**4. Saponin characteristics enabling therapeutic intervention in dry AMD**

Saponins are amphipathic molecules that have hydrophobic and hydrophilic domains that can partition into lipoidal deposits and assist dispersal [73–76]. Saponins extracted from the ginseng plant (Panax ginseng CA Meyer) have a 4-membered triterpenoid ring and are often referred to as ginsenosides or steroidal glycosides because of the structural similarity to the cholesterol molecule (**Figure 4A**). The type and number of sugar units attached at sites R1, R2, and R3

#### **Figure 4.**

*Saponins extracted from the ginseng plant. (A) Structural similarity of saponins to the cholesterol molecule. Sugar attachment sites R1, R2, and R3 lead to the diversity of saponin species. (B) TLC of extracted saponins. G1 to G11 denote the major spots, each spot comprising several species.*

#### *Saponin-Mediated Rejuvenation of Bruch's Membrane: A New Strategy for Intervention… DOI: http://dx.doi.org/10.5772/intechopen.96818*

gives rise to a myriad of species and over 30 have been structurally characterised. Saponins extracted from the roots of the ginseng plant were separated on Silica Gel thin-layer-chromatography (TLC) plates using a solvent mixture comprising chloroform: methanol: acetic acid: water (50:30:8:3 v/v) and colour developed by spraying with 20% sulphuric acid in methanol and heating to 100 <sup>o</sup> C for 5 minutes (**Figure 4B**). Since the separation was dependent on the degree of hydrophilic/ hydrophobic properties, each spot on the chromatogram represents a collection of several species.

These saponin molecules not only bind to various lipid classes, they also display transition metal chelating properties [77, 78]. Thus, saponins can chelate the heavy metal deposits in Bruch's membrane and therefore assist in destabilising the lipid aggregates.
