Evaluation of Anti-asthmatic Activities of Ixora coccinea Linn (Rubiaceae)

Inhibition of phagocytic and intracellular killing activity of human neutrophils by aqueous and methanolic leaf extracts of Ixora coccinea

ETHNOPHARMACOLOGICAL RELEVANCE

Ixora coccinea is widely used in Ayurveda and traditional medicinal practices in Sri Lanka and in Asia for acute bronchitis, reddened eyes and eruptions and dermatological disorders. The aim of this study was to determine the underling mechanism of anti-inflammatory activity of Ixora coccinea with respect to its inhibitory activity on human neutrophils.

MATERIALS AND METHODS

Freeze-dried products of aqueous and methanolic leaf extracts (ALE and MLE) prepared from mature fresh leaves of Ixora coccinea and total human leukocytes purified by Dextran sedimentation were used in this study. Three in vitro functional assays were developed and used to assess the inhibitory effects of ALE and MLE on human neutrophils, (i) assay for change-in-shape (CIS) for inhibitory effects on neutrophil polarization, (ii) yeast phagocytosis assay to investigate phagocytic activity of neutrophils and (iii) an optimized quantitative NBT assay to detect the production of reactive oxygen species (ROS).

RESULTS

Both ALE and MLE demonstrated maximum inhibition at 500 µg/ml for CIS (75% and 79% respectively; IC₅₀ values 44.5 and 24.0 µg/ml respectively), yeast phagocytosis (100%; IC₅₀ values 18.0 and 30.0 µg/ml respectively) and ROS production (47% and 67% respectively; IC₅₀ values 248 and 360 µg/ml respectively). All three inhibitory effects of both ALE and MLE were dose-dependent (P<0.05).

CONCLUSION

This study has shown that both ALE and MLE of Ixora coccinea exhibit potent anti-neutrophil activity that inhibits its intracellular killing which was demonstrated by the significant inhibition of neutrophil activation, phagocytosis, and production of ROS. MLE showed more potent anti-neutrophil activity compared to ALE reflecting a higher anti-inflammatory activity.

Comparison of skin test reactivity of two endodontic biomaterials in rabbits

In this in vivo study, the skin reactivity of rabbits to Mineral Trioxide Aggregate (MTA) and Calcium Enriched Mixture (CEM) was compared. Sixteen albino rabbits were used. The dorsal skin in three areas (2 x 2 cm) of the rabbits was shaved 24 h prior to the test. The areas were randomly covered with freshly mixed biomaterials [MTA (n = 16), CEM (n = 16) and normal saline (control; n = 16)], sterile gauze and bandages were placed for 4 h and the biomaterials were washed. The surface areas of the reactive skin sections were examined by naked eye and measured in 1, 24, 48 and 72 h using the Cavalier technique. The animals were then sacrificed and histological sections were prepared for blind examination. Results of macroscopic examination revealed a significant difference (p = 0.003) between the average erythematous surface areas induced by MTA (1.61 +/- 0.32) and CEM (0.5 +/- 0.16). Results of histological examination showed that the highest inflammation was observed in MTA, followed by CEM and control groups. Comparison of the difference in inflammatory cell count between each group revealed statistically significant differences in all cases (p < 0.001). The results demonstrated that the biocompatibility of CEM cement is higher than MTA; CEM can be considered as a suitable endodontic biomaterial.