Antimicrobial, antioxidant, anti-tyrosinase and anti-urease activities and FT-IR analyses of Helichrysum graveolens (Bieb) Sweet

Helichrysum graveolens (Bieb) Sweet possesses various medicinal applications such as diuretic, treatment of the sand and stone in kidney, regulation of digestion problems and strenghtening of the immune system. The investigation was carried out to reveal ethanol extracts of flower and stem parts of H. graveolens for antimicrobial, antioxidant, anti-tyrosinase and anti-urease activities. Ethanol extract of stem part of H. graveolens exhibited more antibacterial activity against growth of bacteria except for K. pneumoniae. Stem part of H. graveolens has higher copper reducing antioxidant capacity (CUPRAC) and anti-urease activities than flower part of H. graveolens. Anti-tyrosinase activity (IC50 values) of stem and flower parts of H. graveolens was found to be 0.01549 ± 0.0006 μg/ml and 0.01515 ± 0.0016 μg/ml, respectively. This survey suggests that ethanol extracts of different parts of H. graveolens is an alternative source for natural antioxidant and antimicrobial compounds, urease and tyrosinase inhibitors that could be utilized in drug and food industries. Introduction The Helichrysum species are xerophytes growing at altitudes from the sea level up to 1700 m preferably on sandy or loamy soils. Helichrysum species are commonly recognized as ''olmez cicek or altinotu" in Turkish and are widely utilized as herbal tea in Turkey (Bağcı et al. 2013). Helichrysum graveolens is a medicinal plant which belongs to Asteraceae. Plants play a substantial role in primary health care as therapeutic medicines in developing countries. Antibiotic resistance as well as appearance of undesirable side effects of some antibiotics (WHO, 2002) has caused to the investigate of alternative antibacterial agents from medicinal plants (Sharma et al. 2012). Reactive oxygen species (ROS) are continually created inside the human body but excessive or inadequate production of ROS can easily affect antioxidant defense systems. This situation cause many illnesses like cancer, neurodegenerative diseases, arthritis, diabetes mellitus, and ageing process (Patel et al. 2010). Tyrosinase is a the primary enzyme that catalyzes synthesis of melanin in mammalian, plants and microorganisms cells. Melanin biosynthesis inhibitory compounds are beneficial for skin whitening products utilized in cosmetics and also as a medicine for defects in pigmentation. Plants were acquired attention for cosmetic product improvement because they could have less toxicity than the synthetic ones (Rauniyar et al. 2007). Antimicrobial, antioxidant, anti-tyrosinase and anti-urease activities and FT-IR analyses of ethanol extracts of flower and stem parts of H. graveolens were investigated. *Author for correspondence: .