ABSTRACT
Prunellae Spica is a perennial edible and medicinal plant, rich in antioxidant substances. Total flavonoids (TFC), Phenolics (TPC), triterpenoids (TSC), polysaccharides (PC) and their antioxidant capacities (by the FRAP, DPPH and ABTS⁺ methods) of ethyl acetate fraction, n-butanol fraction and other fractions of aqueous extract from Prunellae Spica were investigated in this study. Then the multivariate statistical method was adopted to analyze the relationship between the multiple pharmaceutical ingredients and antioxidant capacities of Prunellae Spica. The results showed that ethyl acetate fraction had relatively high concentration of TFC (0.61±0.10) g·g⁻¹DW, TPC (0.52±0.09) g·g⁻¹DW, and TSC (0.21±0.03) g·g⁻¹DW, with high scavenging capacity of DPPH (3.1±0.38) mmol·L⁻¹·g⁻¹DW and FRAP (2.56±0.35) mmol·L⁻¹·g⁻¹DW. Hierarchical clustering analysis (HCA) and principal component analysis (PCA) results indicated the information from chemical compositions and antioxidant capacity can represent the "differences" of different fractions. Canonical correlation analysis (CCorA) revealed a high positive correlation between the amounts of multiple chemical compositions and the antioxidant capacities (r=0.970 0), and the first canonical variate had been reached. Moreover, ABTS⁺ method showed a low response to the compositions of different fractions, so this method may not be suitable for evaluation of Prunellae Spica antioxidant capacities, while DPPH evaluation method was more suitable for TSC and TPC. The results of this study have important reference significance for the evaluation method on antioxidant activity of Prunellae Spica in the field of food or medicine as well as for the development of related extracts.
Subject(s)
Antioxidants , Flavonoids , Phenols , Plant ExtractsABSTRACT
It has been being some studies on biomedical effects of mulberry leaves in the world. Mulberry trees are widly cultivated in VietNam to take leaves for fed of silkworm. However, there were few studies on extraction, determination and antioxidation of mulberry leaves in VietNam. Objectives: extraction and determination of polyphenol from mulberry leaves. Evaluation of antioxidant capacities of mulberry leaf extract powders. Methods: Mulberry leaf extract powder were extracted from mulberry leaves by five solvens: methanol 100%, methanol 75%, n-hexan 100%, ethylacetat 100%. Polyphenol concentration of the extracts are determined by ferrous sulphate and follin reagent assay. Antioxidant capacities of the powders are based on peroxidation of linoleic acid at 40oC. Results: Among five solvens, the extract by methanol 75% from 50g dried leaves is best. The powder is 1.94g with 2.62% of polyphenol. Polyphenol concentraion of the extract powders are determined by two methods: ferrous sulphate and follin reagent. The result with ferrous sulphate method is more accurate than follin reagent method. The mulberry leave extract powders inhibited linoleic acid peroxidation at the 1h and 12h of reaction (only 15.5% to 42.2% linoleic acid peroxidated) in comparison with control (100% linoleic acid peroxidated). Conclusions: Polyphenol from mulberry leaves was extracted by some solvens. Among them extraction of polyphenol by methanol 75% is best. Polyphenol concentration of extract powders can be dedermined by ferrous sulphat. The extract powders from mulberry leaves exhibited antioxidant capacities in vitro. The extract powder by methanol 75% showed highest antioxidant capacitiy.