Quercetin and Kaempferol Reduce Acute Doxorubicin Injury in Human Cardiac Organoids
Four network-prioritized compounds were tested in human iPSC-derived cardiac organoids. Quercetin and kaempferol improved 24-hour doxorubicin injury readouts, while licochalcone A and naringenin failed to provide effective protection and high-dose kaempferol was cytotoxic.
Computational Ranking Was Followed by Direct Drug Tests
A Journal of Cardiovascular Pharmacology study by Shanghai hospital researchers combined network analysis with human cardiac organoid experiments to investigate constituents of a traditional herbal formulation. The drug-development question was whether the prioritized compounds could reduce doxorubicin-associated cardiac injury, and whether measured changes were consistent with the proposed MAPK signaling mechanism.
Database screening produced 219 ingredient-associated targets and 1,957 heart-failure-associated targets, with 112 overlaps. Network analysis narrowed these to 33 core targets and prioritized four compounds: quercetin, kaempferol, licochalcone A and naringenin. MAPK14, which encodes p38α, was selected for docking and molecular-dynamics simulations. All four compounds had favorable calculated docking scores, ranging from −6.81 to −7.45 kcal/mol. Those calculations predicted possible interactions; they did not measure binding or inhibition in the organoids.
The experimental model used commercially obtained human induced pluripotent stem cells. Aggregates differentiated into beating cardiac organoids, with contraction appearing around days 6–7 and staining for cardiac troponin T, CD31 and α-smooth muscle actin. These markers supported the presence of cardiac and associated cell populations, although the study did not report a panel of independent donor lines or quantify mature adult-heart physiology.
The Injury Assay Used a Short Doxorubicin Exposure
Organoids were exposed to 0.1, 0.3, 1, 3, 10 or 30 μM doxorubicin for 24 hours. Higher concentrations disrupted organoid edges and reduced beating. At 10 μM, the CCK-8 metabolic viability signal was approximately 50% lower than in untreated controls, and this concentration was chosen for subsequent experiments. The reported injury and compound-screening assays used n = 6 measurements.
Doxorubicin increased the cardiac injury-associated markers NT-proBNP and troponin T. Lactate dehydrogenase release rose with concentration but did not reach statistical significance in the initial injury experiment. This difference between metabolic, secretory and membrane-injury readouts is part of the result. Although the paper describes the organoids as a heart-failure model, the actual intervention was acute chemical injury, without a sustained hemodynamic or chronic remodeling setting.
Two Candidates Helped, While Two Failed the Experimental Test
The four candidates were first assessed on their own. Quercetin and naringenin did not show toxicity across 5–40 μM in the reported tests. Kaempferol and licochalcone A reduced viability at 40 μM, and licochalcone A also increased lactate dehydrogenase release at that concentration. The investigators therefore treated higher concentration as a potential liability rather than assuming that the computationally favored compounds were uniformly protective.
In the injury experiment, candidate compounds were coincubated with 10 μM doxorubicin for 24 hours. Quercetin and kaempferol improved CCK-8 viability and lowered lactate dehydrogenase, NT-proBNP and troponin T relative to the doxorubicin group. Licochalcone A and naringenin did not yield effective protective concentrations and showed declining viability. Their failure is a useful experimental counterpoint to the favorable docking scores shared by all four candidates.
Because 40 μM kaempferol was cytotoxic, mechanistic follow-up used 5–20 μM kaempferol and 10–40 μM quercetin. The largest reported reductions in p38 and ERK phosphorylation occurred at 20 μM kaempferol and 40 μM quercetin. These conditions involved simultaneous exposure, so the observed benefit should not be interpreted as reversal after an established injury had already developed.
Protein and Tissue Readouts Supported a Response Pattern
Both compounds reduced the BAX/BCL-2 ratio, consistent with a shift away from apoptosis. Further measurements at 20–40 μM quercetin and 10–20 μM kaempferol showed lower IL-6 and TNFα, fewer TUNEL-positive nuclei and less collagen staining. Protein, inflammatory and histological follow-up generally used n = 3 measurements. The findings link improved short-term viability with several additional injury-associated readouts.
The authors explicitly acknowledge that the experiments did not establish a causal role for the p38/ERK pathway. Docking, reduced phosphorylation and improved injury markers can coexist without proving direct target engagement or showing that this pathway is necessary for protection. The organoid experiments identify two active constituents under defined exposure conditions; they do not test the complete formulation or establish that its proposed mechanism accounts for the compound responses.