Abstract

In this study, the volatile constituents from the aerial parts of Lallemantia royleanaBenth. have been measured by gas chromatography and gas chromatography-mass spectrometry. The antimicrobial activity was determined by both the disk diffusion method and the microbroth dilution method. Thirty-seven compounds were identified and the main constituents were trans-pinocarvyl acetate (26.0), pinocarvone (20.0), -pinene (1.5), (E)--ocimene (4.1), terpinolene (1.1), linalool (3.4), trans- pinocarveol (1.6), 3-thujen-2-one (5.1), myrtenal (1.5), verbenone (7.1), trans-carveol (5.3), cis-carveol (3.5), pulegone (4.4), carvacrol (1.6), dihydrocarvyl acetate (2.5) and -cubebene (2.1). Antifungal screening of the essential oil of L.royleana showed that the oil significantly inhibited the growth of Candidaalbicans and Aspergillusniger (minimum inhibitory concentration MIC=3.1 and 2.5g/mL, respectively). Antibacterial screening of L.royleana essential oil showed that all assayed concentrations significantly inhibited the growth of Staphylococcusaureus, Bacillussubtilis, Klebsiellapneumoniae and Pseudomonasaeruginosa at P<0.05. MIC for S.aureus, B.subtilis and K.pneumoniae were 5.6, 4.8 and 3.5g/mL, respectively; L.royleana oil was inactive against P.aeruginosa in this study. Therefore, L.royleana essential oil has antifungal and antibacterial activities, corroborating the traditional therapeutic uses of this plant, and can be used in the therapy of infectious diseases as well as an antimicrobial additive in foods. Practical ApplicationsToday, many classes of synthetic antifungal and antibacterial drugs are used in medicine to treat infections. However, these antifungal and antibacterial therapies are showing diminishing effectiveness because of the emergence of drug-resistant strains. Hence, using effective natural antifungal and antibacterial agents with fewer side effects is a promising approach to combat fungal and bacterial infection and diseases in medicine, agriculture and related fields. In this study, we have demonstrated the essential oil from Lallemantia royleana (Benth. in Wall.) Benth. to be a novel natural material to inhibit the fungal (Candida albicans and Aspergillus niger) and bacterial (Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumoniae, Pseudomonas aeruginosa ) growth, and we have evaluated the chemical composition of L.royleana essential oil as an antifungal and antibacterial agent.