The antioxidant index and chemometric analysis of tannin, flavonoid, and total phenolic extracted from medicinal plant foods with the solvents of different polarities

Abstract

This study aimed to evaluate the effect of four solvents (water, methanol, ethyl acetate, and n‐hexane) on the extraction of total phenolic content (TPC), tannin, flavonoid, ferric reducing power (FRAP), and radical scavenging activity from Centella asiatica, Musa acuminata, Peperomia pellucida, and Psophocarpus tetragonolobus. The extraction of TPC, tannin, flavonoid, and antioxidant activity varied significantly according to solvent polarity and plant species. The strong linear correlation found between solvent polarity index and TPC, tannin, FRAP as well as radical scavenging activity indicated solvents with increasing polarity favored the extraction of phenolic antioxidants. Plant species and extraction solvents contributed to 51.7% and 21.8% of total activity variation, respectively. C. asiatica, M. acuminata flower, and P. pellucida were best extracted with 80°C distilled water for a short duration, while methanol was preferred for P. tetragonolobus. The antioxidant index could be a potential ranking tool to identify the ideal extraction solvent for medicinal plants. Practical applications Considering the high commercial and health‐oriented values of natural phenolic antioxidants such as tannin and flavonoid, efficient extraction of these phytochemicals from different plant sources remains a challenging task due to their varying physicochemical characteristics and solubility. This study has addressed that the choice of solvents and types of plant species are critical extraction parameters for natural plant products. Comparison of tannin and flavonoid content among the different solvent extracts could reveal the ideal solvent which maximizes the extraction of phenolic antioxidants from different medicinal plants. The finding in this study may inspire nutraceutical, pharmaceutical, and cosmetic industries to re‐evaluate their procedure in selecting the optimal extraction solvent and condition for different plant materials. The proposed antioxidant index in this study could serve as a potential tool to rank extraction solvents based on the antioxidant values extracted from different medicinal plants.

Qualitative and quantitative phytochemical composition, antimicrobial activity, and brine shrimp cytotoxicity of different solvent extracts of Acanthus polystachyus, Keetia gueinzii, and Rhynchosia elegans

“…The tannin content of the extracts ranged from 7.66 to 87.7 mg/g TAE. These values were lower than the aqueous extracts of Cassia asiatica and Musa acuminata [67].…”

Investigation of antioxidant properties of chamomile consumed as herbal tea

“…Additionally, ultrasound‐assisted extraction has been stated as a valuable green alternative procedure to improve solvent extraction of the bioactive compound (Vega Arroy et al., 2017). As in this study, solvent types have an important effect in determining antioxidant properties and change the results obtained (Li et al., 2017; Ng et al., 2020; Yadav et al, 2016). It was determined in this study that the highest yield was obtained with water extracts.…”

Screening the nematicidal potential of indigenous medicinal plant extracts against Meloidogyne incognita under lab. and greenhouse conditions

“…Consequently, higher antioxidants and phenols were extracted using water. Ng et al (2020) reported that polar solvents could extract higher amounts of antioxidants and phenolic compounds, which increase the radical The nature of medicinal plant structure and their derivatives have been discussed extensively but the mode of action of most nematicidal phytochemicals is still ambiguous. Periwinkle achieved more inhibitory effects on egg hatchability than solidago extract.…”