Comprehensive Analysis of 50 Edible Flowers From Yunnan Province: Active Components, Antioxidant Capacity, Tyrosinase Inhibition, and Antimicrobial Activity

Abstract

Edible flowers are widely consumed for their potential health benefits. This study assessed the active components and in vitro antioxidant properties of 50 edible flowers from Yunnan to explore their potential uses. A 70% ethanol extract was prepared, and the total polyphenol content (TPC), total flavonoid content (TFC), and total anthocyanin content (TAC) were analyzed. Antioxidant capacity was evaluated using the ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) assays. Additionally, tyrosinase inhibition and antimicrobial activities were determined, and the correlation between active components and antioxidant capacity was investigated. The results showed that Prunus mume had high polyphenol content, Osmanthus fragrans Lour. had high flavonoid content, and Rosa rugosa Thunb. (Dianhong) had high anthocyanin content. Rosa rugosa Thunb. (Mohong) exhibited the strongest DPPH and ABTS radical scavenging activities. Clerodendranthus spicatus (Thunb.) C. Y. Wu demonstrated the highest FRAP activity, whereas Punica granatum L. showed the highest tyrosinase inhibition activity. Nymphaea coerulea exhibited significant antimicrobial effects against Escherichia coli and Staphylococcus aureus. Extracts from Hibiscus rosa-sinensis and Platycodon grandiflorus (Jacq.) A. DC. demonstrated excellent antimicrobial effects against Pseudomonas aeruginosa. Correlation analysis indicated a positive relationship between TPC and antioxidant activities, suggesting that polyphenols are closely linked to antioxidant capacity. This study highlights the potential of these edible flowers as antimicrobial agents and natural antioxidants. Analysis using the membership function identified N. coerulea, R. rugosa, P. granatum, and Lagerstroemia indica L. as having the highest comprehensive scores, indicating their superior quality as sources of bioactive compounds.

Keywords: anthocyanin; antimicrobial activity; antioxidant capacity; edible flowers; flavonoid; polyphenol; tyrosinase inhibition.

FIGURE 1

Information on 50 varieties of edible flowers. A, Agapanthus africanus (Amaryllidaceae); B, Lycoris radiata (L'Her.) Herb. (Amaryllidaceae); C, Narcissus tazetta L. var. chinensis Roem. (Amaryllidaceae); D, Chimonanthus praecox (Linn.) Link (Calycanthaceae); E, Platycodon grandiflorus (Jacq.) A. DC. (Campanulaceae); F, Canna indica L. (Cannaceae); G, Lonicera japonica Thunb. (Caprifoliaceae); H, Dendranthema morifolium (Ramat.) Tzvel. (Compositae); I, Cucurbita moschata (Duch. ex Lam.) Duch. ex Poiret (Cucurbitaceae); J, Rhododendron lapponicum (Ericaceae); K, Gentiana macrophylla Pall. (Gentianaceae); L, Gentiana sino‐ornata Balf. f. (Gentianaceae); M, Hypericum monogynum L. (Guttiferae); N, Iridis Japonica (Iridaceae); O, Iris tectorum (Iridaceae); P, Iris pseudacorus (Iridaceae); Q, Clerodendranthus spicatus (Thunb.) C. Y. Wu (Labiatae); R, Lavandula angustifolia (Labiatae); S, Albizia julibrissin Durazz. (Leguminosae); T, Clitoria ternatea (Leguminosae); U, Sophora japonica Linn. (Leguminosae); V, Hemerocallis citrina Baroni (Liliaceae); W, Lilium formosanum Wallace (Liliaceae); X, Buddleja officinalis Maxim. (Loganiaceae); Y, Lagerstroemia indica L. (Pink) (Lythraceae); Z, Lagerstroemia indica L. (Red) (Lythraceae); a, Magnolia denudata Desr. (White) (Magnoliaceae); b, Magnolia denudata Desr. (Purple) (Magnoliaceae); c, Magnolia liliiflora Desr (Magnoliaceae); d, Althaea rosea (Linn.) Cavan. (Malvaceae); e, Hibiscus syriacus Linn. (Double) (Malvaceae); f, Hibiscus rosa‐sinensis (Malvaceae); g, Hibiscus syriacus Linn. (Single) (Malvaceae); h, Musa basjoo (Musaceae); i, Nelumbo nucifera (Nymphaeaceae); j, Nymphaea coerulea (Nymphaeaceae); k, Jasminum nudiflorum Lindl. (Oleaceae); l, Jasminum sambac (L.) Ait. (Oleaceae); m, Osmanthus fragrans (Thunb.) Lour. (Oleaceae); n, Dendrobium officinale Kimura et Migo (Orchidaceae); o, Punica granatum L. (Punicaceae); p, Cerasus serrulate (Rosaceae); q, Chaenomeles speciosa (Rosaceae); r, Rosa rugosa Thunb. (Mohong) (Rosaceae); s, Prunus mume (Rosaceae); t, Prunus persica (Rosaceae); u, Rosa damascene (Rosaceae); v, Rosa rugosa Thunb. (Dianhong) (Rosaceae); w, Camellia japonica L. (Double) (Theaceae); x, Camellia japonica L. (Single) (Theaceae).

FIGURE 2

Heat map and cluster analysis of the active component contents of 50 edible flowers. TPC stands for the total polyphenols content, TFC stands for the total flavonoid content, and TAC stands for the anthocyanin content. The color transition of the rectangle from blue to red indicates an increase in active component contents.

FIGURE 3

Heat map and cluster analysis of the DPPH and ABTS scavenging ability of 50 edible flowers. DPPH stands for DPPH scavenging ability, and ABTS stands for ABTS scavenging ability. The color transition of the rectangle from blue to red indicates an increase in scavenging ability.

FIGURE 4

Ferric reducing antioxidant power (FRAP) of 9 edible flowers with the strongest FRAP among the 50 edible flowers. FRAP stands for ferric reducing antioxidant power. Vitamin C was used as a positive control.

FIGURE 5

Tyrosinase inhibition activity of 9 edible flowers with the strongest TYR inhibition activity among the 50 edible flowers. TYR stands for tyrosinase inhibition activity. Kojic acid was used as a positive control.

FIGURE 6

Pearson correlation analysis of active components, antioxidant indices, tyrosinase inhibition activity, and bacteriostatic activity of the 50 edible flowers. Ellipse in color indicates the correlation between two indicators distributed on the vertical and horizontal axes, respectively. The transition in the shape and color of the ellipse from round to flat and from blue to red indicates increasing correlation strenghth. * and ** denote significant correlation at p < 0.05 and p < 0.01 levels, respectively. BDEC stands for the bacteriostatic diameter of E. coli, BDSA for S. aureus, BDPA for P. aeruginosa .

FIGURE 7

Dendrogram showing clustering pattern of 50 edible flowers on the basis of 10 indices.