This white flower here is called meadowsweet. It is a pretty common plant here in Sweden.
It grows along the roads pretty much all throughout the country.
A lot of people probably consider it a weed.
But what a lot of people don't know is that it has an extremely interesting and important chemical story.
The story starts with this molecule: salicylic acid,
a substance that has long been used for its pain-relieving properties.
Salicylic acid is derived from the metabolism of a compound called salicin,
which is found naturally in for example willow tree bark
and in our meadowsweet.
This has been known for centuries, and the bark from willow trees has often been used to treat pain and fever.
But there were some side effects.
Salicylic acid can also cause digestive issues
such as gastric irritation, vomiting and even worse, if consumed in high doses,
which made the medicinal effects limited.
In the late 1800s, a German scientist called Felix Hoffmann
decided to try and find a way to get rid of the negative side effects, to help his sick father.
He used salicylic acid extracted from meadowsweet
and replaced one of the hydrogens in the molecule
with a so-called acetyl group.
It worked!
By making this small modification,
he improved the effectiveness of the medicine.
The new medicinal drug was named Aspirin,
from the former scientific name of meadowsweet, Spirea ulmaria
and A from the acetyl group that solved the problem with the negative side effects.
Today, Aspirin is one of the most sold pharmaceuticals in the world.
It may sound strange that we can just replace a part of a molecule like this, but this is fundamental in chemical research
in order to create new molecules with desired properties.
But in order to make such changes, we first need to understand how the chemical bonds that hold molecules together work.
In a molecular model, the bonds usually look like this.
But in reality, it is quite different.
Chemical bonds are in fadt the result of electrons being moved and shared between atoms.
But there are a few different ways chemical bonds can form.
First: ionic bonds.
One example of a substance held together by ionic bonds is regular table salt.
In general, elements prefer to have filled electron shells.
To achieve this, the elements can either give off or receive electrons from other elements.
The result is that the atom becomes either positively or negatively charged.
These so-called ions can then bind to other ions of opposite charge
Atoms can also bind to each other by sharing the same electrons.
This is called a covalent bond.
The simplest example is hydrogen gas, where the two hydrogen atoms share both the available electrons
and therefore fill their first electron shell.
But the different elements in a molecule can have different abilities to pull electrons to them.
Take water, for example.
The electrons move around both the hydrogen atoms and the oxygene atom,
but the oxygen atom attracts the electrons more strongly so the electrons end up being pulled to the oxygen atom more than the hydrogens.
This makes the whole molecule polar, meaning that we get a slight difference in charge between the ends of the molecule.
A similar polarity can be found in other molecules held together with covalent bonds.
These polar molecules can in turn form electrostatic forces
and generate weak bonds between molecules.
And then we have the metals, which often have some special properties.
Metals can form a special type of bond, simply referred to as a metal bond
in which electrons can move freely around the atoms,
and form almost like an electron cloud
around the positively charged metal ions.
And even within larger molecules, certain combinations of atoms can form especially strong groups together,
just like in our example with meadowsweet.
With this knowledge, we can experiment with how to break specific chemical bonds
in order to replace certain parts of a molecule with something else.
Just like Felix Hoffmann did to create Aspirin.
And this is still what today's pharmaceutical research is all about!
At AstraZeneca, we develop new pharmaceutical drugs
to cure and treat diseases that affect people today.
We develop small and large molecules that are intended to have a biological effect.
You can put together molecules in many different ways.
You want them to be able to get to the right place in the human body.
You don't want them to be extreted too quickly,
and they cannot have too many negative side effects.
In order to achieve this, AstraZeneca has access to millions of molecules in a giant compound library.
The molecules that you begin with are almost always quite different from the ones that end up as a pharmaceutical drug.
Even if you obtain an effect from a molecule that has been discovered in for example nature,
you often also have several other effects that you want to adjust.
It may have negative side effects,
but it can also have short half-life and be eliminated quickly inside the body.
If that is the case, you have to stop the degradation in order to prolong the effect of the drug.
What makes this job so much fun is being able to affect the basic building blocks that make up the world,
and being able to model them and construct them to your liking in ways that no one has done before.
And from this molecule you can then obtain an effect
either inside the body or in the outside world in the form of a new material.
An understanding of the chemical forces that hold molecules together
and the ability to break specific bonds and replace selected parts with others can literally save lives.
The research that happens here at AstraZeneca is very advanced but with today's technologies,
we can accomplish so much more than people could probably ever imagine at the time Aspirin was first developed.
And just like the meadowsweet and the willow tree that we started with
we still find a lot of medicinal substances here in nature
that start a whole chain of experiments
in the search for future medicinal drugs.
Thanks everyone for watching today!