Screening of medicinal plants from El Salvador for anti-viral activity against Herpes simplex 1.

Herpes simplex virus 1 is one of the most prevalent pathogens worldwide. Resistant strains to current anti-viral treatment have been reported, requiring the search for novel anti-virals. Using a qPCR method to assess anti-herpetic activity from natural products, we analyzed 72 plant extracts from El Salvador and identified eighteen methanolic extracts with anti-viral activity of ≥ 75%. Anti-herpetic activity has not been previously reported in fourteen of the plants (Euphorbia lancifolia, Piper tuberculatum, Cordia alliodora, Tecoma stans, Taraxacum officinale, Hamelia patens, Witheringia solanacea, Emilia fosbergii, Gnaphalium viscosum, Citrus aurantium, Ambrosia peruviana, Carica papaya, Solanum hazenii and Melothria pendula). Four extracts were from species with previously reported anti-herpetic activity (Plantago major, Psidium guajava, Sida acuta and Bursera simaruba). These extracts effective anti-viral concentrations (EC50) were between 203 and 6.31 µg/mL, while the selectivity indexes (SI) were between 55.91 and 2.57. Euphorbia lancifolia showed the most effective anti-viral activity (EC50 = 6.31 µg/mL, SI = 51.82).

Screening of Natural Products Inhibitors of SARS-CoV-2 Entry.

The COVID-19 pandemic has led to the search for new molecules with antiviral activity against SARS-CoV-2. The entry of the virus into the cell is one of the main targets for inhibiting SARS-CoV-2 infection. Natural products are an important source of new therapeutic alternatives against diseases. Pseudotyped viruses allow the study of SARS-CoV-2 viral entry inhibitors, and due to their simplicity, they allow the screening of a large number of antiviral candidates in Biosafety Level 2 facilities. We used pseudotyped HIV-1 with the D614G SARS-CoV-2 spike glycoprotein to test its ability to infect ACE2-expressing HEK 293T cells in the presence of diverse natural products, including 21 plant extracts, 7 essential oils, and 13 compounds from plants and fungi. The 50% cytotoxic concentration (CC50) was evaluated using the resazurin method. From these analyses, we determined the inhibitory activity of the extract of Stachytarpheta cayennensis, which had a half-maximal inhibitory concentration (IC50) of 91.65 µg/mL, a CC50 of 693.5 µg/mL, and a selectivity index (SI) of 7.57, indicating its potential use as an inhibitor of SARS-CoV-2 entry. Moreover, our work indicates the usefulness of the pseudotyped-virus system in the screening of SARS-CoV-2 entry inhibitors.

Extractos vegetales de tres especies del género Baccharis inducen la proliferación de células mononucleares humanas / Plant extracts of three species of the genus Baccharis induce human mononuclear cells proliferation

Las plantas de uso en medicina tradicional constituyen una fuente importante de compuestos con actividad inmunomoduladora; entre ellas las especies del género Baccharis, conocidas popularmente como "Jaguareteka´a" en nuestro país, son ampliamente empleadas. En este estudio se evaluó la actividad inmunomoduladora de extractos metanólicos de tres especies del género Baccharis (B. trimera, B. notosergilay B. punctulata) sobre la proliferación de células mononucleares humanas de sangre periférica. Los extractos de las tres especies estudiadas estimularon la proliferación de las células mononucleares. Específicamente, el extracto de B. notosergila estimuló la proliferación celular a todas las concentraciones probadas (5, 10, 25 y 50 µg/mL), mientras que los extractos de B. trimera y B. punctulata mostraron este efecto a 5 y 10 µg/mL. Además, por presentar mayor inducción de la proliferación, se realizó un fraccionamiento con diferentes solventes del extracto metanólico de B. notosergila y B. punctulata. La fracción de acetato de etilo de ambos extractos vegetales aumentó la proliferación celular, sugiriendo que compuestos de polaridad media son los responsables de esta actividad. Estos resultados demuestran que los extractos de B. trimera, B. notosergila y B. punctulata poseen actividad inmunomoduladora sobre células mononucleares humanas y servirán de base a otros estudios para determinar el o los componentes activos de los extractos sobre el sistema inmune(AU)

Plants used in traditional medicine are an important source of compounds with immunomodulatory activity. Species of the genus Baccharis, popularly known as "Jaguareteka'a" in our country, are used in folk medicine for the treatment of liver, gastrointestinal, inflammatory and infectious diseases. In this study, we evaluated the immunomodulatory activity of methanolic extracts of three species of the genus Baccharis (B. trimera, B. notosergila and B. punctulata) on the proliferation of human peripheral blood mononuclear cells. Extracts of the three species studied stimulated the proliferation of mononuclear cells. The extract of B. notosergila stimulated cell proliferation at all concentrations tested, while extracts of B. trimera and B. punctulata stimulated at 5 and 10 µg/mL. In addition, we carried out a separation with different solvents of the methanolic extract of B. notosergila and B. punctulata. The ethyl acetate fraction of both plant extracts induced the proliferation of immune cells. These results show that the extracts of B. trimera, B. notosergila and B. punctulata had immunomodulatory activity on human mononuclear cells. Future work will be required to identify the components responsible for the activity on the immune system(AU)