Flowers of Hibiscus (rosa-sinensis Linn) popularly known as “China-rose flowers” contain significant flavonoids (such as anthocyanin and quercetin) known to have antidepressant activity.
The antidepressant effect may be from its antioxidant activity; there are few controlled studies on human populations. Hibiscus has been used in Hawaiian cultures to treat postpartum depression.
Another herbal tea, made from the sepals of Hibiscus flowers are beautiful, showy red flowers that are harvested and dried like most teas. This plant contains bioflavonoids, which are believed to help prevent an increase in LDL cholesterol, and to lower blood pressure. The research is quite clear on these effects. It may work by boosting nitric oxide production, generally an advantage for cardiovascular activities (aerobic exercise).
Again, why bother to make tea with this food and limit the nutrient availability when you can eat it! I use a heaping tablespoon in my morning smoothie. I also like to blend it with green tea and ice, then strain it into water bottles as a drink during exercise.
 Butterweck, V., Jürgenliemk, G., Nahrstedt, A., & Winterhoff, H. (2000). Flavonoids from Hypericum perforatum Show Antidepressant Activity in the Forced Swimming Test. Planta Medica, 66(1), 3-6. doi:10.1055/s-2000-11119.
 Vanzella, C., Bianchetti, P., Sbaraini, S., Vanzin, S. I., Melecchi, M. I., Caramão, E. B., & Siqueira, I. R. (2012). Antidepressant-like effects of methanol extract of Hibiscus tiliaceus flowers in mice. BMC Complementary and Alternative Medicine, 12(1). doi:10.1186/1472-6882-12-41.
 Kobayashi, J. (1976). Early Hawaiian Uses of Medicinal Plants in Pregnancy and Childbirth. Journal of Tropical Pediatrics, 22(6), 260-262. doi:10.1093/tropej/22.6.260.
 Siddiqui, A., Wani, S., Rajesh, R., & Alagarsamy, V. (2006). Phytochemical and pharmacological investigation of flowers of hibiscus rosasinensis linn. Indian Journal of Pharmaceutical Sciences Indian J Pharm Sci, 68(1), 127. doi:10.4103/0250-474x.22986.