The bark, houpu, though, has a more catholic application in traditional Chinese medicine and numerous devious formulations are made of it to treat lung disorders like coughs and asthma and intestinal ones like infections and spasms. Also, the houpu forms a major component of medicines targeting abdominal swellings and edema (Dharmananda, Undated).
The active components of the flower buds lack alkaloids and none have been found to date while aromatics with their decongestant properties like monoterpenes and sesquiterpenes have been abundantly evident (Dharmananda, Undated).
In contrast, the bark, houpu, has a more composite nature and contains numerous carbon compounds. The pleasant fragrance is attributed to two sets of non-alkaloids - the mildly scented biphenols magnolol and honokiol and the strongly scented triterpene eudesmol (Dharmananda, Undated). These latter biphenols and triterpene - magnolol, honokiol and eudesmol - are the main medicinal constituents from the bark houpu. Magnolol (2-11%), honokiol (0.3-4.6%) and eudesmol (>1%) vary from species to species and also from region to region. Modern pharmacological investigations have revealed that these three constituents have the following properties - 1) anxiolytic effects; 2) abilities to enhance steroid production by the adrenal cortex; 3) abilities to inhibit bacteria and fungi; 4) antioxidant effects; 5) abilities to reduce inflammation and pain; 6) abilities to alleviate seizures; and 7) active antitoxic effects against organophosphoric pesticides (Dharmananda, Undated).
The bark huopu also contains some alkaloids - benzylisoquinoline ones such as magnoflorine, magnocurarine and salicifoline. Of these, the most abundant is magnocurarine at >0.2% of the commercial bark material (Dharmananda, Undated). Other trace alkaloids are oxuoshinsunine, anonaine and michelabine. These alkaloids are not believed to take part in the pharmacological action of the bark though it is believed that they do have partial roles in its antispasmodic effects (Dharmananda, Undated).
Though it is settled among pharmacologists that the three main alkaloids are common to this species there is varying report of other alkaloids detected in trace quantities in the same or different sub-species. Thus, Rowe and Conner, 1979, report that, aside from the three above-mentioned main alkaloids, certain magnolia sub-species also contain other alkaloids such as D-O-methylarmepavine in the stem. Also, the sub-species evident in the Southern parts of the US contains traces of anolobine, N-nornuciferine, liridenine and candicine (Rowe and Conner, 1979). There is also report of the Southern magnolia sub-species containing the glycosides magnolidin, magnolenin and magnosidin (Rowe and Conner, 1979).
Traditional Chinese Viewpoint:
One classical medical text from China 'Shen nong ben cao jing' (Chinese Medical Classics, Pregadio, Undated) lists houpo as a '3rd class remedy' (Forrest, 1995). This is because though the alkaloid magnocurarine is useful in minute quantities it is toxic in larger doses and proves contraindicative for pregnant women. In contrast, the flower buds' extract is listed in the same text as a 1st class remedy and prescribed for women, including pregnant ones (Forrest, 1995).