New substances of Equisetum hyemale L. extracts and their in vivo antitumoral effect against oral squamous cell carcinoma. (1st March 2023)

• Record Type: Journal Article
• Authors: de Queiroz, Lucas Nicolau; Da Fonseca, Anna Carolina Carvalho; Wermelinger, Guilherme Freimann; da Silva, Diego Polo Dutra; Pascoal, Aislan Cristina Rheder Fagundes; Sawaya, Alexandra Christine Helena Frankland; de Almeida, Elan Cardozo Paes; do Amaral, Bruno Sergio; de Lima Moreira, Davyson; Robbs, Bruno Kaufmann
• Is Part Of: Journal of ethnopharmacology. Volume 303(2023)
• Publication Date: 2023-03-01
• Subjects: Equisetum hyemale -- Cancer therapy -- Apoptosis -- Cytotoxicity -- Phytochemical analysis; Ethnopharmacology -- Periodicals; Pharmacognosy -- Periodicals; Herbs -- Periodicals; Herbs -- Periodicals; Pharmacognosy -- Periodicals; Pharmacognosie -- Périodiques; Herbes -- Périodiques; 615.1
• DOI: 10.1016/j.jep.2022.116043
• Languages: English
• ISSNs: 0378-8741

Abstract

Abstract: Ethnobotanical relevance: Equisetum hyemale is used in traditional medicine as an anti-inflammatory, antioxidant, diuretic and anticancer agent. Recent studies have observed antiproliferative activity of this species in some tumor cell lines. Aim of the study: The aim of this study was to evaluate the antiproliferative activity of the ethanol extract of E. hyemale and its partitions in oral squamous carcinoma cell lines, the death pathways induced by the most active partition, the acute toxicity and therapeutic activity, and the identification of the main compounds. Materials and methods: The ethanol crude extract was prepared from the stems of E. hyemale and partitions were obtained from this extract with n -hexane, dichloromethane and ethyl acetate. Cytotoxicity assays were performed using MTT on human oral tumor lines SCC-9, SCC4 and SCC-25, and normal primary fibroblasts. The main pathways of programmed cell death were analyzed. Acute toxicity in mice was performed using the most active partition, ethyl acetate. Antitumor activity was accessed in xenotransplants grafts of SCC-9 cells in Balb/nude mice. Phytochemical analysis was performed using UHPLC-MS/MS and dereplication was done using Global Natural Product Social Molecular Networking (GNPS) analysis. Results: Ethanol extract, n -hexane and ethyl acetate partitions showed dose-dependent activity and selectivity towards oral tumor cells, with the ethyl acetate being the most bioactive. This medium polarity partition was shown to induce tumor cell death through apoptosis due to the presence of activated caspase 3/7, DNA fragmentation, chromatin condensation and phosphatidylserine exposure. The ethyl acetate partition also produced low toxicity in mice, provoking mild hepatic changes, but without causing necrosis and significantly reduced tumors volume and weight in xenotransplants of SCC-9 cells. Phytochemical analysis allowed identification of kaempferol glycosides and cinnamic acid derivatives previously described for E. hyemale . In addition it was possible to identify 6 new non-glycolyzed flavonoids 5-Hydroxy-3′, 4′, 7, 8-tetramethoxyflavone (14), 5, 4′-Dihydroxy-7, 8, 3′-trimethoxyflavone (15), 5, 7-Dihydroxy-3′, 4′-dimethoxyflavone (16), 3′, 4, 5, 7-Tretramethoxyflavone (17), 5-Hydroxy-3′4′, 7-trimethoxyflavone (18), and 5, 4′-Dihydroxy-3′-7′-dimethoxyflavone (19); besides 5 compounds already determined to be cytotoxic in other species, Isoferulic acid (1), Ferulic acid (2), Atractylenolide III (6), Dihydroxy-3′, 4′-dimethoxyflavone (16), and 5-Hydroxy-3′4 ′, 7-trimethoxyflavone (18). Conclusion: The results indicate that the E. hyemale extract and partitions inhibited 3 different cell lines of OSCC in a highly selective nontoxic way by inducing apoptosis of the cells. We identified 6 new non-glycosylated flavonoids and 5 other substances in this species. Graphical abstract: Image 1 Highlights: Equisetum hyemale extract show high cytotoxicity and selectivity toward cancer cells. E. hyemale dichloromethane partition induces cell death via apoptosis. Significant reduction in tumor growth in mice induced by E. hyemale partition. Several substances being identified for the first time in this species.