Antibacterial and Antimycobacterial Lignans and Flavonoids from Larrea tridentata


Dr. María del Rayo Camacho-Corona, Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Av. Universidad s/n, Ciudad Universitaria, San Nicolás de los Garza, Nuevo León CP 66451.



Three lignans and four flavonoids were isolated and characterized from Larrea tridentata and compounds were tested against 16 bacterial species/strains. Results showed that: dihydroguaiaretic acid (1) had activity towards methicillin resistant (MR) Staphylococcus aureus (minimum inhibitory concentration (MIC) 50 µg/mL) and multidrug-resistant (MDR) strains of Mycobacterium tuberculosis (MIC 12.5–50 µg/mL); 4-epi-larreatricin (2) was active against Enterobacter cloacae (MIC 12.5 µg/mL), as well as sensitive (MIC 50 µg/mL) and MDR strains of M. tuberculosis (MIC 25 µg/mL). 3′-Demethoxy-6-O-demethylisoguaiacin (3) displayed activity against sensitive and resistant S. aureus (MIC 25 µg/mL), Enterococcus faecalis (MIC 12.5 µg/mL), Escherichia coli (MIC 50 µg/mL), E. cloacae (MIC 12.5 µg/mL) and MDR strains of M. tuberculosis (MIC 12.5 µg/mL). 5,4′-Dihydroxy-3,7,8,3′-tetramethoxyflavone (4) and 5,4′-dihydroxy-3,7,8-trimethoxyflavone (5) were active against M. tuberculosis MDR strains having MIC values of 25 and 25–50 µg/mL, respectively, while 5,4′-dihydroxy-7-methoxyflavone (6) was active against S. aureus (MIC 50 µg/mL) and E. faecalis (MIC 50 µg/mL). We concluded that lignan 3 is the main compound responsible for the antibacterial activity of L. tridentata. Lignans 1 and 2 as well as flavonoid 6 contribute with some degree of antibacterial activity. On the other hand, compounds 1, 2, 3, 4 and 5 contributed to the antimycobacterial activity found in L. tridentata. Copyright © 2012 John Wiley & Sons, Ltd.