Chemical Composition of Essential Oils from Different Parts of _Zingiber kerrii_ Craib and Their Antibacterial, Antioxidant, and Tyrosine Inhibitors Activities  
[PERSON]  
1 Center of Chemical Innovation for Sustainability (CIS) and School of Science, Mae Fah Laung University, Chiang Rai 57100, Thailand; p.aknarin@gmail.  
evaporation and recover non-volatile compounds via OS extraction [5; 8; 9]. Therefore, the content and the chemical composition of an essential oil may vary according to the extraction method.  
Recently, monoterpenes, oxygenated monoterpenes, sesquiterpenes, oxygenated sesquiterpenes, phenylpropanoids, and miscellaneous compounds were identified from the essential oils of some _Zingiber_ species [1; 9; 10; 11]. Thirty constituents comprising 99.99% of the total material were identified in fresh rhizome essential oils of _Z. zerumber_ using gas chromatography-mass spectrometry (GC-MS). The major constituents included zerumbone (74.82%), humulene (6.02%), and \(\beta\)-copaen-4\(\alpha\)-ol (4.32%) [12]. The chemical composition of the essential oils from the leaves and the rhizomes of _Z. cassumunar_ included 64 and 32 components, accounting for 94.60% and 98.56% of the oils, respectively. Sabinene (14.99%) and \(\beta\)-pinene (14.32%) were identified as the major components in the leaves, and triquinacene,1,4-bis(methoxy) (26.47%), (_Z_)-ocimene (21.97%), and terpinen-4-ol (18.45%) were reported as the major components of _Z. cassumunar_ rhizomes [13]. Moreover, 37 and 34 chemical components were identified in the rhizome essential oils of _Z. officinal_ and _Z. americans_. (_E_)-Citral (20.98%) and zerumbone (40.70%) were exhibited as the main compounds in the essential oils [14].  
Previous reports showed that many species of the Zingiberaceae family possessed antioxidant properties, such as _Z. officinal_[15; 16], _Z. zerumber_[12; 17; 18], and _Curcuma longa_[15]. The rhizomes of _Z. officinal_ are used in traditional medicine for stomach-aches, gastric ulcers, and flatulence in Thailand, and _Z. zerubet_ rhizomes are used as traditional medicines for the treatment of swelling, coughs, colds, stomach-aches, and skin diseases. The rhizomes of _Z. zerumbet_ contain the main compound of zerumbone, which showed antioxidant, antimalarial, and cytotoxic activities [12; 18]. _Z. cassumunar_ rhizomes are used as traditional medicine in Thailand and Indonesia; these were shown to possess strong antioxidant and anti-inflammatory activities [19; 20]. Moreover, the rhizomes of _Z. montanum_ are used for the treatment of various diseases in Thailand [21]. The major constituents in rhizome essential oils include terpinen-4-ol and (_E_)-1(3, 4-dimethylphenyl) butadiene, which were shown to demonstrate high antioxidant, anti-inflammatory, and anti-allergic activities. In addition, the new complex curcuminoids isolated from the rhizomes of _Z. montanum_ exhibited stronger antioxidant activities than curcumin [21; 22].  
A great deal of research has been conducted on the chemical composition and the biological activities of _Zingiber_ species; however, _Zingiber kerrii_ Craig has not yet been studied. Therefore, this is the first study to investigate the composition of the essential oils from _Z. kerrii_ and their antibacterial, antioxidant, cytotoxic, and tyrosinase inhibitory activities.