Which plant is identified as a source of Flavonoids?

Sambucus nigra, commonly known as elderberry, is recognized as a significant source of flavonoids. These compounds are a class of plant secondary metabolites known for their numerous health benefits, including antioxidant, anti-inflammatory, and potential antiviral properties. The fruits, flowers, and leaves of elderberry are particularly rich in flavonoids, which contribute to the plant's traditional uses in herbal remedies for colds and flu.

Curcuma longa, known as turmeric, primarily contains curcuminoids, rather than flavonoids, and is more famous for its active compound curcumin, associated with anti-inflammatory effects. Dioscorea villosa, or wild yam, is known for its steroidal saponins rather than flavonoids, being used for hormonal treatments. Trigonella foenum-graecum, or fenugreek, contains a variety of compounds, including saponins and alkaloids, but is not particularly noted for its flavonoid content. This helps clarify why Sambucus nigra is the correct identification for a source of flavonoids among the given choices.