The Tetradium ruticarpum-Zingiber officinale Roscoe herb pair inhibits atherogenic events: A study of the synergistic effects and active ingredient combination of a two-herb formula.

Abstract

The Tetradium ruticarpum (E)-Zingiber officinale Roscoe (Z) herb pair is a well-known herbal formulation with multiple beneficial cardiovascular pharmacological activities. Therefore, E and Z are potentially natural products for Atherosclerosis (AS). However, it is not clear whether E and Z work synergistically in the treatment of AS and which of their components is responsible. This study was to determine the synergistic effect of E and Z in the treatment of AS, to identify the active ingredient combination (AIC) that exerts the action of the original formula and to determine its molecular mechanism. First, the combined effects of E and Z were assessed in an ApoEmouse model and then confirmed in vascular smooth muscle cells (VSMCs) by the combination index (CI). In addition, the AIC of E-Z was evaluated by cascade analysis and its efficacy was confirmed in vitro and in vivo. The results showed that both E, Z and E-Z had anti-AS effects in ApoEmice, with E-Z having the most significant effect. Moreover, the CI method demonstrated that E, Z could synergistically inhibit the proliferation of VSMCs. In addition, the AICs obtained by the cascade analysis strategy effectively inhibited VSMCs proliferation in vitro and significantly reduced the formation of neoplastic endothelium in mice in vivo. This inhibitory effect was associated with the reduction of ROS levels and activation of the Nrf2/HO-1 signaling pathway in VSMCs. This study provides an effective method for characterizing herbal combinations, exploring their active ingredients, and promoting efficacy-based herbal quality control.