The invention relates to the development of a simple and eco-friendly process of extraction of sweet glycosides: steviosides from the leaves of Stevia rebaudiana. In particular, certain embodiments provide enhanced isolation of steviosides by enzyme assisted extraction, in combination with metal salts, followed by pressurized aqueous extraction. Thus obtained stevia extract was further processed for clarification and purification using multi-stage membrane filters (micro-filtration, ultra-filtration and nano membrane filtration) to obtain high purity steviosides from the Stevia leaves. This improved process confirms the isolation of high purity steviol glycosides i.e., Stevioside and Rebaudioside-A as the final products, with improved organoleptic properties. Thus, this superior process helps in obtaining pure steviosides from the Stevia leaf extract, without impurities and obnoxious residues, using easy operational technology without any damage to the environment.