Triterpenes and sterols from Ziziphus spina-christi, cytotoxicity evaluation in vitro and in silico

Aim This study aimed to discover active anti-cancer components from Ziziphus spina-christi (L.) Desf. Methods Multiple chromatography techniques were used to isolate pure compounds. The structures of isolates were determined by feasible spectroscopic techniques and comparing the data with reported ones. All obtained compounds were evaluated in vitro against four cell lines (three cancer cell lines MCF7, H460, and HeLa, and a normal cell line BJ). Besides, in silico pharmacokinetics and drug-likeness prediction of all compounds were performed. Moreover, all isolated compounds were performed for docking study by an essential receptor of breast cancer HER-2, to figure out the interactions. Results Seven compounds ( 1 ‒ 7 ) were obtained, including five triterpenoid derivatives, lupeol ( 1 ), betulinaldehyde ( 3 ), betulin ( 4 ), betulinic acid ( 5 ), and 2-O- E - p- coumaroyl alphitolic acid ( 6 ), along with two sterol derivatives, β-sitosterol ( 2 ) and β-sitosterol glycoside ( 7 ). Among them, 4 and 6 were isolated for the first time from Z. spina-christi . 1 and 5 were found to be active on cancer cell lines, but also cytotoxic for normal cell line BJ. 3 and 4 were reported for the first time to be active and non-cytotoxic. compound 7 was identified as a hit compound with a docking score of -8.420 kcal/mol and two H-bond interactions with ASP 863 residue of the binding site. Remarkably, all compounds met more than three of Lipinski’s rule of five (RO5). Notably, all compounds were within the normal range for QPP ^MDCK , QPlog ^BB , and QPP ^Caco , except 6 was observed to be above ‒5. Compound 7 was identified as a hit compound interacting with a key protein in breast cancer, HER-2. Validation of the docking procedure by MM/GBSA showed that 6 (‒53.435 kcal/mol)) has the highest free binding energy. Conclusions This study suggests compounds from Z. spina-christi could be potent HER-2 inhibitors and experimentally verified as lead compounds in search of HER-2 antagonists for breast cancer.