Development of Oral Microemulsion Spray Containing Pentacyclic Triterpenes-Rich Centella asiatica (L.) Urb. Extract for Healing Mouth Ulcers

Several publications have shown that Centella asiatica (L.) Urb. and its active constituents (pentacyclic triterpenes) are effective in wound healing. The pentacyclic triterpenes-rich C. asiatica extract (PRE) was prepared following a previous study by microwave-assisted extraction (MAE) and fractionation with macroporous resin. This method provided the pentacyclic triterpene content in the extract up to 59.60% w/w. The PRE showed potent anti-inflammatory activity by inhibiting nitric oxide (NO) production with an IC50 value of 20.59 +/- 3.48 mu g/mL and a potent fibroblast proliferative effect (165.67%) at concentrations of 10 mu g/mL. The prepared microemulsion consisted of a water: oil: surfactant mixture of 2: 2: 6, using coconut oil: clove oil (1:1) as the oil phase and Tween 20: Span 20 (2:1) as the surfactant mixture and 1.0, 2.5, and 5.0% PRE. Cell proliferation, migration, and collagen production of the microemulsion base and microemulsions containing 1.0%, 2.5%, and 5.0% PRE were evaluated. The results revealed that the microemulsion containing 1% PRE had the highest proliferation effect (136.30 +/- 3.93% to 152.65 +/- 3.48% at concentrations of 10 mu g/mL), migration activities (100.00 +/- 0.0% at 24 h), and collagen production in human dermal fibroblast (HDF) and human gingival fibroblast (HGF) cells when compared with other formulations or blank. Moreover, the anti-inflammatory activity of microemulsions containing 1% PRE was slightly lower than standard indomethacin. Anti-inflammation of the microemulsion containing PRE exhibited a dose-dependent trend, while 5% PRE was more potent than the standard drug. Considering the potent wound-healing activities and the good anti-inflammatory activity of the microemulsion containing PRE, the microemulsion with 1% PRE was identified as the most suitable oral spray formulation for oral ulcer treatment.

Automated summary

Several publications have shown that Centella asiatica and its active constituents, pentacyclic triterpenes, have positive effects on wound healing. In this study, a microwave-assisted extraction (MAE) method was used to prepare a pentacyclic triterpenes-rich extract from Centella asiatica. The extract showed strong anti-inflammatory activity and fibroblast proliferative effect. A microemulsion was formulated using the extract and was evaluated for its effects on cell proliferation, migration, and collagen production. The microemulsion containing 1% of the extract showed the highest efficacy in promoting cell proliferation, migration, and collagen production, making it a suitable oral spray formulation for oral ulcer treatment.