Anti-inflammatory activities of Coleus forsteri (formerly Plectranthus forsteri) extracts on human macrophages and chemical characterization

Front Pharmacol. 2023 Jan 9:13:1081310. doi: 10.3389/fphar.2022.1081310. eCollection 2022.

Abstract

Introduction: Formerly named Plectranthus forsteri, Coleus forsteri (Benth.) A.J.Paton, 2019 is a Lamiaceae traditionally used to treat flu-like symptoms and shock-related ecchymosis, especially in the Pacific region. Few studies investigated chemical composition and anti-inflammatory potential of this plant. Method: Herein, we investigated anti-inflammatory potential of C. forsteri ethanolic (ePE) and cyclohexane (cPE) plant extract on LPS-induced human macrophages models and quantified cytokines and quinolinic acid (QUIN) as inflammatory markers. Results: Our results show that extract of ePE and cPE significantly inhibit inflammatory cytokine IL-6 and TNF-α induced by LPS on PMA-derived THP-1 macrophages. QUIN production is also diminished under ePE and cPE treatment in activated human monocyte-derived macrophages (MDMs). Seven abietane diterpenes were characterized from C. forsteri cPE including coleon U (1), coleon U-quinone (2), 8α,9α-epoxycoleon U-quinone (3), horminone or 7α-hydroxyroyleanone (4), 6β,7α-dihydroxyroyleanone (5), 7α-acetoxy-6β-hydroxyroyleanone (6) and 7α-formyloxy-6β-hydroxyroyleanone (7). Discussion: We discussed potential contributions of these molecules from C. forsteri extracts for their anti-inflammatory activities.

Keywords: Coleus forsteri; abietane; anti-inflammatory; cytokine; diterpene; macrophage; quinolinic acid (QUIN); traditional plant.

Grants and funding

This research was funded by the “Fonds de cooperation économique, sociale et Culturelle pour le Pacifique” of “Fonds Pacifique” (Project 1707, N° SPP 28-1-2017) supported by the French Ministry of Foreign Affairs, the French Ministry of Higher Education, Research and Innovation (MESRI), the Institut Pasteur of New Caledonia (IPNC) and the Pasteur Network. Prof Guillemin is supported by the National Health and Medical Research Council (NHMRC), Fellowship #APP1176660, and by Macquarie University. MM position is financed by the Government of New Caledonia.