Oleandrin is a molecule that is extracted from Nerium oleander plant and is specifically formulated for oral administration. Oleandrin belongs to the class of compounds known as cardiac glycosides contained in plant tissues (cardenolides) from the plant Nerium oleander. This plant has been used throughout the world in different medical systems in the treatment of a wide range of conditions including: cardiac illnesses, asthma, dermatologic issues, cancer, and epilepsy (Dastur, 1962; Dey & Chaudhuri, 2016; Ding, 2013; Duke, 1985; Ghosh, 2008).
Oleander-derived cardiac glycosides were examined for possible therapeutic value in treating congestive heart failure in the mid-1930s; the best described cardenolide is digitalis (digitoxin from foxglove) (Langford & Boor, 1996). In addition, oleandrin has been used as: an antibacterial (Hadizadeh et al., 2009; Hussain & Gorsi, 2004), as well as for pain relief (Erdemoglu et al., 2003), anti-anxiety (Singhal & Gupta, 2011), neuroprotective (Leung et al., 2006), hepatoprotective (Singhal & Gupta, 2012), anti-inflammatory and anticancer (Fu et al., 2005; Pan et al., 2015), and antioxidant properties (Dey et al., 2012) have been established (Dey & Chaudhuri, 2016).
Cardiac glycosides have also been recognized to exhibit anti-cancer and antiviral activities.
Oleandrin at low concentrations kills cultured human cancer cells with no detriment to healthy human cells. (Lin et al., 2008; Newman et al., 2006; Pathak et al., 2000)
Oleandrin showed considerable activity against both influenza virus and herpes simplex virus (Rajbhandari et al., 2001). Studies also showed that oleandrin has strong antiviral activity against HIV (100 ng/mL of oleandrin) (Singh et al., 2013) and against HTLV-1 at increasing concentrations (10-100 ng oleandrin) (Hutchison et al., 2019) with a unique property of producing viral progeny with a greatly diminished potential to infect new target cells.
Oleandrin’s antiviral effect was observed against SARS-CoV-2 (COVID-19) in Vero (African Green monkey kidney) cells. The low concentration of 0.01 ug/mL of oleandrin resulted in a significant reduction in plaque forming units (Newman, 2020). This study was performed at the World Reference Center for Emerging Viruses and Arboviruses at the University of Texas Medical Branch (UTMB), in Galveston over this past spring and summer. UTMB has conducted tests on some 53,000 potential COVID-19 therapeutics by their count.