Methylspinazarin is a rare naphthoquinone pigment produced by a strain of Streptomyces filipinensis, isolated by Nagatsu and colleagues at Ochanomizu University, Japan in 1973. Methylspinazarin inhibits catechol-O-methyl transferase (COMT) and exhibits a strong hypotensive effect in spontaneously hypertensive rats. Methylspinarazin is inactive as an antibacterial.