Aqueous Extract of Artemisia annua Shows In Vitro Antimicrobial Activity and an In Vivo Chemopreventive Effect in a Small-Cell Lung Cancer Model

Artemisia annua (A. annua) has been used as a medicinal plant in the treatment of several infectious and non-infectious diseases in the forms of tea and press juice since ancient times. The aim of this study was to evaluate the aqueous extract of A. annua (AAE) as an antimicrobial agent in vitro and to evaluate its chemopreventive efficacy in vivo in a small-cell lung cancer (SCLC) animal model. The dried powder of AAE was prepared using the Soxhlet extraction system from the leaves of Artemisia annua. The in vitro activity of AAE was determined against Candida albicans (C. albicans), Enterococcus faecalis (E. faecalis), Klebsiella pneumoniae (K. pneumoniae), and methicillin-resistant Staphylococcus aureus (MRSA) using the agar well diffusion method and propidium iodide (PI)-stained microbial death under a confocal microscope. The pretreatment of mice with AAE was initiated two weeks before the first dose of benzo[a]pyrene and continued for 21 weeks. The chemopreventive potential of the extract was evaluated by flow cytometry and biochemical and histopathological analyses of the tissues and serum accordingly, after sacrificing the mice. The data revealed the antimicrobial potential of AAE against all the species investigated, as it showed growth-inhibitory activity by MIC, as well as confocal microscopy. The pretreatment of AAE exhibited significant protection in carcinogen-modulated, average body weight (ABW), and relative organ weight (ROW) cancer biomarkers in the serum and antioxidants in the lungs. The hematoxylin and eosin (H&E) staining of the tissues revealed that AAE prevented malignancy in the lungs. AAE also induced apoptosis and decreased intracellular reactive oxygen species (ROS) in the lung cells analyzed by flow cytometry. The current findings demonstrated the use of AAE as an alternative medicine in the treatment of infectious disease and the chemoprevention of lung cancer. To our knowledge, this is the first study that summarizes the chemopreventive potential of AAE in a lung cancer model in vivo. However, further investigations are suggested to understand the role of AAE to potentiate the therapeutic index of the commercially available drugs that show multiple drug resistance against microbial growth and high toxicity during cancer chemotherapy.