In vitro cytotoxic effect of stigmasterol derivatives against breast cancer cells

Abstract

Background Stigmasterol is an unsaturated phytosterol that belong to the class of tetracyclic steroids abundant in Rhoicissus tridentata. Stigmasterol is an important constituent since it has shown impressive pharmacological effects such as anti-osteoarthritis, anticancer, anti-diabetic, anti-inflammatory, antiparasitic, immunomodulatory, antifungal, antioxidant, antibacterial, and neuroprotective activities. Furthermore, due to the presence of π system and hydroxyl group, stigmasterol is readily derivatized through substitution and addition reactions, allowing for the synthesis of a wide variety of stigmasterol derivatives. Methods Stigmasterol (1) isolated from Rhoicissus tridentata was used as starting material to yield eight bio-active derivatives (2–9) through acetylation, epoxidation, epoxide ring opening, oxidation, and dihydroxylation reactions. The structures of all the compounds were established using spectroscopic techniques, NMR, IR, MS, and melting points. The synthesized stigmasterol derivatives were screened for cytotoxicity against the hormone receptor-positive breast cancer (MCF-7), triple-negative breast cancer (HCC70), and non-tumorigenic mammary epithelial (MCF-12 A) cell lines using the resazurin assay. Results Eight stigmasterol derivatives were successfully synthesized namely; Stigmasterol acetate (2), Stigmasta-5,22-dien-3,7-dione (3), 5,6-Epoxystigmast-22-en-3β-ol (4), 5,6-Epoxystigmasta-3β,22,23-triol (5), Stigmastane-3β,5,6,22,23-pentol (6), Stigmasta-5-en-3,7-dion-22,23-diol (7), Stigmasta-3,7-dion-5,6,22,23-ol (8) and Stigmast-5-ene-3β,22,23-triol (9). This is the first report of Stigmasta-5-en-3,7-dion-22,23-diol (7) and Stigmasta-3,7-dion-5,6,22,23-ol (8). The synthesized stigmasterol analogues showed improved cytotoxic activity overall compared to the stigmasterol (1), which was not toxic to the three cell lines tested (EC50 ˃ 250 µM). In particular, 5,6-Epoxystigmast-22-en-3β-ol (4) and stigmast-5-ene-3β,22,23-triol (9) displayed improved cytotoxicity and selectivity against MCF-7 breast cancer cells (EC50 values of 21.92 and 22.94 µM, respectively), while stigmastane-3β,5,6,22,23-pentol (6) showed improved cytotoxic activity against the HCC70 cell line (EC50: 16.82 µM). Conclusion Natural products from Rhoicissus tridentata and their derivatives exhibit a wide range of pharmacological activities, including anticancer activity. The results obtained from this study indicate that molecular modification of stigmasterol functional groups can generate structural analogues with improved anticancer activity. Stigmasterol derivatives have potential as candidates for novel anticancer drugs.

Network Pharmacology and Experimental Validation to Explore the Potential Mechanism of Nigella sativa for the Treatment of Breast Cancer

“…Research suggests that stigmasterol has anti-inflammatory, antioxidant, and anticancer effects [28]. In a study, Dube et al [29] synthesized eight derivatives of stigmasterol and explored their antibreast cancer activity against the HCC70 cell line. They concluded that structural analogues of this phytochemical after modifications in functional groups can improve anticancer activity, and the compound and its derivatives have potential as lead anticancer drugs.…”

Stigmasterol Exerts an Anti-Melanoma Property through Down-Regulation of Reactive Oxygen Species and Programmed Cell Death Ligand 1 in Melanoma Cells

“…Phytosterols are bioactive substances occurring naturally in various plants. Stigmasterol (STIG), a phytosterol, is abundant in several plants [ 17 ], and it exhibits a range of pharmacological effects, including antioxidant [ 18 ], anti-cancer [ 19 ], and anti-inflammatory properties [ 20 ]. Regarding melanoma, it has been reported that STIG has cytotoxic effects on human malignant melanoma cell lines [ 21 ] and mouse malignant melanoma (B16F10) cell lines [ 22 ].…”