Black currant is a natural remedy sourced from Ribes nigrum, a plant native to parts of Europe and Asia. Black currant extract is typically derived from black currant fruit or from the oil of black currant seeds. In addition to vitamin C, blackcurrants have plenty of antioxidants and anthocyanins. These can help strength your immune system, soothe sore throats, and ease flu symptoms. Black currant leaves also have a range of properties, including antimicrobial.