Experimental and Modeling Studies of Andrographolide Extraction from Andrographis paniculata in a Soxhlet Extractor

Andrographolide is the main diterpenoid lactone contained in the leaves of Andrographis paniculata. This bioactive component has multifunctional medicinal properties such as activity against fever, dysentery, diarrhoea, inflammation, and sore throat as well as immune disorder. The objectives of this work were to study the effect of polarity and Hildebrand solubility parameter of solvents in the extraction of andrographolide from A. paniculata and to develop a mathematical model to quantitatively describe the extraction phenomena. The extraction was carried out by employing various organic solvents and their mixtures with water as solvents using standard soxhlet method. Five grams of ground - dried A. paniculata leaves was extracted using 1.50 10-4 m3 of solvent for 10,800 seconds. The standard soxhlet extraction method was conducted using methanol at different extraction times to verify the mathematical model proposed in this work. The crude extracts were then analysed for their andrographolide content using high performance liquid chromatography. Methanol was found to be the best solvent for the extraction of andrographolide from A. paniculata. The Hildebrand solubility parameter concept was not able to predict the extraction of andrographolide using polar organic solvents. The final form of the proposed model based on rapid mass transfer at the interphase of the solid-liquid surface and the introduction of volumetric mass transfer coefficient is Es = 0.12 (1- e-(1.69E-04) t), where Es = total extract, (g) and t = extraction time, (second). The model showed good agreement with the experimental data by generating AARD of about 0.46 %.