In vitro study on efficacy of PHELA, an African traditional drug against SARS-CoV-2.

In 2019, coronavirus has made the third apparition in the form of SARS-CoV-2, a novel strain of coronavirus that is extremely pathogenic and it uses the same receptor as SARS-CoV, the angiotensin-converting enzyme 2 (ACE2). However, more than 182 vaccine candidates have been announced; and 12 vaccines have been approved for use, although, even vaccinated individuals are still vulnerable to infection. In this study, we investigated PHELA, recognized as an 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; as a candidate therapy for COVID-19. In vitro testing found that PHELA inhibited > 90% of SARS-CoV-2 and SARS-CoV infection at concentration levels of 0.005 mg/ml to 0.03 mg/ml and close to 100% of MERS-CoV infection at 0.1 mg/ml to 0.6 mg/ml. The in vitro average IC50 of PHELA on SARS-COV-2, SARS-CoV and MERS-COV were ~ 0.01 mg/ml. Secondly in silico docking studies of compounds identified in PHELA showed very strong binding energy interactions with the SARS-COV-2 proteins. Compound 5 showed the highest affinity for SARS-COV-2 protein compared to other compounds with the binding energy of - 6.8 kcal mol-1. Our data showed that PHELA has potential and could be developed as a COVID-19 therapeutic.

Selection ofMycosphaerella fijiensis-resistant cell lines from micro-cross sections of banana and plantain.

Anin vitro selection system using microcross sections of banana and plantain cultivars belonging to AAA and AAB genomic groups were used to produce plants resistant against the Black Sigatoka disease. The fungus resistant plantlets were obtained in a double selection system. This involved in a first step the use of a fungal crude filtrate and in the second step the purified host-specific toxin 2,4,8-trihydroxytetralone extracted from the fungusMycosphaerella fijiensis (M. fijiensis), the causal agent of Black Sigatoka disease. Resistant plantlets obtained from the double selection system were inoculated with conidia ofM. fijiensis in a growth chamber to reproduce Black Sigatoka symptoms. Compared to non-treated control plantlets, which were highly susceptible to the fungus, 10.7-19.3% toxin-resistant plantlets which arose from tissues that went through the double selection system were resistant againstM. fijiensis. This technique of using micro-cross sections for selection on fungal toxins seems to be amenable to differentMusa genotypes for the production of fungus-resistant plants.