Plants and the chemicals they make
March 15th, 2023 by Dr. Hannah Sivak
Gold will do nothing for your skin except adorn it. Right now I am wearing a gold chain with a pendant. Why do we use gold for adornment? Because it is practically inert in or on our bodies (gold crowns for teeth used to be common if you were rich). Conversely, silver will react with the skin and the environment and oxidize quickly enough. To benefit the skin or the body, you need interactions, which gold can’t give you (silver will interact but without benefit or worse, google argyria). Good interactions that is. For example, metals that our enzymes need to help catalyze chemical reactions to keep us alive. Gold…
May 18th, 2022 by Dr. Hannah Sivak
I am worried about all that talk about “plant-based” you see in skincare advertising. Why? Because it seems that in pursuit of anything and everything “plant”, we are going in the wrong direction. Example: alkanes. I love alkanes: linear carbon and hydrogen chains, make up waxes that will protect leaves and fruits from losing water. They also work great at preventing water loss from our skin, and the most expensive skincare products use inexpensive petrolatum and mineral oil to make a cream that will prevent water loss and accelerate healing. Most of the petrolatum and mineral oil we use comes from ancient organic matter, the same source of the gas/petrol…
May 12th, 2021 by Dr. Hannah Sivak
Avoid them! And beware of eating foods that contain furocoumarins if you plan to go outside. Furocoumarins (psoralens) and derivatives are found in many plants. Psoralens are chemicals found in many plants, like fig, celery, parsley, parsnip, lime, lemons and clove, and some fungi. These chemicals are natural and can be deadly, they are potent plant defenses against insects …and us. Crazy fact: psoralens was used in tanning accelerators until 1996! Never mind that it can lead to skin cancer or skin loss. However dangerous, they can be useful when used by experts. Seeds of Psoralea corylifolia were used hundreds of years ago in India for repigmentation in vitiligo patients.…
October 25th, 2020 by Dr. Hannah Sivak
Our skin has so many jobs! One of them is to defend us from pathogens, and the skin has the means (and cells!) to do this. What is the innate immune response? Is the one ready to fight even before our body has actually encountered the new enemy and will help to equip for the adaptive response. It is clear that if we depended solely on antibodies formed days or weeks after the encounter of a brand new pathogen, we could not survive long: the new virus or bacteria would invade, reproduce and kill before the first antibodies were even formed! Just like plants, invertebrates, and other living organisms, we…
March 27th, 2020 by Dr. Hannah Sivak
Answer: in many different ways. With soap and water: dissolve its coat and expose the nucleic acid. RNA will break down quickly. DNA is a lot more resistant. You can get a similar result with alcohol (higher than 60% and a bit less reliable). Time: RNA will decay. Essential oils: these work in many different ways because essential oils are made of many different chemicals so the answer will depend on the chemical/s. Remember selectivity: you don’t want to kill your own cells while destroying viral particles! Essential oils are concentrated chemical solutions, you can dissolve plastic with some of them! How do plant chemicals stop a virus? Here are…
February 11th, 2020 by Dr. Hannah Sivak
Burdock, Latin name Arctium, is a herb used in traditional Chinese medicine. We don’t rely on traditional medicine anymore, at least not as an effective tool, unless there is scientific evidence that it actually works for a specific problem. In many countries now facing yet another viral threat, a coronavirus “born” in 2019, doctors are testing some antiviral chemicals that helped with other viruses in the past. What are the mechanisms of action in antiviral chemicals? They vary a lot: inactivate proteases that the virus needs to assemble or nucleoside analogs that inhibit replication of the nucleic acid that forms the core of the virus, or ribozymes that cut the…
January 19th, 2020 by Dr. Hannah Sivak
I am here, writing this post while drinking my morning coffee, so I can’t pretend to be impartial. How safe is it? Very: it is used to stimulate breathing in premature babies. What can it do for your skin? Figure. Caffeine. The dry data The purine alkaloid caffeine is a major component of many beverages such as coffee and tea. Caffeine and its metabolites theobromine and xanthine have been shown to have antioxidant properties. Benefits Caffeine decreases the risk of skin cancer promoted by UV irradiation, apparently by slowing down repair of DNA mutations caused by UV making it more precise and preventing mutations that may lead to cancer.…
January 18th, 2020 by Dr. Hannah Sivak
The flowers of Helichrysum italicum are so tempting for marketing. Immortelle (in French), everlasting (in English), siempreviva (in Spanish). Words are powerful, and together with our brains, always looking for magic in a world that does not offer it, is a great combination that can be used to sell you, the potential customer, anything. It seems obvious that the essential oil of this flower has nothing to do with extending human life, it is just that the clusters of yellow flowers retain their color after picking and are used in dry flower arrangements. Another name for this pant is “curry plant” but you could not sell a product with that…
December 24th, 2019 by Dr. Hannah Sivak
This is a good example of skin care ingredients that are adopted too quickly. The silly argument: it is natural (so is vitamin A!) as if natural chemicals couldn’t hurt us. Nature is not out there for our skin benefit, and the sooner you learn this lesson, the sooner you will stop hurting your skin with irritating and allergenic natural chemicals (balsam of Peru anybody?). The equivalent in synthetic drugs is thalidomide. And I don’t want to accuse bakuchiol of being a tragic ingredient because there is no indication that it is. But look at what bakuchiol is said to be: a replacement for retinoids without side effects. Somehow, it…
December 22nd, 2019 by Dr. Hannah Sivak
My favorite plants have little to do with skin care. Carnations, gladioli, jasmine (the one in Argentina is actually Gardenia jasminoides) because they remind me of my mother. From my later life, the orange flower (neroli) is my favorite because it remind me of Andalusia and good times spent with my dear friends. When it comes to active ingredients that are great for the skin, there are so many! I will give you a few examples. EGCG from tea (Camellia sinensis), antioxidant and chemopreventive, fucoidan from brown algae, antiviral, antioxidants and promotes collagen synthesis. I could go on for hours (or days). Plants don’t make these chemicals for our benefit…
December 17th, 2019 by Dr. Hannah Sivak
The plant: Vitis vinifera Suggestions: You can listen to Libiamo ne’ lieti calici (La traviata) while reading this post. I say grape and you think wine. But you should also remember grape seed oil. And grape seed pronathocyanidins. And resveratrol! Besides the chemicals involved in basic everyday life, like chlorophyll, Rubisco, cellulose, etc., Vitis is full of “secondary metabolites”. The chemicals Vitis vinifera red cultivars are rich in anthocyanins that impart their color to the berries (generally in the skin). Anthocyanins can be found in the skin of the berries, hydroxycinnamic acids in the pulp and condensed tannins of the proanthocyanidins type in the seeds. Stilbenoids can be found in…
December 15th, 2019 by Dr. Hannah Sivak
Important: don’t thank plants (or Mother Nature, or Gaia) for the fantastic chemicals that benefit you. They are not made for your benefit. Conversely, those lethal poisons that may be hiding in the pretty fruits are probably meant for you or other predators. Chemical ecology studies the interactions between organisms and their environment that are mediated by naturally occurring chemicals. Many of us wake up in the morning looking forward to a hot water extract of the roasted seeds from Coffea arabica L., a.k.a. coffee. I like to drink my capuccino in the morning. It stimulates me (caffeine!) and it is a lovely way to start my day. Let’s look…
December 13th, 2019 by Dr. Hannah Sivak
Let’s start at the begiining. What is bearberry? A plant. What is arbutin? A chemical. Now that we sorted that out, let’s look at the details. Figure. Thomé Flora von Deutschland, Österreich und der Schweiz 1885. This is a plant that has been used in folk medicine to alleviate an assortment of ailments. It contains many phytochemicals, some of them good for you, others not so much. Among those chemicals is arbutin. Arbutin is a derivative of hydroquine present in many plants. Other names are arbutoside and hydroquinone β-D-glucopyranoside. This means that there is a glucose attached to the hydroquinone part of the molecule in a “beta” link. The glucose…
November 11th, 2019 by Dr. Hannah Sivak
Never apply an essential oil directly to your skin! They are powerful chemicals, powerful enough to dissolve plastic and kill your skin cells. The very volatile molecules in essential oils reach the olfactory bulbs in our noses giving us great pleasure. Essential oils are extracted from a variety of plants and contain the volatile chemicals that can be evaporated by distillation, although sometimes they are pressed directly from leaves and fruit peel. The high price of some flower essential oils is due to the very low yield, i.e. many pounds of plant material need to be treated to get just a few drops of essential oil. Essential oils are a…
October 27th, 2019 by Dr. Hannah Sivak
Because it contains essential fatty acids. But, you may ask, what is an essential fatty acid? Essential fatty acids are, like essential amino acids and vitamins, chemicals we need for life but do not have the ability to make ourselves. For this reason, they must be in our diet and, for the skin they must be applied topically. Why can’t we make those very important fatty acids ourselves? During evolution we lost the enzymes required to make them. Just like we can’t make vitamin C (L-ascorbic acid). Unless you ingest ascorbic acid (in a vitamin pill or orange juice), you get very sick!. Why do we need essential fatty acids?…
October 24th, 2019 by Dr. Hannah Sivak
Because you don’t want to have the very thin skin that “old” old people have. Healthy skin protects our bodies from water loss, oxidants in the air and infection, and it feels better and more comfortable! Figure. The Madonna dell’Impanatta by Raphael shows you the difference in appearance between young and old skin. Old skin will be unable to protect your body as well as young skin does. There is stuff we cannot change and stuff we can change, so it is important that we learn what good skin care products can do for us. For that, please have a look at Skin Actives. Using run-of-the-mill skin care, even if…
September 14th, 2019 by Dr. Hannah Sivak
What makes an oil “special”? Its fatty acid composition. Why? Because we, humans, can’t make every fatty acid we need, so we must obtain what we can’t make from the outside world, as food or topically (for our skin). What are the so called essential fatty acids, i.e. those we can’t make by ourselves? They are two: alpha-linolenic acid (an omega-3 fatty acid) and linoleic acid (an omega-6 fatty acid). Other fatty acids are considered “conditionally essential”, in the sense that they can become essential under some developmental or disease conditions; they include docosahexaenoic acid (an omega-3 fatty acid) and gamma-linolenic acid (an omega-6 fatty acid). How do you make…
August 22nd, 2019 by Dr. Hannah Sivak
Incidentally, the “celery tacos” is an obscure reference dedicated to mothers and grandmothers of children 2-5 years old who watch Wonder Pets. Some plants, like lime, lemon, celery and many others, contain chemicals called furocoumarins that absorb UV radiation. If a product containing this chemical is applied to the skin, UV will start a chain of chemical reactions that can damage the skin severely. The phototoxic inflammatory eruption usually appears 24 hours after exposure and peaks within 48-72 hours. Initial burning erythema is followed by blistering, epidermal necrosis and desquamation. Hyperpigmentation is one the the long-term effects. Furocoumarins absorb UV-A (320-380 nm) light enable furocoumarins, increasing the energy state of…
July 17th, 2019 by Dr. Hannah Sivak
First of all, WHY do you have to use retinoids? Because retinoids will help you with very common problems that everybody will have at one time or another: acne and skin aging (wrinkles, etc.). What retinoids do After retinoic acid enters the cell, it binds to specific nuclear receptors. These “activated” nuclear receptors, in turn, bind to specific regulatory sequences (called retinoic acid response elements) in the DNA inside the nucleus and directly change gene expression of specific genes. Such changes in gene expression translate into changes in the production of proteins, and are responsible for the biological and therapeutic effects of retinoids. Acne and retinoids In the 1970s, retinoic…
June 14th, 2019 by Dr. Hannah Sivak
Argan oil is extracted from the seeds of the fruit of the argan tree (Argania spinosa). The fruit takes a long time to mature and is not really edible, it is used as animal feed. Everything in the fruit is used: the peel and pulp of the fruit for animal feed, and the same for the paste that remains of the kernel after the oil is extracted by pressing. The nut inside the fruit contains one (occasionally two or three) small, oil-rich seeds; the oil is pressed from these seeds. The method used to extract the oil depends on what is available. Using stones is the most basic method. The…