Elderberry

Elderberry refers to the fruit of Sambucus nigra, a deciduous shrub native to Europe, which has been used in folk medicine for centuries to treat respiratory infections. The berries are rich in anthocyanins (particularly cyanidin-3-glucoside), flavonols such as quercetin, and phenolic acids that collectively exert antioxidant and immunomodulatory effects. In vitro studies demonstrate that elderberry extract can inhibit viral replication by preventing viral entry into host cells and by upregulating cytokine production. A meta-analysis of randomised controlled trials found that elderberry supplementation substantially reduced upper respiratory symptoms caused by viral infections. Raw elderberries contain cyanogenic glycosides and lectins that can cause nausea and vomiting, so only properly cooked or commercially processed preparations should be consumed. Standardised elderberry extracts are widely available as syrups, lozenges, and capsules.