Ethyl acetate partition obtained from the methanol extract of Muntingia calabura leaf exerts effective in vitro antiproliferative activity against the HT-29 colon cancer

Methanol extract of Muntingia calabura L. leaf (MEMCL) has been shown to exert the antiproliferative activity against the HT-29 (human colon adenocarcinoma) cell line. To further investigate on the medicinal potential of this plant, MEMCL was sequentially partitioned to obtain the petroleum ether, ethyl acetate and aqueous partitions, which was then tested against the HT-29 cell line and also subjected to the in vitro anti-inflammatory study. The most effective partition was also subjected to the phytoconstituents analysis using the UHPLC-ESI-MS. Findings showed that the ethyl acetate partition (EAP) exerts the most effective antiproliferative activity (IC50 = 58.0 ± 12.9 µg/mL) without affecting the 3T3 normal fibroblast cells, exhibits the highest anti-inflammatory effect when assessed using the lipoxygenase (> 95%) and xanthine oxidase (> 70%) assays, and contained various types of polyphenolics. In conclusion, M. calabura exerts apoptotic-mediated antiproliferative activity, partly via the anti-inflammatory action and synergistic action between the polyphenolics

Possible mechanisms of antinociception of methanol extract of Melastoma malabathricum leaves

Melastoma malabathricum L., Melastomaceae, has been traditionally used to relieve diverse pain-related ailments. The objectives of the present study were to determine the antinociceptive activity of methanol extract of M. malabathricum leaves and to elucidate the possible mechanisms of antinociception involved using various rats’ models. The extract (100, 250, and 500 mg/kg) was administered orally 60 min prior to subjection to the respective test. The in vivo acetic acid-induced abdominal constriction, formalin-induced paw licking, and hot plate tests were used as the models of nociception to evaluate the extract antinociceptive activity. Further studies were carried out to determine the role of opioid and vanilloid receptors, glutamate system and nitric oxide/cyclic guanosine phosphate (NO/cGMP) pathway in modulating the extract antinociceptive activity. From the results obtained, M. malabathricum exhibited significant (p < 0.05) antinociceptive activity in all the chemical- and thermal-induced nociception models. Naloxone (5 mg/kg), a non-selective opioid antagonist, failed to significantly affect the antinociceptive activity of MEMM when assessed using the abdominal constriction-, hot plate- and formalin-induced paw licking-test. M. malabathricum also significantly (p < 0.05) reversed the nociceptive response in capsaicin- and glutamate-induced paw licking test. Furthermore, only l-arginine (a nitric oxide precursor) alone, but not, NG-nitro-l-arginine methyl esters (l-NAME; an inhibitor of NO synthase), methylene blue (MB; an inhibitor of cGMP), or their combination thereof, significantly (p < 0.05) block the antinociceptive activity of M. malabathricum. In conclusion, M. malabathricum exerted a non-opioid antinociceptive activity at the central and peripheral levels partly via the inhibition of vanilloid receptors and glutamatergic system, and activation of the NO-mediated/cGMP-independent pathway. Keywords: Melastomaceae, Herbal, Pain-killing, Natural products, Drug discover