Non-antimicrobial properties of tetracyclines--dental and medical implications.

The tetracyclines are a group of broad-spectrum antimicrobial agents. The first of these compounds, chlortetracycline was isolated from Streptomyces aureofaciens by Benjamin Duggar and introduced into the market in 1948. In 1952, tetracycline was derived semisynthetically from chlortetracycline by removal of its chlorine atom by catalytic hydrogenation. Methacycline, doxycycline and minocycline are all semi-synthetic derivatives. The tetracyclines are closely congeneric derivatives of the polycyclic napthacenecarboxamide. The tetracyclines possess a wide range of antimicrobial activity against gram-positive and gram-negative bacteria. In vitro, these drugs are primarily bacteriostatic. Tetracyclines have been used extensively as antimicrobial agents for the treatment of various types of periodontal diseases until light was shed on their equally important non-antimicrobial properties by Golub. The tetracyclines and their non-antimicrobial, chemically modified analogues have properties that appear to modulate host response by inhibiting the activity of the matrix metalloproteinases that cause collagen destruction. They also inhibit osteoclast function, stimulate osteoblastic bone formation, and regulate angiogenesis.