Everlasting flowers: Phytochemistry and pharmacology of the genus Helichrysum

The plants belonging to the genus Helichrysum (Asteraceae) are known as everlasting flowers and widely used in traditional medicine worldwide. Surveys on their traditional uses as well as phytochemical and pharmacological studies have revealed the potential of these plants for drug discovery. Although there are several studies on some of the species, most of the plants need to be investigated thoroughly. The aim of this review is to present a collated and coherent overview of the documented traditional uses, pharmacological activities and particularly bioactive constituents of Helichryswn species. Scientific databases including Scifinder, ISI Web of Knowledge, PubMed and Scopus as well as several traditional texts and books were searched to collect the data. Review of studies showed that Helichrysum spp. have been used in different systems of traditional and folk medicines for the treatment of various infections, wounds, digestive problems, diabetes and colds, of which some are confirmed in modem medicine such as the antimicrobial activity. Phytochemical investigations have shown that these plants are rich in phenolic compounds such as flavonoids, pyrones, phloroglucinols and essential oils, and in some species terpenes such as sesquitepenes and diterpenes are dominant. However, among these compounds, pyrones and phloroglucinols have been reported to be the bioactive constituents in most of the studies. Overall, according to the potential of these plants, further phytochemical, ethnopharmacological and pharmacological studies are required since only a few species have been investigated so far.