Free fatty acids from the crude hexane extract of the aerial parts of Heliotropium indicum Linn. Growing in Phitsanulok, Thailand

Sixteen free fatty acids from the crude hexane extract of the aerial parts of Heliotropium indicum Linn. growing in Phitsanulok, Thailand, have been identified after conversion to their methyl esters with boron trifluoride-methanol followed by quantification by GC-FID and identification by GC-MS analysis. They accounted for 95% of the chromatographable components, with 9,12-octadecadienoic acid, (39.7%), 9-octadecenoic acid (32.4%), hexadecanoic acid (14.2%) and octadecanoic acid (5.1%), as the major constituents. A small amount of 6,10,14-trimethyl-2-pentadecanone and 3,7,11,15-tetramethyl-2-hexadecen-1-ol as well as a homologous series of n-alkanes present at trace level and ranging from C25 to C31 was also found (see Table 1). The crude hexane extract has been shown to have modest antituberculosis activity (MIC of 100 mg/mL) against Mycobacterium tuberculosis H37Ra.