In Vitro Effect of Some Medicinal Plant Extracts on Stimulating the Immune System in Cancer Patients PDF

Keywords

Proliferation Assay, Peripheral Blood Lymphocytes, Medicinal Plants, Sage, Immunostimulation, Polyclonal Mitogen

Abstract

The difficulty to treat cancer without side effects by surgery, chemotherapy, radiotherapy and immunotherapy, has led investigators to look for phytotherapy as a new strategy in cancer medicine. The immune system plays an important role in anti-tumor defenses, thus, we evaluated the proliferation potential of aqueous extracts from five medicinal plants on peripheral blood lymphocytes (PBLs) from 118 properly consented volunteers. We examined the aqueous extract of Thyme, Sage, Clove, Calament and Black Seed in vitro on PBLs from 100 cancer patients seeking treatment at Al-Basheer Hospital in Amman and 18 apparently healthy volunteers. PBLs were isolated from blood samples collected in heparin tubes. Then, Ficoll-Hypaque density gradient centrifugation was employed to enrich for lymphocytes. Cells were collected in RPMI containing 10% human serum at 106/mL before culturing them at an appropriate density. Three concentrations of the aqueous extract from each plant were assayed in duplicates on cultured PBLs for 72 hours. Cell proliferation was quantified using 3-(4, 5-Dimethylthiazol-2yJ)-2, 5-diphenyltetrazolium bromide (MTT) standard method. Phytohemagglutinin (PHA) was used as a positive proliferation control, and sterile RPMI medium was used as a negative control. Among the five different aqueous extracts used in this study, only sage aqueous extract demonstrated promising results. Sage extract was effective in proliferating PBLs of all normal controls and cancer patients tested. Proliferation of the majority of PBLs from cancer patients was highly effective. However, some samples showed a weaker index of proliferation. PBLs proliferation exhibited a dose-dependent effect. The effectiveness among cancer patients was age, sex, cancer-type, and cancer-stage independent. Our data suggest that the aqueous extract of sage contains a polyclonal mitogen(s) that enhances the immune system in a non-specific fashion.