Millettia aboensis ameliorates oxidative stress through synergic interaction of its active compounds.

Background M. aboensis has wide ethnopharmacological applications but very little has been done on the pharmacological basis for these indications. This study evaluated the antioxidant potentials of the leaf extracts of M. aboensis. Methods Total phenolic content of the extract and fractions was carried out using folin-ciocalteu method while in vivo site specific effect determined using carbon tetrachloride (CCl4)-induced liver oxidative damage. Chromatographic separations of the most active fraction led to the isolation of compounds 1 and 2 with their structures elucidated by a combination of 1D and 2D NMR and mass spectrometry. Inhibition of liver microsome lipid peroxidation was used to evaluate the antioxidant activities of these compounds while DPPH test was used to study their interaction. Results Ethyl acetate fraction had the highest phenolic content of 305.2 mgGAE/g with n-hexane fraction having the least (26.1 mgGAE/g). Structural elucidation revealed compound 1 as epicathechin-(2ß→O→7, 4ß→8)-cathechin and compound 2 as epicathechin-(2ß→O→7, 4ß→8)-epicathechin. Compounds 1 & 2 inhibited liver microsome lipid peroxidation with EC50 of 46 and 55 µg/mL respectively. Combination of the compounds produced synergic inhibition of DPPH radical with EC50 of 7 µg/mL against 9 µg/mL produced by ascorbic acid. Conclusion M. aboensis expressed strong antioxidant property which may explain its diverse ethnopharmacological uses.

Upregulation of CD4+ T-Lymphocytes by Isomeric Mixture of Quercetin-3-O-Rutinoside and Quercetin-3-O-Robinobioside Isolated from Millettia aboensis.

BACKGROUND: Millettia aboensis (Hook. F.) Baker (Fabaceae) is popular in ethnomedicine for its acclaimed efficacy in a number of disease conditions. This study evaluated the immunomodulatory effect of the leaf extract as a possible mechanism of its ethnomedicinal uses. METHODS: Humoral and cellular immune responses of Balb/c mice to tetanus toxoid and cyclophosphamide, respectively, were used to monitor immunomodulatory activities of the ethanol leaf extract and fractions of M. aboensis at 200, 300 and 400 mg/kg. Active (butanol) fraction of the extract was subjected to chromatographic purifications to isolate the active compound and the structure elucidated by a combination of 1D and 2D NMR and mass spectrometry. Stimulation of specific T-lymphocytes using intracellular cytokine staining technique was used to evaluate immune-enhancing activity of the isolated compound. RESULTS: The extract and fractions evoked increase in both humoral and cellular immunity. At 400 mg/kg of butanol fraction, the normalized mean secondary production of IgG1 and IgG2a antibodies were 9.0 and 7.7, respectively. Serum cytokine production by butanol fraction following secondary challenge with tetanus toxoid showed that IL-12, IL-17A and IFN-γ were expressed by 48.14, 41.37 and 38.22%, respectively. Structural elucidation of the active compound revealed presence of isomeric mixtures of quercetin-3-O-rutinoside and quercetin-3-O-robinobioside (Compound 1a/b). Compound 1a/b exhibited in vitro upregulation of specific CD4+ T-lymphocytes that were largely IFNγ releasing with up to 43.7% stimulation at 6.25 µg/mL compared to the baseline effect in DMSO vehicle control group. CONCLUSION: M. aboensis expressed strong immune-enhancing properties, which may explain its ethnopharmacological use in disease management.

The Useful Medicinal Properties of the Root-Bark Extract of Alstonia boonei (Apocynaceae) May Be Connected to Antioxidant Activity.

Folkloric use of root-bark extract of Alstonia boonei in the treatment and management of many disease conditions may be associated with free radical scavenging as part of its mechanisms of action. We therefore evaluated the ability of different solvent fractions of the methanol extract, crude precipitate from the extract, and isolated compound from the crude precipitate for scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. Phytochemical analysis revealed the presence of useful phytocompounds. Ethyl acetate fraction showed better antioxidant activity with IC50 of 54.25 µ g/mL while acetone and methanol fractions have 121.79 and 141.67 µ g/mL, respectively. The crude precipitate and isolated compound showed IC50 values of 364.39 and 354.94 µ g/mL, respectively. The crude precipitate, fractions, and compound 1 showed antioxidant activity against DPPH radical although lower than that of ascorbic acid.