Sesquiterpene lactones are naturally occurring compounds mainly found in the Asteraceae family. These types of plant metabolites display a wide range of biological activities, including antiprotozoal ...activity and are considered interesting structures for drug discovery. Four derivatives were synthesized from estafietin (
), isolated from
(Asteraceae): 11βH,13-dihydroestafietin (
), epoxyestafietin (
and
), 11βH,13-methoxyestafietin, (
) and 11βH,13-cianoestafietin. The antiprotozoal activity against
and
of these compounds was evaluated. Epoxyestafietin was the most active compound against
trypomastigotes and amastigotes (IC
values of 18.7 and 2.0 µg/mL, respectively). Estafietin (
) and 11βH,13-dihydroestafietin (
) were the most active and selective compounds on
promastigotes (IC
values of 1.0 and 1.3 μg/mL, respectively). The antiparasitic activity demonstrated by estafietin and some of its derivatives make them promising candidates for the development of effective compounds for the treatment of Chagas disease and leihsmaniasis.
Essential oils from aerial parts of Senecio nutans, Senecio viridis, Tagetes terniflora and Aloysia gratissima were analysed by GC-MS and their antifungal activities were assayed on toxigenic ...Fusarium and Aspergillus species. Sabinene (27.6 ± 0.1%), α-phellandrene (15.7 ± 0.3%), o-cymene (9.6 ± 0.2%) and β-pinene (6.1 ± 0.2%) in S. nutans, 9,10-dehydrofukinone (92.7 ± 0.2%) in S. viridis, β-thujone (36.1 ± 0.1%), α-thujone (32.2 ± 0.2%), 1,8-cineol (10.7 ± 0.1%) and sabinene (6.2 ± 0.2%) in A. gratissima, and cis-tagetone (33.6 ± 0.2%), cis-β-ocimene (17.1 ± 0.2%), trans-tagetone (17.0 ± 0.1%), cis-ocimenone (8.0 ± 0.2%) and trans-ocimenone (8.2 ± 0.1%) in T. terniflora. The oils showed moderate antifungal activity (1.2 mg/mL > MIC >0.6 mg/mL) on the Fusarium species and a weak effect on Aspergillus species. The antifungal activity was associated on F. verticillioides to the high content of cis-tagetone, trans-tagetone, cis-β-ocimene, cis-ocimenone, trans-ocimenone and on F. graminearum due to the total content of oxygenated sesquiterpenes and 9,10- dehydrofukinone. The oil of S. viridis synergized the effect of fungicides and food preservatives on F. verticillioides.
Essential oils from aerial parts of Acantholippia deserticola, Artemisia proceriformis, Achillea micrantha and Libanotis buchtormensis were analysed by GC-MS. The major compounds identified were ...β-thujone (66.5 ± 0.2%), and trans-sabinyl acetate (12.1 ± 0.2%) in A. deserticola; α-thujone (66.9 ± 0.4%) in A. proceriformis; 1,8-cineole (26.9 ± 0.5%), and camphor (17.7 ± 0.3%) in A. micrantha and cis-β-ocimene (23.3 ± 0.3%), and trans-β-ocimene (18.4 ± 0.2%) in L. buchtormensis. The oils showed a weak antimicrobial effect (MIC
100
> 1.5 mg/ml) on most phytopathogens tested. A moderate antimicrobial activity (MIC
100
between 0.5 and 1.5 mg/ml) was displayed by the oils of A. deserticola, A. micrantha and L. buchtormensis on Septoria tritici and by the oil of A. deserticola on Septoria glycine. The antimicrobial activity was associated to the contents of β-thujone, trans-sabinyl acetate and trans-sabinol. Our results indicate that the tested essential oils have little inhibitory potency not suitable for use as plant protection products against the phytopathogens assayed.
The composition of essential oils from leaves of Kazakhstan medicinal plants was analysed by GC-MS. The major compounds identified were 1,8-cineole (34.2%), myrcene (19.1%) and α-pinene (9.4%) in ...Ajania fruticulosa; 1,8-cineole (21.0%), β-thujone (11.0%), camphor (8.5%), borneol (7.3%) and α-thujone (6.5%), in Achillea nobilis; camphor (47.3%), 1,8-cineole (23.9%), camphene (9.8%) and β-thujone (6.0%) in Artemisia terrae-albae; 1,8-cineole(55.8%) and β-pinene (6.2%) in Hyssopus ambiguus; α-thuyene(46.3%) and δ-cadinene(6.3%) in Juniperus sibirica; sabinene (64%) in Juniperus sabina; and α-pinene (51.5%), β-phellandrene (11.2%) and δ-cadinene (6.3%) in Pinus sibirica. The essential oils did not show antifungal effect (MIC > 1.20 mg/mL) on Aspergillus carbonarius and Aspergillus niger, while the oils from A. nobilis, A. terrae-albae, H. ambiguus and J. sabina exhibited moderate and moderate to weak antimicrobial activities on Fusarium verticillioides (MIC = 0.60 mg/mL) and Fusarium graminearum (MIC = 0.60-1.20 mg/mL), respectively. A principal component analysis associated the antifungal activity (r
2
> 0.80, p = 0.05) with the presence of borneol, camphor, camphene, 1,8-cineole,α- and β-thujone, and of the oxygenated monoterpenes.
The main secondary metabolite of
Senecio nutans
is 4-hydroxy-3-(3-methyl-2-butenyl)acetophenone (4HMBA). The antifungal activity of this compound and three derivatives was assessed using
Candida ...albicans
. 4HMBA exhibited the highest antifungal activity among the assayed compounds. The Fractional Inhibitory Concentration (FIC = 0.133) indicated a synergistic fungicidal effect of 4HMBA (5 mg L
−1
) and fluconazole (FLU) (0.5 mg L
−1
) against the
C.
albicans
reference strain (ATCC 10231). Microscopy showed that 4HMBA inhibits filamentation and reduces cell wall thickness. Our findings suggest that 4HMBA is an interesting compound to diminish resistance to commercial fungistatic drugs such as fluconazole.
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