The aim of this study was to investigate the antiinflammatory potential of an aqueous leaf extract (ALE) of Ixora coccinea (Rubiaceae) in rats after oral administration (500, 1000 and 1500 mg=kg). This was done using the carrageenan-induced paw edema (acute inflammatory model) and cotton pellet granuloma tests (chronic inflammatory model). In the former test, ALE significantly impaired both early and late phases of the inflammatory response and also the edema maintained between the two phases. In the latter test, it significantly suppressed granuloma formation (only highest dose tested). Collectively, these data show promising anti-inflammatory activity against both acute and chronic inflammation. ALE showed strong antihistamine and antioxidant activities that can account for its anti-inflammatory potential. In addition, inhibition of prostaglandins and bradykinins may play a role.

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In Sri Lankan traditional medicine, the endemic plant Vernonia zeylanica (L.) Less (Asteraceae) is recommended for the treatment of boils and bone fractures. A strong possibility thus exists that this plant could possess antinociceptive activity, but this has not been scientifically tested. The aim of this study was to investigate the antinociceptive potential of aqueous stem extract (ASE) of V. zeylanica in rats using two models of nociception (hot-plate and tail-flick tests) and different concentrations (750, 1500, and 2500 mg=kg, given orally). The results showed that ASE possessed marked and significant (p < 0.05) antinociceptive activity (in terms of prolongation of reaction time) when evaluated in the hotplate test but not in the tail-flick test. The antinociceptive action had rapid onset (within 1 h) and moderately long duration of activity (up to 3 h), but was 2-to 5-fold weaker than morphine. Further, the ASE significantly suppressed the number of paw lickings and the time spent on paw licking in both phases of the formalin test. Naloxone, an opioid receptor antagonist, blocked the antinociceptive activity of ASE. Collectively, these observations suggest that ASE-induced antinociception was mediated centrally at the supraspinal level via opioid receptor mechanisms and is also effective against neurogenic and inflammatory pain. The ASE had mild antioxidant and moderate sedative actions, which are likely to contribute to its antinociceptive action. The ASE is well tolerated (in terms of overt signs, or renal, hepatic, or hemotoxicities) and nontoxic (by brine shrimp lethality assay). Phytochemical analysis revealed the presence of alkaloids, phenols, and steroids, which could contribute to the antinociceptive action. It is concluded that ASE of V. zeylanica has safe and moderate oral antinociceptive action.

Plant based remedies are of much importance in healthcare due to low side effects. The effective constituents contained in seeds of a papaya have not been utilized efficiently in the production of medicines. The purpose of this study was driven towards determining the total phenolic content, total flavonoid content, antioxidant capacity, anti-inflammatory activity and antibacterial properties of the aqueous seeds extract of a Sri Lankan variety (Red Lady) of papaya (AESP). The AESP prepared according to the method of “Kasaya” in Ayurvedic medicine was used for the investigations according to standard procedures. Total phenolic content and the total flavonoid content of the AESP were 13.5±2.2 mg (pyrogallol equivalence)/g and 315.9±104.6 mg (quercetin equivalence)/g respectively. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of AESP ranged from 12.4% to 81.2% for concentrations of 1.0-20.0 mg/ml; ascorbic acid gave 31.7% - 91.9% activity. The AESP displayed strong reducing power compared to ascorbic acid in the reducing power assay. The hydroxyl radical scavenging activity of the AESP ranged from 6.6% to 69.1% for concentrations ranging from 20.0-95.0 mg/ml; ascorbic acid activity was 37.7%-74.9%. The nitric oxide radical scavenging activity of AESP was 23.9%-62.7% for concentrations of 2.0-20.0 µg/ml; ascorbic acid gave 26.8%-63.5% activity. AESP concentrations ranging from 75.0-150.0 µg/ml exhibited human red blood cell (HRBC) membrane stabilization protection of 15.5%-22.7% compared to 50.8%-58.4% for aspirin. The AESP showed antibacterial activity against Bacillus subtilis and Staphylococcus aureus bacterial species. AESP possess promising antioxidant, anti-inflammatory and antibacterial activity. The aqueous decoction of the discarded seeds of papaya would facilitate remedies for many diseases in which radicals are implicated as well as assist against certain bacterial infections and also has an anti-inflammatory potential.