Challenges in delivery of plant actives

Bioactive compound discovery has faced many challenges and the diversity of natural products offers a huge number of opportunities for new lead candidates. Plants are the source of most of the potential candidates since they have several and interesting biological activities. However, their in vivo efficacy is recurrently limited due to low permeation through the biological barriers and also to low or very low water solubility. Thus, enhancing the bioavailability of natural products through the improvement of their biopharmaceuticals features, as well as their targeting efficacy, are crucial steps in the development of these new products. In this chapter, we reviewed the most representative examples as a rising approach for delivery systems, presenting smart carriers, mostly in nanometric range that can selectively deliver appropriate levels of a bioactive agent. This overview also describes many types of carriers with structural and functional differences between them which can be chosen according to the encapsulated bioactive agent characteristics, the specific target or even accordingly to the desired release rate. Regarding natural products, we also highlight several examples that are already commercialized or in clinical studies phase with impressive progresses. On the other hand, this review also describes examples or natural products that are being used as encapsulant materials in these pioneering systems. In addition, a special focus is also drawn to the questions addressing the safety and efficacy evaluation of the nanopharmaceuticals for natural product delivery. Nonetheless, research into sophisticated, science-driven solutions is still continuing; expectations related to safety and efficacy are high to meet clinical needs, but the progress made has been noticeable so far.