Isolation and characterization of active elderberry fractions that inhibit melanoma growth in vitro and in vivo

Alexandra M Okihiro, Purdue University

Abstract

The incidence rates of melanoma continue to rise annually despite recent progression in cancer treatments. Cancer is the most prevalent amongst elderly individuals, where immunosenescence has compromised some immune function, and therefore decreased certain tumor detection abilities. Current tumor removal strategies include radiation, chemotherapy and surgical excision: treatments that aim to lower cancer cells, but may also affect normal cells in the process. In the case of chemotherapy, which targets and kills rapidly dividing cells, many immune cells are lowered as a side effect, leaving many patients immune-suppressed and more susceptible to infection. There is a need for naturopathic treatments capable of decreasing tumor cell proliferation without compromising the body's normal immune function. Extracts from elderberry (Sambucus nigra) may be able to satisfy this need. Previous reports suggest that phytochemicals, such as the ones present in elderberry, may stimulate the immune response by secretion of cytokines, provide antioxidant protection to prevent cellular damage, and inhibit tumor growth directly. Our primary goal was to separate the active components of elderberry and assess their inhibitory effects on the growth of multiple cancerous and transformed cell lines, as well as characterize their effects on stimulation of T lymphocyte proliferation and IL-2 secretion in vitro. Murine melanoma model experiments were also performed with crude elderberry and elderberry fractions to analyze the tumor-suppressive activity of elderberry treatments in vivo. Spleen cell proliferation and in vivo experiments were also performed with different aged groups of mice to uncover the tumor -inhibiting and immune-inducing effects of elderberry and active elderberry fractions on aged mice. Active elderberry fractions were then preliminarily identified. All separated elderberry fractions were able to significantly suppress the growth of B16-F10 murine melanoma and SH-SY5Y human neuroblastoma cells in vitro. Several separated fractions also inhibited growth of a human melanoma cell line, MeWo, and a transformed non-cancerous line, CHO-K1. When incubated with concanavalin A (Con A, a known mitogen) and spleen cells from a middle aged and old mouse, separated fractions of elderberry did not increase proliferation above the positive control (cells incubated with con A only) , however, they induced a larger proliferation response in the older mouse spleen cells. Three active fractions induced secretion of IL-2 from spleen cells above the positive control. In general, mice induced to produce tumors developed smaller, localized tumors when treated with crude elderberry compared to mice treated with water, whose tumors were larger and metastatic. The active elderberry fractions were too potent to be successfully implemented in an in vivo experiment, and need to be diluted for future mouse model experiments. Of the four primary anthocyanins in elderberry, cyanidin 3-sambubioside and cyanidin 3-glucoside were identified as the major tumor-inhibiting, immune-inducing components in different active fractions separated from elderberry. The positive benefits of active fractions on tumor suppression and potentially on modulation of immune-inducing mechanisms provide further support for the use of bioactive phytochemicals in preventative cancer treatment.

Degree

M.S.

Advisors

Blumenthal, Purdue University.

Subject Area

Organic chemistry|Immunology|Oncology

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