Chemical constituents of industrial hemp roots and their anti-inflammatory activities

Abstract

Objective: Although the chemical constituents of the aerial parts of Cannabis have been extensively studied, phytochemicals of Cannabis roots are not well characterized. Herein, we investigated the chemical constituents of industrial hemp (Cannabis sativa L.) roots and evaluated the anti-inflammatory activities of phytochemicals isolated from the hemp roots extract.

Methods: An ethyl acetate extract of hemp roots was subjected to a combination of chromatographic columns to isolate phytochemicals. The chemical structures of the isolates were elucidated based on spectroscopic analyses (by nuclear magnetic resonance and mass spectrometry). The anti-inflammatory effects of phytochemicals from hemp roots were evaluated in an anti-inflammasome assay using human monocyte THP-1 cells.

Results: Phytochemical investigation of hemp roots extract led to the identification of 32 structurally diverse compounds including six cannabinoids (1-6), three phytosterols (26-28), four triterpenoids (22-25), five lignans (17-21), and 10 hydroxyl contained compounds (7-16), three fatty acids (29-31), and an unsaturated chain hydrocarbon (32). Compounds 14-21, 23, 27, and 32 were identified from the Cannabis species for the first time. Cannabinoids (1-5) reduced the level of cytokine tumor necrosis-alpha (by 38.2, 58.4, 47.7, 52.2, and 56.1%, respectively) and 2 and 5 also decreased the interleukin-1β production (by 42.2 and 92.4%, respectively) in a cell-based inflammasome model. In addition, non-cannabinoids including 11, 13, 20, 25, 29, and 32 also showed selective inhibition of interleukin-1β production (by 23.7, 22.5, 25.6, 78.0, 24.1, 46.6, and 25.4%, respectively) in THP-1 cells.

Conclusion: The phytochemical constituent of a hemp roots extract was characterized and compounds from hemp roots exerted promising anti-inflammatory effects.

Keywords: Cannabinoids; Cannabis sp. phytochemicals; Hemp; Inflammasome.

Fig. 1

Chemical structures of compounds 1–32 including cannabinoids (1–6) and non-cannabinoids (7–32) isolated from hemp roots

Fig. 2

Anti-inflammatory effects of cannabinoids (1–5) isolated from hemp roots. Inflammasome activation in THP-cells was induced by the stimulation with LPS-nigericin. Effects of 1–5 (at 50 µM) on the production of pro-inflammatory cytokines including IL-1β (A) and TNF-α (B). Data are presented as means ± standard deviation from samples with three replicated experiments (n = 3). Statistical analysis was performed with a one-way analysis of variance with multiple comparisons and the significance was noted as: ***p < 0.001, ****p < 0.0001 vs. the model (LPS-nigericin stimulated) group and ####p < 0.0001 vs. the control group

Fig. 3

Anti-inflammatory effects of non-cannabinoids isolated from hemp roots (11, 13, 19, 20, 25, 29, and 32). Inflammasome activation in THP-cells was induced by the stimulation with LPS-nigericin. Effects of 11, 13, 19, 20, 25, 29, and 32 (at 50 µM) on the production of pro-inflammatory cytokines including IL-1β (A) and TNF-α (B). Data are presented as means ± standard deviation from samples with three replicated experiments (n = 3). Statistical analysis was performed with a one-way analysis of variance with multiple comparisons and the significance was noted as: *p < 0.005, ****p < 0.0001 vs. the model (LPS-nigericin stimulated) group and ####p < 0.0001 vs. the control group