###### Abstract  
_Syzygium formosum_ (SF) leaves have long been used in traditional medicine for the treatment of skin-related diseases such as atopic dermatitis and psoriasis. To understand the underpinning pharmacological mechanism of skin relief functionality, the quantitative profile of phytochemicals in the leaf extract has been performed. Twenty phytochemical components including eight flavonoids, three phenolic acids, and nine triterpenneoids were identified and quantitatively analyzed from the SF leaves. The dominant flavonoids of the SF leaves were found to be catechin and myricetin-3-O-rhmoside. Gallic acid was the most abundant phenolic acid. Among triterpenneoids, asiatic acid, corosolic acid, and betulinic acid exhibited a high concentration ranging 2.78-8.59, 3.19-3.91, and 3.58-6.14 mg/g dry leaf, respectively. The total triterpenneoid contents were 14.18-19.00 mg/g dry leaf which were 3-fold higher than those in the Indonesian _Centella asiatica_ leaves. In human keratinocytes assay, industrial scale extract of SF significantly reduced expressions of proinflammatory cytokines and cyclooxygenase-2. Furthermore, that SF extract exhibited very strong antibacterial activity on _Staphylococcus aureus_ and _C Antibacterialium acnes_ that possibly induce serious skin problems. Our results proved that _S. formosum_ leaf extract with high content of biologically active compounds could be a superior bioactive ingredient in cosmetic and pharmaceutical products. _Keywords:_Syzygium formosum; phytochemicals; triterpenneoids; phenolic compounds; anti-inflammation; antibacterial activity +
Footnote †: journal: _Sci. that _S. formosum_ leaves contain those bioactive secondary metabolites, including phenolics and triterpenoids [6; 10]. T triterpenoids are a class of terpen formed by the polymerization of isoprene unit as a monomer. Triterpenoids are biosynthesized by the cyclization of their precursor squalene and can be grouped into amyrin, lupeol, and lanosterol based on their chemical structures. Triterpenoids have been found in the traditional oriental herbal medicine. Among the bio-functional phytochemicals, triterpenoids are currently identified as promising pharmaceutical and cosmeceutical ingredients. It has been reported that they exhibit strong biological activities such as anti-oxidation, anti-inflammation, anti-allergy, or anticancer [11]. For instance, ginseng, which are famous and well-studied phytochemicals from Ginseng, are also a glycoconjugated triterpenoid modified from \(\beta\)-amyrin or dammarenediol. As another example, _Alisma orientale_ has been used for a long time in China to treat edema, leukorrhea, diarrhea, and dizziness. The phytochemicals identified as characteristic constituents in _A. orientale_ are terpen including protostane triterpenoids and guaiane sesquiterpenoids. These active constituents exhibit a wide range of pharmacological functionalities such as diuretic, anti-urolithiatic, antinephritic, anti-atherosclerotic, immunomodulatory, and hepatoprotective activities [12]. Centrella asiatica (L) Urban is also a famous medicinal plant, the use of which is not limited to a functional food but has also been extended to the pharmaceuticals. _C. asiatica_ has been used in traditional medicine for hundreds of years in a wide range of Asian countries to treat various diseases such as neurological, endocrine, cardiovascular, gastrointestinal, immune, gynecological, and particularly dermatological symptoms such as skin smoothing or wound healing, and to act as a brain tonic [13; 14; 15]. Among phytochemicals, triterpenoids are biologically active substances in _C. asiatica_. Asiaticoside and macdessoside are triterpenoids which are responsible for its pharmacological activities [16; 17]. Indeed, recent studies have reported that the methanolic extracts of triterpenoids from _Centrella asiatica_ exhibited anti-inflammation activity and therapeutic potential on some skin diseases such as wounds, atopic dermatitis, and acne [14; 18; 19].