To The Question On The Formation Possibility Of Some “Adducts” Of Ñ60 With Faty Acids During C60 Dissolution In Olive Oils.
September 27, 2012 DeadMeat make post #68 on http://www.longecity...post__p__537336, in which he cited the work of Franco Cataldo. Solubility of Fullerenes in Fatty Acids Esters: A New Way to Deliver In Vivo Fullerenes. Theoretical Calculations and Experimental Results. Chapter 13 in "Medicinal Chemistry and Pharmacological Potential of Fullerenes and Carbon Nanotubes Carbon Materials: Chemistry and Physics", 1, 2008, 317-335. http://dx.doi.org/10...-4020-6845-4_13 .
The full text of this article could have been found also some time ago on: http://www.owndoc.co...enes-in-oil.pdf (from the beginning 2013 Ukrainian internet-servers have ceased to see the site of Vaughter Wellness. It is interesting, why?)
In this article, on page 331-332, the spectra of C60 solutions in oils are shown and, particularly, it is stated that:
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"…The new absorption band at 435 nm in the C60 spectrum has been attributed to the 1,2 addition to the fullerene cage to the fatty acid chains either across to the double bonds by a Diels-Alder addition or, more simply, by radical addition (Cataldo and Braun, 2007). Thus, fatty acid esters are able to not only dissolve C60, but also react with this molecule causing the addition of the fatty chain to the fullerene cage. In fact, the bands at 435 nm shown in Fig. 13.3 appear only when C60 is stirred at 75°C for a couple of hours in the esters of fatty acids. Only for olive oil the new band appears much weaker than in the other cases and displaced at 450 nm (Fig. 13.3B). Since this oil contains chlorophyll, the displacement may be probably due also to a charge–transfer interaction between C60 and chlorophyll or with other impurities.
On standing in air, at room temperature the C60 fullerene solutions in vegetable oils are not stable, but change their colour from violet to reddish. The electronic absorption spectra show a gradual increase in the absorption band in the visible initially in the range between 450 and 550 nm. Similar results are obtained both by heating the solutions in air or under nitrogen. In the latter case prolonged heating is needed to achieve the same results. Heating C60 solutions in linseed or other oils for 15 minutes at 150°C (in air) causes the entire spectrum of C60 in the visible to disappear completely as shown in Fig. 13.3F…”
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The same words and spectra (see Fig. A below) have been given in his earlier work (e.g. Fig. 13.3F = Figure 1F in F. Cataldo and T. Braun (2007), 'The Solubility of C60 Fullerene in Long Chain Fatty Acids Esters', Fullerenes, Nanotubes and Carbon Nanostructures, 15:5 331-339, http://dx.doi.org/10...63830701512450.
For comparison, I give below the Ñ60 spectra (Fig B, from the article of Nobel Prize winner H. Kroto, who discovered fullerenes), showing that in the range between 450 and 550 nm the characteristics of C60 spectra in hexane are similar to the spectra indicated by F. Cataldo.
Such spectra characteristics are related to the low-intensity absorption bands so called forbidden electron transitions in the symmetric molecule Ñ60. As soon as Ñ60 molecule forms either donor-acceptor complexes (e.g., see below spectrum of C60HyFn, Fig. C), or forms mono-, bi-, tris-, etc. adducts with other molecules, these peculiarities immediately disappear in the absorption bands as a result of the symmetry breaking of electronic oscillations in pristine C60 molecule.
Note that known to me Ñ60 solutions in ÎÎ, that were prepared within some weeks, have peculiarities of the C60 electronic spectrum (in the range of 420 and 650 nm) are completely similar to the spectrum of Ñ60 solutions in ‘lipid-like’ hexane (like in Kroto’s work, see Fig. B).
And what is very important is that the growth of the intensity of these absorption bands was directly proportional to the portion of dissolved C60!
From all above mentioned information, the conclusion is that the solubility of C60 in OO is not a result of formation of some C60 “adducts” with unsaturated fatty acids of triglycerides of ÎÎ.
However, we shall return to the article of Cataldo et al (2008), where, for some obscure reason, he decided not to mention interesting facts about date of FT-I(nfra)-R(ed) spectroscopy of solutions of Ñ60 in oils and of which he informed in his article for 2007. There it has been told:
"…We have run another experiment under more drastic conditions: heating linseed or other oils for 15 minutes at 150° C (in air). Under these circumstances, the entire spectrum of C60 in the visible disappears completely as shown in Figure 1F, suggesting a more complex reaction between C60 and fatty acids. Unfortunately, the FT-IR spectroscopy made on these samples was not sensitive enough to give us any further indications about the reaction of C60 with the solvent medium"…
What could that mean?
Trying to understand the causes of dissolution of Ñ60 in ÎÎ, Cataldo et al (2007) were surprised by negative results of FT-IR analysis (besides, it is a very sensitive analytical method), when they could not find any products of chemical interaction of C60. Nevertheless, they resolved to assume that one of the causes of dissolution is Diels–Alder reaction C60 with unsaturated fatty acids.
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OK! Lets see on Wikipedia:
"The Diels–Alder reaction is an organic chemical reaction (specifically, a cycloaddition) between a conjugated (1,3-)diene and a substituted alkene, commonly termed the dienophile, to form a substituted cyclohexene system".
Conjugated 1,3-dienes has common formula R1--CH=CH--CH=CH--R2.
It is important that in many known Diels–Alder reactions C60 acts as dienophile and does not exhibit characteristics of conjugated 1,3-diene.
In our case and according to the mechanism of Diels–Alder reaction, in order that adducts of Ñ60 with unsaturated fatty acids of olive oil could be produced, these fatty acids must have --CH=CH--CH=CH—fragments in their chemical structure.
Polyunsaturated fatty acids with such structures are not found in the olive oil and even if available in it than they are in negligibly small quantity.
On the other hand, the work of Cataldo states that polyunsaturated fatty acids with such fragments can be produced under the influence of thermal oxidation and oxidative (radical) polymerization, as it was found with linolenic and linoleic acids. Such processes require quite a significant heating (e.g. much more then 75° C) of fatty acids at presence of atmospheric oxygen (for comparison, see, e.g. http://dx.doi.org/10...ett.2013.02.035 !!!).
Similar heat treatment, as we know and understand, shall not be applied when preparing C60_EVOO!
Taking into account all the above mentioned we can draw conclusion that there are no strong scientific evidences allowing to state that, when preparing C60_OO, some covalent adducts of C60 with natural fatty acids are produced in it. Moreover, there are no reasons to claim that in C60_OO the whole C60 is available in the form of similar adducts.
That is why the statement that bioactivity of C60_OO is stipulated by adducts of C60 with natural (unoxidized) unsaturated fatty acids is incorrect and hasty!
In such case, what is an alternative for C60 “adducts” to explain bioactivity of C60_EVOO?
For that purpose we shall consider the problem of solubilization of C60 in water through ionic and nonionic detergents (SDS, CTA, Tween-s, Triton-s, PVP, etc). There are enough facts for discussing of such problem in the scientific literature. In this case, to please for seeming and “standard” highly hydrophobic properties of Ñ60, it is considered that the solubilization of Ñ60 itself takes place due to hydrophobic interactions of Ñ60 with hydrophobic “tails” of such detergents.
But what is actually observed in such cases?
At the first stage of solubilization, and due to hydrophobic interactions with lipid-like chains of oils, really the systems get magenta shades (typical color for solutions of Ñ60 in hydrophobic solvents such as hexane, toluene and similar ones).
However, later the color of such systems (solutions) changes to reddish-brown and their absorption spectra become quite like spectra of C60HyFn solutions. Why? And here the issue is not about the oxidation processes or detergents (their lipidic components), or Ñ60 itself.
The cause of color change is in the solution structure transformation so that it becomes more advantageous for Ñ60 molecules to “adapt” in the solution and to create a stable system not due to their interaction with hydrophobic lipid-like chains, but due to donor-acceptor (charge transfer) interactions with polar groups of detergents.
In case of OO, such donor-acceptor interactions establish between Ñ60 and carboxyl [Ri--C(=O)O--Rj] groups of triglycerides of fatty acids with creation of weak donor-acceptor complexes Ñ60 with their polar –C(=O)O- fragments.
Such transformations cause appearance and increase in reddish-brown color during Ñ60 dissolution in ÎÎ.
In other words, upon dissolving Ñ60 in ÎÎ, in oily solution we have a great number of polarized donor-acceptor complexes with chlorophylls, and with polyphenols, and with triglycerides, and with other molecules which can contain in various sorts of ÎÎ.
Such donor-acceptor complexes can interact with water, hydrolyze and, later, facilitate of Hydrated Fullerenes formation (http://www.longecity...hyfn-formation/)!
And as we know, it is enough to have very small (“homeopathic”) doses and concentrations of Hydrated Fullerenes in order to the biological effects, much like those that were already found by Big Rats in their experiments with C60_EVOO, become apparent (were visualised).
Conclusion:
Till now there are no strict scientific proofs, what is actually the active principle in C60_OO which causes some positive biological effects of C60_OO which, however, in many respects coincide with that can do C60HyFn and its water solutions.
Attached Files
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Fig.A - Fig.1F (Cataldo, 2007) or Fig.13 (Cataldo, 2008).jpg 36.37KB
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Fig.B - Title and C60 and C70 Spectra in hexane and benzene (H.jpg 132.66KB
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Fig.C - Typical Spectrum of C60FWS (water solutions of C60HyFn).png 4.52KB
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This message about C60 and fatty acid in the form of formated pdf-files.pdf 104.87KB
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Edited by GVA, 29 March 2013 - 08:29 PM.
