Riccardo Petrelli 1 , * , Giuseppe Orsomando 2 , Leonardo Sorci 2 , Filippo Maggi 1 , * , Farahnaz Ranjbarian 3 , Prosper C. Biapa Nya 4 , Dezemona Petrelli 5 , Luca A. Vitali 1 , Giulio Lupidi 1 , Luana Quassinti 1 , Massimo Bramucci 1 , Anders Hofer 3 , Loredana Cappellacci 1
13 August 2016
Erigeron floribundus (Asteraceae) is an herbaceous plant widely used in Cameroonian traditional medicine to treat various diseases of microbial and non-microbial origin. In the present study, we evaluated the in vitro biological activities displayed by the essential oil obtained from the aerial parts of E. floribundus, namely the antioxidant, antimicrobial and antiproliferative activities. Moreover, we investigated the inhibitory effects of E. floribundus essential oil on nicotinate mononucleotide adenylyltransferase (NadD), a promising new target for developing novel antibiotics, and Trypanosoma brucei, the protozoan parasite responsible for Human African trypanosomiasis. The essential oil composition was dominated by spathulenol (12.2%), caryophyllene oxide (12.4%) and limonene (8.8%). The E. floribundus oil showed a good activity against Staphylococcus aureus (inhibition zone diameter, IZD of 14 mm, minimum inhibitory concentration, MIC of 512 µg/mL). Interestingly, it inhibited the NadD enzyme from S. aureus (IC 50 of 98 µg/mL), with no effects on mammalian orthologue enzymes. In addition, T. brucei proliferation was inhibited with IC 50 values of 33.5 µg/mL with the essential oil and 5.6 µg/mL with the active component limonene. The essential oil exhibited strong cytotoxicity on HCT 116 colon carcinoma cells with an IC 50 value of 14.89 µg/mL, and remarkable ferric reducing antioxidant power (tocopherol-equivalent antioxidant capacity, TEAC = 411.9 μmol·TE/g).