Optimization of curcumin extraction from Curcuma domestica Vahl. rhizome with microwave-assisted extraction technique in inhibiting nitric oxide production and cell viability

Abstract

Curcumin is a yellow dye derived from the turmeric plant (Curcuma domestica Vahl.). In turmeric rhizome, there are active compounds that are often used as traditional medicine in the form of curcuminoids. The microwave-Assisted Extraction (MAE) technique is an extraction technique that utilizes microwave radiation to heat the solvent quickly and efficiently and is also very suitable for extracting compounds that are not resistant to heat. This research was conducted to determine the level of curcumin from C. domestica Vahl. Extract with MAE using virgin coconut oil (VCO) as solvent. Extraction of curcumin was carried out using C. domestica Vahl powder with various weights (1 g, 1.5 g, 2 g, and 2.5 g) and VCO as solvent (mL), with an extraction time of 10 mins and power of 270 W. Curcumin from the extract was measured using High-Performance Liquid Chromatography (HPLC). The results showed that the method has a limit of detection (LOD), which is 3.57±0.01 µg/mL, a limit of quantification (LOQ) of 11.91±0.04 ppm, and good linearity with a correlation coefficient (r) of 0.9993. The curcumin level was determined with HPLC from each various weight (1.27±0.03 mg/g); 1.5 g (1.20±0.02 mg/ g); 2 g (3.45±0.02 mg/g) and 2.5 g (3.44±0.01 mg/g) respectively. The results showed that the optimum weight for curcumin extraction with MAE is 2 g with 20 mL of VCO with 10 mins extraction time and power (270 W). The best results were shown at a 1.56 µg/mL concentration and had the highest % of living cells, cell viability testing showed that curcumin was not toxic to RAW 264.7 cells. The nitric oxide (NO) production results show that cells stimulated with LPS had higher nitrite levels at 31.25 g/mL and lower nitrite levels at 62.5 µg/mL; 125 µg/mL; 250 µg/mL, implying that curcumin MAE extract can inhibit NO production, whereas extract-stimulated cells showed a decrease in nitrite levels.