Unraveling the Therapeutic Mechanisms of Aloe-Emodin: A Natural Anthraquinone With Promising Health Benefits.

Abstract

Aloe-emodin (AE), known as 1,8-dihydroxy-3-hydroxymethyl-anthraquinone, is a naturally occurring anthraquinone that has attracted attention for its diverse pharmacological applications. AE is mainly found in plant species, such as Aloe vera, Rheum palmatum, and Polygonum multiflorum. Accumulating preclinical studies suggest that AE exerts anticancer, antimicrobial, antiviral, antiparasitic, hepatoprotective, neuroprotective, cardioprotective, and anti-inflammatory properties. In particular, its anticancer effects, involving apoptosis induction, oxidative stress inhibition, mitochondrial dysfunction, and inhibition of proliferative and metastatic pathways across multiple cancer cell lines, are especially well-characterized. AE demonstrates promising preclinical results, with a range of effective in vitro doses of 0.05 to 100 µM and in vivo doses of 25-100 mg/kg in animals; however, higher micromolar concentrations have been reported to have cytotoxic and hepatotoxic effects, highlighting AE's translational potential while necessitating further safety evaluation. Simultaneously, proliferative signaling pathways, such as PI3K/Akt/mTOR and MAPK, are widely investigated; some potential signaling pathways, like PIP2 stimulation, which also activates the AKT/mTOR pathway, are still unexplored. AE combats various infectious diseases targeting gram-positive and gram-negative bacteria, influenza A, herpes simplex virus, Japanese encephalitis virus, enterovirus 71, and parasites such as Leishmania. Despite the promising pharmacological effects of AE, its clinical application is limited by poor pharmacokinetics, such as low bioavailability, rapid clearance, and inadequate intestinal absorption, along with safety risks like liver, kidney, and light-induced toxicity. Overcoming these challenges require improved delivery systems, structural modifications, and detailed toxicity profiling. Our review consolidates current pharmacological evidence, identifies research gaps, and suggests modifications and future directions for AE as a potential therapeutic agent.