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Recently in plant responses to the environment Category

I was idly skimming the Herald's website when I came across an article with the headline "Is plant medicine really that effective?" Since the article appears to be in the nature of an advertorial, the answer is, it depends on who you ask.

Unlike man-made chemical drugs that have been developed as novel medicines from the 19th century onwards, plant medicines have been used in human healthcare for millennia. 

This is what's known as an appeal to antiquity - because something's been in use for ages, it must work. It's repeated later in the article, with the claim that 

[t]raditional plant medicines have a rich history of being effectively used for over 2500 years

A rich history of being used is not the same as a history of being used "effectively". In Hippocrates’ time, for example, ‘plant medicine’ & basic surgery were about all physicians had to work with. That doesn’t mean that they necessarily achieved a high cure rate. The implication that plants are somehow better than their modern pharmaceutical counterparts is an example of another logical fallacy, the appeal to nature. (Tim Minchin was spot-on when he said “You know what they call alternative medicine that's been proved to work? - Medicine.”)

They share a long co-evolution with humans and are the foundation of their modern chemistry-based counterparts.

There are certainly many examples of coevolution involving plants and animals. However, much of this coevolution has taken the form of an arms race: as mutations that make plants less attractive to eat (e.g. spiny, less palatable, or downright poisonous) spread through a species, this can act as a selective agent on herbivores: animals with gene combinations that allow them to process the poisons are more likely to survive and spread those own genes around, and so that species evolves in turn. Coevolution does not mean, as previous articles by Clair imply (see here, for example), that plants are thus well suited by coevolution to our own needs in terms of acting as medications. The defensive alkaloids produced by many plants can certainly have a physiological impact, but as part of the plant’s anti-herbivore armoury. We can make use of some of those chemicals, sure, but natural selection didn't design them for medical (or recreational) use in any directed way. (Deliberate selection by humans is another matter.) 

But yes, many modern pharmaceutical drugs are derived from plant extracts, and pharmaocognosy is an important field of research in the search for new drugs and investigation of how traditional treatments might work. The difference being that modern pharmacology means that we can control things like dose, concentration and purity, which isn't really possible if you're using the entire plant prepared fresh each time. The chemotherapy drug taxol (isolated from the Pacific yew tree) is a good example, but there are many others, including: digitalis (foxgloves), salicin/salicylic acid (meadowsweet and willow bark), vinblastine (derived from the Madagascar periwinkle), and quinine (chinchona bark). For some drugs (e.g. vinblastine) yields from the actual plants are low, and the cost of obtaining the drug is high, so modern production methods make the drugs available to far more people than could ever avail themselves of the natural source.

... research confirms their beneficial effects for rebalancing hormones, aiding sleep, dealing with stress, in depression or strengthening the immune system. 

"Rebalancing hormones" seems to be one of those 'catch-all' phrases - which hormones are we talking about, & why do they need "rebalancing"? How did they get out of whack in the first place? Similarly, "strengthening the immune system": it's a meaningless term and ignores the fact that in the great majority of people the immune system works just fine. Other than the use of vaccines, "strengthening" or "boosting" may not be such a good idea... And in some instances evidence for other uses is conflicting.

Plant medicine can provide you with essential building blocks for organ health that cannot be found through diet alone, and have a cumulative effect on the body to help build or restore your physiology to the optimal levels.

Sorry, what? Which 'building blocks' would those be? All the building blocks of life – amino acids, di- & monosaccharide sugars, fatty acids, nucleotides, vitamins & minerals – are provided in an average diet. So what are these things that diet supposedly doesn't deliver?

In fact, Western biomedicine is historically rooted in plant medicine, given that it was the main form of medicine until the establishment of the new economic order after the industrial revolution.

And why did medical practices change at that point? Perhaps, because it became much easier to identify the actual active ingredients, and produce standardised doses of known concentrations and purity? Perhaps because the ability to do this meant that some drugs, at least, could become more widely available? Certainly the use of lab-made ingredients would help to protect species such as the Madagascar periwinkle, or plants such as goldenseal & ginseng, which in the US anyway have become endangered in parts of their range due to overharvesting for 'traditional' uses. 

Since the mid-1980s there has been an explosion of research into complementary and alternative medicines (CAMs), driven by consumer demand for natural medicines. There have been over 40,000 studies conducted over the past three decades. This means that in addition to traditional empirical evidence, we have increasing evidence based on newer methodologiesA such as randomised controlled trials. They overwhelmingly confirm traditional medical applications of plants.

Some citations would be nice. This would enable us to answer questions such as: of these 40,000 studies, how many were randomised controlled trials (RCTs)B? How many of those were properly blinded? Were they in vitro studies, carried out in petri dish or test tube, or in vivo, using animal models? Were they studies based on whole plants, or on extracts thereof? And – what were their results? 

Traditionally, plant medicine incorporates the whole plant and its extracts, and with this it brings a full spectrum of active constituents that work synergistically on different parts of the body's physiological functions. 

There are certainly examples where different plant constituents can act in a synergistic manner. One such example, looking at antibacterial activity in extracts of the plant goldenseal, is discussed here. It identified the actual compounds, their structure, and their likely modes of actionC. (What’s not to like?) Notably, while the goldenseal article was written in 2011, evidence that the same action occurs in vivo is (as far as I could tell from a quick pubmed search) still lacking. It’s also worth pointing out – should this evidence eventuate – that a synthetic preparation of the 3 compounds would be a much more reliable source than a tisane or a poultice of the whole plant.

Plant medicines will only work if they have been expertly compounded – from harvesting the plant at the right time at their peak potency, to careful processing them to preserve their active constituents and then to the correct formulation.This means to reap the many benefits of plant medicine, you must ensure you are getting them form [sic] a trusted company or registered Medical Herbalist.

And thence, my comment on advertorials.

 

A The idea of RCTs isn’t actually a modern invention. Perhaps the first such trial (albeit an imperfect one) was run by James Lind, back in 1747, in seeking a treatment for scurvy. He subsequently followed this up with a systematic review of the subject.

B There are some good explanations & examples in terms of trial design at this link.

C Thus the statement in a 2015 op.ed by the same writer, that “we simply do not have the technology yet to understand exactly how they work”, is incorrect. (Nor, from that same article, is it accurate to say that there are no side-effects if you use a whole plant remedy: see here, here, & here, for example.)

 

 

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EDIT (11 Feb): it seems that the writer of the 'we're eating poison' piece has decided to remove that page from their site. Which I guess is an improvement over the original. However, the good people over at Metabunk provided some useful links to the past, and this site appears to be the source used for the 'poison' post.

No sooner have I written a post about the synergy between FB and blogging then it happens again :) Again, hat-tip to Yvette d'Entremont, who posted a link to an article purporting to tell consumers how to distinguish between GM & 'regular' tomatoes. The writer of that article certainly wears their heart on their sleeve - just look at the title: "We're Eating A Poison!" And they are wrong, wrong, wrong. Even the image at the top of their article is misleading. 

I did leave a polite comment requesting evidence to support their claims. It appears that the owner of the page didn't like it. I am shocked! Shocked, I say!

Anyway. The main reason that they are wrong is that ...

...

... currently there aren't any genetically-engineered tomatoes on the market. 

There used to be one, the "Flavr Savr", which came out with much fanfare in 1994. It had been modified to enhance its shelf life, but apparently was not a commercial success and was withdrawn in 1997. To date, nothing has replaced it, although there's apparently quite a bit of research still going on into e.g. delayed ripening and resistance to pests and environmental stressors.

At this point it's probably worth noting that the tomatoes we grow (or buy) & eat are themselves the result of centuries of modification by conventional selective breeding - and also techniques such as mutagenesis, which are not exactly 'natural'. Nor are they subject to the same controls and rigorous testing required of any GM organism or product, despite the fact that mutagenesis creates much larger genetic changes than today's very precise techniques for genetic engineering (think CRISPR). And yet conventional breeding methods can also cause problems: they led to the withdrawal of some potato varieties in the US & Sweden, because the spuds thus produced contained dangerously high levels of the poisonous compound alpha-solanine.

Then there's that image. 

They'd obviously like us to think that one - perhaps the lushly rich red one to the left? - is natural/organic, and the other, a GMOA. Especially when they ask, "can you tell the difference between a regular tomato and a genetically modified one?" But, as we know, all commercially-available tomatoes are produced by conventional means. Still, I guess they feel that an image speaks a thousand words. (I woudn't want that rich red one in my sandwich though - it looks like a quick route to sogginess.)

And then there's the supposed "mounting evidence that links [GE foods] to toxic & allergic reactions, sick, sterile and dead livestock, and damage to virtually every organ studied in lab animals". Now, at the very least, I'd expect to see links or citations supporting a sweeping statement like that, but the article offers none. (I asked for them, when I made my sin-binned comment.) Anway, on the livestock front, there are now 22 years' worth of data available on stock fed mostly on GMO foods. Back in 2014 Steven NovellaB wrote about a very extensive review study that looked at the first 19 years of information. The animals covered by the various studies reviewed in the paper Novella discussed number in the billions (that is not a typo). It did not identify any problems of the sort listed in the OP that I'm discussing here. (The split between industry-funded & independent research projects into GMOs is roughly 50:50.)

On allergies - apparently the great majority of food-related allergic reactions in the US are caused by antigens from 8 foods: peanuts, tree nuts, milk, eggs, wheat, soy, shellfish, and fish. only GM soybeans are commercially available. There are a number of fairly stringent tests required of those applying to market foods with a GE component, & in New Zealand the results of these tests have to be reviewed by Food Safety Australia NZ. The goal of these safety assessments?

The goal of the safety assessment is not to establish the absolute safety of the GM food but rather to consider whether the GM food is comparable to the conventional counterpart food, i.e., that the GM food has all the benefits and risks normally associated with the conventional food.

So far no food derived from GMOs has been found to cause new allergies.

TL;DR: a scary headline & some scary 'factoids', unsupported by data of any sort. Colour me unimpressed. 

A And in fact, a reverse image seach on google brings up a large number of iterations of this image, including several pages that make it clear that the paler tom of the two is supposedly teh ebil GMO version. They clearly avoid letting the facts get in the way of a good story. 

B Novella has a couple of more recent posts on this subject here and here. The second link makes for fascinating reading. 

 

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A couple of years ago I spent a lovely afternoon in the huge domed glasshouses of Singapore's "Gardens on the Bay". The 'cloud forest' was my favourite - both for the concept & for the wonderful range of epiphytes on show there.

Singapore cloud forest mountain.jpg

So you'll understand that I enjoyed reading about it again on this blog, written for the New Zealand Epiphyte Network. Anyone with even a passing interest in New Zealand's native plants should drop by the site. And maybe sign up to be part of their citizen science project while you're there?

Go on, you know you want to :)

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For the last few years our Centre for e-Learning has run WCeLfest - a day of presentations & discussion around using various technology tools to enhance teaching & learning. I always find these sessions very valuable as there are a lot of people doing some really interesting things in their classrooms, & there's always something new to learn & try out myself. I offered to run a session myself this year, which is what I'm going to talk about here, but I was also asked to be on the panel for a discussion around what universities might look like in the future, and that was heaps of fun too.

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singapore conservatory dome.jpgAfter goggling (a mixture of gobsmacked & ogling) the supertrees, our little party of escapees from the day's official IBO program made our way into the Flower Dome, the first of the two great conservatories in Singapore's Gardens in the Bay. Cue more 'oh, wow!' moments as the scale of the building became apparent - this is what it looks like once you're through the doors (& into the wondrous coolness of the huge space):

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I often think it's a real pity that so many students seem to actively dislike learning about plants. Why is this? Is it because plants don't seem to 'do' anything interesting? I used some of the information described here in a test question this year - the results were a salutory reminder to spend more time working with students on how to read and interpret data sets.

One of the Biology Standards year 13 students [currently] study is called 'Describe animal behaviour & plant responses'. Now, if 'behaviour' = response to a stimulus, then that's really what plants are doing too. I guess it's just hard to think that something (usually) green, (usually) fixed in place, & with no nerves or muscles is able to behave - but plants do, & some of their behaviour is really quite subtle. You're probably familiar with plant responses to stimuli, including tropisms, circadian rhythms, & flowering in response to changes in photoperiod. But there's more: not only are there plants that actively hunt, but plants can also communicate - with each other, & in some cases with animals as well.

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When I set essays for my first-year students to write during the semester, I try to give them a scientific paper on each topic to start them off. This means that I need to do some extra bedtime reading as I need to select those papers carefully. Today’s post is based on one of those: a paper about a fascinating mutualistic relationship between marine algae and a species of isopod (the same crustacean group as the more familiar slater).

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ResearchBlogging.org

A while ago now I discussed how some plants are able to warn others when they're under attack by grazing animals. Now it seems that these responses and interactions are even more subtle - a new paper describes how signalling chemicals in tobacco plants can be altered by the grazers' saliva (Allmann & Baldwin, 2010).

As I described in that earlier post, plants demonstrate a number of responses to grazing. They may produce chemicals that directly harm the grazing animal in some way: poisons, maybe, or substances that inhibit the animal's digestive processes. Other, volatile, chemicals allow communication with other plants - they signal the presence of herbivores and stimulate those plants receiving the signal to produce defensive chemicals in advance of any grazing attack. And it appears that some of these volatiiles can attract predators that in turn feed on the grazers.

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ResearchBlogging.org

Your immune system is a wonderful, complex, multipartite mechanism that usually allows you to fight off the attentions of the various pathogenic organisms (bacterial, fungal, and viral) that you'll meet during your life. I say 'usually' because it's not always successful on its own, and even where it is, you can be laid low for quite some time - think of flu, but also think of measles, mumps, smallpox, polio... This is where vaccination comes in: this 'primes' your immune system so that it can react far more rapidly when it encounters the actual pathogens themselves. NB for a taste of some 'alternative' thinking on this concept, try this thread over on SciBlogsNZ.

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This is a new story & potentially a very exciting one (& I must thank Grant for drawing this story to my attention!). A Nature News item (Petherick, 2010) describes the discovery of green algae apparently living within the cells of salamander embryos. I'll wait with interest for the published paper, but if this finding's confirmed then it will be the first recorded instance of endosymbiosis in a vertebrate.

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