Tulsi

Tulsi (also known as holy basil, Ocimum tenuiflorum, Ocimum sanctum Linn, Ocimum sanctum, tulasi, or thulasi)

Immune system
In a study of 24 healthy volunteers, consumption of Tulsi in on an empty stomach led to increased levels of IFN-γ and IL-4 cytokines, as well as increased percentages of T-helper cells and natural killer cells after four weeks as compared to placebo.