In vitro growth inhibition and bactericidal activity of spathulenol against drug-resistant clinical isolates of Mycobacterium tuberculosis

ABSTRACT Spathulenol was isolated from an extract of Azorella compacta Phil., Apiaceae, by various chromatographic method; identification of the chemical structure was confirmed by comparing its spectroscopic data with those reported in the literature. The anti-Mycobacterium tuberculosis activity of spathulenol was evaluated on MDR, pre-XDR, and XDR clinical isolates of M. tuberculosis, as well as on the reference susceptible strain H37Rv and its cytotoxic activity was evaluated on the Vero Cell Line. The anti-M. tuberculosis activity of spathulenol was twice as potent against the MDR, pre-XDR, and XDR clinical isolates (6.25 µg/ml) than on the susceptible H37Rv strain (12.5 µg/ml). Additionally, the anti-M. tuberculosis activity shown by spathulenol was established as bactericidal on drug-resistant and susceptible strains of M. tuberculosis. Finally, cytotoxic activity on the Vero cell line (CC50 = 95.7 µg/ml) indicated that spathulenol is a selective anti-M. tuberculosis compound, with a selective index of 15.31 against drug-resistant clinical isolates of M. tuberculosis.

Antioxidant activity of 50 percent aqueous: ethanol extract from Acantholippia deserticola

The antioxidant properties oí Acantholippia deserticola, a herb used in traditional northern Chilean medicine was studied using free radical - generating systems. The 50 percent aqueous - ethanol extract oí Acantholippia deserticola protected against non-enzymatic lipid peroxidation in microsomal membranes of rat, induced by an Fe++ - ascorbate system and measured spectrophotometrically by the TBARS test, and had strong free radical scavenging capacities on stable ABTS and DPPH radicáis. The results shows that the IC50 valué of the 50 percent aqueous - ethanolic extract oí A.deserticola is 18 ± 0.5 μg/mL in DPPH radical - scavenging, 15 ± 0.8 μg/mL in lipid peroxidation , Total Antioxidant Activity (TAA) is 0.95 mM of Trolox per mg/mL of extract. The total phenolics content of extract is 725 ± 12 mg of gallic acid equivalent per g of dried extract. The results indicate that the 50 percent aqueous - ethanol extract oí Acantholippia deserticola clearly has antioxidant properties.