Screening of aqueous plant extracts for immunomodulatory effects on immune cells and cytokine production: In vitro and in vivo analyses

This study investigates the immunomodulatory effects of various aqueous plant extracts on immune cells and cytokine production. In vitro, several extracts, including holy basil (Ocimum sanctum), patawali (Tinospora crispa), and Indian borage (Plectranthus amboinicus L.), significantly increased CD3(+) T-cell populations, while soap pod (Acacia concinna), garlic (Allium sativum L.), and neem (Azadirachta indica) also boosted CD45RA(+) B-cells. In vivo, the extracts had subtle effects on spleen morphology and Peyer's Patches, with milk bush (Euphorbia tirucalli L.) and Indian borage enhancing T-cell responses, while soap pod stimulated B-cells. Additionally, we observed that Neem and milk bush significantly suppressed B-cell populations. Furthermore, cytokine analysis showed that garlic and patawali reduced IL-2, while soap pod, holy basil, and patawali increased TNF-alpha levels. Soap pod also elevated IL-10 and IL-17A, indicating both anti-inflammatory and pro-inflammatory signaling, while patawali induced an increase in IL-4. In conclusion, Thai medicinal plants show strong potential as both immunostimulants and immunosuppressants. They can enhance lymphocyte proliferation, particularly in T-cells, and modulate B-cell populations. Their aqueous extracts play a key role in regulating Th1, Th2, and Th17 cytokine production. Thus, these plants could serve as natural agents and alternative medicines for boosting or modulating immune function.