PB0766 - Essential oils and their sesquiterpenes reduce DENV-2-induced platelet activation

Background: Dengue virus (DENV) infection causes dengue illness, leading sometimes to serious disease and death. DENV-driven exacerbate platelet activation, and DENV nonstructural protein-1 (NS1) protein contribute to inflammatory amplification and thrombocytopenia during dengue. Since there are no effective drugs for the treatment, essential oils (EOs) could be good resource for developing drugs that prevent dengue from progressing to severity.

Aims: To evaluate the in vitro inhibitory effect of EOs and their sesquiterpenes on human platelet activation induced by DENV-2 and NS1 protein.

Methods: EOs were extracted by MWHD from plants grown in Colombia. GC/MS was used to determine the chemical composition of Lippia origanoides (phellandrene chemotype), Turnera diffusa (EO), Lippia alba EOs (citral, carvone chemotypes) and three sesquiterpenes (trans-β-caryophyllene, caryophyllene oxide and germacrene D). Molecular interactions with DENV/platelets proteins were predicted with an in silico analysis. Platelets isolated from healthy donors blood and purified by CD45 depletion were exposed to DENV-2 (MOI=1) or recombinant NS1 (5µg/mL) for 4h and 3h, respectively, in the presence of non-cytotoxic sample concentrations. Platelet activation was determined through flow cytometry and detection of activation markers in the supernatant.

Results: Twenty-nine compounds in the EOs studied were identified; some of them (trans-β-caryophyllene, caryophyllene oxide, germacrene D, α-humulene, and α-selinene) were capable of strongly binding to proteins important to the DENV-platelet interaction (DC-SIGN, HSP70, TLR4, and TLR2) (Fig.1). EOs exposition for 4h did not affect platelet viability (Fig.2A). In addition, treatment with EOs could reduce the platelet surface expression of activation markers and secretion of α-granule products induced by exposure to DENV and NS1. Lippia alba-carvone EO reduced CD62p and CD63 surface expression, PF4/CXCL4 and RANTES/CCL5 secretion. trans-β-Caryophyllene and caryophyllene-oxide reduced CD62p expression, PF4/CXCL4 and RANTES/CCL5 secretion (Fig.2B and C).

Conclusion(s): The EOs and sesquiterpenes reduce platelet activation induced by DENV-2 and NS1 protein and may act as potential therapeutic agents.