Lipidomic Profile of Rhodotorula toruloides by GC/MS and Antioxidant Capacity of the Oil by DPPH and TLC-Plate Methods

This work was undertaken to evaluate the antioxidant capacity of Rhodotorula toruloides lipid extract in TLC plate, using the (DPPH) (1,1-diphenyl-2-picril-  hydrazine) method as an innovative way to visualise lipid groups that comprise this activity. Similarly, carotenoids and crude oil were analysed for  antioxidant capacity by the DPPH and β-carotene/linoleic acid methods. The lipidomic profile extract analysis was performed by GC/MS and HPLC/DAD.  The sample preparation for the GC/MS analysis was made by ultrasound-assisted transesterification. Free compounds were silylated with BSTFA (N,O-Bis  (trimethylsilyl) trifluoracetamide) + 1% TMCS (Trimethylchlorosilane). The analysis of the lipid extract showed that in the saponifiable fraction saturated  fatty acids (SFA) and monounsaturated fatty acids (MUFA) were present; and in the unsaponifiable fraction were steroids and carotenoids. The antioxidant  capacity was expressed as IC50 reaching 6.4 mg/L that means relative efficiency. The oil profile, using TLC, shows the chemical groups:  carotenoids, acylglycerols, free fatty acids and steroids. Similarly, the GC/ MS analysis shows the fatty acids and steroids. The HPLC analysis describes the  carotenoids profile, highlighting b-carotene as the majority and the presence of β-carotene-5,8-epoxide, zeaxanthin and b-cryptoxanthin, characterising  the lipidomic study of this yeast

Evaluation of the Genotoxic and Antigenotoxic Effects of Andiroba ( Carapa guianensis

The Carapa guianensis (andiroba) oil is commonly used by the Amazon population for medicinal purposes. The objective of this study was to determine the genotoxic and antigenotoxic potential of the andiroba oil (AO) and nanoemulsion (AN) using Swiss mice. Therefore, we used the comet assay and micronucleus test. The AO predominant compounds were oleic (39.13%), palmitic (33.22%), and linoleic (16.86%) acids. AN composition obeyed the surfactant/oil ratio of 0.69, and the Tween 80/Span 80 ratio was held at 0.9. Our results showed no cytotoxicity or genotoxicity in the mice treated with AO and AN alone. However, there was a significant reduction in the polychromatic erythrocytes (PCEs) numbers in all groups treated with doxorubicin (DOX), including those pretreated with AO and AN. Thus, the samples tested did not protect against DOX. On the other hand, our results showed a large increase in micronucleus (MN) formation when the mice were treated with DOX alone; these numbers were reduced when the animals were pretreated with AO and AN. The results indicate a protective effect of andiroba on MN formation and show no evidence of genotoxicity in mice

Stilbenes from Deguelia rufescens var. urucu (Ducke) A. M. G. Azevedo leaves: effects on seed germination and plant growth

The Amazon biodiversity may provide plants whose chemical substances are capable of controlling weeds. In this study we report the isolation and identification of five stilbenes from the leaves of "timbó vermelho" (Deguelia rufescens var. urucu): 4-methoxylonchocarpene (1); 3,5-dimethoxy-4´-hydroxy-3´-prenyl-trans-stilbene (2), lonchocarpene (3), 3,5-dimethoxy-4´-O-prenyl-trans-stilbene (4) and pterostilbene (5). Compounds 2 and 4 are new natural products although 2 has been previously cited as synthesis product. Potential allelopathic activity for 1, 2 and 4 was evaluated over seed germination and plant growth of Mimosa pudica weed. The observed effects on seed germination did not vary significantly (p > 0.05) when the analysis of phytotoxicity was performed with the substances alone, the maximum inhibition did not exceed 20%. The most intense inhibitions on radicle and hypocotyl development were found for compound 4 (p 0,05) quando a análise da fitotoxidade foi realizada com as substâncias isoladamente, cuja inibição máxima não ultrapassou 20%. A inibição mais intensa, quanto ao desenvolvimento da radícula e do hipocótilo, foi encontrada para o composto 4 (p < 0,05). Isoladamente, 4 causou efeito inibitório significativamente maior (p < 0,05) no desenvolvimento da radícula e do hipocótilo, do que 1 e 2. Quando testados aos pares, apresentaram antagonismo para a germinação de sementes e sinergismo para o desenvolvimento da radícula e hipocótilo

Fungicidal properties and insights on the mechanisms of the action of volatile oils from Amazonian Aniba trees

The Amazonian Aniba species are world-renowned for their essential oils (EOs). The molecules derived from EOs have been intensively investigated in regards to their potential for disease control in plants. The aim of this study was to investigate the antifungal properties of Aniba canelilla EO (ACEO) and Aniba parviflora EO (APEO) when used against eight phytopathogenic fungi. Gas chromatography-mass spectrometry (GC–MS) analysis of oils showed that 1-nitro-2-phenylethane (∼80%) and linalool (∼40%) are the major compounds in ACEO and APEO, respectively. The ACEO and APEO treatments displayed remarkable antifungal effects against Aspergillus flavus, Aspergillus niger, Fusarium oxysporum, Fusarium solani, Alternaria alternata, Colletotrichum gloeosporioides, Colletotrichum musae and Colletotrichum guaranicola, for which the IC50 values ranged from 0.05 to 0.28 μL mL−1 and 0.17 to 0.63 μL mL−1, respectively. Furthermore, the oil caused the inhibition of conidial germination by at least 83% for ACEO and 78% for APEO. The ACEO and APEO at 5 μL mL−1 induced leakage of nucleic acids and protein, suggesting that inhibition could be linked to the breakdown of membrane integrity of the conidia. In addition, the detection of fluorescent dye propidium iodide (PI) on F. solani conidia treated with ACEO and APEO indicates damage on the conidia cytoplasmic membrane. The findings of this study may be of biotechnological interest for the development of new plant protection products, with the advantage of being less harmful than the agrochemicals currently available. © 2019 Elsevier B.V