Chemical composition and biological activities of the essential oil of Athanasia brownii Hochr. (Asteraceae) endemic to Madagascar

The essential oil hydrodistilled from flowering aerial parts of Athanasia brownii (Asteraceae) was studied for chemical composition by GC/FID and GC/MS and for biological activity, namely antioxidant, antimicrobial and chemopreventive potential by DPPH, ABTS and FRAP, disk diffusion test and MTT assay, respectively. The oil was characterized by a high content of oxygenated sesquiterpenes (71.2%), with selin-11-en-4-α-ol (24.6%), caryophyllene oxide (8.7%), humulene epoxide II (5.1%) and (E)-nerolidol (4.9%) as the predominant compounds. The oil showed a moderate activity against streptococci as well as radical scavenging potential, while worthy were the inhibitory effects against human cancer cells examined such as A375 (malignant melanoma) and HCT 116 (colon carcinoma), with IC50 values of 19.85 and 29.53 µg/ml, respectively.