
Figure 1. Ball and Stick model of Vinpocetine

Figure 2. Same thing different perspective
PubChem Chemical ID: 443955
Empiracal Formula: C22H26N2O2
Molecular Weight: 350.46
Synonyms:
Cavinton
Ceractin
Apovincaminic acid ethyl ester, and a plethora of others
Vinpocetine is a synthetic compound derived from Vincamine which is found in Vinca Minor, the common Periwinkle. In the US it is sold as a supplement, but it has been shown to be a cerebral vasodilator, and help utilize oxygen in the brain, and more. People use it as Nootropic for general memory enhancement, but its efficacy has seems to be under question. In Germany it is a prescription drug sold as Cavinton. There it is used as a Nootropic, and also for treating vascular diseases of the eyes (1, 2).
A search in Pubmed yields 705 entries that include Vinpocetine. One study shows that is effective in improving concentration of patients with epilepsy and dementia however minimal in patients with dementia (3).
Side effects according to one source are about 1 out of 100, but for your info here they are:
An increase in blood cholesterol levels,
Headache
Dizziness
Lowering of blood pressure
Discomfort in the stomach
Dry mouth
Nausea
The status of Vinpocetine in the US as a supplement is a bit nebulous. Since it is not a natural substance, it has no protection by the Dietary Supplement Health and Education Act (DSHEA) act, which excludes non natural products. This makes it quite surprising that it is available without a subscription in the first place. From what I can gather it is difficult for the FDA to ban a substance from being sold as a supplement if it seems relatively safe. Considering this, it may remain on the shelves for a long time.
There has been a massive amount of research done on Vinpocetine, I barely just grazed the surface. Some of it is conflicting as well, so it seems we still have a lot to learn about this substance.
Remember kids, consult your doctor before taking a supplement, especially one that technically is not. ;-) Also of course for interactions with other drugs and supplements.
In my posts I will always include a 3D Molecular model (AKA Ball and Stick) of the chemical if it is Organic. In the Chemical sciences Organic means the compound has a Carbon backbone. Since molecular models can look cluttered on 2D plane we also use line models such as #3. You will notice dashed narrow triangular lines, these are called dash-wedge notation. They are either dashed or solid. Dashed means the atom or group is back behind the plane of the screen, and solid means it is pointing out towards you. One more thing to note about line models is that Hydrogen(s) are generally omitted when attached to Carbons. They are understood to be there. Carbon can make 4 bonds (each bond a line) so if you see 3 lines then you know a Hydrogen is taking the last one.

Figure 3, Line drawing, a little easier to see all the connections eh?
Color Scheme:
Grey = Carbon
Red = Oxygen
White = Hydrogen
Blue = Nitrogen
(1)
https://www.webmd.com/vitamins/ai/ingredientmono-175/vinpocetine
(2)
https://www.meds4sure.com/blog/what-is-cavinton-forte-and-what-is-it-used-for.html
(3)