**2. Natural plant extract and phytoconstituents**

In this chapter four different plant extracts and its phytoconstituents (Black seed oil containing thymoquinone, Jute leaf extract containing phytol, *Aphanamixis polystachia* leaf extract, green tea extract containing EGCG) are discussed (**Figure 2**), which were formulated as phospholipid based nano drug delivery systems (PBNDDS).

Thymoquinone a natural component of Black seed oil, which can be obtained from the seeds of *Nigella sativa*, found to have different pharmacological activity for the treatment of various diseases [22–26]. However, despite the various pharmacological properties of thymoquinone, its administration *in-vivo* remains crucial due to its poor water solubility and stability issues. Therefore an advanced drug

*Phospholipid Based Nano Drug Delivery Systems of Phytoconstituents DOI: http://dx.doi.org/10.5772/intechopen.101040*

#### **Figure 2.**

*Chemical structure of phytol, thymoquinone and epigallocatechin gallate.*

delivery system is required to improve the therapeutic outcome of thymoquinone by enhancing the solubility and stability in water [27].

Jute leaf obtained from *Corchorus olitorius L.* [28, 29] has been used as traditional medicine. Jute leaf extract contains different phytoconstituents which are medicinally active and exhibits pharmacological effects against different diseases [30–33]. Phytol is one of the main phytoconstituents found in jute leaf extract demonstrates pharmacological activity against different diseases and in different *in-vitro* cell line studies [29, 34]. Phytol due to its multiple ring structure shows poor water solubility and absorption through the intestinal wall.

*Aphanamixis polystachya* a natural plant which contains phytoconstituents found to have different medicinal activities [35–38]. Leaf extract of *A. polystachya* plant showed CNS activities [39], therefore in this chapter *A. polystachya* leaf extracts and its phospholipid based nano drug delivery system (PBNDDS) activity against animal model of dementia is discussed.

Epigallocatechin-3-gallate (EGCG) is a main potent constituent of green tea extract (*Camellia sinensis)*, which is one of the major catechins [40]. EGCG exhibit pharmacological activity against different diseases [41, 42] and also showed activity against carcinogenic effects in different animal models with different cancers [43–46]. EGCG has high water solubility however it exhibits low permeability across the gastrointestinal tract (GIT) leading to poor bioavailability [47, 48].

#### **3. Issues with natural phytoconstituents**

Phytoconstituents showed a range of pharmacological activity and less side effects compared to synthetic drugs; however phytoconstituents exhibit low water solubility, poor permeability through gastrointestinal tract and impede fast systemic clearance [49]. Physical and chemical stability of phytochemicals is another issue [50–54]. Treatment of CNS and cancer diseases require targeted drug delivery for better therapeutic outcome. Nano drug delivery systems may be a promising platform for the improvement of aforementioned issues of natural plant extracts and their phytoconstituents. Therefore phospholipid based nano drug delivery systems of natural phytoconstituents could be the potential delivery system with better performance and stability [55].
