Another fun fact: that these chemicals, fur[an]ocoumarins, are also potent CYP3A4 inhibitors. As such they interact with about ~50% of medications. The most common ones are bergamottin and 6',7'-dihydroxybergamottin [1, 2] found in grapefruit juice and in the peels of various citrus fruits like limes.

This is why grapefruit juice among other things may cause increased side effects associated with birth control pills.

[1] https://en.wikipedia.org/wiki/Bergamottin

[2] https://en.wikipedia.org/wiki/Grapefruit%E2%80%93drug_intera...

Thank you, I was wondering about the chemistry of this.

When they say to avoid grapefruit juice, it's not because of something innocuous like indigestion. But until recently that had been my assumption.

It is always said that grapefruit interacts with medication.

> I've always wondered if anybody ever tried it intentionally to "tan"

Yes they have, for centuries at least. Quote from the article that you're commenting on:

> Though it's likely not top-of-mind for most cooks, the phenomenon has been noted for centuries. For instance, in ancient Egypt, people who experienced loss of skin pigment (vitiligo) would treat the condition by covering their skin with the juice of false bishop's weed (Ammi majus) and then lying in the sun to darken their skin.

Yup grew up in Brazil. I have childhood memories of that knowledge being drilled into my head.

Did you drink many caipirinhas as a child?

There's a splash zone ok you don't need contact =]

Hahah true.

I didn't know about limes but knew about cow parsnip (Heracleum maximum) which contains similar compounds that cause burns when exposed to sun but I just avoid touching the plant and its typically obvious and easy to avoid (unlike poison oak).

I've been exposed to cow parsnip, and it looked bad - big fluid filled blisters on my legs - but it was painless and mostly just an annoyance.

There is an invasive species of the same genus in North America called Giant Hogweed (Heracleum mantegazzianum) that is much more potent and dangerous.

Oh, maybe thats the one I thought was cow parsnip. Didn't realize there was a difference.

Well, I would definitely avoid cow parsnip even though Giant Hogweed is supposed to be much worse. The blisters didn't hurt but they left scars after they healed that took a few years to fade. And I heard about a woman who had to be evacuated by helicopter from a hiking trip because she had most of her legs and a lot of her torso exposed. She was also hiking on a glacier so UV exposure was probably pretty high, too.

Fortunately, we only have cow parsnip around here. (So far, the qualifier we always have to use with invasive species.) From what I understand, Giant Hogweed looks very similar, only larger.

I was going to post something about giant hogweed, too. Never felt its wrath, thankfully, but some stories I've read are horrible.

Is this queen annes lace? We had a lot of it amongst hundreds of other plants that were in this garden of a house my parents bought as a kid. There was some mystery plant in there that gave bad burns but we never suspected the queen Anne’s lace and weren’t really enthusiastic about doing the testing necessary to deduce what the problem plant was

No, it looks quite similar but Queen Anne’s lace doesn’t cause burns. It’s kind of tricky to tell the difference.

Dandelion juice is the same I think. Always leaves hard-to-remove stains on your fingers.

Yup, it's usually one of the first few things that a Brazilian will tell an estrangeiro (foreigner) at the beach, right after the suggestions to use sunscreen religiously while out in the sun, doubly so if they're with their mothers.

why with their mothers?

US, GA here. My mom was big on tanning and warned of us this (lemons are also bad). I believe she said something about it being used on purpose for tanning, but that you had to be careful or you would badly burn. She probably did that around the late 80s or early 90s.

> I've always wondered if anybody ever tried it intentionally to "tan".

I forget where I got it, but as a kid I once had this thing which looked like a glue stick. You could draw on your skin with it and it would make you extra tanned there. I imagine it was this same kind of chemical in the stick.