# _Helichrysum arenarium_: From Cultivation to Application
## 6 Pharmacological Properties
### Antimicrobial Activities
In both studies, sandy everlasting essential oils inhibited the growth of the most dangerous pathogens _S. aureus_ and _C. albicans_, but the results are difficult to compare as the preparations were obtained using different methods. Helichrysum arenarium extracts and herbal teas have been used traditionally in European countries. The antioxidant and antimicrobial activities of two subspecies of _H. arenarium_ (L.) Moench, erzincanicum Davis and Kupicha, Erzican and rubicundum (C.Koch.) Davis and Kupicha, Erzurum, collected from different regions of Turkey, were analyzed. Methanolic extracts from the whole dried plants were screened against 15 strains of bacteria and fungi using the agar-well diffusion method, and the results were compared with standard antibiotics [87; 88]. Statistical differences were found among the chemical compositions and the antimicrobial and antioxidant activities of these subspecies. Additionally, extracts were active against _Aeromonas hydrophila_, _B. brevis_, _B. cereus_, _Klebsiella pneumoniae_, _Pseudomonas aeruginosa_, and _S. aureus_ ATCC 29,213, but no activity was detected against tested strains of _E. coli_, _Morganella morganii_, _Protea mirabilis_, _Mycobacterium smgematis_, _Yersinia enterocolitia_, or yeast _S. cerevisiae_[87; 88]. However, at the highest concentration (100,000 ug/mL), methanolic extracts were similar to or less effective than the standard antibiotics. Dried flowers collected from northeastern Romania were used to prepare extracts and to analyze their phenolic content and antimicrobial activity [22; 85]. [PERSON] tested the antibacterial activity of the methanolic extract of _H. arenarium_ subsp. _arenarium_ and noticed that another _S. aureus_ ATCC 25,923 was more susceptible to the plant extract than _Streptococcus pneumoniae_ ATCC 49,619 with an MIC of 0.62 compared to 1.25 mg/mL [85]. Moreover, the extract showed antibacterial effects against clinical isolates methicillin-resistant _S. aureus_, penicillin-resistant _S. pneumoniae_ (MIC = 2.5 mg/mL), and 16 times higher activity against the ampicillin-resistant _Moraxella catarthalis_ strain (MIC = 0.15 mg/mL). Again, the extract was less active than antibiotic ciprofloxacin and the extract-antibiotic interaction was analyzed [72]. In another experiment, the antibacterial and antifungal activities of methanolic, ethanolic, and 70% (_v/v_) ethanolic extract were compared based on the obtained MIC values, and _S. aureus_ ATCC 49,444 and _E. coli_ ATCC 25,922 proved to be the most sensitive strain [22]. In the case of the Gram-negative bacteria, methanolic and ethanolic extracts had similar activities (MIC = 7.81 mg/mL and MBC = 15.62 mg/mL), while the least effective on Gram-positive bacteria was 70% (_v/v_) ethanolic extract (MIC = 15.62 mg/mL and MBC = 31.25 mg/mL). The authors concluded that phenolic compounds, especially the higher amount of chlorogenic acid detected in the plant extracts could be responsible for the antibacterial effect [22]. Antifungal activity was tested against five strains, including _Penicillium funiculosum_ and _C. albicans_, with the highest sensitivity for 70% (_v/v_) ethanolic extracts. Still, compared to standard controls, streptomycin and fluconazole, the antimicrobial activities were modest. The antiviral effects of Turkey _H. arenarium_ plants were revealed for the first time in recent research that used aqueous and ethanol 80% extracts [89]. Viruses Herpes simplex Type-1 (HSV-1) and Parainffluenza-3 (PI-3), both important human pathogens, were tested using Madin-Darby bovine kidney and the Vero cell line. In particular, the ethanolic extract at the maximum nontoxic concentration (32 ug/mL for HSV-1 and 64 ug/mL for PI-3) were found with antiviral potential on both DNA and RNA viruses, with higher inhibitory action than acyclovir. In the same study, both extracts proved to be more potent against Gram-positive (_S. aureus_, _E. Faecalis_) than Gram-negative pathogens (_E. coli_, _P. aeruginosa_, _P. mirabilis_, _A. baumanii_, _K.