Induction of apoptosis and cytokines secretion of Houttuynia cordata Thunb. flavonoids in human leukemic cells

Leukaemia is a hematopoietic cancer and the treatment has many side effects. For this reason, herbal therapy is an alternative treatment for leukaemia to reduce the side effects. The medicinal herb Plucao ( Houttuynia cordata Thunb.) has a vary biological activities including anti-cancer, anti-leukemic, anti-microbial, anti-oxidant, anti-inflammatory and immunomodulatory effects. The active components in Plucao are alkaloids and flavonoids. Quercetin, quercitrin and hyperoside are flavonoid and flavonoid glycosides founded in Plucao. In this study, we extracted Plucao by both distilled deionized water and ethanol. We found that H.cordata ethanolic extract had total flavonoid content more than H.cordata water extract. Total flavonoid of H.cordata ethanolic extract was 224.90 ± 2.80 mg Quercitrin Equivalent (QE)/g dried H.cordata while total flavonoid of H.cordata water extract was 130.79 ± 4.89 mg QE/g dried H.cordata. Moreover, H.cordata extract, quercetin, quercitrin and hyperoside did inhibit the proliferation of Jurkat and U937 leukemic cell lines. The half maximal inhibitory concentration (IC50) values of H.cordata ethanolic extract, H.cordata water extract quercetin, quercitrin and hyperoside on Jurkat were 403.30 ± 5.35, 445.10 ± 6.49, 68.50 ± 2.86, 73.10 ± 2.59, and 75.60 ± 2.25 mg/ml, respectively while IC50 values of H.cordata ethanolic extract, H.cordata water extract quercetin, quercitrin and hyperoside on U937 were 386.20 ± 5.28, 416.40 ± 6.78, 60.50 ± 2.95, 70.10 ± 3.01 and 75.10 ± 1.77 mg/ml, respectively. In addition, our cytokines study found that H.cordata extract and flavonoids especially H.cordata ethanolic extract and quercetin substantially reduced the hematopoietic (IL-2, G-CSF and GM-CSF) and inflammatory (IL-6, IL-10, IL-13, IL-17, IFN-γ, MIP-1β, TNF-α) cytokines. Therefore, we conclude that H.cordata has anti-leukemic and anti-inflammatory activities and may be a potential herbal treatment for leukaemia in complementary medicine.