*4.4.3 Polyphenolic compounds delivery*

Secondary plant metabolites in the form of polyphenolic compounds have gained wide attention by scientists due to their wide spectrum of pharmacological activities, including antioxidant, antimicrobial and anticancer properties. Most however suffer from poor systemic bioavailability following oral administration due to low solubility and susceptibility to GI degradation. To overcome this constraint, chitosan-based NP have been proposed as a possible delivery intervention, which not only protect these APIs from GI degradation but also improves bioavailability [112]. Curcumin (CUR) is a polyphenol that has been studied extensively. It is derived from the rhizomes of *Curcuma longa* and active against a range of cancers in *in vitro* setups [113, 114]. However, preclinical and clinical data indicate that oral administration of CUR results in poor systemic bioavailability and high susceptibility to metabolic degradation [115]. In a study by AlKhader et al., the pharmacokinetic and anti-colon cancer properties of curcumin-containing chitosan-pectinate NP (CUR-CS-PEC-NPs) were evaluated. The cellular uptake and subsequent anti-proliferative effects of the CUR-CS-PEC-NPs were boosted at low CUR concentration after 48 and 72 hours of treatment compared to free CUR at equivalent dose. Besides, the carrier provided protection to CUR from acidic degradation. After oral administration of CUR-CS-PEC-NPs and free CUR at

10 mg/ml in rats a 4-fold increase in CUR concentration was detected compared to that of free CUR. Their findings indicated a null release of CUR in the upper GIT and a successful delivery of CUR to the colon with increased bioavailability of delivered CUR with time from CUR-CS-PEC-NPs for 24 h. Hence, rapid degradation metabolism of free CUR was noticed at the same duration. They concluded that this formulation may serve as a suitable delivery system for CUR to the colon in which CUR will be available on site for its chemotherapeutic activity against tumour [116].
