The evolution of cosmetic products results in the growing demands for cosmetics that are preservatives free. Plant essential oils were found to be a promising antimicrobial and also antioxidant agent. In this study, Cymbopogon citratus (lemongrass), Laurus nobilis (bay leaf) and Backhousia citriodora (lemon myrtle) essential oils were selected and evaluated for their antimicrobial properties. It was found that Laurus nobilis exhibited strong antimicrobial activity against the selected bacteria Streptococcus saprophyticus (ATCC 49619), Streptococcus aureus (ATCC 22923), Streptococcus pyogenes (ATCC 29436), Pseudomonas aeruginosa (ATCC 13048), Klebsiella pneumoniae (ATCC 700603), Escherichia coli (ATCC 22922) with MIC ranging between 7.8 ug/mL to 250 μg/mL. The antioxidant activity of selected essential oils was determined by antioxidant assays which were 1,1-Diphenyl-2-picrylhydrazyl assay (DPPH), determination of ferric reducing antioxidant power assay (FRAP) and β-Carotene/linoleic acid bleaching assay. Backhousia citriodora and Laurus nobilis showed the highest antioxidant activity.
n-Octanal and β-Selinene were identified to be the major components with peak area of 26.37 % and 13.92 % respectively in secondary metabolites analysis by Gas Chromatography-Mass Spectrometry (GCMS).
Famili Piperaceae pada keseluruhannya terdiri daripada 1,000 hingga 2,000 spesies yang boleh dijumpai di kawasan tropika dan subtropika. Dalam kajian ini, ekstrak etanol digunakan untuk melihat aktiviti sitotoksik ke atas sel kanser hati manusia (HepG2) dan sel bukan kanser hati Chang melalui kaedah pengasaian MTT (3,4 [dimetiltiazol-2-yl]-2, 5-difeniltetrazolium bromida). Sebanyak lapan spesies daripada famili Piperaceae telah terpilih untuk analisis aktiviti antitumor. Hasil kajian mendapati kesemua spesies Piperaceae (P. sarmentosum, P. ramifilum, P. paucistigmum, P. betle, P. macronatum, P. ridleyi, P. magnibaccum dan P. miniatum) menunjukkan aktiviti sitotoksik dengan ekstrak etanol Piper sarmentosum mempunyai nilai bacaan IC50 yang paling rendah ke atas sel HepG2 iaitu 12.5 μg/mL. Tiada aktiviti sitotoksik telah ditunjukkan oleh kesemua ekstrak etanol tumbuhan yang diuji aktiviti sitotoksik ke atas sel Chang kerana nilai bacaan IC50 kesemua ekstrak etanol yang diperlakukan ke atas sel Chang melebihi nilai piawai iaitu 30 μg/mL. Kaedah analisis viabiliti sel menggunakan tripan biru pula mendapati ekstrak etanol P. sarmentosum menurun secara signifikan (p<0.05) terhadap sel HepG2 berbanding kawalan. Kesimpulannya, kaedah MTT menunjukkan kesemua ekstrak etanol famili Piperaceae memberikan aktiviti sitotoksik dan kaedah tripan biru merupakan kaedah alternatif bagi penentuan kesitotoksikan sesuatu ekstrak.