Feruloylmonotropeins: promising natural antioxidants in Paederia scandens

Paederia scandens (Lour.) is a widely used medicinal herb in Vietnam, China, India, and Japan for the treatment of a variety of conditions, including toothache, chest pains, piles, and spleen inflammation. There is broad interest in identifying the composition of its extracts and confirming their numerous biological activities, including anti-nociceptive, antiviral, and anticancer properties. Two iridoid glucosides obtained from the MeOH extract of P. scandens, 6'-O-E-feruloylmonotropein (6-FMT) and 10'-O-E-feruloylmonotropein (10-FMT), are potential antioxidants based on their structure. In this study, the hydroperoxyl scavenging activity of 6-FMT and 10-FMT was examined in silico by using density functional theory. These FMTs are predicted to be weak antioxidants in non-polar environments, whereas a good HOO scavenging activity is expected in polar environments (pH = 7.4) with k(overall) = 3.66 x 10(7) M-1 s(-1) and 9.45 x 10(6) M-1 s(-1), respectively. This activity is better than many common antioxidants such as trolox and nearly equivalent to ascorbic acid and resveratrol. The hydroperoxyl scavenging activity was exerted mainly by the di-anion form of FMTs in water at physiological pH following the single electron transfer mechanism. The results suggest that FMTs are promising natural antioxidants in aqueous physiological environments.

Automated summary

Paederia scandens is a widely used medicinal herb in Vietnam, China, India, and Japan for various conditions. Two iridoid glucosides obtained from P. scandens (6-FMT and 10-FMT) are potential antioxidants. In non-polar environments, these FMTs are predicted to be weak antioxidants, but they exhibit good HOO scavenging activity in polar environments.