Walber Toma

Dr. Walber Toma


Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 September 2014 in Revista Brasileira de Farmacognosia
Verified
Journal Article
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WTWalber Toma
Walber Toma
LGLuciana Lopes Guimarães
Luciana Lopes Guimarães
ABAlba R.M.S. Brito
Alba R.M.S. Brito
ASAldo R. Santos
Aldo R. Santos
FCFernando S. Cortez
Fernando S. Cortez
Camilo Dias Seabra PereiraCamilo Dias Seabra Pereira
Camilo Dias Seabra Pereira
Gastric ulcers are a significant medical problem and the development of complications lead to significant mortality rates worldwide. In Brazil, Carthamus tinctorius L., Asteraceae, seeds essential oil, the safflower oil, is currently used as a thermogenic compound and as treatment for problems related to the cardiovascular system. In this study, by Raman spec- troscopy, it was shown that oleic and linoleic acids are the compounds present in higher concentrations in the safflower oil. We demonstrated that safflower oil (750 mg/kg, p.o.) de- crease the ulcerogenic lesions in mice after the administration of hydrochloric acid-ethanol. The gastric ulcers induced by non-steroidal anti-inflammatory drug (NSAID) in mice treated with cholinomimetics were treated with four different doses of safflower oil, of which, the dose of 187.5 mg/kg (p.o.) showed significant antiulcerogenic properties (**p < 0.01). More- over, the safflower oil at doses of 187.5 mg/kg (i.d.) increased the pH levels, gastric volume (**p < 0.01) and gastric mucus production (***p < 0.001), and decreased the total gastric acid secretion (***p < 0.001). The acute toxicity tests showed that safflower oil (5.000 mg/kg, p.o.) had no effect on mortality or any other physiological parameter. Ecotoxicological tests per- formed using Daphnia similis showed an EC50 at 223.17 mg/l, and therefore safflower oil can be considered “non-toxic” based on the directive 93/67/EEC on risk assessment for new noti-fied substances by European legislation. These results indicate that the antiulcer activity of Safflower oil may be due to cytoprotective effects, which serve as support for new scientific studies related to this pathology.

9 November 2021 in Resources
Verified
Journal Article
Open access
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RCRenato Sakai Cid
Renato Sakai Cid
VRVinicius Roveri
Vinicius Roveri
Diogo Guedes VidalDiogo Guedes Vidal
Diogo Guedes Vidal
Maria Alzira Pimenta DinisMaria Alzira Pimenta Dinis
Maria Alzira Pimenta Dinis
FCFernando Sanzi Cortez
Fernando Sanzi Cortez
LGLuciana Lopes Guimarães
Luciana Lopes Guimarães
Antiretrovirals (ARVs) have been detected in aquatic ecosystems throughout the world; however, studies focused on assessing their ecotoxicological effects on marine aquatic organisms are still rare. In the present study, the predicted environmental concentration (PEC) of 13 ARVs was estimated for surface seawater from Santos Bay, Brazil, according to the European Medicines Agency (EMEA) guidelines. The results indicated that all ARVs need to be assessed for their ecological effects, considering that they all exceeded the EMEA guideline limits (PEC > 0.01 µg L−1). In this sense, three ARVs (namely atazanavir, nevirapine and efavirenz) were selected for the acute and chronic tests with sea urchin (Echinometra lucunter). Furthermore, the Environmental Risk Assessment (ERA) for these three ARVs was also performed by calculating the risk quotient. The acute and chronic toxicity results showed inhibitory concentrations (IC) for the fertilization (IC50; 1 h; range: 11.46–84.61 mg L−1) and for the embryo–larval development (IC50; 42 h; range: 0.52–0.97 mg L−1) of the sea urchin, respectively. Moreover, the ERA showed that these three ARVs are potentially hazardous for aquatic life in Santos Bay, raising concerns about the continuous introduction of ARVs in aquatic ecosystems. The data presented may contribute to the provision of subsidies for the development of monitoring public policies that aim to reduce the introduction of ARVs into the aquatic environment.

15 October 2024 in Coasts
Verified
Journal Article
Open access
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LGLuciana Lopes Guimarães
Luciana Lopes Guimarães
BLBárbara Faria Lourenço
Bárbara Faria Lourenço
FPFabio Pusceddu
Fabio Pusceddu
FCFernando Sanzi Cortez
Fernando Sanzi Cortez
RKRafael Kiyotani
Rafael Kiyotani
VRVinicius Roveri
Vinicius Roveri
Emerging pollutants, like phytoestrogens, are gaining attention in the scientific community for their impact on aquatic organisms. Nevertheless, there is a paucity of studies examining their effects on tropical aquatic species. In this context, the objective of this study was to (i) conduct chronic ecotoxicological assays with the sea urchin Echinometra lucunter with two phytoestrogens, namely genistein and daidzein (both derived from soy plant), and compare the results to the synthetic estrogen ‘estradiol valerate’; (ii) predict the potential risks of these phytoestrogens through an ecological risk assessment; and (iii) create a prioritization list of the most hazardous phytoestrogens using environmental persistence, bioaccumulation, and toxicity (PBT criteria). The results of chronic exposure demonstrated the following order of toxicity: daidzein (IC50 = 2.60 mg/L); genistein (IC50 = 3.37 mg/L); and estradiol valerate (IC50 = 28.40 mg/L). The results classify genistein and daidzein as “toxic” and estradiol valerate as “harmful” to the sea urchin. The final ranking of the PBT approach in coastal waters was as follows: biochanin A (the highest priority), followed by formononetin, genistein, enterolactone, daidzein, estradiol valerate, coumestrol, and 8-prenylnaringenin. The dataset highlights the importance of environmental monitoring to track phytoestrogens in Latin American coastal areas, particularly in developing countries.