No abstract

The MEMC exerted gastroprotective effect via several mechanisms including the anti-secretory, antioxidant and anti-inflammatory activities. These activities could be attributed to the presence of tannins, saponins and flavonoids (e.g. rutin, quercitrin, fisetin and dihydroquercetin).

Muntingia calabura L. (family Elaeocarpaceae) has been traditionally used to relieve various pain-related ailments. The present study aimed to determine the antinociceptive activity of methanol extract of M. calabura leaves (MEMC) and to elucidate the possible mechanism of antinociception involved. The in vivo chemicals (acetic acid-induced abdominal constriction and formalin-, capsaicin-, glutamate-, serotonin-induced paw licking test) and thermal (hot plate test) models of nociception were used to evaluate the extract antinociceptive activity. The extract (100, 250, and 500 mg/kg) was administered orally 60 min prior to subjection to the respective test. The results obtained demonstrated that MEMC produced significant (P < 0.05) antinociceptive response in all the chemical- and thermal-induced nociception models, which was reversed after pretreatment with 5 mg/kg naloxone, a non-selective opioid antagonist. Furthermore, pretreatment with L-arginine (a nitric oxide (NO) donor), NG-nitro-L-arginine methyl esters (L-NAME; an inhibitor of NO synthase (NOS)), methylene blue (MB; an inhibitor of cyclic-guanosine monophosphate (cGMP) pathway), or their combination also caused significant (P < 0.05) change in the intensity of the MEMC antinociception. In conclusion, the MEMC antinociceptive activity involves activation of the peripheral and central mechanisms, and modulation via, partly, the opioid receptors and NO/cGMP pathway.

BackgroundMelastoma malabathricum L. (Melastomaceae) is a small shrub with various medicinal uses. The present study was carried out to determine the gastroprotective mechanisms of methanol extract of M. malabathricum leaves (MEMM) in rats.MethodsThe extract's mechanisms of gastroprotection (50, 250, 500 mg/kg) were studied using the pylorus-ligation in rat model wherein volume, pH, free and total acidity of gastric juice, and gastric wall mucus content were determined. The involvement of endogenous nitric oxide (NO) and sulfhydryl (SH) compounds in the gastroprotective effect of MEMM were also measured. MEMM was subjected to the antioxidant, anti-inflammatory and phytochemical analysis and HPLC profiling.ResultsMEMM contained various phyto-constituents with quercitrin being identified as part of them. MEMM and quercitrin: i) significantly (p < 0.05) reduced the volume and acidity of gastric juice while increasing the pH and gastric wall mucus content.; ii) significantly (p < 0.05) increased the level of SOD, GTP and GTR while significantly (p < 0.05) reduced the level of CAT, MPO and TBARS activities.; iii) exerted gastroprotective activity when assessed using the ethanol-induced gastric ulcer assay, which was reversed by NG-nitro-l-arginine methyl esters (L-NAME; an inhibitor of NO synthase) and N-ethylmaleimide (NEM; a sulfhydryl (SH) blocker). MEMM inhibited the lipoxygenase (LOX) and xanthine oxidase (XO) activities with the highest affinity for the former while quercitrin showed high affinity for XO activity.ConclusionsMEMM exhibited a gastroprotective activity due partly to the presence of quercitrin, its antioxidant and anti-inflammatory activities, and via the modulation of NO and SH groups.

Background: Muntingia calabura L. (family Muntingiaceae), commonly known as Jamaican cherry or kerukup siam in Malaysia, is used traditionally to treat various ailments. The aim of this study is to elucidate the possible underlying gastroprotective mechanisms of ethyl acetate fraction (EAF) of Muntingia calabura methanolic leaves extract (MEMC).