Immunomodulatory effects of citrus fruit auraptene in vitro and in vivo

Immunomodulatory and antioxidant effect of liposomal auraptene against cyclophosphamide-induced immunosuppression in BALB/c mice

INTRODUCTION

Cyclophosphamide (CP), which is a commonly used chemotherapy drug, can lead to a range of side effects such as immunosuppression, bone marrow suppression, leukopenia, and oxidative stress. This study aims to explore the effects of Auraptene (AUR), which has immunomodulatory and antioxidant properties, on immune function in mice that are experiencing suppression induced by CP.

MATERIALS AND METHODS

The experiment involved 60 male BALB/c mice that underwent a 10-day treatment. On days 1, 3, and 9, CP was given at 80 mg/kg IP doses to induce immunosuppression. The mice were divided into five groups: Control group, CP group, CP + liposomal AUR 0.2 mg/kg (AUR 0.2), CP + liposomal AUR 0.25 mg/kg (AUR 0.25), and liposomal vehicle group. Various parameters were measured, including mouse weight, immune organ weight index (spleen and thymus), spleen and thymus histopathology, levels of inflammatory cytokines (IL2, IL10, IL4, IFN-γ), TH1/TH2 balance ratio, IgG and IgM immunoglobulin levels, white blood cell count, platelets, neutrophils, lymphocytes, and oxidative activity measured by MDA, SOD, and Total Antioxidant.

RESULTS

In the group treated with CP, the mice showed a significant decrease in weight compared to the control group. In contrast, the group treated with AUR maintained their weight and did not show a significant difference from the control group. AUR 0.25 reduced the damage to the spleen and thymus caused by CP. Additionally, AUR 0.25 demonstrated a significant decrease in IL4 and IL10 levels compared to the CP group (p = 0.04), approaching the levels of the control group. Furthermore, IL2 and IFN-γ levels in the AUR 0.25 group significantly increased (p = 0.04) compared to the CP group, reaching levels similar to the control group. AUR also increased serum IgM and IgG levels two to three times compared to the CP group, approaching the levels of the control group. MDA levels in the AUR 0.25 group decreased to normal and control levels. AUR 0.25 also showed increased SOD and Total Antioxidant levels. Additionally, white blood cells, platelets, neutrophils, and lymphocytes in the AUR group significantly increased compared to the CP group, reaching normal levels similar to the control group. The TH1/TH2 ratio in the AUR group exhibited a significant increase of two and a half times (p = 0.002) compared to the CP group.

CONCLUSION

These results show that AUR protects against the side effects of CP by increasing the function of the humoral and cellular immune system through the balance of TH1/TH2 and increasing the level of immunoglobulins, as well as increasing the antioxidant activity and the protective role of cytotoxicity.

Retrieval of High Added Value Natural Bioactive Coumarins from Mandarin Juice-Making Industrial Byproduct

Cold pressed essential oil (CPEO) of mandarin (Citrus reticulata Blanco), a by-product of the juice-making industrial process known to contain large amounts of polymethoxyflavones, was exploited for its content in high added value natural coumarins. The study herein afforded a method referring to the evaporation of CPEO volatile fraction under mild conditions (reduced pressure and temperature below 35 °C) as azeotrope with isopropanol. This allowed the isolation of high added value coumarins from the non-volatile fragment using preparative High Performance Liquid Chromatography (HPLC). Pilot-scale application of this procedure afforded for each kg of CPEO processed the following natural bioactive coumarins in chemically pure forms: heraclenol (38-55 mg), 8-gerayloxypsoralen (35-51 mg), auraptene (22-33 mg), and bergamottin (14-19 mg). The structures of coumarins were verified by Nuclear Magnetic Resonance (NMR) spectroscopy and HPLC co-injection with authentic standards. Thus, the low market value mandarin CPEO with current value of 17 to 22 EUR/kg can be valorized through the production of four highly bioactive natural compounds worth 3479 to 5057 EUR/kg, indicating the great potentials of this methodology in the terms of the circular economy.

Anti-inflammatory effect of aqueous extract from Kawachi-bankan (Citrus maxima) peel in vitro and in vivo

Kawachi-bankan (Citrus maxima) is one of the citruses produced in Ehime, Japan. Although health functions of flavonoids and carotenoids in citrus peel have been studied very well, those of water-soluble substances in the peel have not been focused. We herein indicated the anti-inflammatory effect of Kawachi-bankan peel aqueous extract (KPE) in vitro and in vivo. KPE significantly inhibited the production of inflammatory cytokines such as interleukin (IL)-6 and tumor necrosis factor (TNF)-α by LPS-stimulated RAW264.7 cells without cytotoxicity. KPE also significantly inhibited the mRNA expression levels of IL-6 and TNF-α in the cells, suggesting that KPE inhibits the production of inflammatory cytokines by suppressing the gene expression levels. Immunoblot analysis revealed that KPE shows an anti-inflammatory effect on macrophages through the suppression of the phosphorylation of p38 and the translocation of NF-κB into nucleus. The oral administration of KPE inhibited the serum levels of inflammatory cytokines and improved the survival rate in systemic inflammatory response syndrome (SIRS) model mice. Our experiments using a cell line suggested that KPE inhibits the production of inflammatory cytokines by macrophages in hyperinflammatory state. In addition, experiments in vivo showed that the oral administration of KPE inhibited the serum levels of inflammatory cytokines and improved the survival rate in SIRS model mice. Our findings indicated that KPE contributes to alleviating of a hyperinflammatory response.

Effect of kumquat (Fortunella crassifolia) pericarp on natural killer cell activity in vitro and in vivo

Natural killer (NK) cells play a key role in innate immune defense against infectious disease and cancer. A reduction of NK activity is likely to be associated with increased risk of these types of disease. In this study, we investigate the activation potential of kumquat pericarp acetone fraction (KP-AF) on NK cells. It is shown to significantly increase IFN-γ production and NK cytotoxic activity in human KHYG-1 NK cells. Moreover, oral administration of KP-AF significantly improves both suppressed plasma IFN-γ levels and NK cytotoxic activity per splenocyte in restraint-stressed mice. These results indicate that raw kumquat pericarp activates NK cells in vitro and in vivo. To identify the active constituents, we also examined IFN-γ production on KHYG-1 cells by the predicted active components. Only β-cryptoxanthin increased IFN-γ production, suggesting that NK cell activation effects of KP-AF may be caused by carotenoids such as β-cryptoxanthin.