Ngungeni Yonela, A Aboyewa Jumoke, Moabelo Koena L, Sibuyi Nicole R S, Meyer Samantha, Onani Martin O, Meyer Mervin, Madiehe Abram M
Nanobiotechnology Research Group, Department of Biotechnology, University of the Western Cape, Bellville 7535, South Africa.
DSI/Mintek Nanotechnology Innovation Centre, Biolabels Node, Department of Biotechnology, University of the Western Cape, Bellville 7535, South Africa.
ACS Omega. 2023 Jul 11;8(29):26088-26101. doi: 10.1021/acsomega.3c02260. eCollection 2023 Jul 25.
Disposal of agricultural waste has a negative impact on the environment and human health and may contribute to the greenhouse effect. The field of nanotechnology could provide alternative solutions to upcycle agricultural wastes in a safer manner into high-end value products. Organic waste from plants contain biomaterials that could serve as reducing and capping agents in the synthesis of nanomaterials with enhanced activities for use in biomedical and environmental applications. (avocado) is a fruit with a high nutritional value; however, despite its rich phytochemical profile, its seed is often discarded as waste. Therefore, this study aimed to upcycle avocado seeds through the synthesis of gold nanoparticles (AuNPs) and evaluate their anticancer, antioxidant, and catalytic activities. The biosynthesis of avocado seed extract (AvoSE)-mediated AuNPs (AvoSE-AuNPs) was achieved following the optimization of various reaction parameters, including pH, temperature, extract, and gold salt concentrations. The AvoSE-AuNPs were poly-dispersed and anisotropic, with average core and hydrodynamic sizes of 14 ± 3.7 and 101.39 ± 1.4 nm, respectively. The AvoSE-AuNPs showed excellent antioxidant potential in terms of ferric reducing antioxidant power (343.88 ± 0.001 μmolAAE/L), 2,2-diphenyl-1-picrylhydrazyl (128.80 ± 0.0159 μmolTE/L), and oxygen radical absorbance capacity (1822.02 ± 12.6338 μmolTE/L); significantly reduced the viability of Caco-2 and PC-3 cells in a dose-dependent manner; and efficiently reduced 4-nitrophenol (4-NP) to 4-aminophenol. This study demonstrated how avocado seeds, an agricultural waste, can be used as sources of new bioactive materials for the synthesis of AuNPs, which have excellent antioxidant, anticancer, and catalytic activities, showing AvoSE-AuNPs' versatility in various applications. In addition, the AvoSE-AuNPs exhibited good stability and recyclability during the catalytic activity, which is significant because some of the primary issues with the use of metallic NPs as catalysts are around the cost-effectiveness, recovery, and reusability of the catalyst.
农业废弃物的处理对环境和人类健康有负面影响，并可能导致温室效应。纳米技术领域可以提供替代解决方案，以更安全的方式将农业废弃物升级转化为高端有价值产品。植物产生的有机废弃物含有生物材料，这些生物材料可以在合成具有增强活性的纳米材料时用作还原剂和封端剂，用于生物医学和环境应用。牛油果是一种营养价值很高的水果；然而，尽管其富含植物化学成分，但其种子常被当作废弃物丢弃。因此，本研究旨在通过合成金纳米颗粒（AuNPs）对牛油果种子进行升级利用，并评估其抗癌、抗氧化和催化活性。在优化包括pH值、温度、提取物和金盐浓度等各种反应参数后，实现了牛油果种子提取物（AvoSE）介导的AuNPs（AvoSE-AuNPs）的生物合成。AvoSE-AuNPs呈多分散且各向异性，平均核心尺寸和流体动力学尺寸分别为14±3.7纳米和101.39±1.4纳米。AvoSE-AuNPs在铁还原抗氧化能力（343.88±0.001微摩尔AAE/L）、2,2-二苯基-1-苦基肼自由基（128.80±0.0159微摩尔TE/L）和氧自由基吸收能力（1822.02±12.6338微摩尔TE/L）方面表现出优异的抗氧化潜力；以剂量依赖方式显著降低Caco-2和PC-3细胞的活力；并能有效地将4-硝基苯酚（4-NP）还原为4-氨基苯酚。本研究证明了作为农业废弃物的牛油果种子如何能够用作合成具有优异抗氧化、抗癌和催化活性的AuNPs的新型生物活性材料来源，显示了AvoSE-AuNPs在各种应用中的多功能性。此外，AvoSE-AuNPs在催化活性过程中表现出良好的稳定性和可回收性，这很重要，因为使用金属纳米颗粒作为催化剂的一些主要问题涉及催化剂的成本效益、回收和再利用。
