Resumo

VILLA-RUANO, Nemesio et al. Lipophilic constituents and some biological activities of hexanic extracts from Zaluzania montagnifolia, (SCH. BIP.) SCH. BIP. (Asteraceae). Agrociencia [online]. 2013, vol.47, n.4, pp.335-346. ISSN 2521-9766.

Zaluzania montagnifolia, an antidiabetic and abortive shrub 1 to 3 m high, grows actively in xeric scrublands in some states of México. Zulazanins and some flavonoids are the foremost constituents of the polar extracts in this species; however, there is no available information about the lipophilic compounds from non-polar extracts. The objective of this study was to describe the gas chromatography-mass spectrometry (GC-MS) profile of hexanic preparations, exclusivelly with dissolve lipophilic molecules, in order to sustain the empirical uses and the new biological activities reported in this study for the plant. These preparations were obtained from flowers, leaves and roots of Z. montagnifolia which were collected in Oaxaca, México, in October 2011. In addition to the chemical study, antibacterial, allelopathic and antioxidant properties of the hexanic extracts were determined. The chemical profile revealed two majoritarian ent-kaurane diterpenes. According to the relative endogenous levels, grandiflorenic acid (35.5 %) and ent-kaurenoic acid (28.3 %) were the most abundant natural molecules in aerial and underground structures of the plant, and more than 50 different volatile organic compounds (VOC's) were identified according to their mass spectra and retention index. Antibacterial tests were carried out by the broth microdilution method in combination with hexanic extracts and conventional antibiotics as reference standards. The analyisi of results reveal potent inhibitory on Escherichia coli TOP10 F' (MIC=49.2 µg mL^-1) and DH5α (MIC= 32.4 µg mL^-1) strains as well as for Agrobacterium tumefaciens LBA 4404 (MIC=30.4 µg mL^-1) strain. Allelopathic properties were determined using the lettuce seed system, showing that the root extracts had a significant effect (p≤0.01). An acceptable antioxidant activity of leaf and flower extracts (IC₅₀=158.3-253.5 µg mL^-1) was found by using 2,2-diphenyl-1-picryl hydrazyl radical (DPPH). The latter biological activities are strongly related to VOC's and ent-kaurane derivatives which play an essential role as antibacterial and allelopathic agents.

Palavras-chave : Zaluzania montagnifolia; grandiflorenic acid; ent-kaurenoic acid; VOC's; biological activities.

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