PHYTOCHEMICALS, ANTIOXIDANT AND ANTIMICROBIAL ACTIVITY OF CENTELLA ASIATICA EXTRACTED BY SOLVENT-FREE MICROWAVE EXTRACTION

Abstract

Solvent-free microwave extraction (SFME) is a green extraction method that requires no solvent and has a short extraction time. This study extracted Centella asiatica using SFME and analysed the extract for its phytoconstituents, phenolic content, antioxidant, and antimicrobial activity. Extraction of 20 g fresh C. asiatica by SFME was carried out for 15 min at 300 W, under vacuum and with stirring. Analysis by gas chromatography-mass spectroscopy (GC-MS) demonstrated that the extract contained phytonutrients such as flavonoids, polyphenol, tannins, and volatile oils. The extract from SFME also produced an IC50 of 0.06 mg/ml and 10.75±0.61 mg GAE/g dry weight of TPC. Using the disc diffusion method, the extract of C. asiatica also exhibited antimicrobial activity against Escherichia coli, Bacillus subtilis, Staphylococcus aureus, Enterobacter sp., Aspergillus niger, Aspergillus flavus, Penicillium chrysogenum and Aspergillus japonicus. This study showed that the C. asiatica extract from SFME retained the antioxidant and antimicrobial properties but in a shorter extraction time and without any solvent. As a result, using green extraction to extract this plant can help to preserve its nutritional content and valuable compounds, which is essential when formulating pharmaceutical, food, and cosmetic products.