So are you saying both egg phosphatidylcholine and 50% phosphatidylcholine from soybean will work with Fisetin ?
I'm not an expert in the chemistry of PL, however the references I mentioned say that Fisetin has an affinity for egg PL, and so there must be something different about it from other PLs. In fact, upon further searching -this is so - as stated here in this study...
A review on phospholipids and their main applications in drug delivery systems
"Phospholipids are molecules in which hydrophilic head group and hydrophobic acyl chains are linked to the alcohol. The variation in head groups, aliphatic chains and alcohols leads to the existence of a wide variety of phospholipids. In addition, the different sources of phospholipids also enhance the species of phospholipids. Various phospholipids, such as soybean phosphatidylcholine, egg phosphatidylcholine, or synthetic phosphatidylcholine, as well as hydrogenated phosphatidylcholine, are commonly used in different types of formulations. Phospholipids become intriguing as they can offer various options. However, the species diversity of phospholipids make how to select an appropriate phospholipid to achieve the therapeutic purpose become a crucial problem in the design of DDS, so we summarized the structures, main sources, properties of phospholipids which can give a guideline in the design of DDS."
So what this indicated to me is that just taking some PL, any old PL ,will likely not make a good formulation for Fisetin. There's no harm in trying, but how can you be sure? Alternatively, someone has done the work to find that egg PL does work... so why not use that type. Just saying.
More chemistry from the same article....
"However, soybean and egg yolk have differences in the contents and species of phospholipids, mainly including: 1) egg yolk lecithin contains a higher amounts of PC; 2) phospholipids in egg yolk exist long chain polyunsaturated fatty acids of n-6 and n-3 series, primarily arachidonic acid (AA) and docosahexaenoic acid (DHA), which are absent in soybean lecithins; 3) animal lecithins have characteristic of the presence of SM [18]; 4) the saturation level of egg yolk lecithins is higher than that of soybean lecithins [19], so their oxidative stability is better than that of soybean lecithins; 5) for egg yolk phospholipids, saturated fatty acid is usually at sn-1 position, and unsaturated fatty acid is at sn-2 position [9], while for soybean lecithin, sn-1 and sn-2 position can be both unsaturated fatty acids"