Prorobinetidin

Prorobinetidins are a type of condensed tannins formed from robinetinidol. They form robinetinidin when depolymerized under oxidative conditions.

Mimosa and quebracho tannins are, according to a comparative ¹³C NMR study of polyflavonoids, found to be predominantly profisetinidin/prorobinetidin-type tannins.^[1]

Stryphnodendron adstringens ( the barbatimão), a species of legume found in Brazil, produces prorobinetinidins in its stem bark. These are robinetinidol-(4β → 8)-epigallocatechin, robinetinidol-(4α → 8)-epigallocatechin, robinetinidol-(4β → 8)-epigallocatechin 3-O-gallate, robinetinidol-(4α → 8)-epigallocatechin 3-O-gallate, robinetinidol-(4α → 6)-gallocatechin and robinetinidol-(4α → 6)-epigallocatechin, in addition to the tentatively characterized, robinetinidol [4β → 6(8)]-gallocatechin and robinetinidol-(4α → 8)-gallocatechin.^[2][3]

References

1. Rahim, Afidah A; Rocca, Emmanuel; Steinmetz, Jean; Jain Kassim, M; Sani Ibrahim, M; Osman, Hasnah (2008). "Antioxidant activities of mangrove Rhizophora apiculata bark extracts". Food Chemistry. 107: 200–207. doi:10.1016/j.foodchem.2007.08.005.
2. Prorobinetinidins from Stryphnodendron adstringens. Palazzo de Mello J.; Petereit F.; Nahrstedt A., Phytochemistry, 1996.
3. Ishida, K; De Mello, J. C. P; Cortez, D. A. G; Filho, B. P. D; Ueda-Nakamura, T; Nakamura, C. V (2006). "Influence of tannins from Stryphnodendron adstringens on growth and virulence factors of Candida albicans". Journal of Antimicrobial Chemotherapy. 58 (5): 942–949. doi:10.1093/jac/dkl377. PMID 16973655.