Phytochemical studies of Helichrysum, especially from species of South and East Africa, established the presence of characteristic flavonoids, many of them are distinguished by an unsubstituted B-ring and by prenyl substituents, as well as of phloroglucinol derivatives (Bohlmann et al., 1980a; Jakupovic et al., 1986b, 1989a).
Thirty-five lipophilic phenolic constituents were isolated from eight Helichrysum species endemic to Madagascar.
Chalcones comprised the largest group of compounds encountered, followed by flavonols, flavanones, flavones, benzophenones and phloroglucinol derivatives. Many of the flavonoids were characterized by unsubstituted B-rings and/or C- or O-bound prenyl or neryl substituents (Randriaminahy et al., 1992). Several diterpenes have been also isolated from Helichrysum species (Jakupovic et al., 1989b, 1990).
Thiophenes and polyacetylenes were also identified from some species (Lourens et al., 2008).The chemical composition of the essential oils from several species had been reported e.g. Helichrysum aureonitens (Yani et al., 2005), Helichrysum bracteiferum (DC). H. Humb. (Ramanoelina et al., 1992), Helichrysum cymosum, Helichrysum fulgidum (Bougatsos et al., 2004), Helichrysum italicum (Roth) G. Don (Djihane et al., 2017), Helichrysum stoechas (Sobhy and El-Feky, 2007) and several others.
The essential oils of six Helichrysum species from Madagascar were investigated and 46 components were identified.
The main constituents were 1,8-cineole for Helichrysum gymnocephalum (59.7%) and Helichrysum bracteiferum (27.3%); β-pinene for Helichrysum selaginifolium (38.2%); (E)-caryophyllene for Helichrysum cordifolium (55.6%), Helichrysum faradifani (34.6%) and Helichrysum hypnoides (34.0%) (Cavalli et al., 2001).