easter egg is an almost exact quotation from a speech given by Benjamin Disraeli in 1878. Disraeli (who was referring to W.E. Gladstone) used the word "inebriated" rather than "intoxicated".
It might come as a surprise but there is an interesting goof in the film. In the introduction scene between Rishi Kapoor and Neetu Singh, Rishi's character Akbar Illahabadi calls Neetu Singh's character Dr Salma by her real name and not with her character's name. This goof is noticeable enough, but no efforts were taken to correct it in the movie. This is the scene when Akbar comes to Dr Salma for a health check-up and he refers to Dr Salma as Neetu.
The story of Amar Akbar Anthony is really interesting and director Manmohan Desai got the idea while reading a newspaper! He read a news piece of a drunk man named Jackson, who was fed up of his life and hence decided to drop his three children in the park. Similarly, in the film, Pran takes his children and drops them in a park at the beginning of the film. In the story, the eldest kid is adopted by a Hindu police officer, and the other two by a Muslim tailor and a Catholic priest, respectively.
Manmohan Desai initially did not plan to have a heroine for Vindo Khanna's character. But Vinod insisted that he must also have one since Amitabh and Rishi had Parveen and Neetu playing their heroines. Desai decided to create a small role for his love interest and finally signed Shabana Azmi who was already playing his heroine in Parvarish at that time.
According to Director Manmohan Desai, the character of Anthony Gonzalves (played by Amitabh Bachchan) was based upon a real person from his youth.