Sitosterol-rich Digera muricata against 7-ketocholesterol and lipopolysaccharide-mediated atherogenic responses by modulating NF-ΚB/iNOS signalling pathway in macrophages

Sangeetha Ravi; Parimalanandhini Duraisamy; Mahalakshmi Krishnan; Livya Catherene Martin; Beulaja Manikandan; Manikandan Ramar

doi:10.1007/s13205-023-03741-6

Sitosterol-rich Digera muricata against 7-ketocholesterol and lipopolysaccharide-mediated atherogenic responses by modulating NF-ΚB/iNOS signalling pathway in macrophages

3 Biotech. 2023 Oct;13(10):331. doi: 10.1007/s13205-023-03741-6. Epub 2023 Sep 3.

Authors

Sangeetha Ravi¹, Parimalanandhini Duraisamy¹, Mahalakshmi Krishnan¹, Livya Catherene Martin¹, Beulaja Manikandan², Manikandan Ramar¹

Affiliations

¹ Department of Zoology, University of Madras, Guindy Campus, Chennai, 600 025 India.
² Department of Biochemistry, Annai Veilankanni's College for Women, Chennai, 600 015 India.

PMID: 37670802
PMCID: PMC10475456 (available on 2024-10-01)
DOI: 10.1007/s13205-023-03741-6

Abstract

Digera muricata L., commonly known as Tartara, is an edible herb used as traditional medicine in many countries of Africa and Asia. This study aimed to elucidate the effect of a phytosterol-rich extract of D. muricata on 7-ketocholesterol-mediated atherosclerosis in macrophages. The extract was examined by phytochemical analyses, GC-MS, TLC, DPPH scavenging and hRBC membrane stabilization assays. Macrophage polarization was studied with experimental groups framed based on alamar blue cell viability and griess assays. Regulations of arginase enzyme activity, ROS generation, mitochondrial membrane potential, cell membrane integrity, pinocytosis, lipid uptake and peroxidation, as well as, intracellular calcium deposition were determined. In addition, expressions of atherogenic mediators were analysed using PCR, ELISA and immunocytochemistry techniques. Diverse phytochemicals with higher free radical scavenging activity and anti-inflammatory potential have been detected in the D. muricata. Co-treatment with D. muricata markedly reduced the atherogenic responses induced by 7KCh in the presence of LPS such as ROS, especially, NO and O₂^- along with lipid peroxidation. Furthermore, D. muricata significantly normalized mitochondrial membrane potential, cell membrane integrity, pinocytic activity, intracellular lipid accumulation and calcium deposition. These results provided us with the potentiality of D. muricata in ameliorating atherogenesis. Additionally, it decreased the expression of pro-atherogenic mediators (iNOS, COX-2, MMP9, IL-6, IL-1β, CD36, CD163 and TGFβ1) and increased anti-atherogenic mediators (MRC1 and PPARγ) with high cellular expressions of NF-κB and iNOS. Results showed the potential of sitosterol-rich D. muricata as a versatile biomedical therapeutic agent against abnormal macrophage polarization and its associated pathologies.

Keywords: 7-ketocholesterol; Atherosclerosis; Cytokines; Macrophages; Phytosterol.

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