Microscopical characters, total phenolic content, and antioxidant activity of Albizia myriophylla Benth

Abstract

Albizia myriophylla Benth. of Fabaceae family is a medicinal plant used in southern Thailand. It is used as a medicinal ingredient in various preparations for the treatment of caries, diabetes and dermatitis. The investigation of microscopic character of 3 collections (VI01 VI02 and VI03) of A. myriophylla in southern Thailand led to the identification of ray parenchyma, ray parenchyma with starch grains, ray parenchyma with prism of calcium oxalate, border-pitted vessels, phloem fibers, phloem parenchyma with starch grains, fibers with calcium oxalate prism, stone cell, prisms of calcium oxalate, and starch grains in their powdered drugs. The most common tissues in powdered drugs of the 3 collections of A. myriophylla were starch grains, border-pitted vessels, and  phloem parenchyma with starch grains. From DPPH and FRAP methods, the ethanol extract (DPPH, IC₅₀ 46.23-67.95 µg/mL; FRAP, 380.53-847.31 mM FeSO₄/g) from all 3 collections of A. myriophylla showed higher antioxidant capacity than the water extract (DPPH, IC₅₀ 53.53-67.95 µg/mL; FRAP, 239.78-377.05 mM FeSO₄/g) of this plant. Among the extracts of 3 collections of A. myriophylla, VI01 extract showed the best antioxidant activity. The total phenolic content of the extracts from 3 collections of A. myriophylla was analyzed using spectrophotometry. The results have revealed that the total phenolic content in VI01, VI02, and VI03 extracts was in accordance with their antioxidant activity in DPPH and FRAP assays. In this case, the ethanol extracts of all 3 collections had higher total phenolic content than their water extracts. VI01 appeared to have higher total phenolic content than the others. Furthermore, it was found that the water extract from VI01 had total phenolic content and good antioxidant activity similar to that containing A. myriophylla and licorice (Glycyrrhiza glabra L.). In this study, the ethanol extract containing A. myriophylla and G. glabra had the highest total phenolic content and demonstrated good antioxidant activity compared to the others tested. Our results provide preliminary scientific data related to the use of A. myriophylla wood as a raw material in Thai traditional medicine for the treatment of oxidative stress associated diseases.