Журнал биомолекулярных исследований и терапии

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Three - (-) Catechin-O-Rhamnosides from the Eastern Nigeria Mistletoe with Potent Immunostimulatory and Antioxidant Activities

Omeje Edwin Ogechukwu, Osadebe Patience Ogoamaka, Akira Kawamura, Amal Hassan, Abdessamad Debbab, Esimone Charles Okechukwu, Nworu Chukwuemeka Sylvester, Nwodo Ngozi and Proksch Peter

In an attempt to provide further convincing evidence for the variously reported immunomodulatory potentials of mistletoes, bioassay-guided fractionation of the eastern Nigeria mistletoe afforded three compounds: - (-) catechin- 7-O-rhamnoside (1), - (-) catechin-3-O- rhamnoside (2) and a 4′-methoxy-7-O-rhamnoside (3). Their effects on C57BL6 mice splenocytes proliferation and expression of CD69 molecule were determined using flow cytometry techniques and compared to Lipopolysaccharide (LPS; 10 μg/ml) and Concanavalin A (ConA; 2 μg/ml) as standards. The antioxidant study was by the DPPH model with ascorbic acid as standard. The compounds (1-3) at 100 μg/ml showed statistically significant (p<0.05) stimulatory activity with values of 91.49 ± 0.22%, 95.17 ± 0.01% and 94.23 ± 0.07% respectively compared to 2.65 ± 0.33% for the unstimulated control. However, the CD69 expression assay showed only moderate stimulation. Their measured antioxidant potentials (effective concentration; EC50) were high (≤ 55.42 ± 0.99 mg/ml) when compared to ascorbic acid (17.6 ± 1.78 mg/ml). Characterization of the compounds was achieved by chromatographic and spectroscopic methods.