Activity of C-glucosidic ellagitannins from Lythrum salicaria L. supporting its traditional use in external treatment of inflammatory associated diseases

Lythrum salicaria L. (Lythraceae) herb is used in traditional medicine in treatment of diseases possessing inflammatory background such as haemorrhoidal disease, dysentery, chronic intestinal catarrh, eczema and periodontosis. Because these diseases are closely associated with excessive inflammatory response of stimulated neutrophils the influence of aqueous extract and isolated C-glucosidic ellagitannins (dimeric salicarinins A, B and C, vescalagin, castalagin) on their pro-inflammatory functions was examined.

Lythrum salicaria L. aqueous extract was shown to modulate LPS triggered production of IL-8 (at 20 µg/mL 16.6 ± 4.2% of inhibition), but had no influence on MMP-9 production. It was active towards cytochalasin A/f-MLP stimulated myeloperoxidase release (at 1 µg/mL 26.5 ± 5.4% of inhibition) and f-MLP and PMA induced reactive oxygen species production (at 20 µg/mL 67.0 ± 3.9% and 66.5 ± 1.9% of inhibition respectively). Extract was also shown to inhibit expression of integrin CD11b on neutrophils surface without the influence on selectin CD62L shedding. Dose dependent inhibition of hyaluronidase activity was observed with IC₅₀= 10.1 ± 1.2 µg/mL. Dominating C-glucosidic ellagitannins were shown to be responsible for all of these activities with more significant participation attributable to dimeric salicarinins A, B, C. The study have shown potent activity of aqueous extract towards stimulated neutrophils, which enhanced response is known to cause pathological changes in skin and mucosa tissues. These observations can support and explain L. salicaria L. herb traditional use in therapy of certain diseases possessing inflammatory background. C-glucosidic ellagitannins, especially dimeric salicarinins are pointed as the factors responsible for the determined effects.

Acknowledgements: The project was financially supported by Polish National Science Center research grant PRELUDIUM- DEC-2012/07/N/NZ7/01136 and PhD scholarship ETIUDA decision number DEC-2013/08/T/NZ7/00011.

Keywords: Lythrum salicaria, ellagitannins, neutrophils, inflammation, hyaluronidase,