▁in ▁o ak ▁and ▁ch est nut ▁wood ▁and ▁in ▁the ▁stem ▁b arks ▁of ▁An oge iss us ▁lei oc arp us ▁and ▁Terminal ia ▁av ic en no ides . ▁ ▁Cast al agin ▁is ▁the ▁( 3 3 beta )- is omer ▁of ▁ves cal agin . ▁During ▁ag ing ▁of ▁alco h ols ▁in ▁o ak ▁bar rel s , ▁ves cal agin ▁can ▁be ▁extracted ▁from ▁the ▁wood ▁and ▁can ▁subsequently ▁be ▁transformed ▁into ▁new ▁derivatives ▁by ▁chemical ▁re actions . ▁V es cal agin ▁is ▁one ▁of ▁the ▁most ▁abund ant ▁ell agit ann ins ▁extracted ▁from ▁o ak ▁wood ▁using ▁white ▁wine . ▁ ▁Der iv atives ▁ ▁The ▁flav ono - ell agit ann in ▁known ▁as ▁ac ut iss imin ▁A ▁is ▁created ▁when ▁the ▁o ak ▁t ann in ▁ves cal agin ▁interact s ▁with ▁a ▁flav ono id ▁in ▁wine . ▁ ▁B ios yn thesis ▁ ▁In ▁some ▁plants ▁including ▁o ak ▁and ▁ch est nut , ▁the ▁ell agit ann ins ▁are ▁formed ▁from ▁ 1 , 2 , 3 , 4 , 6 - pent ag al loy l - gl uc ose ▁and ▁further ▁elabor ated ▁via ▁ox id ative ▁de h ydro gen ation ▁( t ell im ag rand in ▁II ▁and ▁cas u ar ict in ▁form ations ). ▁After ▁conversion ▁of ▁cas u ar ict in ▁to ▁ped un cul agin , ▁the ▁py ran ose ▁ring ▁of ▁the ▁gl uc ose ▁opens ▁and