Hunteriasines A - D, tryptamine-derived alkaloids from Hunteria umbellata.

Four undescribed tryptamine-derived alkaloids, hunteriasines A - D, were isolated and identified from Hunteria umbellata (Apocynaceae), together with fifteen known indole alkaloids. The chemical structure and absolute configuration of hunteriasine A were determined by spectroscopic and X-ray crystallographic data analyses. Hunteriasine A, featuring with a unique scaffold comprised of tryptamine and an unprecedented "12-carbon unit" moiety, is a zwitterionic indole-derived and pyridinium-containing alkaloid. Hunteriasines B - D were identified by spectroscopic data analyses and theoretical calculations. A plausible biogenetic pathway for hunteriasines A and B was proposed. The lipopolysaccharide-stimulated mouse macrophage cell line J774A.1 cell-based bioactivity assays revealed that (+)-eburnamine, strictosidinic acid, and (S)-decarbomethoxydihydrogambirtannine enhance the release of interleukin-1ß.

Antinociceptive and antioxidant activities of Hunteria umbellata stem bark: possible role of the serotonergic, opioidergic and dopaminergic pathways.

Background Hunteria umbellata (HU) (K. Schum) is used in ethnomedicine for the management of pain, diabetes mellitus and dysmenorrhoea. This study evaluated the analgesic and antioxidant activities of aqueous extract of HU stem bark and the possible mechanism(s) of action. Methods The antinociceptive effect of HU was evaluated using acetic acid mouse writhing, tail flick, hot plate and formalin-induced paw licking models. To establish the possible mechanism(s) of action of HU, separate group of animals were pretreated with naloxone (1 mg/kg, i.p.), atropine (1 mg/kg, i.p.), haloperidol (0.1 mg/kg, i.p.), ondansetron (1 mg/kg, i.p.) and phenoxybenzamine (0.1 mg/kg, i.p.), 15 min before HU. The in vivo and in vitro antioxidant potential was evaluated using established methods. Results The extract at 150 and 300 mg/kg, significantly (p<0.05) reduced the number of writhes and paw licking times and increased pain threshold in writhing assay, paw licking and hotplate tests respectively. Pretreatment of animals with ondansetron, naloxone and haloperidol, significantly (p<0.05 and p<0.01) attenuated the analgesic activity of HU. The extract demonstrated significant (p<0.05) radical scavenging activity (IC50 0.39 µg/mL), with high phenol content and reducing property. The total phenol content was 124.19 per gram of gallic acid. In vivo antioxidant assay showed significant (p<0.05) increase in catalase and superoxide levels. Conclusions Results obtained in this study suggest the involvement of serotonergic, opioidergic and dopaminergic pathways in the analgesic effect of HU stem bark, in addition to its potent antioxidant potential.

Sub-acute Toxicity of Aqueous Fruit Pulp Extract of Hunteria umbellata in Albino Wistar Rats.

Hunteria umbellata K. Schum (Apocynaceae) is used in herbal medicine for the treatment of diabetes, peptic ulcers, piles, yaws, dysmenorrhea, fevers, infertility, and helminthic infections. The present study investigated the in vivo sub-acute toxicity of the aqueous fruit pulp extract of Hunteria umbellata (H. umbellata). Sub-acute toxicity was evaluated after administering daily oral doses of 200, 400 and 800 mg/kg of H. umbellata extract, for 28 days to the rats. Anthropometric, biochemical, hematological and histopathological parameters were assessed using standard procedures. There were significant reductions (p<0.01) in the pattern of weight gain in 200 and 400 mg/kg H. umbellata -treated rats but no significant differences in the organ weight index between control and treated animals. Hematological and biochemical analysis showed no marked differences in any of the parameters examined in either the control or treated groups but there was significant (p<0.05) thrombocytosis. Pathologically, neither gross abnormalities nor histopathological changes were observed. H. umbellata led to activation of the reticulo endothelial tissue of the spleen as evidenced by proliferation of the sinus histocytes and activation of the lymphoid aggregates in the lungs, indicating activation of the local immune system of the lungs. H. umbellata fruit pulp is relatively nontoxic in animals but there is increased tendency to cause thrombocytosis on prolonged use.

Anti-inflammatory activity of aqueous fruit pulp extract of Hunteria umbellata K. Schum in acute and chronic inflammation.

The anti-inflammatory effect of the aqueous fruit pulp extract of Hunteria umbellata K. Schum (Apocynaceae) was evaluated using the carrageenan- and dextran-induced rat paw edema, xylene-induced ear edema and formalin-induced arthritis inflammation tests. Oral administration of the extract produced significant (p < 0.05) antiedematogenic effect with a dose of 500 mg/kg throughout the period of the experiment in the dextran induced paw edema and at the 3 h in the carrageenan model. The extract (250 and 500 mg/kg) exhibited a dose-related and significant (p < 0.01) inhibition of xylene induced ear edema and the effect was similar to that produced by dexamethasone (1 mg/kg). In the chronic inflammation (formalin induced arthritis) the extract did not show any significant anti-inflammatory activity. Oral acute toxicity assays did not show any mortality at 15 g/kg of the plant extract. The results indicate that the aqueous extract of H. umbellata possesses acute inflammatory activity which may be mediated by either inhibition or by blocking the release of prostaglandins and histamine, thus supporting the usage of the plant in traditional medicine treatment of inflammation.