It has been reported that Houttuynia (H.) cordata extracts have diverse pharmacological effects including antiviral and antibacterial, antiallergic, antioxidant and antimutagenic activities. Thus, H. cordata Thunb has been used as an Oriental medicine for the therapy of inflammatory diseases such as ulcerative colitis.
Recent studies revealed that the constituents of H. cordata essential oil are methyl nonyl ketone, β-myrcene, β-pinene, α-pinene, α-terpineol and n-decanoic acid, and that the anti-inflammatory effects of this oil were also demonstrated. Notably, the essential oil constituents and their concentrations varied with different extraction methods. Recently, supercritical extraction technology has been adopted for the total extraction of constituents from natural plant sources.