| 摘要 |
PROBLEM TO BE SOLVED: To obtain an antibiotic having an excellent antibiotic action by compounding a specific indole derivative (intramolecular salt, salt or hydrate) obtained from a sea alga as an active ingredient. SOLUTION: This antibiotic contains an indole derivative (intramolecular salt, salt, hydrate) of formula I [R1-R7 are each H, a halogen, a lower alkyl, a lower alkoxy, a lower alkylthio, a group of formula II [R11 and R12 are each H, a halogen, a lower alkyl (having a substituent) or the liked, a group of formula III [R21 and R22 are each H, a halogen, amino, sulfo or the like; R23 and R24 are each H, a halogen, a lower alkyl, a (substituted) aryl or the like] or the like, provided that a case wherein all of R1-R7 are each H is excluded} (for example, 2,4,6-tribromo-3-methylthio-1H-indole) as an active ingredient. The derivative is obtained by purifying an extract obtained from Laurecia brongniatii which is a kind of sea alga. |
