Some bioactive potentials of two biflavanols isolated from Garcinia kola on cadmium-induced alterations of raw U937 cells and U937-derived macrophages

Flavonoids regulate tumor-associated macrophages - From structure-activity relationship to clinical potential (Review)

In recent years, the strategy for tumor therapy has changed from focusing on the direct killing effect of different types of therapeutic agents on cancer cells to the new mainstream of multi-mode and -pathway combined interventions in the microenvironment of the developing tumor. Flavonoids, with unique tricyclic structures, have diverse and extensive immunomodulatory and anti-cancer activities in the tumor microenvironment (TME). Tumor-associated macrophages (TAMs) are the most abundant immunosuppressive cells in the TME. The regulation of macrophages to fight cancer is a promising immunotherapeutic strategy. This study covers the most comprehensive cognition of flavonoids in regulating TAMs so far. Far more than a simple list of studies, we try to dig out evidence of crosstalk at the molecular level between flavonoids and TAMs from literature, in order to discuss the most relevant chemical structure and its possible relationship with the multimodal pharmacological activity, as well as systematically build a structure-activity relationship between flavonoids and TAMs. Additionally, we point out the advantages of the macro-control of flavonoids in the TME and discuss the potential clinical implications as well as areas for future research of flavonoids in regulating TAMs. These results will provide hopeful directions for the research of antitumor drugs, while providing new ideas for the pharmaceutical industry to develop more effective forms of flavonoids.

Garcinia kola treatment exhibits immunomodulatory properties while not affecting type 1 diabetes development in an experimental mouse model

Objective

T cells orchestrate an inflammatory response that destroys pancreatic insulin-producing β cells during the development of autoimmune type 1 diabetes (T1D). Garcinia kola Heckel (GK) is a plant widely exploited in West African traditional medicine. Some of the therapeutic effects of GK nut’s extract (GKE) have been suggested to be due to its anti-inflammatory potential. Since GKE has never been investigated in a T1D experimental model, nor in the T cells’ context, we aimed to determine whether GKE exhibits antidiabetic properties and affects T cells by its anticipated anti-inflammatory action.

Methods

The effect of aqueous GKE (aGKE) ingestion, 100 mg/kg daily by drinking water over the period of 6 weeks, has been tested in a low-dose streptozotocin-induced (LDSTZ) mouse model of autoimmune T1D. T cells were studied in vitro and in vivo in mice treated by aGKE.

Results

The results showed that aGKE treatment, which started a week before induction of disease, neither delayed the development of T1D, nor reduced glycemia severity. Interestingly, aGKE treatment did affect T cells and their function, significantly decreasing the frequency of helper (T_H) and cytotoxic (T_C) T cells, while elevating the levels of pro-inflammatory cytokines, TNF-α, IL-6, and IFN-γ, and suppressing IL-2.

Conclusion

In conclusion, our results did not confirm the antidiabetic property of GKE, while suggesting its therapeutic exploration in T_H2-dependent pathologies that benefit from an aggravated T_H1 response, such as allergies.

The In Vitro Anti-Proliferative Interaction of Flavonoid Quercetin and Toxic Metal Cadmium in the 1321N1 Human Astrocytoma Cell Line

Cadmium (Cd) is a toxic heavy metal occurring in the environment as an industrial pollutant. The systematic accumulation of Cd in the human body may lead to major health problems. Quercetin (QE) is a natural flavonoid widely distributed in plants and is a part of human diet. Many studies have demonstrated the multiple benefits of QE to humans in protecting cells of our bodies. The aim of this study was to investigate the effect of QE and Cd on the proliferation of astrocytoma 1321N1 cells. Results indicated that the simultaneous exposure of the cells to 200 µM QE and 16 μM Cd significantly reduced cell viability to 6.9 ± 1.6% with respect to vehicle-treated cells. Other experiments of QE pre-treatment followed by the exposure to Cd alone or with QE indicated significant but decreased ability of QE or Cd to reduce proliferation of the cells compared to their co-incubation. Our study suggested a synergetic anti-proliferative interaction of Cd and QE in malignantly transformed cells. This adds new information regarding the biological effects of QE.