Hemolysis by Saponin Is Accelerated at Hypertonic Conditions

Evaluation of the antiproliferative, cytotoxic and phytochemical properties of Zimbabwean medicinal plants used in cancer treatment

BACKGROUND

Cancer cases have been on the rise globally and several treatment strategies have been developed but mortality rates remain high. Zimbabwe, like many other countries, has also experienced a surge in cancer cases. In Zimbabwe, medicinal plants have been widely used to treat cancer for centuries. However, there has been limited research on the effectiveness, safety, and chemical composition of these plants. The current study assessed antiproliferative, cytotoxic and phytochemical properties of selected Zimbabwean medicinal plants.

METHOD

Cytotoxic activity of Agelenthus pungu, Carissa edulis, Dombeya rotundifolia, Flacourtia indica, Lannea discolor, Leonotis ocymifolia, Leucas martinicensis, Plicosepalus kalachariensis, Pseudolachnostylis maproneifolia, Solanum incanum, Strychnos cocculoides, Strychnos spinosa and Viscum verrucosum extracts were evaluated on normal murine peritoneal cells and sheep erythrocytes while antiproliferative activity was assessed on Jurkat T and HL60 cell lines. Cell viability was determined using the trypan blue exclusion and sulforhodamine B assay. Additionally, the effect of reduced glutathione on cytotoxic extracts was examined. The phytochemicals of the methanolic extracts were qualitatively determined using standard methods.

RESULTS

Agelenthus pungu, Carissa edulis, Flacourtia indica, Strychnos cocculoides, Strychnos spinosa and Viscum verrucosum were cytotoxic to normal murine peritoneal cells. Flacourtia indica and Viscum verruscosum caused haemolysis of sheep erythrocytes at a concentration of 250 µg/mL for both plant extracts and 125 µg/mL for Viscum verrucosum. Cell viability increased on addition of 25 µg/mL of reduced glutathione to the extracts considered the most cytotoxic extracts, Agelenthus pungu and Viscum verrucosum. Agelenthus pungu, Carissa edulis, Leonotis ocymifolia, Leucas martinicensis and Viscum verrucosum significantly inhibited Jurkat T and HL60 cell proliferation. Viscum verrucosum was the most potent with the lowest half-maximum inhibitory concentration (IC50) values of 33 and 34 µg/mL on Jurkat T and HL60 cell lines respectively. The most dominant phytochemical classes were alkaloids, flavonoids and saponins.

CONCLUSION

This study demonstrates that Agelenthus pungu, Carissa edulis, Leonotis ocymifolia, Leucas martinicensis and Viscum verrucosum have antiproliferative activity against Jurkat T and HL60 cell lines. Viscum verrucosum was the most potent. These findings emphasise the importance of medicinal plants as well as their potential use as sources of novel compounds in anticancer drug discovery.

In Situ Monitoring of Morphology Changes and Oxygenation State of Human Erythrocytes During Surfactant-Induced Hemolysis

Erythrocytes, the most abundant blood cells, are a prevalent cell model for the analysis of the membrane-damaging effects of different molecules, including drugs. In response to stimuli, erythrocytes can change their morphology, e.g., shape or volume, which in turns influences their main function to transport oxygen. Membrane active molecules can induce hemolysis, i.e., release of hemoglobin into the blood plasma. Free hemoglobin in the blood circulation is toxic causing serious health problems including vasoconstriction, high blood pressure and kidney damage. Therefore, early recognition of the risk of massive hemolysis is highly important. Here, we investigated surfactant induced hemolysis applying UV-vis spectrophotometry. Saponin, sodium dodecyl sulfate and Triton X-100, detergents known to provoke hemolysis at different concentrations and by different mechanisms, were applied to initiate the process. Whole absorption spectra of erythrocyte suspensions in the range 300-750 nm were recorded every 15 s for following the process in real-time. The hemolysis process, with respect to morphological changes in the erythrocytes and their influence on the oxygenation state of hemoglobin, was characterized by the absorbance at 700 nm, the height relative to the background and the wavelength of the Soret peak. The results suggest that these UV-vis spectrophotometry parameters provide reliable information in real-time; not only about the process of hemolysis itself, but also about pre-hemolytic changes in the erythrocytes, even at sub-hemolytic surfactant concentrations.

Effects of Saponins on Lipid Metabolism: The Gut-Liver Axis Plays a Key Role

Unhealthy lifestyles (high-fat diet, smoking, alcohol consumption, too little exercise, etc.) in the current society are prone to cause lipid metabolism disorders affecting the health of the organism and inducing the occurrence of diseases. Saponins, as biologically active substances present in plants, have lipid-lowering, inflammation-reducing, and anti-atherosclerotic effects. Saponins are thought to be involved in the regulation of lipid metabolism in the body; it suppresses the appetite and, thus, reduces energy intake by modulating pro-opiomelanocortin/Cocaine amphetamine regulated transcript (POMC/CART) neurons and neuropeptide Y/agouti-related peptide (NPY/AGRP) neurons in the hypothalamus, the appetite control center. Saponins directly activate the AMP-activated protein kinase (AMPK) signaling pathway and related transcriptional regulators such as peroxisome-proliferator-activated-receptors (PPAR), CCAAT/enhancer-binding proteins (C/EBP), and sterol-regulatory element binding proteins (SREBP) increase fatty acid oxidation and inhibit lipid synthesis. It also modulates gut-liver interactions to improve lipid metabolism by regulating gut microbes and their metabolites and derivatives-short-chain fatty acids (SCFAs), bile acids (BAs), trimethylamine (TMA), lipopolysaccharide (LPS), et al. This paper reviews the positive effects of different saponins on lipid metabolism disorders, suggesting that the gut-liver axis plays a crucial role in improving lipid metabolism processes and may be used as a therapeutic target to provide new strategies for treating lipid metabolism disorders.

Change in Osmotic Pressure Influences the Absorption Spectrum of Hemoglobin inside Red Blood Cells

Absorption spectra of red blood cell (RBC) suspensions are investigated in an osmolarity range in the medium from 200 mOsm to 900 mOsm. Three spectral parameters are used to characterize the process of swelling or shrinkage of RBC-the absorbance at 700 nm, the Soret peak height relative to the spectrum background, and the Soret peak wavelength. We show that with an increase in the osmolarity, the absorbance at 700 nm increases and the Soret peak relative height decreases. These changes are related to the changes in the RBC volume and the resulting increase in the hemoglobin intracellular concentration and index of refraction. Confocal microscopy and flow cytometry measurements supported these conclusions. The maximum wavelength of the Soret peak increases with increasing osmolarity due to changes in the oxygenation state of hemoglobin. Using these spectrum parameters, the process of osmosis in RBCs can be followed in real time, but it can also be applied to various processes, leading to changes in the volume and shape of RBCs. Therefore, we conclude that UV-Vis absorption spectrophotometry offers a convenient, easily accessible, and cost-effective method to monitor changes in RBC, which can find applications in the field of drug discovery and diagnostics of RBC and hemoglobin disorders.

Dioscin: Therapeutic potential for diabetes and complications

Diabetes mellitus is a widespread metabolic disorder with increasing incidence worldwide, posing a considerable threat to human health because of its complications. Therefore, cost-effective antidiabetic drugs with minimal side effects are urgently needed. Dioscin, a naturally occurring compound, helps to reduce the complications of diabetes mellitus by regulating glucose and lipid metabolism, protecting islet β cells, improving insulin resistance, and inhibiting oxidative stress and inflammatory response. Plant-derived dioscin reduces the risk of toxicity and side effects associated with chemically synthesized drugs. It is a promising option for treating diabetes mellitus because of its preventive and therapeutic effects, which may be attributed to a variety of underlying mechanisms. However, data compiled by current studies are preliminary. Information about the molecular mechanism of dioscin remains limited, and no high-quality human experiments and clinical trials for testing its safety and efficacy have been conducted. As a resource for research in this area, this review is expected to provide a systematic framework for the application of dioscin in the treatment of diabetes mellitus and its complications.