Anti-Microbial Activity of Aliphatic Alcohols from Chinese Black Cardamom ( Amomum tsao - ko ) against Mycobacterium tuberculosis H37Rv.

The fruits of Amomun tsao-ko (Chinese black cardamom; Zingiberaceae) contain an abundance of essential oils, which have previously demonstrated significant antimicrobial activity. In our preliminary search for natural anti-tuberculosis agents, an acetone extract of A . tsao - ko (AAE) exhibited strong antibacterial activity against Mycobacterium tuberculosis H37Rv. Therefore, the aim of this study was to find the principal compounds in an AAE against M . tuberculosis . Nine aliphatic compounds ( 1 - 9 ) including a new compound ( 1 , tsaokol B) and a new natural unsaturated aliphatic diester ( 6 ), together with three acyclic terpenoids ( 10 - 12 ), were isolated from an AAE by repetitive chromatography. The structures of the isolates were determined by spectroscopic data analysis. All isolates were evaluated for activity against M . tuberculosis H37Rv. Isolated compounds 1 - 6 , and 11 had MICs ranging from 0.6-89 µg/mL. In contrast, compounds 7 to 10 , and 12 had MICs that were >100 µg/mL. Tsaokol A ( 3 ) was the most active compound with MICs of 0.6 µg/mL and 1.4 µg/mL, respectively, against replicating and nonreplicating M . tuberculosis . These results are the first to illustrate the potency of tsaokol A ( 3 ) as a natural drug candidate with good selectivity for treating tuberculosis.