Natural products have been widely explored since ancient times to heal human diseases. Due to their biological activities and relative safety, natural products have found applications in functional foods, medicine, pharmaceuticals and nutraceuticals. However, applications are often limited by poor aqueous solubility, instability and poor bioavailability following oral administration. For instance, many natural products exhibit excellent in vitro pharmacological activity, and no or less in vivo activity as a result of poor gastrointestinal absorption. Here we review techniques and materials for bioavailability enhancement such as particle size reduction, surfactant use, pH change, solid dispersion, cyclodextrin complexation, phytosome technology, solid-lipid nanoparticles, liposome and polymeric nanoparticles. Natural substances include quercetin, naringenin, curcumin, hesperetin, andrographolide, ellagic acid, resveratrol, bilobalide sinomenine, genistein, ginkgolide and glycyrrhizin. The clinical use of piperine as bio-enhancer with rifampicin is key achievement in the treatment of tuberculosis.

自古以来，人们就对天然产物进行了广泛的研究以治愈人类疾病。由于其生物活性和相对安全性，天然产物已在功能性食品，药物，药品和营养保健品中得到应用。然而，口服给药后水溶性差，不稳定性和生物利用度差常常限制了其应用。例如，由于胃肠道吸收差，许多天然产物表现出优异的体外药理活性，而没有或几乎没有体内活性。在这里，我们回顾了用于提高生物利用度的技术和材料，例如减小粒径，使用表面活性剂，改变pH值，固体分散体，环糊精络合，植物体技术，固体脂质纳米颗粒，脂质体和聚合物纳米颗粒。天然物质包括槲皮素，柚皮苷，姜黄素，橙皮素，穿心莲内酯，鞣花酸，白藜芦醇，白叶内酯青藤碱，染料木黄酮，银杏内酯和甘草甜素。胡椒碱作为利福平生物增强剂的临床应用是治疗结核病的关键成果。