Biotransformation of erythrodiol for new food supplements with anti-inflammatory properties.

Erythrodiol, a typical pentacyclic triterpenic diol in olive oil and its byproduct, olive pomace, frequently appears in food additives for the prevention of cardiovascular disease because of its antioxidation, anti-inflammatory and antitumor activities. To develop new derivatives of erythrodiol (1), preparative biotransformations were investigated through Streptomyces griseus ATCC 13273, Penicilium griseofulvum CICC 40293, Bacillus subtilis ATCC 6633, and ten new (1a-1j) and one known metabolites were isolated. Their structures were elucidated by HR-ESI-MS and 1D and 2D NMR spectroscopy. Furthermore, relative to 1, most metabolites exhibited lower toxicity and more potent inhibitory activities against nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. In particular, the glycosylated metabolite 1k showed a dramatically increased inhibitory effect with an IC50 value of 2.40 μM, which is even lower than that of quercetin. Thus, biotransformation of erythrodiol is a viable strategy for discovering new triterpenes as food supplements with anti-inflammatory properties.