Cutting Apple Science

𝗖𝗮𝗻 𝘁𝗵𝗲 𝗰𝘂𝗿𝗿𝗲𝗻𝘁 𝘁𝗿𝗲𝗻𝗱 𝗳𝗼𝗿 𝗱𝗶𝘀𝗽𝗹𝗮𝘆𝗶𝗻𝗴 𝗮 𝗰𝘂𝘁 𝗮𝗽𝗽𝗹𝗲 𝗯𝗲 𝗰𝗼𝗻𝘀𝗶𝗱𝗲𝗿𝗲𝗱 𝗮 𝘃𝗮𝗹𝗶𝗱 𝗱𝗲𝗺𝗼𝗻𝘀𝘁𝗿𝗮𝘁𝗶𝗼𝗻 𝗼𝗳 𝘁𝗵𝗲 𝗲𝗳𝗳𝗲𝗰𝘁𝗶𝘃𝗲𝗻𝗲𝘀𝘀 𝗼𝗳 𝗮𝗻 𝗶𝗻𝗴𝗿𝗲𝗱𝗶𝗲𝗻𝘁 𝗳𝗼𝗿 𝗮𝗻𝘁𝗶𝗼𝘅𝗶𝗱𝗮𝗻𝘁 𝗯𝗲𝗻𝗲𝗳𝗶𝘁𝘀?

I will take just about any opportunity to carry out an experiment, I am no super scientist but can just about manage to rake up from the depths of my rusty old brain enough memories of applied science study to offer my opinion beyond knowledge of cosmetic science and question if this latest trend could really be holding up as a good scientific experiment.

Before you think I should get back in my box, I appreciate my focus is on cosmetic chemistry, but it is also true that in order to be able to apply yourself to that area of science it is necessary to possess at least some basic foundation in other relative subjects including human biology and biochemistry, so whilst I am not claiming to be an expert, least of all in plant biology, I would like to propose an argument in my own way that considers not only the ingredient in question, Vitamin C and it's differing chemical properties dependant on its form but that recognises the considerable histological differences between a fruit and human skin.

Prior to physically performing my fun DIY experiment, I had already identified several reasons how it seems to not perhaps be a good or accurate example to demonstrate how a Vitamin C ingredient has superior action as an antioxidant skincare ingredient. But I carried it out happily, not just to be able to share a visible result but also because I will admit it was good fun.

There could be other tests that using an apple could be valid for in terms in skincare, such as perhaps lightening ingredients, but they would surely need to take into even further consideration the differences between a fruit and human skin composition and how the various forms of Vitamin C ingredients are structured.

So I took my slices of apple put into dishes and applied ascorbic acid, in some of the various forms that we use within Dermogenera as a brand and also L-ascorbic acid.

I left them at room temperature and measured visible changes at 6 hrs and 12 hrs. (I have placed side by side to photograph at end of each timeframe)

Please note this was a really very basic trial, but it does I think show how each piece reacted differently to application of ingredient over a period of time and enable me to explain the reasons as to why that might be.

I do not use base form L-ascorbic as an ingredient within our formulations, which will be explained further on, so in the attempt to make this anywhere near what could pass as an interesting experiment, I created a dilution at 3% of each ingredient using in the hydrosoluble forms water & propylene glycol as solvents and in the case of the liposoluble form, I used caprylic capric triglycerides.

This was because if I compared using formulations even with a specific pH including not only Vitamin C ingredients but various others alongside, each different and many additional ingredients that would hugely affect the outcome of a test for enzymatic browning, it also could not be used as a comparison test if wanting to include the L-ascorbic acid.

Firstly, our skin is not an apple of course, permeation of any ingredient into the human skin is much more complex and difficult to achieve, vastly different to the flesh of an apple and also we must consider the molecular weight, if it is a Dalton weight over 500 then it is unable to penetrate human skin beyond the surface, so then we must consider the presence of penetration enhancers which can also make one form of Vitamin C more effective than another in terms of skincare, a thing impossible to determine when applied to an apple instead of human skin where you have a different composition including the significant presence of lipids. Then to consider the focus of this trend, the browning of, or oxidation of an apple which is caused by the enzyme polyphenol oxidase, a pH related enzymatic reaction rather than free oxygen, this browning reaction can be prevented with not only the antioxidant ascorbic acid, but with any acid, so any acid ingredient would have had the same result. This occurs with fruit and is why when making a fruit salad you add lemon or orange juice to slow down this effect and prevent an unappealing soggy discoloured mess.

The prevention of the browning is not necessarily an indication of effective antioxidant activity. Therefore if considering purely for this purpose the experiment doesn't really say that much about real antioxidant benefits, it says only that it can prevent an enzymatic process not relevant to protecting human skin where a different oxidative stress test would be more relevant.

It also does not take into consideration the highly effective antioxidant ability of any liposoluble ingredient such as Ascorbyl Tetraisopalmitate, as the apple tissue is water based so therefore a water based ingredient would penetrate where the potency of serum for skincare will depend on how the human skin processes it and skin being composed entirely differently to the flesh of an apple.

It is important also to consider in brief the different forms of ascorbic acid I selected for my experiment and that are also widely used in skincare. Their structure, how they are created to enhance penetration, for stability, compatibility with other ingredients, long term performance within a formulation. In simplified terms each is ascorbic acid, restructured or engineered for enhanced performance and various applications to then turn into active free form when applied to the skin and each with a different process for doing so.

You have very different considerations for performance of Vitamin C as an ingredient in skin care compared to when placed on cut fruit. A cut apple does not have the ability of the human to auto regenerate or to produce certain vital cellular responses and benefit from the numerous positive benefits ascorbic acid provides as an ingredient for healthy skin function.

L-ascorbic Acid; Hydrosoluble pH 2.0 - 2.2 Molecular weight 182.08 Base form of ingredient without encapsulation. L-ascorbic acid is difficult to formulate with as not only is it highly unstable with a required low pH not particularly practical for many skin care applications but it oxidates faster. Its small molecular size is also aggressive, therefore considering also that fast absorption in skincare, this is not always the ideal, rather for skin a slower release and improved compatability with certain ingredients to obtain a positive function is desired rather than inflammation and reaction that you don't have to consider with apple flesh.

When applied directly the the apple it successfully prevents the enzymatic process, it is visibly superior as an ingredient for this purpose, as as acid pH this would explain it's efficiency.

Ascorbyl Glucoside; Hydrosoluble pH 2.5 Molecular weight 338.26 The molecule is linked with glucose creating a stable time released form of ascorbic acid. It maintains stability in a fairly wide range of pH and is highly tolerable. When applied it is broken down slowly releasing active ascorbic acid.

In this test it offered same ability to prevent the oxidase as L-Ascorbic Acid. As as acid pH this would explain it's efficiency.

Sodium Ascorbyl Phosphate; Hydrosoluble pH 9.0 - 10.0 Molecular weight 322.05 The molecule is salified and a phosphate group replaced in the cyclic ring, it is a stable and bioavailable form of vitamin C, easily inserted in cosmetic formulations. Sodium Ascorbyl Phosphate is enzymatically broken down on the skin and releases active ascorbic acid.

In this test it offered poor ability to prevent the polyphenol oxidase, as expected given its alkalinity.

Ascorbyl Tetraisopalmitate; Liposoluble pH - Molecular weight 1129.8 The molecule is esterified, rendering it oil soluble like with ascorbyl palmitate, but a step further in providing enhanced permeation and superior stability than it's water soluble cousins. It does not offer anrioxidant activity until the isopalmitate moieties are broken down after application and interaction with human skin releases active ascorbic acid.

Considering skin permeation and effectiveness, its lipid function is key to understanding how it is a superior form and highly stable in terms of a skincare ingredient.

In this test, that focuses on enymatic polyphenol oxidase on a water based subject, it obviously offers little benefit for preventing that visible browning due to its liposolubility.

Yet is no indication of its effectiveness as an antioxidant ingredient due to proven ability to prevent lipid peroxidation.

In conclusion I can fully understand how this DIY test could be considered a useful tool for marketing purposes by some, but it really in my opinion cannot seriously be used to demonstrate scientifically the effectiveness of a skincare product containing Vitamin C for its antioxidant ability.

Personally even if I selected a single product with a low pH containing one or even multiple forms of Vitamin C ingredients I would feel it could be inaccurate for me to use this experiment to seriously demonstrate its relative effectiveness for skin antioxidant benefits.

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