Immunomodulatory effect of Premna odorata volatile oils in Mycobacterium tuberculosis by inhibiting TLR4/NFκB pathway

Introduction: The development of multi drug resistant (MDR) tuberculosis (TB) and extensively drug resistant (XDR) TB, increased the interest in the usage of medicinal plants that are complementary to antibiotics to improve antiTB efficacy. The present study aimed to confirm the antiTB efficacy of volatile oils (VOs) isolated from different parts of Premna odorata in vivo, and moreover, to test the possible involvement of TLR4/NFκB signaling pathway in its antiTB efficacy.Methods: Thirty mice were divided into six equal groups. Group 1: healthy mice (negative control). Groups 26 were injected intravenously with a positive TB solution of purified MeDiPro Mycobacterium tuberculosis (MTB) antigen for 7 days to induce tuberculosis. Group 36: TBinjected mice treated respectively with leaves VO (300 μL/d), young stems VO (300 μL/d), flowers VO and a combination of the three essential VOs (1:1:1). Various immunologic factors and antioxidant activity were evaluated and compared in the groups.Results: TBinfected mice showed a significant increase in the serum levels of tumor necrosis factorα (TNFα), interferongamma (IFNγ), interleukin (IL) 1β and the mRNA expression levels of tolllike receptor 4 (TLR4) nuclear factorκB (NFκB) and a decrease in IL10 total antioxidant capacity (TAC). While pretreatment with VOs extracted from leaves, flowers, young stems and a combination of the three oils reversed these effects.Conclusion: The immunomodulatory effects of VOs extracted from different parts of P. odorata against TB infection involve the TLR4/NFκB signaling pathway as well as, antioxidant effects, recommending that the use of this plant may help TB infected patients.