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首页> 外文期刊>The Internet Journal of Toxicology >Vitamin E and Trolox? reduce toxicity of Aloe barbadensis Miller juice in Artemia franciscana nauplii but individually are toxic at high concentrations
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Vitamin E and Trolox? reduce toxicity of Aloe barbadensis Miller juice in Artemia franciscana nauplii but individually are toxic at high concentrations

机译:维生素E和Trolox?降低芦荟无节制无节幼体中芦荟米勒汁的毒性,但高浓度时个别有毒

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This study reports on the acute toxic effects of Aloe barbadensis Miller (Aloe vera) juice as well as high doses of the antioxidants vitamin C, vitamin E and Trolox? (a water soluble vitamin E analogue) to the salt water crustacean Artemia franciscana. Aloe vera juice exposure resulted in acute toxicity, being capable of inducing mortality at dilutions as low as 4 % juice and having an LC50 at 24 h of 4.6 % ± 0.3. 6% Aloe vera juice dilutions were capable of causing 100% mortality within 4 h of exposure to A. franciscana. All of the antioxidants tested were also toxic to A. franciscana when tested in high doses. Toxicity of the antioxidants at 24 h was in the following order of toxicity: vitamin C (LC50 203.1 μg/ml ± 11.3) > Trolox? (LC50 = 283.3 μg/ml ± 25.8) > vitamin E (only low toxicity was observed at 24 h with the tested concentrations). However, in lower doses vitamin E and Trolox? were non-toxic and could block the toxicity induced by Aloe vera juice. Vitamin E was more effective than Trolox? at blocking Aloe vera juice induced toxicity. Treatment of A. franciscana with antioxidants prior to exposure to juice was significantly more effective than the simultaneous treatment of antioxidant and the toxin. These data suggest that the lethality induced by Aloe vera juice is due to oxidative stress which can be blocked by antioxidant addition. Financial support of this work was provided by the School of Biomolecular and Physical Sciences, Griffith University. Introduction Aloe barbadensis Miller (Aloe vera) has a long history of use for medicinal and dietary purposes and as a major component of many cosmetic preparations. Amongst its therapeutic uses, Aloe vera been shown to have anti-inflammatory activity [ 1,2 ] immunostimulatory activity [ 3 ], antibacterial activity [ 4 ], antiviral activity [ 5 ], accelerated wound healing [ 6 ] and a reduction of radiation induced skin reactions [ 7 ]. However, there have also been reports of toxic effects of Aloe vera leaf components. Various low molecular weight components of Aloe vera gel have been reported to be cytotoxic to fibroblasts [ 8 ] and both normal human skin cells and tumour cells in vitro [ 9 ]. Recently, we have found toxicity of Aloe vera leaf gel components towards Artemia franciscana nauplii [ 10 ] and a range of bacteria and fungi [ 11 ]. The mechanism of toxicity was not established in these studies but the induction of oxidative stress was considered likely. Many active constituents have been isolated from A. barbadensis leaves and their biological activities studied. The anthraquinones, anthrones and chromones in particular have received much recent attention and have been shown to be effective at counteracting various diseases [ 2,12 ]. Yen et al. [ 13 ] have investigated the antioxidant activity of various anthraquinones. In particular, aloe emodin was found to inhibit lipid peroxidation. Tian and Hua [ 14 ] have demonstrated that aloe emodin and aloin may act as either a pro-oxidant or an antioxidant, their action being dependent on their concentration. Therefore these compounds may act in either a protective or toxic manner at different concentrations. It has been suggested that the mode of toxicity for certain Aloe vera gel components is oxidative stress induction [ 14 ]. Conversely, at lower concentrations, these same components act as antioxidants and protect from oxidative stress [ 15 ]. The use of antioxidants such as vitamin E and vitamin C to reduce the effects of oxidative stress has received much recent attention. However, these studies have proved confusing, with some studies showing therapeutic effects [ 16,17 ], whilst other studies indicate that these antioxidants may be toxic [ 18 ]. It has been shown in a variety of human and animal models that the effects of vitamin E and vitamin C are dose dependent, with low doses functioning as antioxidants and blocking toxicity, while high doses induce toxicity through oxidative stress [ 19 ]. The Artemia
机译:这项研究报告了芦荟汁的急性毒性作用以及高剂量的抗氧化剂维生素C,维生素E和Trolox? (一种水溶性维生素E类似物)与盐水甲壳类Artemia franciscana。芦荟汁暴露会导致急性毒性,在低至4%汁液的稀释液中也能引起死亡率,并且在24小时的LC50为4.6%±0.3。 6%的芦荟汁稀释液能够在Francscana暴露于4小时内导致100%的死亡率。当以高剂量测试时,所有测试的抗氧化剂也对弗朗西斯菌有毒性。抗氧化剂在24小时的毒性按以下毒性顺序排列:维生素C(LC50 203.1μg/ ml±11.3)> Trolox? (LC50 = 283.3μg/ ml±25.8)>维生素E(在测试浓度下,仅在24小时内观察到低毒性)。但是,较低剂量的维生素E和Trolox?无毒,可阻止芦荟汁诱导的毒性。维生素E比Trolox更有效?在阻断芦荟汁诱导的毒性。在暴露于果汁之前用抗氧化剂治疗方济会比起同时使用抗氧化剂和毒素来治疗更为有效。这些数据表明,芦荟汁诱导的致死性是由于氧化应激所致,而氧化应激可被添加抗氧化剂阻止。这项工作的经费由格里菲斯大学生物分子和物理科学学院提供。简介芦荟(Aloe barbadensis Miller)(芦荟)用于医药和饮食用途并作为许多化妆品的主要成分已有很长的历史。在其治疗用途中,芦荟被证明具有抗炎活性[1,2]免疫刺激活性[3],抗菌活性[4],抗病毒活性[5],加速伤口愈合[6]和减少辐射诱导皮肤反应[7]。但是,也有关于芦荟叶成分的毒性作用的报道。据报道,芦荟凝胶的各种低分子量成分对成纤维细胞具有细胞毒性[8],在体外对正常人皮肤细胞和肿瘤细胞均具有细胞毒性[9]。最近,我们发现芦荟叶片凝胶成分对法国大青蒿无节幼体[10]以及一系列细菌和真菌[11]具有毒性。在这些研究中尚未建立毒性机制,但认为可能诱发了氧化应激。从巴巴德那曲叶中分离出许多活性成分,并对其生物学活性进行了研究。蒽醌,蒽酮和色酮尤其受到了最近的关注,并显示出可以有效抵抗各种疾病[2,12]。颜等。 [13]研究了各种蒽醌的抗氧化活性。特别地,芦荟大黄素被发现抑制脂质过氧化。 Tian和Hua [14]已经证明芦荟大黄素和芦荟素可以作为前氧化剂或抗氧化剂,其作用取决于它们的浓度。因此,这些化合物可以在不同浓度下以保护性或毒性方式起作用。有人提出,某些芦荟凝胶成分的毒性模式是氧化应激诱导[14]。相反,在较低的浓度下,这些相同的成分充当抗氧化剂并保护其免受氧化应激[15]。近来,使用抗氧化剂例如维生素E和维生素C来减少氧化应激的影响已得到关注。然而,这些研究已证明令人困惑,有些研究显示出治疗效果[16,17],而另一些研究表明这些抗氧化剂可能是有毒的[18]。在各种人和动物模型中已经表明,维生素E和维生素C的作用是剂量依赖性的,低剂量可起到抗氧化剂和阻断毒性的作用,而高剂量则可通过氧化应激诱导毒性[19]。卤虫病

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