<prompt> Tocopherols are the derivatives ofIsoprenoid ringTocolSterolRibitol  <response>: Active vitamine E was isolated from wheat germ oil and named tocopherolA chromane ringtocol system with an isoprenoid side chain is present in all naturally occurring tocopherols.Vitamine K is naphthoquinone derivative with a long isoprenoid side chain.Reference: DM Vasudevan biochemistry page no: 460 