title: Orthosiphon stamineus protects Caenorhabditis elegans against Staphylococcus aureus infection through immunomodulation.
abstract: Amidst growing concerns over the spread of antibiotic-resistant Staphylococcus aureus strains, the identification of alternative therapeutic molecules has become paramount. Previously, we utilized a Caenorhabditis elegans-S. aureus screening platform to identify potential anti-infective agents from a collection of natural extracts and synthetic compounds. One of the hits obtained from the screen was the aqueous extract of Orthosiphon stamineus leaves (UE-12) that enhanced the survival of infected nematodes without interfering with bacterial growth. In this study, we used a fluorescent transgenic reporter strain and observed that the repressed expression of the lys-7 defense gene in infected nematodes was restored in the presence of UE-12. Analysis of a selected panel of PMK-1 and DAF-16-regulated transcripts and loss-of-function mutants in these pathways indicates that the protective role of UE-12 is mediated via the p38 MAP kinase and insulin-like signaling pathways. Further analysis of a panel of known bioactive compounds of UE-12 proposed eupatorin (C18H16O7) as the possible candidate active molecule contributing to the anti-infective property of UE-12. Taken together, these findings strongly suggest that the O. stamineus leaf extract is a promising anti-infective agent that confers an advantage in survival against S. aureus infection by modulating the immune response of the infected host.
authors: School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, 43600 UKM Bangi, Selangor, Malaysia.
authors: Cin
authors: C
authors: Kong
authors: Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305-5120, USA Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305-5124, USA Present address: Department of Infectious Disease, Genentech, Inc., South San Francisco, CA 94080, USA.
authors: Man-Wah
authors: MW
authors: Tan
authors: School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, 43600 UKM Bangi, Selangor, Malaysia sheila@ukm.edu.my.
authors: Sheila
authors: S
authors: Nathan
keywords: Anti-infective; C. elegans; Immunomodulation; O. stamineus; S. aureus