Episarcin is not a commonly used word, but it's worth noting that it's spelled with "epi-", which comes from the Greek meaning "above" or "over." The second part, "-sarcin," is derived from the Greek word "sarx," meaning "flesh" or "muscle." The correct IPA transcription of episarcin would be /ɛpɪˈsɑːksɪn/, with the stress on the second syllable, where the long "a" sound is pronounced. This word is likely to come up in medical or biological contexts when discussing muscle anatomy.
A purin base having the formula, C4H6N3O.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.