Marantodes pumilum (Primulaceae) has been used in Malaysian
folk medicine to help women regain strength after delivery and for "sickness in the bones." It was previously revealed that its extracts inhibited
xanthine oxidase (XO) activity in vitro. The leaves and roots of M. pumilum var. alata (MPA), var. pumila (MPP), and var. lanceolata (MPL) were individually extracted in
ethanol (80%). The anti-hyperuricemic activity was initially assessed by XO inhibition with a spectrophotometric in vitro assay. The most active extract was further investigated on hyperuricemic rat model induced by
potassium oxonate to determine serum
uric acid levels and liver XO effect. The in vitro anti-inflammatory activity was carried out on
monosodium urate (MSU) crystal-induced pro-inflammatory
cytokines (i.e.,
interleukin (IL)1α, IL-1β, IL-6, IL-8, and
tumor necrosis factor (TNF)-α) secretion using human peripheral blood mononuclear cells and ELISA technique, and
prostaglandin E2 (
PGE2)secretion using radioimmunoassay. The active extract was then investigated on
gout-induced
inflammation with MSU crystals to determine pro-inflammatory
cytokines and
PGE2 secretion levels in the synovial fluid of rat knee joint. Quantitative analysis using validated HPLC was performed on the extracts to determine presence of bioactive
flavonoids. The findings revealed that extract of MPP leaves gave the highest inhibitory activity on XO (IC50 130.5 μg/mL) compared to other extracts tested. However, all extracts possessed significantly lower activity compared to
allopurinol (IC50 0.13 μg/mL).
Oral administration of MPP leaf extract (200 mg/kg) significantly reduced serum
uric acid level in hyperuricemic rats in time-dependent manner to the baseline level and it was as effective as
allopurinol (5 mg/kg). The extract also inhibited liver XO activity (25%) compared to
allopurinol (45%). In vitro anti-inflammatory assay showed that extract of MPP roots inhibited MSU crystals-induced secretion of IL-1α, IL-1β,
IL-8, TNF-α, and
PGE2 with IC50 values of 36, 25, 38, 18, and 46 μg/mL, respectively.
Oral administration of the MPP root extract (200 mg/kg) significantly decreased IL-1α, IL-1β,
IL-6, TNF-α, and
PGE2 levels in rat's synovial fluid as effective as
indomethacin. There were no significant
body weight changes of all experimental animals. MPP extracts showed presence of
myricetin,
quercetin and
kaempferol.
Myricetin was detected with values of 0.2 and 0.6 mg/g for root and leaf extracts, respectively. The anti-hyperuricemic of MPP leaf and anti-inflammatory of MPP root indicated that MPP may be promising for complementary
therapy of
gout.