Scar formation is the result of natural healing process which occurs after wounds, trauma, burns, surgical incision or disease. In order to close a wound, skin repair itself from normal to scar tissue and thus prevent infection [1
]. Keloid is an end of the full spectrum of scar which extends beyond the boundaries of the original wound. It can spread to the surrounding skin by invasion. Clinical appearance of keloid is a raised growth and usually related with pruritus and pain. Keloid scars commonly occur only in humans. Keloid healing remains impaired since the pathogenesis of biochemical mechanisms of keloid is still unknown [2
]. Development of keloid contains atypical fibroblasts and consists of overabundant of extracellular matrix components include collagen, fibronectin and certain proteoglycans.
Recently we reported the antimicrobial properties of Tualang honey [3
], but the volatile compounds in Tualang honey from Malaysia and its effectiveness for treating keloid scar remain unknown. As Tualang honey is found in Malaysia's forest, various field of research on it has been widely carried out by researchers. The honey was used mainly to investigate its effect to certain diseases and compared this traditional treatment to modern treatment. Recently, Tualang honey has been used to determine its anticancer potential. For example, previous study has focused on the treatment of oral squamous cell carcinomas (OSCC) and human osteosarcoma (HOS) with various concentration of Tualang honey in vitro
. Current modern treatment to these types of oral cancers such as surgery or radiotherapy can cause loss of function, disfigurement and reduced quality of life. From the finding, it is suggested that Tualang honey showed antiproliferative and apoptotic effect towards both oral cancer cell lines [4
]. Human breast adenocarcinoma and cervical carcinoma (HeLa) cell lines were found potential to be treated with Tualang honey as it induced apoptosis of cancer cells via depolarization of the mitochondrial membrane. Thus, Tualang honey is found useful as an anticancer agent [5
The Tualang tree which is also known as Koompassia excelsa
found widely in Southeast Asia rainforests best known for the disk-shaped honeycombs which hang from its horizontal branches. It is mostly found in lowland forests of Peninsular Malaysia, southern Thailand, northern Sumatra and Borneo, and can grow to heights greater than 85 meters. The trees are valued by the locals due to its honey. In fact, a standing Tualang tree is more valuable for its honey than if it were felled for its timber. The honey from the combs of this tree is known as Tualang honey, and is produced by Apis dorsata
or Asian rock bees [6
Previously, continuous liquid-liquid extraction with diethyl ether has been used for the extraction of polar phenolic and acidic substances [7
]. It has also been used for the determination of linalool derivatives in New Zealand honeys [10
]. A simple liquid-liquid extraction method is advantageous as it does not involve heating which may lead to loss of volatiles or the formation of artifacts [11
]. Therefore, extraction of honey samples using this method is more popular. The concentration of volatile constituents in honey are very low, therefore a sensitive technique such as gas chromatography-mass spectrometry (GC-MS) is needed. GC-MS is a simple instrument and requires very little time for quantification of compounds when compared to other methods such as high performance liquid chromatography. By using GC-MS methods, many important organic compounds have been detected in different types of honeys [12
To our knowledge, no report has focused on determination of the volatile profile of Tualang honey. A continuous liquid-liquid extraction technique using five different organic solvents was selected due to its speed, low cost, and lack of sample heating.