Abstract：
Curcumin is a multitargeting nutraceutical with numerous health benefits, however, its efficacy is limited due to poor aqueous solubility and reduced bioavailability. While nano-formulation has emerged as an alternative to encounter such issues, it often involves use of toxic solvents. Microbial synthesis may be an innovative solution to address this lacuna. Present study, for the first time, reports exploitation of Aureobasidium pullulans RBF4A3 for production of nano-curcumin. For this purpose, Aureobasidium pullulans RBF4A3 was inoculated in YPD media along with curcumin (0.1 mg/mL) and incubated for 24 h, 48 h, and 72 h. Subsequently, residual sugar, biomass, EPS concentration, curcumin concentration, and curcumin nanoparticle size were measured. As a result, nano-curcumin with an average particle size of 31.63 nm and enhanced aqueous solubility was obtained after 72 h. Further, investigations suggested that pullulan, a reducing polysaccharide, played a significant role in curcumin nano-formulation. Pullulan-mediated nano-curcumin formulation, with an average particle size of 24 nm was achieved with conversion rate of around 59.19 %, suggesting improved aqueous solubility. Additionally, the anti-oxidant assay of the resulting nano-curcumin was around 53.7 % per μg. Moreover, kinetics and thermodynamic studies of pullulan-based nano-curcumin revealed that it followed first-order kinetics and was favored by elevated temperature for efficient bio-conversion. Also, various physico-chemical investigations like FT-IR, NMR, and XRD reveal that pullulan backbone remains intact while forming curcumin nanoparticle. This study may open up new avenues for synthesizing nano-polyphenols through a completely green and solvent free process with plausible diverse applications.
摘要：
姜黄素是一种具有多种健康益处的多目标营养食品，然而,由于水溶性差和生物利用度降低，其功效有限。虽然纳米配方已成为遇到此类问题的替代方法，它通常涉及使用有毒溶剂。微生物合成可能是解决这一空白的创新解决方案。目前的研究，第一次,报道了利用出芽梭菌RBF4A3生产纳米姜黄素。为此,在YPD培养基中与姜黄素(0.1mg/mL)一起接种出芽梭菌RBF4A3并孵育24小时,48h,和72小时。随后，残糖,生物量，EPS浓度,姜黄素浓度,并测量姜黄素纳米颗粒的尺寸。因此,72h后得到平均粒径为31.63nm、水溶性增强的纳米姜黄素。调查显示普鲁兰，一种还原性多糖，在姜黄素纳米制剂中发挥了重要作用。普鲁兰多糖介导的纳米姜黄素制剂，平均粒径为24nm，转化率约为59.19%，表明水溶性得到改善。此外,所得纳米姜黄素的抗氧化剂含量约为53.7%/μg。此外，基于普鲁兰的纳米姜黄素的动力学和热力学研究表明，它遵循一级动力学，并且受到高温有效生物转化的青睐。此外，各种物理化学研究，如FT-IR，NMR,和XRD显示支链淀粉骨架在形成姜黄素纳米颗粒时保持完整。这项研究可能为通过完全绿色和无溶剂的方法合成纳米多酚开辟新的途径，并具有多种应用。
