Protopine, an isoquinoline alkaloid contained in plants in northeast Asia.IC50 Value:Target:In vitro: Protopine was found to reduce nitric oxide (NO), cyclooxygenase-2 (COX-2), and prostaglandin E(2) (PGE(2)) production by LPS-stimulated Raw 264.7 cells, without a cytotoxic effect. Pre-treatment of Raw 264.7 cells with protopine reduced the production of pro-inflammatory cytokines [2]. Protopine is a novel microtubule stabilizer with anticancer activity in HRPC cells through apoptotic pathway by modulating Cdk1 activity and Bcl-2 family of proteins [3]. In HepG2 cells, protopine significantly increased CYP1A1 mRNA levels after 24h exposure at concentrations from 25 and 10 μM. Protopine also dose-dependently increased CYP1A1 and CYP1A2 mRNA levels in human hepatocytes [4].In vivo: Assays were performed on MDA-MB-231 human breast cancer cells, and the result showed that protopine exhibited anti-adhesive and anti-invasion effects in MDA-MB-231 cells; after treatment with protopine for 90 min, the expression of EGFR, ICAM-1, αv-integrin, β1-integrin and β5-integrin were remarkably reduced [1].

References:
[1]. Bae DS, et al. Protopine reduces the inflammatory activity of lipopolysaccharide-stimulated murine macrophages. BMB Rep. 2012 Feb;45(2):108-13.
[2]. Chen CH, et al. Protopine, a novel microtubule-stabilizing agent, causes mitotic arrest and apoptotic cell death in human hormone-refractory prostate cancer cell lines. Cancer Lett. 2012 Feb 1;315(1):1-11.
[3]. Vrba J, et al. Protopine and allocryptopine increase mRNA levels of cytochromes P450 1A in human hepatocytes and HepG2 cells independently of AhR. Toxicol Lett. 2011 Jun 10;203(2):135-41.
[4]. He K, et al. Protopine inhibits heterotypic cell adhesion in MDA-MB-231 cells through down-regulation of multi-adhesive factors. Afr J Tradit Complement Altern Med. 2014 Jan 28;11(2):415-24.