Immunomodulatory activities of common vegetables and spices of Umbelliferae and its related coumarins and flavonoids

Abstract

Carrots, celery, coriander, fennel and parsley of the Umbelliferae family have been used as common vegetables and spices in many different cultures of the world. In this study, we evaluated the immunomodulatory activities of coumarins and flavonoids obtained from the above foods on human peripheral blood mononuclear cells (PBMC). Studies were conducted on lymphocyte transformation, ELISA assay and flow cytometry. Results provided the evidence of a health-modulating effect of these vegetables and spices which possessed a direct role in immunomodulatory function. Some of non-nutritional constituents of these foods such as coumarins and flavonoids also exhibited a similar immunomodulatory activity. At non-cytotoxic concentrations, the above phytoconstituents exhibited three types of immunomodulation including type 1 of PHA, ConA and quercetin (increased lymphocyte activation and IFN-γ secretion); type 2 of isopimpinellin (enhanced lymphocyte activation) and type 3 of rutin, bergapten and xanthotoxin (elevated IFN-γ secretion). The augmentation of lymphocyte proliferation was closely correlated to an increase in the number of lymphocyte cells including CD8⁺ T cells and activated PBMC, whereas elevation of IFN-γ secretion was due to the activated CD8⁺ T cells.

Introduction

Celery (Apium graveolens L.), coriander (Coriandrum sativum L.), carrots (Daucus carota L.), fennel (Foeniculum vulgare Mil.) and parsley (Petroselinum crispum Nyman Ex A.W. Hill) are popular vegetables and spices of Umbelliferae. There are many nutrients in these foods, particularly immunomodualtory nutrients, including vitamins (A, B₂, C, E) and minerals (copper, zinc, iron, selenium) (Bhaskaram, 2002, Chandra, 1991). Additionally, the above vegetables and spices also contain several bioactive phytochemicals such as flavonoids (quercetin, rutin) and coumarins (bergapten, isopimpinellin, xanthotoxin), which are reported to have curative, preventive, or nutritive value (Duke, 1992). There are several reports of the efficacy of quercetin and rutin against infections of bacteria, fungi and viruses (Bae et al., 2000, Chiang, Chiang, Liu, et al., 2003, Paulo et al., 1997, Wang et al., 1989, Weidenborner et al., 1990) and their anti-allergy (Cheong et al., 1998), anti-inflammation (Shoskes, 1999) and immunosuppression activities (Lee et al., 1995, Namgoong et al., 1994). The above coumarins have also been found to inhibit multiplication of bacteria, fungi and viruses (Hudson et al., 1993, Juan et al., 1997, Kofinas et al., 1998, Yang and Yen, 1979), and demonstrated anti-allergy (Kimura & Okuda, 1997), anti-inflammation (Chen, Tsai, & Wu, 1995) and immunosuppression activities (Cox et al., 1988, Kuzel et al., 1992).

An inappropriate immunity has been shown as a common etiology in an ever-growing array of pathological processes including infections, cancer, allergy, aging and a variety of disorders of various organs (Peakman & Vergani, 1997). To date, there is only a modest body of knowledge about the non-nutritiously active compounds in vegetables and spices and their collective roles in promoting human health by immunomodulation. Recently, we have reported that several phytochemicals in wild vegetables of Plantago species possess immunomodualtory activity, especially immunostimulating activity of phenolic compounds such as caffeic acid, chlorogenic acid, ferulic acid and p-coumaric acid, which have been reported to be as common phenolic acids in the above vegetables and spices of this study (Chiang, Ng, et al., 2003, Duke, 1992).

To explore the potentially health-promoting role of popular vegetables and spices of Umbelliferae, we evaluated the immunomodulatory activities of the crude extracts and two common chemical classes of five related pure compounds from Umbelliferae (Duke, 1992) on human PBMC.