Abstract

Background: Osteosarcoma is a tumor of mesenchymal origin characterized by uncontrolled production of immature osteoid tissue. It is more common in children and adults over the age of 65. Many studies reported the cytotoxic effect of many plant extracts, including Salvia triloba, on different cancer cell lines when used alone or in combination with other chemotherapeutic agents.

Methods: In our study, the methanolic extract obtained from the air-dried leaves of Salvia triloba leaves from Palestine was screened for its total phenolic and flavonoid contents. The major components of phenolics and flavonoids were detected using LC-QToF-MS technique. The two phenolics caffeic and chlorogenic acids and the two flavonoids rutin and hesperidin were detected and quantified using HPLC technique. The antioxidant activity, cytotoxicity, and metastasis inhibition of the extract were assessed on U2OS osteosarcoma cell line using DPPH antioxidant activity, MTT cell viability, and scratch wound healing assays, respectively.

Results: The methanolic extract of Salvia triloba leaves had high total phenolic content of 170.68 ± 6.52 expressed in mg caffeic acid/g dry extract and total flavonoid content of 44.71 ± 5.67 expressed in mg rutin/g dry extract. The qualitative LC-QToF-MS indicated the presence of three phenolics (caffeic, chlorogenic, and rosmarinic acids) and seven flavonoids (rutin, hesperidin, quercetin, apigenin, apigenin 7-O-glucoside, luteolin, and luteolin 7-O-glucoside) in the extract. HPLC showed that the most abundant compound among the four quantified phenolics and flavonoids is rutin (7.10 ± 0.026 mg/g extract) followed by hesperidin (5.04 ± 0.1 mg/g extract), chlorogenic acid (1.29 ± 0.005 mg/g extract), and caffeic acid (0.91 ±0.003 mg/g extract). These results suggest that the extract could exhibit good biological activity against cancer due to its high content of phenolics and flavonoids. As for the biological tests, the extract showed a free radical scavenging activity with a half maximal inhibitory concentration (IC50) of 25.17 ± 0.304 μg/mL.. The extract also showed a significant reduction in U2OS cell viability after 72 hrs with IC50 of 77.58 μg/mL. The combination of the extract (77.58 μg/mL) with cisplatin (3.992 μg/mL) reduced U2OS cell migration by 52%. Also, this combination exhibited synergy and inhibited U2OS cell viability by 70% while only 27% of the viability of human skin fibroblast (HSF) was affected by the combined treatment compared to cisplatin treatment alone which significantly decreased U2OS and HSF cell viability by almost 27% and 32%, respectively.

Conclusion: Methanolic extract of Salvia triloba leaves exhibited good antioxidant activity due to its high content of phenolics and flavonoids and the combination between the extract and cisplatin could be used as an alternative treatment for osteosarcoma as the extract enhanced the effect of cisplatin chemotherapy and that suggested that the combination may shorten the duration of the treatment with chemotherapy.

School

School of Sciences and Engineering

Department

Biotechnology Program

Degree Name

MS in Biotechnology

Graduation Date

Winter 2-15-2023

Submission Date

1-24-2023

First Advisor

Asma Amleh

Second Advisor

Mayyada El Sayed

Committee Member 1

Hatem Tallima

Committee Member 2

Wael El Halawany

Committee Member 3

Ahmed Abdellatif

Extent

78 p.

Document Type

Master's Thesis

Institutional Review Board (IRB) Approval

Not necessary for this item

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Available for download on Thursday, January 23, 2025

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