Sword bean, also known as Canavalia gladiata or sword bean seed, is the seed of the legume plant Canavalia gladiata. It has a warm nature and a sweet taste, and contains protein, fat, urease, hemagglutinin, canavanine, starch, and other components. It has the effects of warming the middle and lowering qi, nourishing the kidneys and replenishing the essence. It is used to treat symptoms such as cold and vomiting, abdominal distension, kidney deficiency and low back pain, and phlegm asthma. It is important to note that there are fake sword bean seeds on the market that are made from the seeds of a plant called Canavalia rosea. Be careful when using to distinguish between the two.
Genuine Sword Bean
The appearance is flat oval or flat kidney-shaped, about 2-3.5 cm long, 1-2 cm wide, and 0.5-1.2 cm thick. The surface is light red or purple red, with a few being white or black, slightly glossy, and slightly wrinkled. The edge has a gray-black seed hilum, about 1.5-2.5 cm long, with white membranous remnants resembling pearls. Near the hilum, there is a small concave dot-shaped hole, and on the other end, there is a dark-colored fusion point. There is a raised seed ridge between the fusion point and the hilum. The texture is hard and difficult to break. The seed coat is leathery, and the inner surface is brownish-green. There are two thick cotyledons inside, yellowish-white in color. The embryonic root is small and located at one end of the hilum, leaning to one side. There is no scent, and the taste is mild. When chewed, it has a bean-like fishy taste.
Fake Canavalia rosea dried seeds
The appearance is flat elliptical or slightly flat round, with a brown to dark brown surface. The edge has a black-brown, almost ring-shaped hilum, accounting for more than half of the circumference of the seed. There is a gray-black pearl stalk residue on the hilum. Although it is also hard, the inner surface is blackish-brown, and the cotyledons are gray-white. There is a slight scent, and the taste is also mild, but there is no fishy taste when chewed.
Modern pharmacological research shows that the hemagglutinin contained in sword beans has anti-tumor effects. It can restore tumor cells to their normal growth state. Hemagglutinin can agglutinate deformed cells caused by various carcinogens, but only agglutinates normal cells after treatment with trypsin. This is because it interacts with glucose or mannose-like sites on the surface membrane of deformed cells. Normal cells are masked and therefore do not agglutinate. However, fake Canavalia rosea seeds, although they belong to the same plant family as sword beans, do not have these effects, so they cannot be used as a substitute for sword beans.
