qinghao

Qinghao refers to Artemisia annua L., a small annual herb in the daisy family (Asteraceae). It is commonly known in English as annual wormwood or sweet wormwood and is native to temperate regions of Asia. The plant has a long history in traditional Chinese medicine for treating fever and malaria-like illness, and it is the source of artemisinin, the compound credited with enabling modern antimalarial therapy.

The active constituent of Qinghao is artemisinin, known in Chinese as qinghaosu. In the 1960s and 1970s, Chinese researchers isolated and validated artemisinin from Qinghao, a breakthrough led by Tu Youyou. Artemisinin and its derivatives, such as artesunate and artemether, are fast-acting antimalarial drugs. They form the cornerstone of artemisinin-based combination therapies (ACTs), which pair an artemisinin derivative with another antimalarial to improve efficacy and limit resistance.

Cultivation and use: Artemisia annua is grown in various temperate climates, and the content of artemisinin varies with plant genotype, growing conditions, and harvest timing. The dried leaves and flowering tops may be used directly in traditional preparations, while purified derivatives are formulated into pharmaceutical products for clinical use.

Safety and resistance: ACTs are generally well tolerated, with potential adverse effects including nausea, dizziness, and transient fever. Widespread use has raised concerns about emerging artemisinin resistance in Plasmodium falciparum, prompting surveillance, research, and adjustments to treatment guidelines.