MATLAB: Find matches without repetition from two cell arrays + extra condition

cell arraysfind patternsMATLAB

Hello,
In order to reduce the size of a matrix I need to find all the elements of the periodic table (patterns – cell 1) of all the species considered (cell 2). Also, it has to take in account every number as the end of the evaluable pattern.
Example:
Elements = {'H', 'He', 'Li', .... };
NameSpecies = {'H2','O2','H2O2','CH2OH','C'};
Desired_Result = {'H','O','C'};
At the moment I'm using this piece of code that I found on the net 
Match=cellfun(@(x) ismember(x,NameSpecies), Elements, 'UniformOutput', 0);
Elements = Elements(cell2mat(Match));
but this function is only going to give me the same individuals elements, in the case of the example the result is
Result = {'C'};
Any suggestion to tackle it without brute force?
Thanks for your time!

Best Answer

You don't even need the period table, assuming element start with an Uppercase eventually followed by lower-case
NameSpecies = {'He','O2','H2O2','CH2OH','C'};
Tmp = cell(size(NameSpecies));
for k = 1:length(Tmp)
    Specie = NameSpecies{k}; 
    Specie(Specie>='0' & Specie<='9') = ' ';
    idx = find([(Specie>='A' & Specie<='Z'), true]);
    lgt = diff(idx);
    Tmp{k} = strtrim(mat2cell(Specie, 1, lgt));
end
El = unique(cat(2,Tmp{:}))
The result is:
El =
  1×4 cell array
    {'C'}    {'H'}    {'He'}    {'O'}
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