Influence of Khat Extract (Catha edulis) on corrosion resistance of Co-Cr dental alloys / Influência do extrato de Khat (Catha edulis) na resistência à corrosão de ligas dentais Co-Cr

Objective: The aim of this experimental study was to assess the effect of khat extract with different concentrations on the corrosion resistance of cobalt-chromium (Co-Cr) dental alloys used for removable denture. Material and Methods:The corrosion resistance of three Co-Cr alloys (Neobond II®, Kera 501® and PD Casta H®) was evaluated in artificial saliva in presence of three different concentrations of khat extracts. Fusayama-Meyer artificial saliva was used as a reference solution. The corrosion properties of the alloys were analyzed using potentiodynamic polarization, electrochemical impedance spectroscopy and surface analysis. The data was presented in means, standard deviations, and related figures. Comparison between the different concentrations was done using 1-way ANOVA test. The surface analysis was performed using scanning electron microscopy (SEM). Results: the results showed that the corrosion resistance of the three alloys tested (Neobond II®, Kera 501® and PD Casta H®) decreased in artificial saliva containing khat extract compared with that of the reference solution. Additionally, the corrosion resistance of the three Co-Cr dental alloys decreased by increasing the concentration of khat extract. Furthermore, the results indicate that Neobond II® alloy showed the least corrosion resistance compared with that of Kera 501® and PD Casta H® alloys. Conclusion: Khat extract with different concentrations had negative impact on the corrosion resistance of Cr-Co alloys. More in-vivo studies are highly recommended to confirm the results of the present study (AU)

Objetivo: O objetivo deste estudo experimental foi avaliar o efeito do extrato de khat em diferentes concentrações na resistência à corrosão de ligas dentárias de cobalto-cromo (Co-Cr) utilizadas em próteses removíveis. Material e Métodos:A resistência à corrosão de três ligas de Co-Cr (Neobond II®, Kera 501® e PD Casta H®) foi avaliada em saliva artificial na presença de três concentrações diferentes de extratos khat. A saliva artificial de Fusayama-Meyer foi usada como solução de referência. As propriedades de corrosão das ligas foram analisadas usando polarização potenciodinâmica, espectroscopia de impedância eletroquímica e análise de superfície. Os dados foram apresentados em médias, desvios-padrão e figuras relacionadas. A comparação entre as diferentes concentrações foi feita usando o teste One-way ANOVA. A análise de superfície foi realizada em microscopia eletrônica de varredura (MEV). Resultados: os resultados mostraram que a resistência à corrosão das três ligas testadas (Neobond II®, Kera 501® e PD Casta H®) diminuiu na saliva artificial contendo extrato khat em comparação com a solução de referência. Além disso, a resistência à corrosão das três ligas dentais Co-Cr diminuiu com o aumento da concentração de extrato de khat. Além disso, os resultados indicam que a liga Neobond II® apresentou a menor resistência à corrosão em comparação com as ligas Kera 501® e PD Casta H®. Conclusão: O extrato de Khat com diferentes concentrações teve impacto negativo na resistência à corrosão de ligas de Cr-Co. Mais estudos in vivo são altamente recomendados para confirmar os resultados do presente estudo. (AU)

Oral symptoms significantly higher among long-term khat (Catha edulis) users in Ethiopia / 한국역학회지

OBJECTIVES: Associations between khat (Catha edulis) chewing and different adverse oral-dental health conditions have been reported, yet evidence is still lacking. This study was designed to investigate the association between long-term regular khat chewing and self-reported oral symptoms. METHODS: A cross-sectional study was conducted on a sample of 1,255 university students in southern Ethiopia. Data on khat chewing status, a range of oral symptoms and other pertinent variables were collected using self-administered questionnaires. The association between long-term regular khat chewing and oral symptom count was investigated using negative binomial regression. RESULTS: The mean oral symptom count among long-term regular khat chewers was 1.75 (standard deviation [SD], 2.18; standard error [SE], 0.31), whereas that among those who were not long-term regular khat chewers was 1.18 (SD, 1.68; SE, 0.10). After adjustment for other variables, long-term regular khat chewers had approximately 50% more oral symptoms than those who were not long-term chewers did (adjusted count ratio, 1.53; 95% confidence interval, 1.12 to 2.10). CONCLUSIONS: Long-term khat chewing negatively affects the oral health of young university students.

In vitro hepatotoxcity of Catha edulis Forsk. (khat) phenolic-rich extract on human hepatocytes.

In our previous research, Khat has been shown to be associated with hepatic hypertrophy and hepatotoxicity in male and female SD-rats. However, no in vitro studies have been previously done to test on hepatotoxicity of khat on human experimental models. In vitro toxicological evaluation system plays an important role in the early phase of pharmaceutical development and drug safety. Therefore, the current study was designed to examine the in vitro hepatotoxic effect of phenolic-rich extract of khat (Catha edulis Forsk.). Khat was randomly collected from different places in Yemen [Dhamar (DMR), Ibb (IB), Taiz (TZ) cities] and Ethiopia (HAR). Phenolic-rich extraction was performed using 60% methanol. The effects of khat on HepG2 human hepatocyte cell line were measured using the MTT assay. HepG2 cells are a suitable in vitro model system for the study of human hepatocytes. The potency of cell growth inhibition for khat was expressed as an IC50 value. Cellular proliferation following 24h of exposure to khat samples showed considerable inhibition in khat-treated cells compared to nontreated cells (controls). The IC50 values of DMR, IB, TZ and HAR were 5.1±0.03, 15.3±0.12, 10.2±0.20 and 8.7±0.47 μg/mL, following 24 h of treatment, respectively. The proliferation of khat-treated cells decreased as the khat concentration increased. The method used appears to be a useful and reproducible technique for the in vitro assessment of the khat-induced cytotoxicity in a human liver cell line. Further studies are recommended to understand the molecular mechanism of Khat induced HepG2 cytotoxicity.