Evaluation of antinociceptive activity of methanolic extract of leaves of Stephania japonica Linn.

ETHNAPHARMACOLOGICAL RELEVANCE: Stephania japonica is a common plant, widely distributed in all over Bangladesh. Traditionally, this plant is considered as one of the important ingredients in treatment of a variety of ailments including inflammation, pain, rheumatism, cancer, bone fracture, fever etc. However, the scientific reports regarding the antinociceptive effect of this plant are very limited. This study evaluated the antinociceptive effect of methanolic extract of S. japonica (MESJ) leaves. MATERIALS AND METHODS: The antinociceptive effect of MESJ was investigated using both heat- and chemical-induced nociceptive models such as hot plate, tail immersion, acetic acid-induced writhing, formalin and glutamate tests at the doses of 50, 100 and 200mg/kg. Morphine (5mg/kg) and diclofenac sodium (10mg/kg) were used as reference drugs in thermal and chemical models, respectively. Moreover, naloxone (2mg/kg) was used in the thermal models to justify the possible role of the opioid receptors. RESULTS: MESJ produced a significant and dose-dependent increase in the hot plate and tail immersion latencies which were reversed by the treatment with naloxone, suggests the possible involvement of opioid receptors in this activity. Moreover, MESJ inhibited acetic acid-induced writhing, formalin and glutamate-induced lickings in a dose-dependent manner. In parallel, the reference drugs also produced desired antinociceptive effects in this study. CONCLUSION: These results strongly support the antinociceptive activity of the leaves of Stephania japonica and rationalize the traditional use of the leaves in treatment of different painful conditions.

In vitro antioxidant and cholinesterase inhibitory activities of methanolic fruit extract of Phyllanthus acidus.

BACKGROUND: Alzheimer's disease (AD) is a progressive neurodegenerative disorder clinically characterized by loss of memory and cognition. Cholinergic deficit and oxidative stress have been implicated in the pathogenesis of AD. Therefore, inhibition of acetylcholinesterase and oxidation are the two promising strategies in the development of drug for AD. Phyllanthus acidus, belonging to the family Euphorbiaceae, is a tree and has been used in traditional medicine to treat several pain, inflammatory and oxidative stress related disorders such as rheumatism, bronchitis, asthma, respiratory disorder, also important to promote intellect and enhance memory, thus supporting its possible anti-Alzheimer's properties. In this study, P. acidus was evaluated for its cholinesterase inhibitory and antioxidant activities. METHODS: In this study, we evaluated the antioxidant potential and neuroprotective activity of P. acidus by assessing total phenol content (FCR assay), total flavonoid content, total antioxidant capacity, Fe (3+) reducing power capacity, DPPH (2, 2-diphenyl-1-picrylhydrazyl) and hydroxyl radical scavenging capacity, lipid peroxidation inhibition activity & metal chelating activity. In addition acetylcholinestrase (AChE) and butyrylcholinestrase (BChE) inhibitory activities were performed using Ellman's method. RESULTS: Total phenolic content and total flavonoid content of the extract were 116.98 mg of gallic acid equivalent and 168.24 mg of quercetin equivalent per gm of dried extract. The methanolic extract of P. acidus (MEPA) showed considerable total antioxidant activity and reducing capacity. In DPPH scavenging assay and hydroxyl radical scavenging assay, the MEPA showed 84.33 % and 77.21 % scavenging having IC50 of 15.62 and 59.74 µg/ml respectively. In lipid peroxidation inhibition activity MEPA showed moderate inhibition of peroxidation at all concentrations with IC50 value of 471.63 µg/ml and exhibited metal chelating activity with IC50 value 308.67 µg/ml. The MEPA exhibited inhibition of rat brain acetylcholinesterase and human blood butyrylcholinesterase in a dose dependent manner and the IC50 value was found to be 1009.87 µg/ml and 449.51 µg/ml respectively. CONCLUSION: These results of the present study reveal that MEPA has considerable amount of antioxidant activity as well as anti-acetylcholinesterase and anti-butyrylcholinesterase activity which suggest its effectiveness against Alzheimer's disease and other neurodegenerative disorders.