Effect of PHELA, an African traditional drug, on levels of selected inflammatory cytokines in mammalian cells infected with SARSCoV- 2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes a severe illness, often characterized by an excessive release of proinflammatory cytokines, leading to a cytokine storm associated with disease severity. In this study the effect of PHELA, an accepted herbal combination of four exotic African medicinal plants, namely; Clerodendrum glabrum E. Mey. Lamiaceae, Gladiolus dalenii van Geel, Rotheca myricoides (Hochst.) Steane & Mabb, and Senna occidentalis (L.) Link, was investigated to determine the effect on viral replication of SARS-CoV-2 Omicron infected mammalian cells and the effect on cytokine release. PHELA has previously been proposed for use as an immune booster. In this study mammalian cells were treated with plant extracts before or after infection with SARS-CoV-2. Viral RNA was measured at intervals and selected cytokine levels (IL-1β, IL-2Rα, IL-6, TNF-α, IFN-γ) were monitored. No significant difference in viral RNA was observed between infected cells treated with plant extracts and untreated infected cells. However, PHELA-treated cells showed a delay in viral RNA increase. Infected cells treated with PHELA exhibited significantly lower levels of IL-1β, IL-2Rα, and TNF-α compared to untreated infected cells at 48- and 72-hours post-infection. Post-treatment was more effective in reducing proinflammatory cytokine production than pre-treatment, highlighting the potential of PHELA and its constituents in modulating cytokine responses during SARS-CoV-2 infection.