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Ginsenoside Rh2 (GRh2) exhibits significant potential as an anticancer agent; however, progress in developing chemotherapeutic drugs is impeded by their toxicity toward off-target tissues. Specifically, anemia caused by chemotherapy is a debilitating side effect and can be caused by red blood cell (RBC) hemolysis and eryptosis. Cells were exposed to GRh2 in the antitumor range and hemolytic and eryptotic markers were examined under different experimental conditions using photometric and cytofluorimetric methods. GRh2 caused Ca 2+ -independent, concentration-responsive hemolysis in addition to disrupted ion trafficking with K + and Cl - leakage. Significant increases in cells positive for annexin-V-fluorescein isothiocyanate, Fluo4, and 2,7-dichlorofluorescein were noted upon GRh2 treatment coupled with a decrease in forward scatter and acetylcholinesterase activity. Importantly, the cytotoxic effects of GRh2 were mitigated by ascorbic acid and by blocking casein kinase 1α (CK1α) and mixed lineage kinase domain-like (MLKL) signaling. In contrast, Ca 2+ omission, inhibition of KCl efflux, and isosmotic sucrose aggravated GRh2-induced RBC death. In whole blood, GRh2 selectively targeted reticulocytes and lymphocytes. Altogether, this study identified novel mechanisms underlying GRh2-induced RBC death involving Ca 2+ buildup, loss of membrane phospholipid asymmetry and cellular volume, anticholinesterase activity, and oxidative stress. These findings shed light on the hematologic toxicity of GRh2 which is crucial for optimizing its utilization in cancer treatment., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Sanguinarine (SGN) is a benzophenathridine alkaloid extracted from Sanguinaria canadensis plant. SGN is incriminated in epidemic dropsy (ED) characterized by multiple-organ failure and anemia. Nevertheless, how SGN leads to anemia of ED remains poorly understood. This study was thus initiated to investigate the interaction of SGN with human red blood cells (RBCs) and to delineate associated molecular mechanisms. Heparin- and EDTA-anticoagulated blood was collected from healthy participants and whole blood was analyzed for a complete blood count, while isolated RBCs were examined for hemolytic and eryptotic markers following exposure to 1-100 μM SGN for 24 h at 37 °C. Calcium was measured by Fluo4/AM, hemolysis by hemoglobin leakage, membrane scrambling by Annexin V-FITC, cell size by forward scatter (FSC), cell granularity by side scatter (SSC), and oxidative stress by H 2 DCFDA. SGN led to increased Fluo4 fluorescence and dose-dependent hemolysis which was not ameliorated by exclusion of extracellular Ca 2+ but was nevertheless sensitive to hyperosmotic conditions and to the presence of aspirin. SGN also caused significant increase in Annexin V-positive cells, decreased FSC and SSC values, and elevated DCF fluorescence. Moreover, significantly reduced lymphocyte and basophil percentages along with selective toxicity to platelets was noted. Collectively, SGN possesses sucrose- and cyclooxygenase-sensitive hemolytic potential and elicits eryptosis characterized by Ca 2+ accumulation, phosphatidylserine externalization, morphological alterations including cell shrinkage and loss of granularity, and oxidative stress. In conclusion, this report reveals a novel activity of SGN against human RBCs and informs prospective policies in ED prevention and management., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The prevalence of cancer-associated anemia (CIA) is high, and the mechanisms governing its development remain poorly understood. Eryptosis, the suicidal cell death of red blood cells (RBCs), may account for CIA as it is triggered by clinically approved chemotherapeutics including cisplatin and paclitaxel. Physcion (PSN), an anthraquinone extracted from rhubarb and other plants, has shown great promise as an anticancer agent. However, the potential toxicity of PSN to RBCs remains elusive. RBCs were isolated from heparinized blood, and incubated with 10-100 µM of PSN for 24 h at 37 °C. Hemolysis was photometrically calculated from hemoglobin concentration in the medium at 405 nm, while flow cytometry was employed to investigate cardinal markers of eryptosis. Phosphatidylserine (PS) exposure was detected by Annexin-V-fluorescein isothiocyanate (FITC), intracellular calcium by Fluo4/AM, cellular volume from forward scatter (FSC), and oxidative stress by 2',7'-dichlorodihydrofluorescein diacetate (H 2 DCFDA). PSN induced overt hemolysis at 50 and 100 µM which was not mediated through calcium influx, protein kinase C, casein kinase 1α, or receptor-interacting protein 1. Moreover, PSN caused significant increase in Annexin-V-FITC and Fluo4 fluorescence with no appreciable influence on FSC or DCF values. Accordingly, PSN stimulates premature eryptosis characterized by PS externalization and intracellular calcium overload without cell shrinkage or oxidative damage. In conclusion, this report shows, for the first time, that PSN is cytotoxic to RBCs by inducing hemolysis and programmed cell death which may limit its success as a chemotherapeutic agent.