Background: A. oxyphylla which is a significant component of traditional Chinese medicine have being reported by many studies to be of significant impact in cure for many infectious diseases because of their high pharmacological activities. In this study, the effect of organic compounds nootkatone, chrysin, tectochrysin, alpha-tocotrienol, oxyphyllol C, sitosterol and epicatechin extracted from the leaves of Alpinia oxyphylla were tested against multi-drug resistant bacteria Escherichia coli, Staphylococcus aureus, Klebsiella aerogenes and Proteus vulgaris; isolated from patients with urinary tract infections.The results showed that the bacteria were resistant to the commonly prescribed antibiotics and the multi-drug resistance among them was also high. The Multi drug resistance analysis showed that 13(76.47%) of the E.coli showed Multi drug resistance, however 10(76.92%) and 9(69.23%) of the multi-drug resistance E.coli were susceptible to nootkatone and chrysin respectively at the concentration of 30µg/ml. 100% of K. aerogenes showed multi-drug resistance meanwhile they showed the highest susceptibility to chrysin and nootkatone with values 5(71.43%) and 4(57.14%) respectively. 4(66.67%) of S. aureus showed multi drug resistance however 4(66.67%) of them were also susceptible to chrysin and nootkatone while 5(83.33%) of P. vulgaris showed multi drug resistance and 100% of them were susceptible to nootkatone and chrysin also at the concentration of 30µg/ml. Nootkatone and chrysin showed a high susceptibility to the multi drug resistance bacteria isolated from patients with urinary tract infections. The leaves of A. oxyphylla can be potential sources for extraction of compounds to combat the increasing menace of multi drug resistance bacteria associated with urinary tract infections.

In this study, analysis of the chemical constituents and bioactivities of the unpolar fractions [petroleum ether (PE) and chloroform (C)] of fruits and leaves of Alpinia oxyphylla were carried out, as well as the bioactivities of the main compounds nootkatone and valencene.From PE and C fractions of the fruits, and PE fraction of the leaves, 95.80%, 59.30%, and 82.11% of the chemical constituents respectively were identified by GC-MS. Among these identified compounds, nootkatone was the main compound in all of three fractions, while valencene was the second main compound in the PE fractions of the fruits and leaves. The bioactivities results showed that all of the fractions and the major compound nootkatone showed tyrosinase inhibitory, as well as inhibitory effect on NO production in LPS-stimulated RAW264.7 cells.While valencene only presented inhibitory activity on NO production in RAW264.7 cells. The critical genes involved in nootkatone biosynthesis in A. oxyphylla were identified from the public transcriptome datasets, and protein sequences were preliminarily analyzed. Our studies develop the usage of the unpolar fractions of A. oxyphylla, especially its leaves as the waste during its production, and meanwhile provide the gene resources for nootkatone biosynthesis.