Comparison of Total Phenolic Content, Antioxidant Activity and Extraction Yield from Apium Graveolens Waste Using Unconventional Extraction Methods

Abstract

Apium graveolens is a medicinal and aromatic plant used in pharmaceutical industry, cosmetic industry, gastronomy and traditional medicine. Aerial parts of Apium graveolens (stems and leaves) are rich in bioactive compounds (flavonoids, phenols, furanocoumarins, volatile oils, sesquiterpene alcohols, fatty acids, etc.). It is known for its hepatoprotective, antioxidant, anticancer, antidiabetic, anti-inflammatory, antimicrobial, analgesic, anti-spasmolytic, anti-infertility, cardiotonic activities. This is why studies in this direction have not yet ceased and are increasingly pursuing the discovery of new, unconventional methods for identifying, quantifying and isolating bioactive compounds from Apium graveolens waste. The aim of this study was to determine and correlate the total phenolics, total flavonoids, antioxidant activity and extraction yield from ethanolic extracts (70%) of stems and leaves waste with different unconventional extraction methods. Apium graveolens aerial parts waste were obtained after aqueous extraction of the leaves and stems. The extraction yield was expressed as function of freeze-dried extracts, and the extraction methods were ultrasound assisted extraction, microwave assisted extraction and accelerated solvent extraction. Regarding the chosen extraction methods, numerous studies have shown, especially in the case of microwave assisted extraction, the presence of bioactive compounds in plant waste, in a reasonable percentage, therefore this study aimed to identify an optimal extraction method also in the case of Apium graveolens aerial parts waste. Total phenols content was determined by Folin-Ciocalteu spectrophotometric method, the flavonoids content waste determined by aluminium chloride spectrophotometric method and the antioxidant activity was studied using DPPH (2,2-Diphenyl-1-picrylhydrazyl) spectrophotometric method. The findings of this work indicated a positive dependence between the extraction yield of the waste material and the considerable content of bioactive compounds still present (phenols and flavonoids) for all considered extraction methods.