Magnoliae flos (Chinese name, 辛夷, Xinyi), the flower buds of Magnolia, has a long history of clinical use in Asian countries and is used to treat nasal congestions and airway inflammatory diseases including allergic rhinitis, sinusitis, asthma, bronchitis, and other conditions. A wide range of pharmacological actions of Xinyi has been reported, including anti-allergy, anti-inflammation, and anti-microbial activity (1). Xinyi contains several components with promising biological activity, such as lignans (2-3), neolignans (4-5), and sesquiterpenes (6).

    Lignans are a class of naturally occurring plant compounds exhibiting potent anti-inflammatory properties. Some of the lignans isolated from Xinyi showed powerful antioxidant activities using a superoxide radical-scavenging assay (2).

    Lee et al. (3) studied the anti-inflammatory effects of lignans isolated from Xinyin against chronic obstructive pulmonary disease (COPD). They showed that lignans obtained from a CHCl3 fraction of Xinyi effectively suppressed the inflammatory response in cigarette smoke condensate-stimulated airway epithelial cells, and in a mouse model of COPD established by exposure to cigarette smoke and lipopolysaccharides. They were found to inhibit cigarette smoke condensate-induced interleukin-6 (IL-6) expression in human airway epithelial cells and to suppress the infiltration of inflammatory cells (neutrophils and macrophages) and secretion of inflammatory cytokines, such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the mouse model. These results demonstrated that the lignans isolated from Xinyi could prevent airway inflammatory diseases.

    Lignans and neolignans both are natural products formed by the linking together of two C6C3 units. The lignans are composed of two C6C3 units linked by a β-β (8-8′) bond, while neolignans are compounds that contain two C6C3 units which are not β-β linked.

Some neolignans extracted from Xinyi possessed anti-HIV activities, and some showed cytotoxic activities against several cancer cell lines (kill cancer cells), including human oropharyngeal epidermoid carcinoma which is commonly known as throat cancer or tonsil cancer (4).

    Some neolignans isolated from Xinyi showed anti-inflammatory properties (5). The extracts and pure compounds from Magnolia species were tested for their production of prostaglandin E(2) (PGE(2)) using a mouse macrophage assay where cells were stimulated by lipopolysaccharide. These neolignans significantly inhibited COX-2, the enzyme largely responsible for causing inflammation.

    Nonsteroidal anti-inflammatory drugs commonly inhibit cyclooxygenase enzymes (COX-1 and COX-2 isoforms), which catalyze the first step of prostaglandin, thromboxane, and prostacyclin biosynthesis. COX-2 is implicated in the pathogenesis of many inflammatory diseases. The results of Magnolia extracts inhibiting COX-2 indicated that the reported traditional medicinal use of the Magnolia species was in agreement with the anti-inflammatory activity of their respective compounds (5).

    Sesquiterpenes are naturally found in plants and insects, as semiochemicals, such as defensive agents or pheromones. They can have calming properties and they can be supportive to the immune system in protecting us from harmful microbes, acting as antioxidants, and assisting in cellular repair. Several sesquiterpenes were found in Xinyi, which may also have contributed to Xinyi's medicinal function (6).

    For those who have inflammatory reactions to the nose, drinking some Magnolia flower tea may bring you some relief. If you suffer from chronic nasal congestion, why not try Xinyi?

References:

1.            Shen, Y., Li, C., Zhou, S., Pang, E., Story, D., & Xue, C. (2008). Chemistry and Bioactivity of Flos Magnoliae, A Chinese Herb for Rhinitis and Sinusitis. Current Medicinal Chemistry, 15(16), 1616–1627. doi:10.2174/092986708784911515

2.            Lee, J., Lee, D., Jang, D. S., Nam, J.-W., Kim, J.-P., Park, K. H., … Seo, E.-K. (2007). Two New Stereoisomers of Tetrahydrofuranoid Lignans from the Flower Buds of Magnolia fargesii. CHEMICAL & PHARMACEUTICAL BULLETIN, 55(1), 137–139. doi:10.1248/cpb.55.137

3.            Lee, S.-U., Ryu, H. W., Lee, S., Shin, I.-S., Choi, J.-H., Lee, J.-W., … Oh, S.-R. (2018). Lignans Isolated From Flower Buds of Magnolia fargesii Attenuate Airway Inflammation Induced by Cigarette Smoke in vitro and in vivo. Frontiers in Pharmacology, 9. doi:10.3389/fphar.2018.00970

4.            Schühly, W., Khan, S. I., & Fischer, N. H. (2009). Neolignans from North American Magnolia Species with Cyclooxygenase 2 Inhibitory Activity. Inflammopharmacology, 17(2), 106–110. doi:10.1007/s10787-009-7013-y

5.            Gao X., Shen Y., Yang L., Shu L., Li G., Hu Q.-F. (2012). 8-O-4′-neolignans from flower buds of Magnolia fargesii and their biological activities. J. Braz. Chem. Soc. 23 1274–1279. 10.1590/S0103-50532012000700011

6.            Jung K. Y., Kim D. S., Park S.-H., Lee I. S., Oh S. R., Lee J. J., et al. (1998). 5α,7α(H)-6,8-cycloeudesma-1β,4β-diol from the flower buds of Magnolia fargesii. Phytochemistry 48 1383–1386. 10.1016/S0031-9422(98)00040-5