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Terpenes, Terpenoids & Isoprenes · Hydroponics Daily

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Hi, welcome back to Hydroponics Daily. Today we're going to be talking about
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some of the interesting chemistry that might be in your plants that gives flavour,
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taste, scent, and specifically we're going to be talking about isoprenes,
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terpenes, and terpenoids, which are all related hydrocarbon type of compounds.
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Before I start that, I'd like to give a clarification and correction from a
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previous episode that I did on heat stress, where I said that most plants like
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a temperature of 20 to 25 degrees Celsius.
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And I said that was equivalent to like 80 to 100 degrees Fahrenheit.
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And my good colleague and friend, Everest Fernandez, says, no,
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that's absolute rubbish, Russell.
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20 to 25 degrees Celsius is actually 68 to 77 Fahrenheit. So hopefully you haven't
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cooked your plants on my advice. Apologies for that.
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So yeah so we're going to talk about isoprenes first
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because they're the more simple type
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of compound um or flavor
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not just flavor compound they're very they can be structural as
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well and all sorts of things so isoprenes are the
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basic building blocks they've got five carbons okay
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and they their chemical formula
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is c5 h8 okay so
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it's two two carbons together in the middle and then three carbons off
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the side and a few hydrogens no oxygens no other types of
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elements and why are they important well isoprenes are really important
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because they're really volatile and they plants
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emit an enormous amount
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of isoprenes per year put in the globe and scientists aren't completely sure
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why they do it and this represents 600 million metric tons which is a massive
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amount of hydrocarbon emission up to a third of all the hydrocarbons emitted,
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globally due to this this natural process so it's related to like methane emissions
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and it could be an important part of link to climate change so if we could produce
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plants that had lower isoprene emissions then this would be a good thing.
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For well for climate change why do plants do it well they seems to be they use
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it to combat abiotic stress environmental stress it's shown to protect plants
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against moderate heat stress so around 40 degrees celsius so i'm assuming that
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is around 100 or above fahrenheit ask.
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Everest fernandez to check that it helps
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plants sort of tolerate large fluctuations
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in temperature and they can stabilize cell membranes in
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response to heat stress and they can also help resistance to
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reactive oxygen species which are these chemicals that are produced
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when plants are really stressed so under high light
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levels as well so that's important
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because under high heat stress which we talked
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about in a previous episode your plants will be producing isoprenes
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and certainly things like legal cannabis and hops and poplars
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plants that produce a lot of terpenes they'll
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be releasing these isoprenes and you'll be losing isoprenes and
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terpenes and terpenoids as they break down to isoprenes so
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that's an important thing to know about so these these these
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chemicals will be released when your plants are stressed especially heat stress
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but it's not just flavor smell and stress that they're important for natural
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rubbers are also isoprenes they're polyisoprenes so they're a natural polymer
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that are created from isoprene monomers so that's interesting to know.
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And then example of compounds with a isoprene backbone include carotene,
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phytol, retinol, which is vitamin A.
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It's the fancy word cosmetic manufacturers use for vitamin A.
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Tocopherol, which is vitamin E.
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Squalene. Heme A is an isoprene on it as well. So there's loads of different
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chemicals that contain isoprenes.
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Now, the terpenes are compounds that have, they're not polymers so much of isoprene,
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but they have one or two or three isoprene units they're made from,
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and then they'll change slightly the chemical structure.
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So, monoterpenes have 10 carbon atoms, that's two isoprene units.
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Sesquiterpenes have three, and diterpenes have 20 carbon units.
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Okay so all the terpenes that you find in your
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plants will be derived like this and it's
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us and terpenes are very important chemicals and
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they can even be things like turpentine is
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an example of a of a solvent you can get from plants
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that that is made of just of
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terpenes and it's a hydrocarbon but
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it's a lot less viscous than oils and
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things like this so that's what terpenes are if you ever
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got pure terpenes you can buy them then they're not
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like an oil like a resin they're more
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they're much less viscous than that and
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extremely potent so they smell extremely
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strong and then they can just melt
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plastic because they're such powerful hydrocarbons
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so why do plants produce them well they are.
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Fantastic for plant defense against herbivory so insects
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eating them disease resistance preventing pathogens from
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attacking them and they also with the producing scents
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in flowers then they're obviously going to be attracting pollinators or
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things like this so and making sure the right pollinators come
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come to see them so they're a very interesting
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chemistry and they have a number of them have bioactive activity in humans so
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a very common terpene is limonene a lemony smell that's a monoterpene so it's
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got 10 carbon atoms a very simple structure that's the one that will burn through
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plastic if you're not careful really quickly. Pinene.
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Carvone. Humuline is a sesquiterpene in the cannabis family and hops.
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Some other ones, there are saponins as well, which are triterpenes.
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And the steroids are linked to a sugar molecule, what we call a glycoside.
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So terpenes can also be linked to other molecules as well. So if you link them
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to a sugar, that really modifies their bioactivity.
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And so when we think about terpenes, and people have wondered about
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why certain plants that should in theory contain
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the same terpenes why they have massively modified activity
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it could be that the the molecules are slightly changed they
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might be linked to a certain sugar or they might be have
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a an oxygen added or might have a hydroxide group
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added and things like this so just because they have the
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same terpene it doesn't mean they have the same effect and the
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mixtures of terpenes can have very different effects so
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one terpene can affect the activity of another
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one so an interesting fact we sell yucca
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extract here at utrema where we make gold leaf and liquid gold and we also sell
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so this yucca extract contains these these plant-based steroids these steroidic
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terpenes we used to sell them to some people used to buy it for like weight
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lifting and things like this or to feed.
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Pigs because the steroids would build muscle and also they'd grow hair and things
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like this so are crazy compounds.
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But the saponins, these terpenes, steroids that actually produce really good
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sugar soap action. So they're just a natural soap, really.
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So that's another use of terpenes.
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Now, obviously, I've talked about terpenoids, and that's basically a terpene that contains water.
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An oxygen atom somewhere in the in the
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molecule and the most famous example of that
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is tetrahydrocannabinol which
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is thc and then also cbd
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is a is another terpenoid okay
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so they're not terpenes but when you produce an
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extract that will also contain terpenes and
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terpenoids so a hop extract will contain both
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not all the chemicals in that
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are bioactive in a plant will be terpenes though
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so don't think terpenes and terpenoids are the be-all and end-all so
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for example hops contain phytoestrogen that's.
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Not a terpene is a powerful hormone though and i
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have a friend who his job is just to extract estrogen
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out of hops the stuff that gives you brewer's droop
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and and moobs that it's actually used in
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hrt treatment in women so phytoestrogen not related
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to terpenes but going back to terpenes i think the
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thing that makes plant breeding so interesting for hops and
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other plants in that family is that they
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show they show such diversity in their terpene
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profiles so there's maybe 20 at
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least different types of terpenes and different mixtures
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of those terpenes give wildly different flavors
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and smells and odors and the flavor might not
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be linked to the smell and vice versa it might be and whereas
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you take something like a strawberry a strawberry the smell will
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be coming from terpenes but we no
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longer have a genetic diversity to actually breed different flavors
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of strawberries and mangoes mangoes pineapples
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what are the flavors we think of lemons or the
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citrus now they have a distinct smell but
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plants like hops and and and legal
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cannabis they can have wildly different
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smells and you can breed all the different flavors so it's.
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Not just about the psychoactive and the medicinal activities of these plants
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that is interesting from a breeding perspective it's the fact that you can modify
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the flavors so dramatically by breeding and also by the treatments that you give the plants.
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So if you give a certain fertilizer or a certain biostimulant,
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you can massively increase the way the terpenes are expressed.
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We talked about how isoprenes are emitted under stress while certain terpenes
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are emitted under stress as well.
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So you can modify that, produce a good stress in a certain direction.
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So there's so much scope for experimentation which makes it so exciting in that particular family.
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Whereas in other plants, you just can't.
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Even the growing conditions and breeding, you're just never going to change
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the flavour profile of a strawberry, for example.
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And those isoprenes will be also, the more you can modify them,
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the more they will modify the medicinal effects of the plants.
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Or the brewing effects, or the taste profile, or the way people enjoy a beer
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and things like this when the hops are used.
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You can buy synthetic terpenes it's
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a very controversial area where it it's
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considered second rate to actually producing natural
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terpenes you can extract the terpenes put them back in
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because chem you know being a chemist you can do extractions purifications
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separation so you can separate
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terpenes out according to their different chemical structures it's
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very it's a very interesting but very in-depth field i'm
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just going to do a very surface summary on this
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podcast i'm not going to go deep into terpene chemistry
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because it's not a chemistry podcast it's a hydroponics podcast
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so i'm just talking about the the chemicals that can
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be of interest if you are are growing
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and ways to maximize them there are some products
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out there that have been launched that and you
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put into your irrigation system if you're going hydroponically towards
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the end of your grow to increase the flavor profile of the
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produce you're growing so people like grapes and
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blueberries and lemon and things like this not sure
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i don't know of anyone who uses those sorts of products though but they they
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were big about five years ago in
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america and things like that someone tried to bring them over to the uk
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i'm not sure how much success they had with them i think
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when you've if you're growing a plant for a long time and
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then you get it to harvest the last thing you want to do is
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mess around with putting synthetic flavor profiles in.
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There and some people are very worried
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about certain things going through if you you know
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people talk about oh we could put a a fragrance
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in this fertilizer to make it smell nicer and then
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you have to be careful because people won't use that fertilizer if
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they think it's going to taint the final produce as well so
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that's something else to consider so careful when
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you look at the the name of the terpene as
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well because it you you might infer too
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much from the name so like humeline from hops
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that's got an earthy smell but you
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might from the name think it's going to be really hoppy and then
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and so just be careful you're
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not yeah like just because it's
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limonene you might think well limonene is the citrus
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smell but also mercine is also citrusy
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as well or pinene is the pine one
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but then you might get a different woody smell if you put turpoline in which
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is another woody one so and then so there are lots and lots of different citrusy
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ones so don't just think you need just one particular terpene and you can you
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and you can get produce analyzed for terpene analysis now and you'll find when you.
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Certain seeds you can buy they will even give the
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flavor profile broken down by the terpenes whether that's
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a guess whether that's been analyzed i'm not
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sure you'd have to ask the company themselves to work that
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one out so as i say this is a very very surface level
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brush up on isoprenes terpenes and terpenoids i've
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always found very interesting not least because of the amount of chemicals that
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are released a year from plants i once grew a plant called the burning bush
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and it was thought to be the plant that was named in the bible its scientific name is dictaminus.
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Albus and in theory you can in the
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evenings it produces a lot of isoprenes and.
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Terpenes that are emitted from it especially in.
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Hot summer days so much so that if it's
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a still day you can put a lighter or
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a match near to it and the whole plant will go up in
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flames because there's like a cloud it
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just go bang right so i grew these plants for a
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couple of years i never once got it to go up
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in flames but it is a very very odoriferous plant
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it produces a lot of it releases a really strong
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smell so it's really interesting i
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would if you want to try that try that put i would plant
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it somewhere where it's going to get really really hot during a summer evening
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and then it and then try lighting it on fire
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next well don't burn the plant but just put a
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lighter next to it use safety goggles and ppe and
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stuff like that don't get burn yourself and then say i told you to do it other.
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Plants where you get really good evening scents are like
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wisteria tobacco evening primrose
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these are all plants that release loads of terpenes in
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the evening and give that really lovely evening smell wafting
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back into your house and things like that and they're probably going
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to be attracting moth pollinators at that time of night so
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terpenes really important for attracting moth pollinators whereas
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during the day it's color and nectar and things like this that
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are going to be tracked in most plants so ice cream is really
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important for those evening plants okay thank you very much for listening to
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hydroponics daily for today hope you learned something if you want to connect
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with me on linkedin just search for russell sharp two s's two l's no e on the
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end of sharp and you've got any questions about hydroponics or anything you've
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learned today then let me know thank you very much for listening until tomorrow goodbye.