Optimisation of the extraction conditions for Noni (Morinda citrifolia L.) leaf extract using response surface methodology

Abstract

Noni leaves have long been used as a traditional herb for the treatment of different ailments. Noni leaves have a high content of flavonoids with various biological activities. This study was carried out to optimise the extraction conditions of noni leaves using the response surface methodology with four factors, including solvent concentration, temperature, time, and material-solvent ratio. With the three criteria as total flavonoid content, antibacterial activity, and anti-inflammatory activity, the optimal extraction conditions of noni leaves were determined as follows: ethanol concentration of 70%, temperature of 60o C, time of 90 mins, and materialsolvent ratio of 1/25 (g/ml). The extract obtained at these conditions had the total flavonoid content of 2.227 mg RU/g dry matter, exhibited antibacterial activity (zones of inhibition = 11.5 mm, at the concentration of 100 mg/ ml against P. aeruginosa) and anti-inflammatory activity (IC50=70.21 µg/ml). The study results showed that the noni leaf extract contains high levels of bioactive compound content and biological activities, can be extracted at relatively moderate conditions. This shows the economic advantages and wide applicability on an industrial scale.