Nutritional Value, Volatile Components, Functional Metabolites, and Antibacterial and Cytotoxic Activities of Different Parts of Millettia speciosa Champ., a Medicinal and Edible Plant with Potential for Development

Abstract

Highly nutritious traditional plants which are rich in bioactive substances are attracting increasing attention. In this study, the nutritional value, chemical composition, biological activities, and feed indices of different parts of Millettia speciosa were comprehensively evaluated. In terms of its nutritional value, this study demonstrated that the leaves, flowers and seeds of M. speciosa were rich in elements and amino acids; the biological values (BVs) of these ingredients ranged from 85% to 100%, showing the extremely high nutritional value of this plant. GC-MS analysis suggested that the main chemical components of the flower volatile oil were n-hexadecanoic acid (21.73%), tetracosane (19.96%), and pentacosane (5.86%). The antibacterial activities of the flower and seed extracts were significantly stronger than those of the leaves and branches. The leaf extract displayed the strongest antifungal activities (EC₅₀ values: 18.28 ± 0.54 μg/mL for Pseudocryphonectria elaeocarpicola and 568.21 ± 33.60 μg/mL for Colletotrichum gloeosporioides) and were the least toxic to mouse fibroblasts (L929) (IC₅₀ value: 0.71 ± 0.04 mg/mL), while flowers were the most toxic (IC₅₀ value: 0.27 ± 0.03 mg/mL). In addition, the abundance of fiber, protein, mineral elements, and functional metabolite contents indicated the potential applicability of M. speciosa as an animal feed. In conclusion, as a traditional herbal plant used for medicinal and food purposes, M. speciosa shows potential for safe and multifunctional development.

Keywords: antimicrobial activity; cytotoxic activities; functional metabolites; nutritional value; volatile components.

Figure 1

Amino acid content in different parts of M. speciosa. (A) Type and content of all amino acids in different tissues. (B) Content of essential and nonessential amino acids in different tissues. EAAs are essential amino acids and NEAAs are nonessential amino acids. (C) EAAI and BV in different tissues. EAAI is the essential amino acid index, and BV is the biological value.

Figure 2

Biological activities of extracts from different parts of M. speciosa. (A), Antibacterial activity, (a), test sample concentration 30 mg/mL, (b), test sample concentration 60 mg/mL, (c), test sample concentration 90 mg/mL. AC indicates the positive control, streptomycin sulfate, all at 10 mg/mL. (B), Cytotoxic activity. (C), Antifungal activity. AC indicates the positive control, carbendazim. Different lowercase letters in the graph indicate significant differences (Duncan’s test, p < 0.05).