Systematic characterization of the influence of petroleum spill on terpene metabolism in Suaeda salsa (L.) Pall from coastal wetland: Implication by compound-specific stable isotope.

With the increasing industrialization and urbanization, the ecological environment is suffering from severe deterioration in Liaohe coastal wetland, and petroleum spill is one of the pollution sources. Suaeda salsa (L.) Pall (S. salsa), one of the predominant plants in Liaohe coastal wetland, is facing the increasing degradation. Terpenes are a class of inherent compounds in plants, and play key role in maintain the growth of plants. However, the environmental stress on the terpene metabolism remained unclear in the plants. In the present study, the influence of petroleum spill on terpene metabolism in S. salsa was systematically investigated by analysis of concentrations, compositions and stable carbon isotope. Under the stress of petroleum spill, terpene concentrations showed the decreasing trend, indicating the inhibition effect of petroleum spill on terpene synthesis in S. salsa. The proportions of Sabinene and A-humulene showed the obviously increased with the influence of petroleum spill, implying that these congeners were more sensitive to petroleum spills. The significant changes in stable carbon isotope compositions were observed for Borneol, Dl-menthol, A-humulene and (-) -@-bisabolol, with the enrichment in heavier isotopes in residual fractions. This result indicated that the heavier 13C was preferentially fixed on terpene by S. salsa under the petroleum stress. The similar change trends along the incubation time was observed for A-humulene and (-) - trans caryophyllene, which might imply that A-humulene was one of the products of (-) - trans caryophyllene in S. salsa. Overall, the findings of present study verified the influence of petroleum spill on terpene metabolism in S. salsa, and were meaningful for protecting the plants in the petroleum-pollution wetlands.

In vitro synergistic interactions of oleanolic acid in combination with isoniazid, rifampicin or ethambutol against Mycobacterium tuberculosis.

Reports have shown that oleanolic acid (OA), a triterpenoid, exists widely in food, medicinal herbs and other plants, and that it has antimycobacterial activity against the Mycobacterium tuberculosis strain H37Rv (ATCC 27294). In this study it was found that OA had antimycobacterial properties against eight clinical isolates of M. tuberculosis and that the MICs of OA against drug-sensitive and drug-resistant isolates were 50-100 and 100-200 microg ml(-1), respectively. The combination of OA with isoniazid (INH), rifampicin (RMP) or ethambutol (EMB) showed favourable synergistic antimycobacterial effects against six drug-resistant strains, with fractional inhibitory concentration indices of 0.121-0.347, 0.113-0.168 and 0.093-0.266, respectively. The combination treatments of OA/INH, OA/RMP and OA/EMB displayed either a synergistic interaction or did not show any interaction against two drug-sensitive strains. No antagonism resulting from the OA/INH, OA/RMP or OA/EMB combination was observed for any of the strains tested. OA exhibited a relatively low cytotoxicity in Vero cells. These results indicate that OA may serve as a promising lead compound for future antimycobacterial drug development.