Exploring the immunomodulatory, anti-inflammatory, and cell proliferative potential of Hydrocotyle umbellata L. Leaf extracts: A comparative study with Centella asiatica (L.) Urb

Introduction

Hydrocotyle umbellata L. has traditionally been consumed as a Thai vegetable side dish with curry or chili paste and it was used for the treatment of inflammation in folk phytotherapy. Methods: This explored the phytochemical composition and potential biological activities of H. umbellata leaf extracts in comparison to the well-known medicinal plant Centella asiatica (L.) Urb. H. umbellata leaves were selected and extracted with distilled water and 95% ethanol, with the respective extracts labelled HUW and HUE. CAE referred to the ethanolic extract of C. asiatica leaves. Results: Phytochemical profiling showed that HUW was rich in phenolics, while both HUE and CAE contained higher levels of flavonoids and terpenoids. H. umbellata extracts exhibited strong antioxidant with HUW exhibiting superior DPPH scavenging, while HUE demonstrated significant reducing power, and CAE showed the lowest antioxidant activity among all extracts. Anti-inflammatory assays revealed that HUW had higher protein denaturation inhibition and antiprotease activity than HUE and CAE. In LPS-induced macrophages, all extracts significantly reduced the production of nitric oxide without cytotoxic effects, with CAE being most effective. Cytokine profiling showed that HUW selectively suppressed TNF-α, while HUE and CAE broadly inhibited TNF-α, IL-1β, and IL-6. Gene expression analysis confirmed the downregulation of inflammatory markers, with HUW suppressing IL-6, whereas HUE and CAE predominantly reduced the expression of TNF-α, IL-1β, CCL-2, and iNOS. HUW showing the strongest effect in HDF and HGF cells among all extracts. Conclusion: These findings might support the use of H. umbellata as a functional food with immunomodulatory potential