Effects of Chlorella on Activities of Protein Tyrosine Phosphatases,Matrix Metalloproteinases,Caspases,Cytokine Release,B and T Cell Proliferations,and Phorbol Ester Receptor Binding

Abstract

A Chlorella powder was screened using 52 in vitro assay systems for enzyme activity, receptor binding, cellular cytokine release, and B and T cell proliferation. The screening revealed a very potent inhibition of human protein tyrosine phosphatase (PTP) activity of CD45 and PTP1C with 50% inhibitory concentration (IC₅₀) values of 0.678 and 1.56 μg/mL, respectively. It also showed a moderate inhibition of other PTPs, including PTP1B (IC₅₀ = 65.3 μg/mL) and T-cell-PTP (114 μg/mL). Other inhibitory activities and their IC₅₀ values included inhibition of the human matrix metalloproteinases (MMPs) MMP-1 (127 μg/mL), MMP-3 (185 μg/mL), MMP-7 (18.1 μg/mL), and MMP-9 (237 μg/mL) and the human peptidase caspases caspase 1 (300 μg/mL), caspase 3 (203 μg/mL), caspase 6 (301 μg/mL), caspase 7 (291 μg/mL), and caspase 8 (261 μg/mL), as well as release of the cytokines interleukin (IL)-1 (44.9 μg/mL), IL-2 (14.8 μg/mL), IL-4 (49.2 μg/mL), IL-6 (34.7 μg/mL), interferon-γ (31.6 μg/mL), and tumor necrosis factor-α (11 μg/mL) from human peripheral blood mononuclear cells. Chlorella also inhibited B cell proliferation (16.6 μg/mL) in mouse splenocytes and T cell proliferation (54.2 μg/mL) in mouse thymocytes. The binding of a phorbol ester, phorbol 12,13-dibutyrate, to its receptors was also inhibited by Chlorella with an IC₅₀ of 152 μg/mL. These results reveal potential pharmacological activities that, if confirmed by in vivo studies, might be exploited for the prevention or treatment of several serious pathologies, including inflammatory disease and cancer.