Helichrysum italicum has piqued the interest of many researchers in recent years, mostly for its essential oil, but increasingly for its polyphenolic content as well. In the current study, we examine the polyphenolic composition of H. italicum grown in Bulgaria. The polyphenolic complex was fractionated with solvents of various polarities, including hexane, chloroform, ethyl acetate, and butanol, in order to assess the biological impact of the components. HPLC-PDA and UHPLC-MS/MS were used to examine all fractions. The green coffee fingerprint profile was employed as a "surrogate standard" in the polyphenolic components detection approach. From the UHPLC-MS/MS analysis, we identified 60 components of the polyphenolic complex such as quercetin 3-O-glucuronide, quercetin acetyl-glycoside, isorhamnetin acetyl-glycoside, isorhamnetin caffeoyl-glycoside, quercetin caffeoyl-malonyl-glycoside, isorhamnetin coumaroyl-glycoside, coumaroyl-caffeoylquinic acid, and diCQA-acetyl-derivative were first reported in the composition of H. italicum. The biological activity of the fractions was evaluated in vitro and in silico, which included the fight against oxidative stress (hydrogen peroxide scavenging activity (HPSA), hydroxyl radical scavenging activity (HRSA), metal-chelating activity (MChA)) and nitrosative (nitric oxide scavenging activity) (NOSA)), in vitro anti-inflammatory, and anti-arthritic activity. Results are presented as IC50 ± SD μg/mL. The analysis showed that the EtOAc fraction was characterized by highest HPSA (57.12 ± 1.14 μg/mL), HRSA (92.23 ± 1.10 μg/mL), MChA (5.60 ± 0.17 μg/mL), and NOSA (89.81 ± 2.09 μg/mL), while the hexane and chloroform fractions showed significantly higher in vitro anti-inflammatory activity (30.48 ± 2.33 μg/mL, 62.50 ± 1.69 μg/mL) compared to the standard ibuprofen. All three fractions showed potential anti-arthritic activity (102.93 ± 8.62 μg/mL, 108.92 ± 4.42 μg/mL, 84.19 ± 3.89 μg/mL).
Keywords: ATA; HPSA; HRSA; Helichrysum italicum; IAD; MChA; NOSA; arzanol; bitalin A; in silico molecular docking and dynamics; polyphenols.