Antifungal effects of volatile organic compounds produced by Trichoderma hamatum against Neocosmospora solani.

Neocosmospora solani causes Fusarium wilt disease and root rot, which are serious problems worldwide. To determine the growth inhibition of Neocosmospora solani by Trichoderma hamatum volatile organic compounds (VOCs), the major chemical components of Trichoderma hamatum VOCs and the differences in their contents at different times were analysed, and the activity of these components was evaluated. The antifungal activity of Trichoderma hamatum was measured by a screening test, as Trichoderma hamatum exhibited strong antagonism against Neocosmospora solani in vitro. The double plate technique was used to verify the activity of Trichoderma hamatum VOCs, and the inhibition rate was 63.77%. Neocosmospora solani mycelia were uneven and expanded, the contents of the cells leaked, and the mycelia shrank and presented a diaphragm in the hyphae upon Trichoderma hamatum VOCs treatment. Trichoderma hamatum VOCs and their contents at different times were analysed by using gas chromatography-mass spectrometry. 6-Pentyl-2H-pyran-2-one clearly presented in greater amounts than the other components on day 3, 4, 5, and 6. VOCs from Trichoderma hamatum exhibited evident effects on the percentage of healthy fruit after day 3. Moreover, Trichoderma hamatum can improve the biological control of diseases caused by soilborne pathogens, and can be applied in biocontrol fields.

Design and Synthesis of Thiourea-Conjugating Organic Arsenic D-Glucose with Anticancer Activities.

Organic arsenic compounds such as p-aminophenylarsine oxide (p-APAO) are easier for structural optimization to improve drug-like properties such as pharmacokinetic properties, therapeutic efficacy, and target selectivity. In order to strengthen the selectivity of 4-(1,3,2-dithiarsinan-2-yl) aniline 7 to tumor cell, a thiourea moiety was used to strengthen the anticancer activity. To avoid forming a mixture of α/ß anomers, the strategy of 2-acetyl's neighboring group participation was used to lock the configuration of 2,3,4,6-tetra-O-acetyl-ß-d-glucopyranosyl isothiocyanate from 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl bromide. 1-(4-(1,3,2-dithiarsinan-2-yl) aniline)-2-N-(2,3,4,6-tetra-O-acetyl-ß-d-glucopyranos-1-yl)-thiourea 2 can increase the selectivity of human colon cancer cells HCT-116 (0.82 ± 0.06 µM vs. 1.82 ± 0.07 µM) to human embryonic kidney 293T cells (1.38 ± 0.01 µM vs. 1.22 ± 0.06 µM) from 0.67 to 1.68, suggesting a feasible approach to improve the therapeutic index of arsenic-containing compounds as chemotherapeutic agents.

Evaluation of the antifungal activity of individual and combined monoterpenes against Rhizopus stolonifer and Absidia coerulea.

The development of natural plant extracts and essential oils will help to decrease the negative effects of synthetic chemicals. In the present study, the antifungal activity of individual and combined monoterpenes against Rhizopus stolonifer and Absidia coerulea was evaluated. The results from antifungal tests showed that eugenol, carvacrol, and isoeugenol, among all the tested compounds, exhibited strong antifungal activity against the two tested fungi. Furthermore, carvacrol exhibited the most toxic effects against R. stolonifer and A. coerulea, and the IC50 values of carvacrol for the two fungi were 44.94 µg/ml and 50.83 µg/ml, respectively. The compounds (±)-menthol, b-citronellol, geraniol, 3,7-dimethyl-1-octanol, citral, and cuminaldehyde had only strong antifungal activity against R. stolonifer. In addition, the value of the synergistic co-efficient (SR) of a combination of isoeugenol and eugenol (1:1) showed an additive effect against R. stolonifer. The combination of isoeugenol and cuminaldehyde (1:1) showed an antagonistic effect against A. coerulea. Our results indicated that carvacrol and isoeugenol had potential antifungal effects against the two tested fungi and could be utilized in novel biological fungicide development.