METHOD: Dichloromethane, methanol, and water extracts of the leaves and roots of M. pumilum var. alata, M. pumilum var. pumila, and M. pumilum var. lanceolata were tested using an in vitro xanthine oxidase inhibitory assay. Bioassay-guided fractionation and isolation were carried out on the most active extract using chromatographic techniques. The structures of the isolated compounds were determined using spectroscopic techniques.

RESULTS: The most active dichloromethane extract of M. pumilum var. pumila leaves (IC50 = 161.6 μg/mL) yielded one new compound, 3,7-dihydroxy-5-methoxy-4,8-dimethyl-isocoumarin (1), and five known compounds, viz. ardisiaquinone A (2), maesanin (3), stigmasterol (4), tetracosane (5), and margaric acid (6). The new compound was found to be the most active xanthine oxidase inhibitor with an IC50 value of 0.66 ± 0.01 μg/mL, which was not significantly different (p > 0.05) from that of the positive control, allopurinol (IC50 = 0.24 ± 0.00 μg/mL).

PURPOSE: The present study investigated the effects of oral treatment with M. pumilum var. alata (MPA) extracts on the estrogen receptor, metabolic characteristics and insulin signaling pathway in pancreas and liver of ovariectomised nicotidamide streptozotocin-induced diabetes in female rats.

MATERIALS AND METHODS: Ovariectomised diabetic (OVXS) Sprague-Dawley rats were orally administered with either aqueous leaf extract and ethanol (50%) stem-root extract of MPA (50 or 100 mg/kg) respectively for 28 days. Metabolic parameters were evaluated by measuring fasting blood glucose, serum insulin, oral glucose and insulin tolerance test. Distribution and expression level of insulin, oxidative stress and inflammatory marker in the pancreatic islets and liver were evaluated by immunohistochemistry and western blot, respectively.

RESULTS: Oral treatment with aqueous leaf and ethanol (50%) stem-root extracts of MPA (100 mg/kg) significantly reversed the elevated fasting blood glucose, impaired glucose and insulin tolerance. The protein expression of insulin, glucose transporter (GLUT-2 and GLUT-4) increased in the pancreatic islets and liver. Furthermore, marked improvement in the tissue morphology following treatment with MPA was observed. Similarly, the western blots analysis denotes improved insulin signaling in the liver and decreased reactive oxygen species producing enzymes, inflammatory and pro-apoptotic molecules with MPA treatment.

Objective: To evaluate the inhibitory effects of three M. pumilum varieties on the secretion of lipopolysaccharide (LPS)- and monosodium urate crystal (MSU)-induced cytokines and plasma prostaglandin E2 (PGE2) in vitro.

Materials and Methods: The leaves and roots of M. pumilum var. alata (MPA), M. pumilum var. pumila (MPP), and M. pumilum var. lanceolata (MPL) were successively extracted with dichloromethane (DCM), methanol, and water. Human peripheral blood mononuclear cells and ELISA technique were used for the cytokine assay, whereas human plasma and radioimmunoassay technique were used in the PGE2 assay. Flavonoids content was determined using a reversed-phase high-performance liquid chromatography.

Results: DCM extract of MPL roots showed the highest inhibition of LPS-stimulated cytokine secretion with IC50 values of 29.87, 7.62, 5.84, 25.33, and 5.40 μg/mL for interleukin (IL)-1α, IL-1β, IL-6, IL-8, and tumor necrosis factor (TNF)-α, respectively; while that of plasma PGE2 secretion was given by DCM extract of MPP roots (IC50 31.10 μg/mL). Similarly, the DCM extract of MPL roots demonstrated the highest inhibition against MSU-stimulated IL-1α, IL-1β, IL-6, IL-8, TNF-α, and PGE2 secretion with IC50 values of 11.2, 8.92, 12.29, 49.51, 9.60, and 31.58 μg/mL, respectively. Apigenin in DCM extracts of MPL (0.051 mg/g) and MPP (0.064 mg/g) roots could be responsible for the strong inhibitory activity against IL-1β, IL-6, TNF-α, and PGE2.

Conclusion: The results suggested that DCM extracts of MPL and MPP roots are potential anti-inflammatory agents by inhibiting the secretion of LPS- and MSU-stimulated pro-inflammatory cytokines and PGE2.