In Vitro anti-metastasis of Perilla frutescens leaf water extract on aggressive human breast cancer cells

Abstract

Background: Perilla frutescens is a long-established plant that is often used in foods and traditional medicines in Asian countries. The perilla leaf contains a considerable number of bioactive substances, such as phenolics and flavonoids, which have been demonstrated to possess anticancer activity in vitro and in vivo. Objectives: We aimed to study anti-metastatic activity, anti-invasion activity, and anti-migration activity of perilla leaf water extract (PLW) at 90°C for 1-5 min in MDA-MB-231 aggressive human breast cancer cells. Materials and methods:Dry perilla leaves were extracted using hot water for 1-5 min to obtain crude extract and then lyophilized for PLW powder. PLW was evaluated for total phenolic, total flavonoid, and rosmarinic acid (RA) contents by Folin-Ciocalteau reagent, aluminum chloride colorimetric assay, and ultra-high-pressure liquid chromatography, respectively. Antioxidant activity of PLW was determined by DPPH and ABTS assays. MTT assay was performed to evaluate the cytotoxicity of PLW on MDA-MB-231 cells. Effective PLW was further determined its inhibitory effect on human breast cancer cell metastasis by a Boyden chamber-based transmembrane assay, the MMP-9 activity, and the proteolytic type IV collagenase activity. Results: PLW by 5-min infusion showed the highest amount of total phenolic and flavonoid contents, as well as RA. Moreover, by the 5-min infusion, PLW had the highest antioxidant capacity when compared to PLW by infusions for 1-4 min. Following that, cytotoxicity testing revealed that the PLW is not toxic to MDA-MB-231 cells after a 24-hr exposure. The PLW at non-toxic doses (12.5-100 µg/mL) intensely presents an inhibitory effect on cell invasion and migration. The gelatinolytic activity showed that the PLW at concentrations of 12.5-100 µg/mL decreases MMP-9 activity in a dose-related manner. Furthermore, after treatment with the PLW, the proteolytic type IV collagenase activity was reduced considerably in a dose-related manner. Conclusion: Our findings further showed that the PLW samples inhibit proteolytic enzymes involved in basement membrane breakdown, which might explain the anti-invasion and anti-migration properties of breast cancer cells. From the result, the application of perilla leaf might be developed as an herbal tea and used as an anti-metastatic agent for breast cancer prevention and treatment.