Helichrysum microphyllum subsp. tyrrhenicum: a possible correlation between small volatile compounds and phloroglucinol content

The chemical composition of the flowered aerial parts of four samples of Helichrysum microphyllum subsp. tyrrhenicum collected in South-West Sardinia was investigated with a combined focus on volatile constituents and phloroglucinols to find a possible correlation with the presence of arzanol endowed with the major anti-inflammatory activity. The volatile constituents were analysed by GC-MS as EO-HD and with HS-SPME identifying a total of 95 compounds of which 70 and 77 by EO-HD and HS-SPME respectively. The profile of the non-volatile phloroglucinols was investigated by HPLC-MS/MS. Arzanol concentrations ranged from 2.79 to 21.87 mg/g, helipyrone showed the same trend but in lower concentration. Surprisingly, leaves and stems contain higher concentration of phloroglucinols than the flowers. The concentration of arzanol was positively correlated to the one of γ-curcumene and ethylpyrone in the EO, while a negative correlation was observed with the monoterpene limonene and linalool as well as with the sesquiterpene 5-eudesmen-11-ol.