The Sacred Lotus and the Molecules Behind
Nelumbo nucifera, commonly known as sacred lotus, is an aquatic plant native to Asia that belongs to the Nelumbonaceae family. It has been used in India, China and Japan for thousands of years, not only in their cuisines but also as a symbol of purity and perfection. This flower (Image 1) is associated with Buddha, explaining why it is considered sacred in eastern communities and it is often used in Indian and Chinese medicine for treating many different disorders (1).
More recent studies have elucidated around 250 compounds from different parts of the plant (Image 2). From those almost 20% are alkaloids (extracted mainly from the seeds and leaves), 30% flavonoids (from flowers and leaves) and around 15% terpenoids (from flowers). The rest of the molecules include saturated and unsaturated fatty acids, amino acids, and saccharides. This broad Image 1. Nelumbo nucifera's flower range of compounds, specially of alkaloids, correspond with the many different medicinal properties attributed during the centuries (2), the reason why the scientific community has turned its attention on this kind of metabolites in the lotus.
Image 2. Parts of Nelumbo nucifera.
Alkaloids are a big group of plant secondary metabolites, they are characterized by the presence of one or more nitrogen atoms in a ring, they present basic properties, are not water soluble and often have a bitter taste. They act as defense compounds due to their toxicity and represent a key factor for plant survival. Alkaloids have important pharmacological effects, they have shown strong biological responses in animals and humans at really low doses (3). Among the alkaloids more studied of the sacred lotus are neferine, nuciferine, liensinine and quercetin.
Neferine (Image 3) for example, is obtained from the seeds and has shown anti-hypertensive, anti-thrombotic and anti-cancerous properties(4). This last property is the most studied one, it includes studies of lung, liver, breast and ovarian cancer. However, no clinical trials have been done, so the long-term effects and efficacy remain unknown, consequently more studies are needed to put the neferine as a potential therapeutic molecule.
Image 3. Neferine structure
On the other hand, nuciferine (Image 4) has registered anti-obesity, antidiabetic and anti-fatty liver properties, and has also been studied for its antitumor activity (5). This molecule has been tested in diabetic animal models with a high fat diet, showing promising results for liver damage (6). Another important characteristic of this alkaloid is that it is capable of penetrating the blood brain barrier, so it could be a good candidate for the treatment of brain diseases (7). It is extracted from the leaves of Nelumbo Image 4. Nuciferine structure nucifera, but as the neferine, there's a lot of information missing regarding its toxicity and safety.
Nelumbo nucifera has been used in Asian medicine for centuries due to all the attributed properties. Today we know that most of its pharmacological effects are vinculated with the varied content of metabolites, particularly the alkaloids. In recent years, the interest in the sacred lotus has increased and many of its molecules, like nefereine and nucifering, were and are being investigated. Nevertheless, further studies are required to gather pharmacological information in order to guarantee safety and effectiveness.
Marthandam Asokan, S., Mariappan, R., Muthusamy, S., & Velmurugan, B. K. (2018). Pharmacological benefits of neferine - A comprehensive review. In Life Sciences (Vol. 199, pp. 60–70). Elsevier BV. https://doi.org/10.1016/j.lfs.2018.02.032
Sharma, B. R., Gautam, L. N. S., Adhikari, D., & Karki, R. (2016). A Comprehensive Review on Chemical Profiling ofNelumbo Nucifera: Potential for Drug Development. In Phytotherapy Research (Vol. 31, Issue 1, pp. 3–26). Wiley. https://doi.org/10.1002/ptr.5732
Kurek, J. (2019). Introductory Chapter: Alkaloids - Their Importance in Nature and for Human Life. In Alkaloids - Their Importance in Nature and Human Life. IntechOpen. https://doi.org/10.5772/intechopen.85400
Bharathi Priya, L., Huang, C., Hu, R., Balasubramanian, B., & Baskaran, R. (2021). An updated review on pharmacological properties of neferine—A bisbenzylisoquinoline alkaloid from Nelumbo nucifera. In Journal of Food Biochemistry (Vol. 45, Issue 12). Wiley. https://doi.org/10.1111/jfbc.13986
Huang, X., Hao, N., Chen, G., Liu, S., & Che, Z. (2022). Chemistry and biology of nuciferine. In Industrial Crops and Products (Vol. 179, p. 114694). Elsevier BV. https://doi.org/10.1016/j.indcrop.2022.114694
Zhang, C., Deng, J., Liu, D., Tuo, X., Xiao, L., Lai, B., Yao, Q., Liu, J., Yang, H., & Wang, N. (2018). Nuciferine ameliorates hepatic steatosis in high-fat diet/streptozocin-induced diabetic mice through a PPARα/PPARγ coactivator-1α pathway. In British Journal of Pharmacology (Vol. 175, Issue 22, pp. 4218–4228). Wiley. https://doi.org/10.1111/bph.14482
Li, Z., Chen, Y., An, T., Liu, P., Zhu, J., Yang, H., Zhang, W., Dong, T., Jiang, J., Zhang, Y., Jiang, M., & Yang, X. (2019). Nuciferine inhibits the progression of glioblastoma by suppressing the SOX2-AKT/STAT3-Slug signaling pathway. In Journal of Experimental & Clinical Cancer Research (Vol. 38, Issue 1). Springer Science and Business Media LLC. https://doi.org/10.1186/s13046-019-1134-y