Maltese mushroom (Cynomorium coccineum L.) as source of oil with potential anticancer activity

Abstract

The present study aimed to examine the potential anticancer properties of fixed oil obtained from Maltese mushroom (Cynomorium coccineum L.), an edible, non-photosynthetic plant, used in traditional medicine of Mediterranean countries to treat various ailments and as an emergency food during the famine. We investigated the effect of the oil, obtained from dried stems by supercritical fractioned extraction with CO2, on B16F10 melanoma and colon cancer Caco-2 cell viability and lipid profile. The oil, rich in essential fatty acids (18:3n-3 and 18:2n-6), showed a significant growth inhibitory effect on melanoma and colon cancer cells. The incubation (24 h) with non-toxic oil concentrations (25 and 50 μg/mL) induced in both cancer cell lines a significant accumulation of the fatty acids 18:3n-3 and 18:2n-6 and an increase of the cellular levels of eicosapentaenoic acid (20:5n-3) with anticancer activity. Moreover, the oil exhibited the ability to potentiate the growth inhibitory effect of the antitumor drug 5-fluorouracil in Caco-2 cells and to influence the melanin content in B16F10 cells. The results qualify C. coccineum as a resource of oil, with potential benefits in cancer prevention, for nutraceutical and pharmaceutical applications.

Figure 1

Digital image of aerial parts Cynomorium coccineum (Maltese mushroom, MM) growing in a coastal area of south-western Sardinia, Italy (A) and slices of a specimen (B); gas chromatographic (GC) profile of MM oil (C).

Figure 2

Viability (expressed as % of the control) (MTT assay) induced by 24 h incubation with MM fixed oil (50–1000 μg/mL) in colon cancer Caco-2 and melanoma B16F10 cells (A). Viability (% control) induced by 24 h incubation with 5-fluorouracil (5-FU) (0.5–200 μg/mL) in cancer Caco-2 cells in the absence or in the presence of MM fixed oil (25 or 50 μg/mL) (5-FU + MM 25 and 5-FU + MM 50; the effect of MM 25 and MM 50 on cell viability is reported as detail) (B). Data are expressed as mean ± SD of four independent experiments performed in quadruplicate. Statistically significant differences are indicated by: ^a = p < 0.001; ^b = p < 0.01; ^c = p < 0.05 vs. Ctrl; ^a′: p < 0.001 vs. Ctrl for both cell lines.

Figure 3

Values (expressed as % control) of the unsaturated fatty acids (A) (B—detail of 20:3n-3 and 20:5n-3 fatty acid levels) and cholesterol (C) measured in cancer Caco-2 control cells and after 24 h incubation in the presence of two concentrations of MM fixed oil (25 and 50 μg/mL). Data are expressed as mean ± SD of three independent experiments performed in triplicate. Statistically significant differences are indicated by: ^a = p < 0.001; ^b = p < 0.01; ^c = p < 0.05 vs. Ctrl; ^d = p < 0.001; ^e = p < 0.01; ^f = p < 0.05 vs cells incubated with 25 μg/mL.

Figure 4

Values (expressed as % control) of the unsaturated fatty acids (A) and cholesterol (B) measured in melanoma B16F10 control cells (Ctrl) and after 24 h incubation in the presence of two concentrations of MM fixed oil (25 and 50 μg/mL). Data are expressed as mean ± SD of three independent experiments performed in triplicate. Statistically significant differences are indicated by: ^a = p < 0.001; ^b = p < 0.01; ^c = p < 0.05 vs. Ctrl; ^f = p < 0.05 vs. cells incubated with 25 μg/mL.

Figure 5

Values of melanin (% control) measured in cell pellets and in the supernatant of B16F10 control cells (Ctrl) and after 72 h incubation in the presence of two concentrations of MM fixed oil (25 and 50 μg/mL). Data are expressed as mean ± SD of three independent experiments performed in duplicate. Statistically significant differences are indicated by: ^a = p < 0.001; ^b = p < 0.01; ^c = p < 0.05 vs. Ctrl; ^e = p < 0.01; ^f = p < 0.05 vs. cells incubated with 25 μg/mL.