Chemical Composition and Effect against Skin Alterations of Bioactive Extracts Obtained by the Hydrodistillation of Eucalyptus globulus Leaves

Eucalyptus globulus is planted extensively for pulp, paper and wood production. Although bioactive compounds obtained from its biomass are used as cosmetics ingredients, the skin effects were not yet fully explored. In order to fill this gap, this work aimed to study the protective effect against skin damage provided by the essential oil (EO) obtained from the hydrodistillation of Eucalyptus globulus leaves, and by an extract obtained from the hydrodistillation residual water (HRW). The major compound identified in the EO was 1,8-Cineole, and the phenolic acids in the HRW included gallic acid as the main phenolic constituent. Moreover, non-toxic EO and HRW concentrations were shown to have anti-aging skin effects in vitro, decreasing age-related senescence markers, namely β-galactosidase and matrix metalloproteinases activation, as well as collagen type 1 upregulation. In addition, EO and HRW were found to exhibit depigmenting effects by inhibiting tyrosinase and melanin production, along with potent anti-inflammatory properties. Furthermore, the absence of skin irritation and sensitization in cells exposed to EO and HRW revealed the safety of both extracts for topical use. Taken together, these results highlight the beneficial effects of extracts obtained from Eucalyptus globulus biomass for skin aesthetic and health purposes, which should be explored deeply for the prediction of future pharmaceutical and dermocosmetics industrial applications

Mecanismos de degenerescência celular em dois modelos de "stress" oxidativo induzido por glutamato e pela proteína b-amilóide : implicações para a etiopatogenia da doença de Alzheimer

Tese de doutoramento em Biologia (Biologia Celular) apresentada à Fac. de Ciências e Tecnologia de CoimbraNo presente trabalho, a toxicidade da proteína b-amilóide (Ab) e a do glutamato, associadas à doença de Alzheimer (DA), foram usadas como paradigmas de morte celular induzida por stress oxidativo na linha celular PC12, utilizada como modelo neuronal. O objectivo deste estudo foi um melhor conhecimento dos mecanismos de morte neuronal e, deste modo, possibilitar a utilização de agentes protectores que permitam reverter a disfunção celular que ocorre em várias doenças neurodegenerativas em que o stress oxidativo parece estar envolvido, como é sugerido na DA. A toxicidade do glutamato ocorre por um mecanismo que envolve a inibição da tomada de cistina, conduzindo à depleção dos níveis intracelulares de glutationa (GSH), à produção de espécies reactivas de oxigénio (ROS) e, finalmente, à morte programada das células. O stress oxidativo resultante da excessiva acumulação de ROS está envolvido na alteração da função mitocondrial e na perda da homeostase do Ca2+. O stress oxidativo também é responsável pela potenciação da toxicidade do glutamato em condições de stress metabólico, mimetizado in vitro por inibição da glicólise e/ou da cadeia respiratória mitocondrial. O stress oxidativo desempenha um papel crucial na lesão neuronal induzida pela proteína Ab associada à DA. A toxicidade da Ab parece resultar da formação e libertação do aldeído citotóxico 4-hidroxi-2-nonenal (4-HNE), um produto resultante da peroxidação dos ácidos gordos polinsaturados (PUFAs) da membrana celular, e que normalmente é destoxificado pela GSH. A exposição a Ab aumenta significativamente a acumulação intracelular de ROS, decrescendo os níveis endógenos de GSH e conduzindo à oxidação proteica e à peroxidação dos lípidos membranares. Além disso, antioxidantes previnem o decréscimo da viabilidade celular induzido pela Ab. Os resultados obtidos apoiam a hipótese de que o stress oxidativo desempenha um papel crucial na disfunção metabólica induzida pela Ab uma vez que a inibição mitocondrial (redução da actividade dos complexos I, II-III e IV da cadeia respiratória) e glicolítica (decréscimo dos níveis de piruvato, o produto final da glicólise) é prevenida por vários antioxidantes, sugerindo que as suas propriedades poderão ser exploradas na tentativa de desenvolver estratégias terapêuticas eficazes para o tratamento e prevenção da DA. Finalmente, estudos efectuados em sinaptossomas isolados do cérebro de ratos diabéticos, mostram que a susceptibilidade neuronal à Ab é reduzida em condições de inibição metabólica moderada, indicando que os neurónios são capazes de desenvolver um mecanismo adaptativo, provavelmente, perante o aumento dos níveis basais de stress oxidativo

Synergistic hypoglycemic and hypolipidemic effects of ω-3 and ω-6 fatty acids from Indian flax and sesame seed oils in streptozotocin-induced diabetic rats

Background: Omega-3 and 6 fatty acids (FAs) of flaxseed oil (FSO) and sesame seed oil (SSO) that are being used in traditional foods and medicine have been investigated for their various synergistic biological potencies. However, their synergistic antidiabetic and antilipidemic properties at the world health organization (WHO) recommended ratio have not been studied. Purpose: To evaluate the synergistic antidiabetic and antipidemic potentials of bioactive-fatty acids from flaxseed (FS) and sesame seeds (SS) against streptozotocin (STZ)-induced diabetes mellitus Wistar albino rats. Study design: The study was to determine the in vitro and in vivo synergistic antidiabetic and antipidemic potentials of ω-3 and ω-6 FAs at 1:5 ratio from FSO and SSO in STZ-induced diabetes mellitus rats. Methods: Fifty-four Wistar albino rats were divided into 9 groups: normal control; diabetic control received streptozotocin 45 mg/kg b.w IP; diabetic groups received standard drug tolbutamide orally received 5mg/kg b.w; FSO and SSO orally administered with 250 and 350; 516 and 700 mg/kg b.w PO respectively, and FSO+SSO at 43+292 and 86+584 mg/kg b.w PO respectively. Blood glucose levels were observed on weekly basis. At the end of the experiment, biochemical factors such as the level of antioxidant enzymes, serum liver enzymes, malondialdehyde level, lipid profiles, blood parameters, and pancreas morphology were studied. Results: Twenty-eight days of the treatment significantly increased the in vivo antioxidant enzyme activities such as catalase (CAT), superoxide dismutase (SOD), and glutathione (GSH), whereas, malondialdehyde (MDA) level was markedly decreased in a dose-dependent manner in the pancreas and liver. A noteworthy reduction was observed in the lipid profiles of triglycerides (TG), total cholesterol (TC), low-density lipoprotein (LDL), very-low-density lipoprotein (VLDL), and increase in high-density lipoprotein (HDL), and also significant reduction was observed in the hematological parameters such as aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), creatinine, urea, glycosylated hemoglobin (HbA1c) and decreased blood glucose levels, while, total protein (TP), hemoglobin (Hb) and insulin levels were markedly increased in the treated rats in a dose-dependent manner compared to the diabetic control. Additionally, the results were also confirmed by histopathological examinations. Conclusion: The study suggested that the ω-3 and ω-6 FAs from FSO and SSO, respectively, showed potential synergistic antidiabetic and antilipidemic effects that were mainly mediated by ω-3 and ω-6 FAs present in the respective seed oils. © 2022 The Author(s)The authors gratefully acknowledge the University Grants Commission , New Delhi, India for funding this research work (Grant No. F.No.41–1280/2012(SR)