CAS: Towards sustainable sunscreens: identifying chemical structures in sunscreens linked to phototoxicity in corals

CAS：迈向可持续防晒霜：确定防晒霜中与珊瑚光毒性相关的化学结构

基本信息

批准号：
2114790
负责人：
William Mitch
金额：
$ 45万
依托单位：
Stanford University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2021
资助国家：
美国
起止时间：
2021-12-15 至 2024-03-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2114790&HistoricalAwards=false
关键词：
CAS Towards sustainable sunscreens identifying

项目摘要

A large fraction of the world's coral reefs are at a high risk of extinction. Although much of the threat is due to global factors, coral declines can also be significantly exacerbated by local factors. Recent concern has focused on oxybenzone, a common sunscreen component, due to observations that oxybenzone is toxic to adult corals and reduces survival of juvenile coral. The reasons for this toxicity are unclear, and improved understanding is needed to enable the design of sustainable sunscreens that are truly safe for coral reefs. This research project will characterize the chemical structures within organic sunscreen components or their metabolites that are responsible for phototoxicity to corals, focusing on five of the most common organic sunscreen components: oxybenzone, homosalate, octisalate, octinoxate, and octocrylene. This improved understanding will lay the groundwork for the design of new and sustainable sunscreen components that do not exhibit phototoxicity. The central hypothesis is that the presence or absence of a hydroxyl group adjacent to the aromatic carbonyl (present in each of the five compounds) is a critical determinant of whether a sunscreen component is phototoxic. Sunlight absorption forms excited triplet states of aromatic carbonyls that can generate Reactive Oxygen Species (ROS), resulting in phototoxicity. However, the hydroxyl group adjacent to the aromatic carbonyl in oxybenzone, homosalate, and octisalate inhibits ROS production during sunlight illumination by quenching excited-state triplets. The hypothesis, backed by preliminary evidence, is that oxybenzone, homosalate, and octisalate themselves are not phototoxic, but that coral metabolism glycosylates the hydroxyl groups to form glucoside metabolites that produce ROS and are thus phototoxic. Octinoxate and octocrylene should be directly phototoxic because they lack a hydroxyl group adjacent to the aromatic carbonyl. The research will employ both hard- and soft-coral adults but mainly use the sea anemone Aiptasia, a well characterized model system for corals; like corals, Aiptasia are anthozoans containing endosymbiotic photosynthetic algae. Objective 1 will characterize the mechanism of oxybenzone phototoxicity by: (i) testing whether the presence of oxybenzone leads to mortality only in the presence of the UV wavebands of sunlight, (ii) quantifying the conversion of oxybenzone to glucoside metabolites by the host animal and/or the symbiotic algae, (iii and iv) testing for ROS production under sunlight from glucoside metabolites (iii) in vitro and (iv) in vivo, and (v) quantifying mortality from exposure to glucoside analogues. Objective 2 will replicate these experiments with homosalate, octisalate, octinoxate, and octocrylene to characterize the relevance of this mechanism to sunscreen components being considered as alternatives to oxybenzone. Undergraduate students from underrepresented groups and a high-school science teacher with an accompanying student from an underrepresented group will be recruited to participate in summer research by partnering with existing Stanford University programs. The research should inform policy discussions about which components to regulate in sunscreens and be relevant to the management of coral-reef reserves.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

世界上很大一部分珊瑚礁的灭绝风险很高。尽管大部分威胁是由于全球因素造成的，但珊瑚下降也可能因当地因素而大大加剧。由于观察到氧苯甲酮对成年珊瑚有毒并降低了少年珊瑚的存活率，因此最近关注的关注点是一种常见的防晒成分（一种常见的防晒成分）。这种毒性的原因尚不清楚，需要改进的理解来实现对珊瑚礁真正安全的可持续防晒霜的设计。该研究项目将表征有机防晒成分中的化学结构或其代谢物，这些化学结构负责珊瑚光毒性，重点是五个最常见的有机防晒成分：oxybenzone，oxybenzone，homosalate，homosalate，八叶酸酯，八叶酸酯，八氧化苯甲酸酯和八烯烯。这种提高的理解将为设计不表现出光毒性的新的和可持续的防晒成分的设计奠定基础。中心假设是，与芳族羰基相邻的羟基的存在或不存在（存在于五种化合物中的每种中）是防晒成分是否是光毒性的关键决定因素。阳光吸收形成了芳族羰基的激发三胞胎状态，可产生活性氧（ROS），从而导致光毒性。然而，羟赞酮，荷马酸盐和八叶酸盐中芳香族羰基邻近的羟基通过淬灭激发态三重态在阳光照明期间抑制ROS的产生。在初步证据的支持下，假设是氧苯甲酮，霍马酸酯和八叶酸本身不是光毒性，而是珊瑚代谢糖基化羟基形成产生ROS并因此具有光毒性的葡萄糖苷代谢产物。八氧化物和八烯丙烯应直接是光毒性，因为它们缺乏与芳族羰基相邻的羟基。这项研究将使用硬质和软孔成年人，但主要使用海葵（Anemone Aiptasia），这是珊瑚良好的模型系统。像珊瑚一样，Aiptasia是含有内共生光合藻类的amthozoans。目标1将通过：（i）测试羟苯酮的存在是否仅在阳光的紫外波段存在下才会导致死亡率，（ii）量化宿主动物和/或Gllgae Symii III的启动葡萄糖体的验证（II）（II），（ii）量化量化氧化苯二甲油对葡萄糖苷的验证（III）（II III）（II III）（II III）（III）（ii），（II），目标1通过以下方式表征了目标1。体内代谢物（III）体内和（IV），（v）量化暴露于葡萄糖剂类似物的死亡率。目标2将用霍马森酸盐，八苯甲酸酯，八氧化物和八克烯烯复制这些实验，以表征该机制与防晒成分的相关性，被视为被视为氧化的替代品。来自代表性不足的小组的本科生和一名高中科学老师，由来自代表性不足的小组的陪同学生与现有的斯坦福大学计划合作，参加夏季研究。该研究应告知政策讨论有关在防晒霜中要调节哪些组件的，并与珊瑚Reef储备的管理相关。该奖项反映了NSF的法定任务，并被认为是通过基金会的智力优点和更广泛影响的审查标准通过评估来获得支持的。